Letture consigliate

Questa sezione a cura della SILO contiene una selezione aggiornata di articoli di rilievo provenienti da pubblicazioni scientifiche relative all’uso dei laser in medicina e in odontoiatria.
Tutti gli articoli citati contengono una Preview ed un Collegamento (evidenziato in rosso) al sito web dell’editore per la lettura dell’abstract o del PDF dove disponibile.
 

Use of Phototherapy and Er-YAG Laser in the Management of Mandible Osteoradionecrosis: A Case Report

de Freitas, L.C., Kawamoto, E.L., Souza, A.M.A., Kawakami, P.Y., Gonçalves, A.S. & Azevedo, L.H.
Journal of lasers in medical sciences, 14, p.e58. 2023.

Introduction:
Osteoradionecrosis (ORN) is a secondary complication from radiotherapy, which is difficult to manage and significantly reduces the life quality of the affected patients.
Case Report:
A 59-year-old female patient, diagnosed with infiltration by squamous cell carcinoma in the left cervical region, underwent adjuvant cervical-facial radiotherapy with a total dose of 66.6 Gy of radiation. Eight years after the diagnosis, the patient underwent multiple extractions and, subsequently, the installation of osseointegrated implants, evolving to extensive intraoral bone exposure associated with oral cutaneous fistula. The patient was initially exposed to photobiomodulation therapy (PBMT), with a low-power laser at wavelengths of 660 nm and 808 nm, and thereafter to antimicrobial photodynamic therapy (aPDT). After an improvement in the clinical condition and resolution of the oral cutaneous fistula, a surgical procedure with the Er: YAG laser was performed to remove the remaining necrotic bone. Once the ORN condition was completely treated, the patient’s oral rehabilitation was implemented by the installation of an upper mucous-supported total prosthesis and a lower implant-supported prosthesis.
Conclusion:
The patient is in a clinical follow-up and has no signs of bone necrosis recurrence, suggesting that low and high-power laser treatment can be an effective therapeutic alternative to resolve this condition. Keywords: Osteoradionecrosis of the jaws, Low intensity light therapy, Er-YAG laser, High power laser, Drug-related osteonecrosis of the jaws, Implant Dentistry
 Use of Phototherapy and Er-YAG Laser in the Management of Mandible Osteoradionecrosis: A Case Report

Use of both the diode and Er: YAG lasers in esthetic crown lengthening with the aid of digitally guided dual technique: 3 years follow‐up

Benítez, C.G., Azevedo, L.H., da Silva, I.L.S., de Oliveira Lima, M., Yanai, F.Y. & Llanos, A.H.
Journal of esthetic and restorative dentistry, 2023.

 
Objective:
To explore the feasibility of the usage of digital guides in combination with low‐ and high‐power lasers for the treatment of excessive gingival display, also known as “gummy smile”. Clinical Considerations Excessive gingival display due to altered passive eruption can affect patient’s perception of their own esthetics and consequently have an impact on self‐confidence. Therefore, the management of this condition should offer a predictable and stable long‐lasting solution. To attain these objectives, digital planning emerges as a tool in optimizing the outcomes of crown lengthening surgery for this condition by enhancing precision through the use of surgical guides. Additionally, the usage of high‐ and low‐powered lasers can provide a safe approach because of their tissue selective removal properties. Conclusions The technique described showed satisfactory clinical results in the short‐ and long‐term follow‐up, leading to an improvement in patients’ self‐esteem. This approach integrates digital and laser technologies to deliver a surgical treatment characterized by precision, efficiency, and safety. Clinical Significance Digital dentistry has contributed to innovative dental procedures, as personalizing surgical guides for patients, assisting and guiding incisions of the gingival margins, as well as the extension of the osteotomy, during the procedures for increasing the clinical crown. Furthermore, smile esthetics are directly related to an individual’s improved emotional and social quality of life.
 Use of both the diode and Er: YAG lasers in esthetic crown lengthening with the aid of digitally guided dual technique: 3 years follow‐up

3. Effects of Nd: YAG laser on tumour necrosis factor-alpha, interleukin-1beta and interferon-gamma levels in teeth with apical periodontitis: A clinical study

Baris, S.D., Turkyilmaz, A. & Derici, M.K.
Australian endodontic journal: the journal of the Australian Society of Endodontology Inc. 2023.

Background:
This study aimed to evaluate the levels of tumour necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and interferon-gamma (IFN-γ) with asymptomatic apical periodontitis (AP). A total of 60 participants were randomly divided into two groups: the conventional irrigation (control) and the Nd: YAG laser irradiation. The interstitial fluids were obtained after root canal cleaning (day 0) and 1 week later (day 7). The TNF-α, IL-1β and IFN-γ levels were assayed using the enzyme-linked immunosorbent assay. The Mann-Whitney U, continuity correction chi-square, Pearson chi-square and Fisher exact tests were used. An increased level of cytokines on day 7 in the control group was observed, without statistically significant differences (p > 0.05). All cytokine levels decreased over time in the laser group. Only the IL-1β level showed a significant difference (p < 0.05). Nd: YAG irradiation has a positive effect on decreasing the proinflammatory cytokine level and may help to control infection in teeth with AP.
Keywords: Nd: YAG laser; asymptomatic apical periodontitis; cytokines; inflammatory mediators.
 Effects of Nd: YAG laser on tumour necrosis factor-alpha, interleukin-1beta and interferon-gamma levels in teeth with apical periodontitis: A clinical study

4. Type of surgical treatment and recurrence of oral leukoplakia: A retrospective clinical study

Monteiro L, Barbieri C, Warnakulasuriya S, et al
Med Oral Patol Oral Cir Bucal. 2017; 22(5):e520-e526.

Background
Oral leukoplakia (OL) is the most typical potentially malignant disorder of the oral mucosa. We aimed to evaluate the clinical outcome of oral leukoplakia treated with several types of lasers and with the use of quantic molecular resonance (QMR) lancet, in terms of recurrence rate.
Material and Methods
Eighty-seven previously untreated OL (52 occurring in females and 35 in males, mean age of 59.4 ± 13.9 years) were consecutively submitted to surgical treatment at University Hospital of Parma, Italy, and Hospital de Valongo, Portugal, (1999 to 2012). Interventions were subclassified into 5 groups according to the instrument used for the surgical removal of OL (cold blade – 17; Nd:YAG 1064nm laser – 14; Er:YAG 2940nm laser – 33; CO2 10600nm laser – 15; and QMR scalpel – 8). The mean follow-up period after treatment was 21.6 months (range 1-151 months). The outcome of treatment was scored through the same clinical protocol in the two participating units. Statistical analysis were carried by univariate analysis using chi-square test (or Pearson´s test when appropriate).
Results
Recurrences were observed in 24 cases of OL (27.6%). Malignant transformation occurred in one patient (1.1%) after a period of 35 months. Statistical comparison of the 5 surgical treatment modalities showed no differences in clinical outcomes nor in the recurrence rate of OL. However, when Er:YAG laser group was compared with traditional scalpel, a significantly better outcome in cases treated with Er:YAG laser (P = 0.015) was highlighted.
Conclusions
Our results suggests that Er:YAG laser could be a promising option for the treatment of OL.
 Type of surgical treatment and recurrence of oral leukoplakia: A retrospective clinical study
 

5. Clinical and biochemical effect of laser as an adjunct to non-surgical treatment  of chronic periodontitis.

Jiang, Y., Feng, J., Du, J., Fu, J., Liu, Yitong, Guo, L. & Liu, Yi.
Oral diseases, 2022

Background
To evaluate the clinical and biochemical efficacy of laser therapy as an adjunct to non-surgical treatment in chronic periodontitis.
Methods
A systematic search was performed through the PubMed, EMBASE, and Cochrane Library for eligible articles published as of May 2, 2020, supplemented by information search in the System for Information on Programme Literature in Europe and a manual literature search. Only randomized controlled trials (RCTs) used to compare the adjunctive use of laser and non-surgical treatment alone with an observation period of at least 6 months were included.
Results
Sixteen RCTs with a total of 525 subjects were included. Meta-analysis suggested that the additional use of laser to scaling and root planing (SRP) showed significant superiority over SRP alone among most of clinical parameters involved. Regarding the GCF, although volume in the laser group was lower at week 4 and 12, no significant difference was found regarding the cytokines level. Subgroup analysis revealed that the combined therapy produced no significant difference in PD, CAL and PI at most time points for studies in respect to smokers. No treatment-related adverse events had been reported in the included studies.
Conclusions
Pooled analysis suggested that laser-assisted non-surgical treatment improved clinical outcome to SRP alone in the management of non-smoking chronic periodontitis patients.
 Clinical and biochemical effect of laser as an adjunct to non-surgical treatment of chronic periodontitis
 

6. Evaluation of low intensity Nd: YAG laser and traditional drugs in the treatment of myofascial pain

Li, X., Zhao, N., Liu, Z.-L., Zhang, S.-Y., Cai, Z. & Zhu, C. 2023.
Purpose:
To evaluate the efficacy of low intensity Nd: YAG laser and traditional drugs in the treatment of myofascial pain (MP).
Materials and Methods:
Eighty patients with MP were divided into laser group(n=40) and traditional medicine group(n=40) according to the principle of randomization and double-blindness. The patients in the laser group were treated with low intensity Nd :YAG laser(1 064 nm, 8 J/cm2, 250 mW) , with an interval of 48 h between the two laser treatments. The whole course of treatment was 10 times. Patients in the traditional medicine group uesd celecoxib capsules, 1 capsulet each time(0.2 g), twice a day for 2 weeks. Before and after each treatment, mouth opening, protrusion excursion, lateral movement of the affected side and lateral movement of the contralateral side were measured, and pain visual analogue scores (VAS) were measured and recorded. The data were statistically analyzed with SPSS 22.0 software package.
Results:
Patients in laser group had significantly improved mandibular function and movement status(P<0.05) and pain symptoms(P<0.05); patients in traditional medicine group had the same significant improvement on mandibular functional movement status(P<0.05) and pain symptoms (P<0.05). The total effective rate of the two groups had no significant difference(P>0.05). The VAS score of patients in laser group was lower than that of traditional medicine group, but the difference was not significant(P>0.05).
Conclusions:
Low intensity Nd: YAG laser and traditional medicine can effectively relieve the symptoms of myofascial pain and improve mandibular function and movement. Laser treatment has the advantages of short course of treatment, high efficiency, no pain and fewer side effects, which is worthy of clinical application.
 Evaluation of low intensity Nd: YAG laser and traditional drugs in the treatment of myofascial pain

7. Short-term results of the combined application of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser and erbium-doped yttrium aluminum garnet (Er:YAG) laser in the treatment of periodontal disease: a randomized controlled trial

Laky, M., Müller, M., Laky, B., Arslan, M., Wehner, C., Husejnagic, S., Lettner, S., et al.,
Clinical oral investigations, 2022; (25):6119-6126.

Objectives
Nd:YAG and Er:YAG lasers have been previously used as an adjunct in periodontal therapy. The aim of this single-blinded randomized controlled clinical trial was to evaluate the efficacy of a combined application of Nd:YAG and Er:YAG laser irradiation in periodontal treatment.
Materials and methods
Twenty-two patients with at least one site of ≥ 6 mm periodontal probing depth (PPD) after mechanical debridement with curettes and sonic instruments at periodontal reevaluation were included in the study. Patients were randomly allocated at a 1:1 ratio to either a combined Nd:YAG/Er:YAG laser therapy (test group) or a “turned off” laser therapy (control group). The Nd:YAG laser was used for periodontal pocket deepithelialization and to stabilize the resulting blood clot. The Er:YAG laser was primarily used for root surface modification. PPD (mm), clinical attachment level (CAL, mm), and bleeding on probing (BOP, +/−) at the site of laser treatment were evaluated at baseline and 2 months after treatment.
Results
The mean improvements from baseline to 2-month follow-up for PPD were significantly better in the laser group (2.05 ± 0.82 mm) compared to the control group (0.64 ± 0.90 mm; p = 0.001). Likewise, the gain in CAL was significantly better in the laser group (1.50 ± 1.10 mm) than in the control group (0.55 ± 1.01mm; p = 0.046).
Conclusions
The combined application of Nd:YAG and Er:YAG laser irradiation as an adjunct to conventional non-surgical therapy showed a significant beneficial effect on periodontal treatment results.
Clinical relevance
Combined Nd:YAG and Er:YAG laser irradiation could be a useful procedure additionally to conventional non-surgical periodontal therapy to improve periodontal treatment results.
 Short-term results of the combined application of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser and erbium-doped yttrium aluminum garnet (Er:YAG) laser in the treatment of periodontal disease: a randomized controlled trial

8. Effect of femtosecond and ER:YAG laser systems on shear bond strength of enamel surface and morphological changes

Özüdoğru S, Kahvecioğlu F, Tosun G, Gündoğdu Y, Kılıç HŞ.
Lasers Dent Sci. 2021;5(4):199-205.

Purpose
The present study aimed to investigate the impact of a femtosecond laser and Er:YAG laser as an alternative to orthophosphoric acid etching on the shear bond strength.Methods Thirty permanent mandibular teeth were assigned to one of three groups based on the treatment performed on their buccal/lingual surfaces. Group I, 37% orthophosphoric acid etching; Group II, Er:YAG laser; Group III, femtosecond laser. A 3 × 3 mm diameter bonding area was demarcated on the enamel. Fissure sealant material was applied to the test areas and cured for 20 s in all groups. The shear bond strength of all the specimens was determined using an Instron universal testing machine. After testing, the fracture surfaces were analyzed using a stereomicroscope, and the fracture modes of each sample were categorized according to the adhesive remnant index.ResultsThe results revealed no significant differences in terms of shear bond strength of the femtosecond laser (7.55 ± 0.6 MPa), Er:YAG laser (7.26 ± 0.6 MPa), and acid etching groups (6.61 ± 0.5 MPa) (p > 0.05).Conclusion The present in vitro study showed that the bond strength of the enamel surface following treatment with femtosecond and Er:YAG laser systems alone was sufficient when compared with that after acid etching.Clinical significanceIt is possible to use femtosecond lasers for bonding fissure sealant to enamel surfaces as an alternative to acid etching.
 Effect of femtosecond and ER:YAG laser systems on shear bond strength of enamel surface and morphological changes

9. Systemic inflammatory markers following adjunctive Nd:YAG (1064 nm) laser irradiation to step 2 of periodontal therapy: a 12-month, randomized, controlled trial

Markou, N., Pepelassi, E., Madianos, P., Simopoulou, M. & Karoussis, I.K
Clinical oral investigations, 27(11), pp.6925–6935. 2023.<> 

 Systemic inflammatory markers following adjunctive Nd:YAG (1064 nm) laser irradiation to step 2 of periodontal therapy: a 12-month, randomized, controlled trial

10. Photobiomodulation Therapy for the Symptoms Related to Temporomandibular Joint Disk Displacement

Piotr A. Regulski, Kazimierz T. Szopinski, Špela Levičnik-Höfferle,
Case Reports in Dentistry, vol. 2023, Article ID 5947168, 7 pages

Abstract
Pain related to temporomandibular disorders (TMD) is a common problem that can significantly influence a patient’s quality of life. Laser photobiomodulation (PBM) has been reported as a promising method in medicine for wound and bone healing, pain relief, and treatment of the temporomandibular joint (TMJ). Our clinical case aimed to demonstrate the effectivity of PBM using 1064 nm Nd:YAG laser for the treatment of pain and restricted mandible movement in a patient with anterior disk displacement of the left TMJ, using subjective (pain on visual analogue scale – VAS) and objective outcome measures [dynamic magnetic resonance imaging (MRI)]. PBM was performed on the left condyle in four sessions using a 1064 nm Nd:YAG laser with a flat-top handpiece. Results after 10 weeks showed an increase in mouth opening and a painless joint on palpation, with no reported adverse effects. An MRI of the TMJ confirmed the left disk displacement, however, with no signs of inflammation or effusion and with less pronounced disk deformity as compared with the first MRI examination. Use of PBM with Nd:YAG laser may be an efficient method for the management of orofacial pain in patients with acute and chronic TMJ disk displacements and may reduce the recovery time.
 Photobiomodulation Therapy for the Symptoms Related to Temporomandibular Joint Disk Displacement

11. The efficiency of laser application for debonding laminate restorations manufactured of current CAD-CAM materials with different thicknesses

Celiksoz, O., Recen, D. & Peskersoy, C.
Nigerian journal of clinical practice, 2022;24(5), pp.705–711. 55

Background: 
Using lasers for adhesive restoration removal can be practical and atraumatic.
Aims: 
The purpose of this study was to investigate Er: YAG laser exposure on debonding the adhesive cementation between enamel and feldspar ceramic, lithium disilicate-reinforced and resin nano ceramic composite laminate restorations.
Materials and methods: 
Vita Cerec Blocs, IPS e.max Computer-aided design (CAD). Computer-aided design and manufacturing (CAD-CAM) in full and Lava Ultimate restorative materials were chosen. The 3 × 3 mm2 standardized, 0.5-mm and 1 mm thick specimens were cemented on an enamel surface. After thermocycling, each material group was randomly divided into laser treated and control (non-laser treated) groups. Shear bond strength test was done with a universal testing machine with crosshead speed 0.5 mm/min. Factorial ANOVA Technique and TUKEY HSD multiple comparison test were used for statistical analyses. Moreover, the surface morphology of the debonded samples and the enamel was observed using a scanning electron microscope.
Results: 
The laser application was found to weaken the SBS values significantly (P < 0.05) for all groups; however, the most dramatic SBS decrease was observed for laser treated IPS e.max at both thicknesses.
Conclusions: 
Laser treatment can serve as a practical and effective method that eliminates the risk the enamel damage and restoration fracture.
Keywords: Ceramic resin composite; Er: YAG laser; feldspar ceramic; laser crown debonding; lithium disilicate ceramic.
 The efficiency of laser application for debonding laminate restorations manufactured of current CAD-CAM materials with different thicknesses

12. Stimulation of human gingival fibroblasts viability and growth by roots treated with high intensity lasers, photodynamic therapy and citric acid.

Karam PSBH, Ferreira R, Oliveira RC, et al.
Arch Oral Biol. 2017;81(April):1-6.
Objective
The aim of this study was to compare the effect of root biomodification by lasers, citric acid and antimicrobial photodynamic therapy (aPDT) on viability and proliferation of human gingival fibroblasts (FGH).
Design
Groups were divided in control (CC – only cells), and root fragments treated by: scaling and root planing (positice control – SC), Er:YAG (ER-60mJ,10pps,10Hz,10s,2940nm), Nd:YAG (ND-0.5W,15Hz,10s,1640nm), antimicrobial photodynamic therapy (PDT-InGaAIP,30mW,45J/cm2,30s,660nm,toluidine blue O), citric acid plus tetracycline (CA). Fibroblasts (6th passage, 2×103) were cultivated in a 24-h conditioned medium by the treated root fragments. Cell viability was measured by MTT test at 24, 48, 72 and 96h. In a second experiment, FGH cells (104) were cultivated on root fragments which received the same treatments. After 24, 48, 72h the number of cells was counted in SEM pictures. In addition, chemical elements were analyzed by energy dispersive spectroscopy (EDS). Data was analyzed by two-way ANOVA (first experiment), repeated measures ANOVA (second experiment) and ANOVA (EDS experiment) tests complemented by Tukey’s test (p<0.05).
Results
ND, PDT and CA promoted higher cell viability (p<0.05). ND and ER groups presented higher number of cells on root surfaces (p<0.05). ER group presented higher calcium and CA group a higher carbon percentages (p<0.05).
Conclusions
All treatments but scaling and root planing stimulated fibroblast viability while Er:YAG and Nd:YAG treated root surfaces presented higher number of cells
 Stimulation of human gingival fibroblasts viability and growth by roots treated with high intensity lasers, photodynamic therapy and citric acid.
 
 

13. Smile Improvement: Aesthetic Treatment of Gingival Melanin Hyperpigmentation with Er:YAG Laser

Marcela Bisheimer Chemez, DDS. PhD. MS
Pages: CN09
 Smile Improvement: Aesthetic Treatment of Gingival Melanin Hyperpigmentation with Er:YAG Laser

14. SWEEPS Protocol with Fotona LightWalker, a Game Changer for Root Canal Treatment

Dr. Yanbin Xu, PhD, DMD
Pages: CN24

 SWEEPS Protocol with Fotona LightWalker, a Game Changer for Root Canal Treatment

15. Efficacy of 1064 nm Photobiomodulation Dosimetry Delivered with a Collimated Flat-Top Handpiece in the Management of Peripheral Facial Paralysis in Patients Unresponsive to Standard Treatment Care: A Case Series

Zarkovic Gjurin, S., Pang, J., Vrčkovnik, M. & Hanna, R.
Journal of Clinical Medicine, 12(19), 2023.

Background:
Peripheral facial paralysis (PFP) is a common condition where oxidative stress (OS) is involved in the pathophysiology of facial paralysis, inhibiting peripheral nerve regeneration, which can be featured in Bell’s palsy, Ramsay Hunt syndrome and Lyme disease. The current standard care treatments lack consensus and clear guidelines. Hence, the utilization of the antioxidant immunomodulator photobiomodulation (PBM) can optimize clinical outcomes in patients who are unresponsive to standard care treatments. Our study describes three unique cases of chronic PFP of various origins that were unresponsive to standard care treatments, but achieved a significant and complete recovery of facial paralysis following PBM therapy.
Materials and Methods: 
Case presentations: Case #1: a 30-year-old male who presented with a history of 12 years of left-side facial paralysis and tingling as a result of Bell’s palsy, where all the standard care treatments failed to restore the facial muscles’ paralysis. Eleven trigger and affected points were irradiated with 1064 nm with an irradiance of ~0.5 W/cm2 delivered with a collimated prototype flat-top (6 cm2) in a pulsed mode, with a 100 µs pulse duration at a frequency of 10 Hz for 60 s (s) per point. Each point received a fluence of 30 J/cm2 according to the following treatment protocol: three times a week for the first three months, then twice a week for another three weeks, and finally once a week for the following three months.
Results:
The results showed an improvement in facial muscles’ functionality (FMF) by week two, whereas significant improvement was observed after 11 weeks of PBM, after which the House–Brackmann grading scale (HBGS) of facial nerve palsy dropped to 8 from 13 prior to the treatment. Six months after PBM commencement, electromyography (EMG) showed sustainability of the FMF. Case #2: A five-year-old female who presented with a 6-month history of severe facial paralysis due to Lyme disease. The same PBM parameters were utilized, but the treatment protocol was as follows: three times a week for one month (12 consecutive treatment sessions), then the patient received seven more sessions twice a week. During the same time period, the physiotherapy of the face muscles was also delivered intensively twice a week (10 consecutive treatments in five weeks). Significant improvements in FMF and sustainability over a 6-month follow-up were observed. Case #3: A 52-year-old male who presented with severe facial palsy (Grade 6 on HBGS) and was diagnosed with Ramsay Hunt syndrome. The same laser parameters were employed, but the treatment protocol was as follows: three times a week for three weeks, then reduced to twice a week for another three weeks, then weekly for the next three months. By week 12, the patient showed a significant FMF improvement, and by week 20, complete FMF had been restored.
Conclusion:
Our results, for the first time, showed pulsed 1064 nm PBM delivered with a flat-top handpiece protocol is a valid and its treatment protocol modified, depending on the origin and severity of the condition, which is fundamental in optimizing facial paralysis recovery and alleviating neurological sympt
 Efficacy of 1064 nm Photobiomodulation Dosimetry Delivered with a Collimated Flat-Top Handpiece in the Management of Peripheral Facial Paralysis in Patients Unresponsive to Standard Treatment Care: A Case Series

16.  Immunomodulatory effects of Nd:YAG (1064 nm) and diode laser (810 nm) wavelengths to LPS-challenged human gingival fibroblasts

Papadelli, A., Kyriakidou, K., Kotsakis, G.A., Pepelassi, E., Kallis, A., Vrotsos, I.A. & Karoussis, I.K.
Archives of Oral Biology, 2021;122.

Objective: 
Human gingival fibroblasts (hGFs) are involved in inflammatory responses to bacteria by recognizing pathogen-associated molecular patterns. In search of host modulation strategies to increase LPS tolerance, Low level laser therapy (LLLT) has been suggested as an alternative treatment that reduces periodontal tissue inflammation. In this study, we investigate whether 810 nm (diode) and 1064 nm (Nd:YAG) laser wavelengths, modulate pro-inflammatory responses to LPS challenges in hGFs.
Design: 
Primary hGFs were challenged with Porphyromonas gingivalis LPS and irradiated with either Diode (810 nm) or with Nd:YAG (1064 nm) lasers. Cell cultures were examined for cell proliferation by MTT assay and IL-6 and IL-8 expression by qPCR at 24, 48 and 72 h. IL-6 and IL-8 protein levels were detected via ELISA.
Results: 
Naïve hGF populations irradiated with both Diode 810 nm and Nd:YAG 1064 nm lasers demonstrated cellular proliferation (p < 0.05), but LLLT did not affect cellular viability in LPS-challenged cells. IL-6 and IL-8 gene expression levels revealed significant anti-inflammatory effects of irradiation with both examined wavelengths on hGFs challenged with P. gingivalis LPS. Protein levels of these cytokines were increased by LPS challenge. Treatment with LLLT inhibited this increase for both wavelengths evaluated in the study at a statistically significant level particularly for the first 48 h.
Conclusions: 
The present study demonstrates a modulatory effect of LLLT using both 810 nm diode and Nd:YAG 1064 nm lasers in gingival fibroblasts by decreasing the production of IL-6, IL-8 in response to LPS.
Keywords: Diode 810 nm; Gingival fibroblasts; IL-6; IL-8; LPS; Nd:YAG 1064 nm.
 Immunomodulatory effects of Nd:YAG (1064 nm) and diode laser (810 nm) wavelengths to LPS-challenged human gingival fibroblasts

17. Er:YAG laser in selective caries removal and dentin treatment with chitosan: a randomized clinical trial in primary molars

Santos, R.M.C., Scatolin, R.S., de Souza Salvador, S.L., Souza-Gabriel, A.E. & Corona, S.A.M.
Lasers in medical science, 2023; 38(1), p.208.

 
Background:
This study evaluated the effect of chitosan on dentin treatment after selective removal of caries lesions with Er:YAG laser in reducing Streptococcus mutans, as well as its effect on the performed restorations. The sample consisted of children (aged 7 to 9 years) with active carious lesions and dentin cavitation located on the occlusal surface of deciduous molars.
Materials and Methods:
Eighty teeth were randomly distributed into 4 groups according to the caries removal method: Er:YAG laser (250 mJ/4 Hz) or bur and dentin surface treatment: 2.5% chitosan solution or distilled water. The bacterial load of caries-affected dentin was quantified by counting CFU/mg (n = 10). The teeth were restored and evaluated at 7 days, 6 months, and 12 months using modified USPHS criteria (n = 20). Microbiological data was analyzed by Mann-Whitney and clinical analyses were done using Kruskal-Wallis and Dunn test (α = 0.05).
Results:
The results showed that the Er:YAG laser significantly reduced the amount of Streptococcus mutans (p = 0.0068). After dentin treatment with chitosan, there was a significant reduction in the amount of Streptococcus mutans for both removal methods (p = 0.0424). For the retention and secondary caries criteria, no significant differences were observed along the evaluated time (p > 0.05). The laser-treated group was rated “bravo” for discoloration (p = 0.0089) and marginal adaptation (p = 0.0003) after 6 and 12 months compared to baseline. The Er:YAG laser reduced the amount of Streptococcus mutans and the chitosan showed an additional antibacterial effect. After 1 year, the Er:YAG laser-prepared teeth, regardless of the dentin treatment, showed greater discoloration and marginal adaptation of the restorations.
Keywords: Chitosan; Deciduous; Dentin; Er-YAG laser; Streptococcus mutans; Tooth.
 Er:YAG laser in selective caries removal and dentin treatment with chitosan: a randomized clinical trial in primary molars

18. The effect of antimicrobial photodynamic therapy on periodontal disease and glycemic control in patients with type 2 diabetes mellitus

Brinar, S., Skvarča, A., Gašpirc, B. & Schara, R.
Clinical oral investigations, 2023; 27, 6235–6244.

Objectives:
This study is aimed at determining the efect of concomitant antimicrobial photodynamic therapy (aPTD) on periodontal disease and glycaemic control in patients with type 2 diabetes mellitus (T2DM).
Materials and methods:
Twenty-four patients with T2DM were enrolled in the study. Periodontal clinical parameters were assessed by measuring probing pocket depth (PPD), clinical attachment loss (CAL), gingival recession (GR), full-mouth bleeding score (FMBS), full-mouth plaque score (FMPS), and full-mouth sulcus bleeding score (FMSBS). Glycated haemoglobin A1c (HbA1c) was measured. To determine the presence of the following periodontal pathogenic bacteria, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, subgingival plaque samples were taken from two periodontal pockets per jaw with the greatest PPD using paper tips. Patients were randomly divided into the test and control group. In the test group, full-mouth disinfection was performed in combination with aPTD. In the control group, only full-mouth disinfection was performed.
Results:
The results showed an improvement in periodontal clinical parameters in both groups. The diference between the groups in favour of the test group was statistically signifcant for BOP. The HbA1c level decreased in both groups. The diference was not statistically signifcant. The results of the microbiological analysis suggest that the presence of periodontal pathogenic bacteria is lower with additional antimicrobial photodynamic therapy with statistically signifcant diference for T. forsythia.
Conclusions:
Additional aPDT causes a signifcant reduction in BoP in the proportion of positive sites for periodontal pathogens.
Keywords: Type 2 diabetes mellitus · Periodontal disease · Antimicrobial photodynamic therapy · Indocyanine green
 The effect of antimicrobial photodynamic therapy on periodontal disease and glycemic control in patients with type 2 diabetes mellitus

19. Nd:YAG laser therapy on postoperative pain, swelling, and trismus after mandibular third molar surgery: a randomized double-blinded clinical study

Han, Y., Zhu, J., Hu, S., Li, C. & Zhang, X.
Lasers in medical science, 2023; 38(1), p.176.

Background:
This study aims to evaluate the effect of Nd:YAG laser therapy (NdLT) on postoperative pain, swelling, and trismus after mandibular third molar (M3) surgery.
Materials and Methods:
Three hundred patients were randomly divided into the Nd group (n = 100), medication group (n = 100), and Nd+medication (Nd+m) group (n = 100). The WHARFE classification system was used to assess surgical difficulty. After surgery, the Nd group was irradiated by the Nd:YAG laser in very long-pulsed mode (VLP, pulse duration 1 ms, 20 Hz, 4 W, R21-C3) in 6 regions of the extraction socket with a total energy of 300 J. For the medication group, dexamethasone 0.75 mg and loxoprofen 60 mg were prescribed immediately and every 12 h thereafter for 3 days. The Nd+m group received both treatments mentioned above. Pain assessment was performed at 6, 24, 48, and 72 h postoperatively using the visual analog scale (VAS).
Results:
Swelling was evaluated by changes in the distance from (1) the tragus to the labial commissure, (2) the tragus to the pogonion, and (3) the mandibular angle to the lateral canthus preoperatively and 72 h postoperatively. Trismus was assessed by the change in maximum mouth opening. Groups Nd and Nd+m had lower VAS scores at 6 h, 24 h, and 48 h (F = 13.80, p = 0.00), but the difference between the two groups was not significant (F = 1.34, p = 0.11). However, no significant difference was observed at 72 h (p = 0.10). There was no significant difference in swelling or trismus among the three groups (p > 0.05). NdLT is an effective approach to improve complications after M3 surgery.
Keywords: Mandibular third molar surgery; Nd:YAG laser; Pain; Trismus; swelling.
 Nd:YAG laser therapy on postoperative pain, swelling, and trismus after mandibular third molar surgery: a randomized double-blinded clinical study

20.  The effect of laser therapy on the expression of osteocalcin and osteopontin after tooth extraction in rats treated with zoledronate and dexamethasone

Mergoni, G. et al.
Supportive care in cancer, 2016;24(2), pp.807–813.

Purpose: 
Laser therapy has been used for the prevention and management of medication-related ostenecrosis of the jaw (MRONJ). The aim of this paper was to investigate the action of laser therapy on extraction socket healing in rats in conditions at risk for MRONJ, evaluating the expression of markers of bone metabolism.
Methods: 
Thirty male Sprague-Dawley rats were divided in four groups: control group (C, n = 5), laser group (L, n = 5), treatment group (T, n = 10), and treatment plus laser group (T + L, n = 10). Rats of group T and T + L received zoledronate 0.1 mg/kg and dexamethasone 1 mg/kg every 2 days for 10 weeks. Rats of group C and L were infused with vehicle. After 9 weeks, the left maxillary molars were extracted in all rats. Rats of groups L and T + L received laser therapy (Nd:YAG, 1064 nm, 1.25 W, 15 Hz, 5 min, 14.37 J/cm(2)) in the socket area at days 0, 2, 4, and 6 after surgery. Western blot analysis was performed to evaluate the alveolar expression of osteopontin (OPN) and osteocalcin (OCN) 8 days after extraction.
Results:
Rats of groups L and T + L showed a significant higher expression of OCN compared to rats of groups C and T (+348 and +400 %, respectively; P = 0.013 and P = 0.002, respectively). The expression of OPN did not show significant differences among the different groups.
Conclusions:
 Our findings suggest that laser irradiation after tooth extraction can promote osteoblast differentiation, as demonstrated by the higher expression of OCN. Thus, laser irradiation could be considered a way to improve socket healing in conditions at risk for MRONJ development.
Keywords: Laser therapy; Medication-related osteonecrosis of the jaw; Osteocalcin; Osteopontin; Tooth extraction; Zoledronic acid.
 The effect of laser therapy on the expression of osteocalcin and osteopontin after tooth extraction in rats treated with zoledronate and dexamethasone

21.  Laser and Platelet-Rich Plasma to treat Medication-Related Osteonecrosis of the Jaws (MRONJ): a case report

Fornaini C, Cella L, Oppici A, et al.
Laser Ther. 2017;26(3):223-227.
Aims
The appropriate management of Medication-Related OsteoNecrosis of the Jaw (MRONJ) is still a challenge for dentists and oral surgeons and in these last years high-technology instruments have been proposed at the different steps of interventions, also combined with promoters of tissue repair.The aim of this report is to show the advantages of a combined approach (laser and PRP) for the treatment of MRONJ.
Methods
It is described the case of a patient positive for MRONJ observed at the Odontostomatology and Maxillo-Facial Surgery Unit of the Hospital of Piacenza where surgical approach was performed by using different devices: Er:YAG laser (2940 nm) to remove and vaporize necrotic hard tissue until bleeding bone; Platelet-Rich Plasma (PRP) to stimulate hard and soft tissue healing; diode laser (808 nm) to biostimulate the surgical site.
Results
At the time of suture removal, wound closure was observed and the complete healing of the MRONJ site was observed for the 2 years follow up.
Conclusion
This case may suggest that this kind of combined approach during all the steps of MRONJ treatment allows to perform a faster and less invasive surgery with a more comfortable postoperative healing process and it represents an innovative approach in this severe adverse event.
 Laser and Platelet-Rich Plasma to treat Medication-Related Osteonecrosis of the Jaws (MRONJ): a case report

22. PIPS and retreatment

Pullen AR.
Dent Trib USA. 2014:20-22.<> 

 PIPS and retreatment

23. Efficacy of photon induced photoacoustic streaming ( PIPS ) on root canals infected with Enterococcus faecalis : A pilot study

Jaramillo DE, Aprecio RM, Angelov N, DiVito E, McClammy T V.
Endod Pr. 2012;7(3):28-32.
 
Abstract:
Eradication of microorganisms from an infected root canal before obturation is a primary focus of endodontic treatment, as well as the best predictor for the long-term success of the endodontic therapy. The purpose of this in vitro laboratory study was to evaluate the efficacy of a new tapered and stripped Er:YAG laser tip using PIPS (Photon Induced Photoacoustic Streaming) in root canals infected with Enterococcus faecalis (ATCC4082).
Materials and Methods:
Twenty-four freshly extracted single-rooted human teeth were collected and inoculated with E. faecalis. After 4 weeks, the teeth were divided in four groups, two experimental, one positive, and one negative group. Laser treatment was performed for a period of 20 seconds with 6% sodium hypochlorite in groups 1 and 2, while PBS was used for group 3 and 4. Furthermore, dentin debris was produced, and colony-forming units were determined.
Results:
The combinations of 20 seconds laser activated irrigation with Er:YAG Laser and 6% sodium hypochlorite showed 100% inhibition using PIPS of growth of E. faecalis compared to 50% inhibition with the combination of Er:YAG Laser and PBS.
Conclusions:
The PIPS technology is efficient tool in elimination of Enterococcus faecalis from infected root canals.
 Efficacy of photon induced photoacoustic streaming ( PIPS ) on root canals infected with Enterococcus faecalis : A pilot study

24. PHAST PIPS: The photoacoustic wave of the future?

Pullen AR. 
Dent Trib USA. 2014:18-21.

 
Background:
Photon induced photoacoustic streaming (PIPS) is a low-energy (20mJ) technique based on very short Er:YAG laser-emitted photons introduced into an irrigation solution inside the access of the tooth. This process, which uses the Lightwalker (Lasers4Dentistry), introduces an aggressive and effective photoacoustic streaming or tidal wave of irrigation solution into canals, accessory anatomy and deep into the dentinal tubules of the root canal system. PHAST PIPS can be described as “irrigation on steroids”.
 PHAST PIPS: The photoacoustic wave of the future?

25. Nd:YAG laser biostimulation of bisphosphonate-associated necrosis of the jawbone with and without surgical treatment

Vescovi, P. et al.
British Journal of Oral and Maxillofacial Surgery. 200745(8), pp.628–632.

Background:
Bisphosphonate-associated osteonecrosis was first reported in 2003 and is getting common. Size of lesions, symptoms, and duration of time between starting bisphosphonates and the development of bone necrosis vary. There is currently no effective treatment. We describe our preliminary results with 19 patients affected by bisphosphonate-associated osteonecrosis of the jaws who were treated conventionally with surgical or medical treatment alone or in combination with neodimium: yttrium-aluminium-garnet (Nd:YAG) laser. Clinical variables such as symptoms, presence of pus, and closure of mucosal flaps before and after treatment were evaluated to establish the effect of the laser irradiation. We treated nine patients with laser biostimulation with or without surgical treatment, and in this group there were eight clinical successes and one symptomatic improvement, with a clinical finding better than ones without laser biostimulation (ten patients, five clinical successes, and one symptomatic improvement).
 Nd:YAG laser biostimulation of bisphosphonate-associated necrosis of the jawbone with and without surgical treatment

26. Comparative evaluation of the effects of Nd:YAG and Er:YAG laser in dentin hypersensitivity treatment

Birang R, Poursamimi J, Gutknecht N, Lampert F, Mir M.
Lasers Med Sci. 2007;22(1):21-24.

 
Background:
Dentin hypersensitivity (DH) is one of the most common complications that affect patients after periodontal therapy. So far, many investigators have successfully used different types of laser on DH treatment. The aim of this study was to evaluate the comparative effect of Nd:YAG laser and Er:YAG laser on human teeth desensitization.
Materials and Methods:
A group of nine patients with a total of 63 chronic hypersensitive teeth were selected. Each one of them should at least have three hypersensitive teeth. These teeth were randomly allocated into three groups. Group 1, Nd:YAG laser (1 W, 15 Hz, 60 s, two times); group 2, Er:YAG laser (100 mJ, 3 Hz, 60 s, two times); and group 3 serves as control group without any treatment. Assessment of pain was performed by a visual analysing scale (VAS) after stimulation of sensitive tooth by using the sharp tip of an explorer.
Results:
This test was performed before treatment, immediately after that and at 1-, 3- and 6-month intervals after treatment by one blinded examiner. Analysis of VAS score between the three groups at the time of treatment did not show any significant difference (p = 0.506). However, by using repeated-measurement analysis of variance test, significant differences were seen in the three groups between before-treatment VAS score and after treatment (p < 0.0005). This statistically significant difference in the control group demonstrated a placebo effect. However, the effect of using Nd:YAG and Er:YAG lasers was stronger than this placebo effect, so that after removing the effect of the placebo, differences immediately after, 1, 3 and 6 months post treatment between all three groups still were statistically highly significant (p < 0.0005). Compared to the Er:YAG laser group, using Nd:YAG laser resulted in a significant reduction of VAS score at each follow-up examination (p < 0.0005).
Conclusion:
Although using Nd:YAG and Er:YAG laser in desensitization of hypersensitive teeth showed a placebo effect limited to a short time, results of this study demonstrated that both of these lasers have an acceptable therapeutic effect. The observed effects seemed to last for at least 6 months. It was concluded that Nd:YAG laser is more effective than Er:YAG laser in reduction of patients’ pain.
 Comparative evaluation of the effects of Nd:YAG and Er:YAG laser in dentin hypersensitivity treatment

27.  Rapid debonding of polycrystalline ceramic orthodontic brackets with an Er:YAG laser: an in vitro study

Mundethu, A. R., Gutknecht, N. & Franzen, R.
Lasers in Medical Science, 2014;29(6), pp.1807–1813.

Background:
The usefulness of erbium-doped yttrium aluminum garnet laser irradiation for debonding ceramic brackets is assessed using a single laser pulse. Damon Clear brackets were chosen for their 85% transmission of 2.94 μm radiation and were bonded to 20 human third molars using the Blugloo adhesive system. Laser parameters comprised of 600 mJ pulse energy with 800 μs duration, 1.3 mm fiber tip. Light microscopy was used to assess Adhesive Remnant Index (ARI) scores, and scanning electron microscope (SEM) images were taken of the cross-section of the enamel-adhesive interface. Nineteen brackets (95%) were successfully debonded with a single laser pulse, while one bracket (5%) required eight pulses for debonding. For all teeth, the SEM analysis showed no signs of damage to the enamel, and ARI scores of three were observed, supporting the result that the laser effect is confined in the adhesive. The presented laser parameters are able to rapidly debond suitable brackets. The debonding mechanism was concluded to be thermomechanical ablation for single pulse debonding.
 Rapid debonding of polycrystalline ceramic orthodontic brackets with an Er:YAG laser: an in vitro study

28.  Effects of Nd:YAG laser irradiation on the growth of Candida albicans and Streptococcus mutans: in vitro study

Grzech-Lesniak, K. et al
Lasers in medical science, 2019;34(1), pp.129–137.

Abstract
The purpose of this study was to evaluate the effects of Nd:YAG laser with flat-top handpiece on the in vitro growth of Candida albicans and Streptococcus mutans. The incidence of C. albicans (opportunistic commensal) and S. mutans (facultatively anaerobic) infections is increasing, despite available treatments. Cultures of Streptococcus mutans and Candida albicans were irradiated using Nd:YAG laser (LightWalker, Fotona) with flat-top handpiece (Genova, LightWalker, Fotona) at the following parameters: group G1: 0.25 W, 10 Hz, 15 s, 3 J and group G2: 1 W, 10 Hz, 60s, 59 J. The results were evaluated directly and 24 h after irradiation using a quantitative culture method (estimation of colony-forming units in 1 ml of suspension, cfu/ml), and microscopic analysis with Janus green stain and compared with control group in which laser was not applied. C. albicans was reduced by 20 up to 54% for G1, and for G2 by 10 up to 60% directly after the application. The cfu/ml values for S. mutans decreased by 13% (p = 0.1771) for G1 and 89% (p < 0.0001) for G2. In both test groups 24 h after the application, the number of colony-forming units decreased by 15-46% for G1 and by 15-64% for G2. The arrested cell division, increasing the surface area and increasing the number of metabolically inactive cells, were observed in morphometric analysis. Macroscopic and microscopic analyses revealed a reduction in cell number and a significant decrease of cell metabolism after laser application for both C. albicans and S. mutans.
 Effects of Nd:YAG laser irradiation on the growth of Candida albicans and Streptococcus mutans: in vitro study

29. Nd:YAG and diode laser in the surgical management of soft tissues related to orthodontic treatment

Fornaini C, Rocca JP, Bertrand MF, Merigo E, Nammour S, Vescovi P.
Photomed Laser Surg. 2007;25(5):381-392.
 
Objective:
The aim of this clinical study was to observe and evaluate the surgical management efficiency of soft tissues during orthodontic treatment.
Materials and methods:
Thirty-seven young patients were selected and treated by laser-assisted surgery before or during orthodontic treatment and were classified by sex, age, and type of surgical management. Three different wavelengths were used (diode 810 nm, diode 980 nm, and Nd:YAG 1064 nm) in different surgical situations: maxillary vestibular and lingual frenectomies, surgical exposure and alignment of ectopic or retained teeth, and re-contouring gingival overgrowth.
Results:
In all evaluated patients, the laser treatment was performed without local anesthesia or sutures. Only topical anesthetic was needed.
Conclusion:
These use of these wavelengths of laser energy was a noticeable aid in the surgical management of soft tissues before or during orthodontic treatment. The benefits of laser treatment include reduced bleeding during surgery with consequent reduced operating time and rapid postoperative hemostasis, thus eliminating the need for sutures. The lack of need for anesthetics and sutures, as well as improved postoperative comfort and healing, make this technique particularly useful for very young patients.
 Nd:YAG and diode laser in the surgical management of soft tissues related to orthodontic treatment
 

30.  Treatment Outcome of Oral Leukoplakia with Er:YAG Laser: A 5-Year Follow-Up Prospective Comparative Study

Arduino PG, Cafaro A, Cabras M, Gambino A, Broccoletti R. 
Photomed Laser Surg. October 2018.
Objective
The purpose of this prospective analysis was to evaluate the efficacy of erbium-substituted yttrium aluminum garnet (Er:YAG) laser compared with that of conventional surgery, regarding the long-term outcome of nondysplastic oral leukoplakias (OL). Background: To date, this comparison has never been performed.
Methods
Patients were randomly allocated to two different groups: some underwent surgical excision with traditional scalpel (Group TrSc) and others underwent an ablative session with Er:YAG laser (Group Las), with these modalities: 1.5-W power, 150-mJ pulse energy, 10-Hz frequency, 500-μs pulse duration, and 0.9-mm spot size. During the follow-up period, the evolution of the OL was listed as (1) healing: if novel lesions did not appear in the same place of the surgery and (2) recurrence: if a new mucosal change has been detailed in the equivalent place of the primary disease.
Results
One hundred seventeen lesions were treated. Fifty-eight lesions underwent surgery with traditional scalpel, whereas 59 underwent laser surgery. Follow-up ranged from 24 to 108 months (median of 58). Healing was detailed for 52.99% (n = 62) of the 117 OL, with no statistical differences between the two randomized groups. Conclusions: It seems reasonable to consider the Er:YAG laser as effective as traditional scalpel in terms of healing for OL, with the same rate of recurrences in a period of almost 5 years.
 Treatment Outcome of Oral Leukoplakia with Er:YAG Laser: A 5-Year Follow-Up Prospective Comparative Study
 
 

31. Er:YAG laser in defocused mode for scaling of periodontally involved root surfaces: an in vitro pilot study

Crespi R, Romanos GE, Barone A, Sculean A, Covani U.
J Periodontol. 2005;76(5):686-690.
Background:
The Er:YAG laser may be used on periodontally involved teeth in combination with conventional periodontal therapy in order to improve the efficacy of root instrumentation. The aim of this study was to compare the effect of hand instrumentation on root surfaces of periodontally involved teeth with Er:YAG laser application.
Materials and Methods:
Thirty freshly extracted, non-carious, single-rooted, periodontally diseased human teeth from adult humans with advanced periodontal disease were used in this study. The teeth were divided into three groups of 10 specimens each. Group A was treated with scaling and root planing (SRP) with curets only (control). In group B, the root surfaces were scaled with curets and then lased with an Er:YAG laser (wavelength 2.94 microm). A handpiece with a water spray was used in non-contact mode (defocused) at a distance of 1 cm from root surface. Laser parameters were set at energy of 100 to 200 mJ/pulse, with 10 Hz of frequency. In group C, the root surfaces were lased only with power settings 250 to 300 mJ/pulse and 10 Hz frequency. An epon-araldite plastic embedding technique was used for light microscopic investigation.
Results:
Histologic findings showed significant differences between the test and control sites. In control sites, after hand instrumentation, the surface was smooth, without a cementum layer, and the dentin layer presented opened tubules. Defects on the dentin layer were also present along root surfaces. In the test sites (B, C) root surfaces revealed no thermal damage; no cracking or tissue carbonization were observed. The superficial layers of lased surfaces appeared smooth and melted without alterations.
Conclusion:
Based on these findings, it appears that it may be feasible to use the Er:YAG laser for root instrumentation without prior root planing if the proper parameters are followed.
 Er:YAG laser in defocused mode for scaling of periodontally involved root surfaces: an in vitro pilot study

32. Combined Application of Er:YAG and Nd:YAG Lasers Enhances Osseointegration at Dental Bone-Implant Interface

Zhao, T. & Li, M.
Frontiers in Materials, 2022;9.

 
Background:
The combination of a bone and an implant surface is a dynamic biological process. By improving the osseointegration efficiency of the bone tissue around the implant surface, the implant can obtain long-term stability. In this study, we have investigated the potential applications of dual-wavelength lasers (Er:YAG laser and Nd:YAG laser) in implantations and observed their possible efficacy in promoting tissue repair around the implant. The animal experimental model of a rabbit femoral defect implant was used to simulate the process of tissue reconstruction around the implant in humans. The results indicated that by micro-CT observation, it was obvious that the bone mineral density (BMD) values of the dual-wavelength laser group were significantly higher than those of other groups. Furthermore, VG staining clearly showed that there was no obvious physiological gap detected between the implant and the surrounding bone tissues in the dual-wavelength laser group. HE staining further revealed that no significant influx of inflammatory cells was observed around the implants. Immunohistochemical staining of OCN and VEGF showed that the positive area percentages of the dual-wavelength laser group were significantly higher than other groups at the same time point. Therefore, the application of a dual-wavelength laser in implantations can exhibit a positive effect on promoting the reconstruction of bone tissues.
 Combined Application of Er:YAG and Nd:YAG Lasers Enhances Osseointegration at Dental Bone-Implant Interface

33.  The effect of laser therapy on the expression of osteocalcin and osteopontin after tooth extraction in rats treated with zoledronate and dexamethasone

Mergoni, G. et al.
Supportive care in cancer, 2016;24(2), pp.807–813.

Purpose: 
Laser therapy has been used for the prevention and management of medication-related ostenecrosis of the jaw (MRONJ). The aim of this paper was to investigate the action of laser therapy on extraction socket healing in rats in conditions at risk for MRONJ, evaluating the expression of markers of bone metabolism.
Methods: 
Thirty male Sprague-Dawley rats were divided in four groups: control group (C, n = 5), laser group (L, n = 5), treatment group (T, n = 10), and treatment plus laser group (T + L, n = 10). Rats of group T and T + L received zoledronate 0.1 mg/kg and dexamethasone 1 mg/kg every 2 days for 10 weeks. Rats of group C and L were infused with vehicle. After 9 weeks, the left maxillary molars were extracted in all rats. Rats of groups L and T + L received laser therapy (Nd:YAG, 1064 nm, 1.25 W, 15 Hz, 5 min, 14.37 J/cm(2)) in the socket area at days 0, 2, 4, and 6 after surgery. Western blot analysis was performed to evaluate the alveolar expression of osteopontin (OPN) and osteocalcin (OCN) 8 days after extraction.
Results:
Rats of groups L and T + L showed a significant higher expression of OCN compared to rats of groups C and T (+348 and +400 %, respectively; P = 0.013 and P = 0.002, respectively). The expression of OPN did not show significant differences among the different groups.
Conclusions:
 Our findings suggest that laser irradiation after tooth extraction can promote osteoblast differentiation, as demonstrated by the higher expression of OCN. Thus, laser irradiation could be considered a way to improve socket healing in conditions at risk for MRONJ development.
Keywords: Laser therapy; Medication-related osteonecrosis of the jaw; Osteocalcin; Osteopontin; Tooth extraction; Zoledronic acid.
 The effect of laser therapy on the expression of osteocalcin and osteopontin after tooth extraction in rats treated with zoledronate and dexamethasone

34.  Evaluation of bone healing after osteotomies prepared with Er:YAG laser in contact and noncontact modes and piezosurgery – An animal study.

Gabric, D. et al.
Journal of Oral and Maxillofacial Surgery, 74(1), pp.18–28.

Purpose:
To analyze the healing of bone tissue treated with Er:YAG laser contact and noncontact modes of and piezosurgery in a rat model using triangular laser profilometry.
Materials and Methods:
Twenty-four 10-week-old adult male Wistar rats were used in the study. Three osteotomies on the medial part of tibia were performed in each animal, 1 in the right tibia and 2 in the left tibia. The osteotomies were performed with a piezoelectric device set at maximal power and the Er:YAG laser in contact mode (power, 7.5 W; pulse energy, 375 mJ; repetition rate, 20 Hz; MSP mode) and noncontact mode (power, 7.5 W; pulse energy, 750 mJ; repetition rate, 10 Hz; QSP mode) with a novel type of circular, digitally controlled handpiece (x-Runner). After surgery, 6 animals were immediately euthanized (group 1), and the others were euthanized after 1 week (group 2, n = 6), 2 weeks (group 3, n = 6), and 3 weeks (group 4, n = 6). Bone healing after osteotomy was analyzed using a 3-dimensional laser scanning technique (ie, laser triangulation profilometry).
Results:
The volume reduction rates are similar for all 3 techniques (0.2 to 0.25 mm3 per week). Greater volume reduction of 0.25 mm3 per week was observed for the Er:YAG laser in noncontact mode (x-Runner). After 3 weeks, almost complete healing of the prepared osteotomy was observed.
Conclusion:
Within the limitations of this study, the osteotomies performed by the Er:YAG laser in digitally controlled noncontact mode healed the fastest.
 Evaluation of bone healing after osteotomies prepared with Er:YAG laser in contact and noncontact modes and piezosurgery – An animal study.

35. Comparative effects of SWEEPS technique and antimicrobial photodynamic therapy by using curcumin and nano-curcumin on Enterococcus faecalis biofilm in root canal treatment

Ensafi, F., Fazlyab, M., Chiniforush, N. & Akhavan, H.
Photodiagnosis and photodynamic therapy, 2022;40, p.103130.

 
Objectives:
This study aimed to compare the antimicrobial effects of the shock wave enhanced emission photoacoustic streaming (SWEEPS) technique and Antimicrobial photodynamic therapy (aPDT) with curcumin and nano-curcumin photosensitizers on Enterococcus faecalis (E. faecalis) biofilm in root canals of extracted teeth.
Materials and methods:
This experimental study was conducted on extracted single-rooted human teeth. The teeth were decoronated at the cementoenamel junction, the root canals were instrumented with BioRace system, and their apices were sealed. Smear layer was removed, and the teeth were autoclave-sterilized. E. faecalis strains were cultured in sterile brain heart infusion (BHI) and a bacterial suspension with 0.5 McFarland standard concentration was prepared. The root canals were inoculated with the bacterial suspension and incubated at 37 °C for 4 weeks. The teeth were then divided into 12 groups (curcumin, nano-curcumin, curcumin + LED, nano-curcumin + LED, curcumin + SWEEPS, nano-curcumin + SWEEPS, curcumin + LED + SWEEPS, nano-curcumin + LED + SWEEPS, SWEEPS, positive control and negative control). The number of colony forming units (CFUs) was counted and analyzed by one-way ANOVA and Tukey’s test.
Results:
A significant difference was noted in colony count among the groups (P<0.001). LED alone had the lowest and nano-curcumin + LED + SWEEPS had the highest root canal cleaning efficacy. SWEEPS along with curcumin, nano-curcumin, and LED significantly decreased the bacterial count compared with other groups (P<0.05).
Conclusion:
Application of the SWEEPS technique with curcumin and nano-curcumin as photosensitizer activated by LED in aPDT improved the reduction of E. faecalis in root canals. Keywords: Antimicrobial photodynamic therapy; Enterococcus faecalis; Er:YAG; Root Canals; SWEEPS.
 Comparative effects of SWEEPS technique and antimicrobial photodynamic therapy by using curcumin and nano-curcumin on Enterococcus faecalis biofilm in root canal treatment
 
 
 

36. Er:YAG Laser Ablation of Bovine Bone Tissue: Morphological Evaluation and Ablation Rate

Zanirato Lizarelli, R. de F., Govone, A.B., Pelino, J.E.P. & Bagnato, V.S.
J Oral Laser Applications, 2007;7, pp.167–174.

 
Purpose:
To compare the depth and volume of cavities produced by ablation on bovine bone tissue using different Er:YAG laser parameters.
Materials and Methods:
A bovine femur was cut in blocks and wet polished with 600-grit sandpaper. Different energies per pulse (100 mJ, 300 mJ, and 500 mJ) and different frequencies (5 Hz, 10 Hz, and 15 Hz) were used to create microcavities within a 10-s irradiation time. The samples were analyzed under an optical microscope (40X) and SEM for a better definition of the cavities and their features. The ablated volume was calculated and statistically analyzed with Kruskal-Wallis and Dunn tests.
Results: The ablation rate in many groups showed significant differences up to 5%, where the energy per pulse was the only significant variable. As energy per pulse increased, so did the ablation rate. Morphological analysis showed differences in the homogeneity of the microcavities.
Conclusions:
Er:YAG laser is able to promote cold interaction, suggesting a precise tool for bone ablation. Keywords: bone, ablation rate, Er:YAG, morphology, bovine tissue
 Er:YAG Laser Ablation of Bovine Bone Tissue: Morphological Evaluation and Ablation Rate

37. Treatment of vascular lesions in the head and neck using Nd:YAG laser

Vesnaver A, Dovšak DA
J Cranio-Maxillofacial Surg. 2006;34:17-24.

 
Introduction:
Vascular lesions in the head and neck region, including both haemangiomas and vascular malformations, are common and many different treatment modalities have been used for their removal. In the past decade, the Nd:YAG laser has emerged as a new mode of treatment for vascular lesions, and the purpose of this paper was to determine its clinical value.
Patients and methods:
A prospective study was conducted in 111 patients with vascular lesions in the head and neck region. They were treated with the Nd:YAG laser by photocoagulation. Of these, 96 had small lesions, with surface diameters of less than 3 x 3cm(2), and 5 had large lesions, with surface diameters of more than 3 x 3cm(2). The patients were all followed-up carefully until complete healing was recorded, along with any complications.
Results:
In both groups of patients, tissue sloughing occurred within 2-3 days. Healing time in small lesions was 2-3 weeks, and in large lesions 3-4 weeks. Three patients with small lesions and one patient with a large lesion experienced minor complications.
Conclusion:
The Nd:YAG laser is a safe and effective tool for treating vascular lesions.
 Treatment of vascular lesions in the head and neck using Nd:YAG laser

38. Efficacy of different Er:YAG laser–activated photoacoustic streaming modes compared to passive ultrasonic irrigation in the retreatment of curved root canals

Petričević, G.K., Katić, M., Anić, I., Salarić, I., Vražić, D. and Bago, I.
Clinical Oral Investigations, 2022;26(11), pp.6773-6781.

 
Objectives:
To evaluate the efficacy of passive ultrasonic irrigation (PUI) and super short pulse (SSP) and shock wave–enhanced emission photoacoustic streaming (SWEEPS) modes of Er:YAG laser–activated irrigation (LAI) with two different laser tips, in removing filling remnants after conventional retreatment in severely curved root canals.
Materials and methods:
The study sample consisted of 40 extracted molars with curved mesiobuccal root canals. The canals were instrumented with ProTaper Next and filled with an epoxy resin–based sealer and gutta-percha using continuous wave vertical compaction and warm injection back-filling. After retreatment with ProTaper Universal Retreatment system and sodium hypochlorite (NaOCl), all samples were randomly divided into four groups (n = 10) according to the final irrigation technique: PUI, LAI/SSP, SWEEPS/flat-tip, and SWEEPS/radial-tip, using 6 mL of 3% NaOCl for an activation time of 3 × 30 s. The samples were subjected to micro-CT scans after root canal filling, retreatment, and final irrigation. The filling material volume and percentage reduction were calculated.
Results:
All tested irrigation techniques were successful in the elimination of the filling remnants after the retreatment (p < 0.001). The LAI/SSP group showed a higher reduction rate than the SWEEPS/flat-tip group (p = 0.032). No significant differences were found between the other groups (p > 0.05).
Conclusion:
All tested techniques improved the removal of filling material during retreatment in curved canals. LAI/SSP showed slightly better results than other techniques. Clinical relevance The study highlights the need for additional activated irrigation after the retreatment of curved root canals. The choice between PUI and LAI is not decisive for success.
 Efficacy of different Er:YAG laser–activated photoacoustic streaming modes compared to passive ultrasonic irrigation in the retreatment of curved root canals

39. Efficacy of Photoinduced Photoacoustic Streaming and Diode Laser Irrigation Techniques on Smear Layer Removal, Sealer Penetration and Push-out Bond Strength

Abdelgawad, L.M., ElShafei, N.A.A., Eissa, S.A. & Ibrahim, D.Y.
Journal of Lasers in Medical Sciences, 13(SE-Original Article), p.e12

 
 
 
Introduction:
The present study aimed to test the efficiency of photoinduced photoacoustic streaming using 2940 nm Er: YAG laser and 980 nm diode laser agitation on smear layer removal, sealer penetration and push-out bond strength.
Materials and Methods:
Sixty single canaled human permanent teeth were collected for this study. Specimens were grouped into three experimental groups (20 teeth in each group), depending on the activation protocol used for final irrigation: Group I (needle agitation), group II (980nm diode laser agitation) and group III (photon induced photoacoustic streaming (PIPS) using 2940 nm Er: YAG laser. The quantity of irrigant was standardized in all groups to 4 ml. The irrigant was activated for 40 seconds in different groups under continuous flow. Two teeth from each group were used to check the smear layer removal, and then the remaining teeth in each group were randomly divided into three equal experimental subgroups according to methods of evaluation used: subgroup A: Sealing ability evaluated by dye penetration method; subgroup B: SEM for sealer penetration; and subgroup C: Push-out bond strength assessed by the universal test machine.
Results:
As regards smear layer removal, results showed that the PIPS group had opened dentinal tubules, followed by the diode laser group, while the least cleaning effect was found in the Side-vented needle group. As for Sealing ability and dye penetration, a statistically significant difference was found between all of the three groups, with the Er:YAG laser (PIPS) having the best sealing ability and sealer penetration. Push-out bond strength results showed no statistically significant difference between diode and Er:YAG groups, with a significant difference between each of them and the Side-vented needle group.
Conclusion:
Using the diode or Er:YAG laser (PIPS) for irrigant activation led to better irrigant penetration and smear layer removal which subsequently led to obvious sealer penetration, better sealing, and strength properties of endodontic treated teeth. Keywords: Diode laser, Er:YAG laser, PIPS, laser agitation, smear layer removal, Sealer penetration, Push-out bond strength
 Efficacy of Photoinduced Photoacoustic Streaming and Diode Laser Irrigation Techniques on Smear Layer Removal, Sealer Penetration and Push-out Bond Strength

40. Antimicrobial Effects of Three Different Treatment Modalities on Dental Implant Surfaces

Larsen OI, Enersen M, Kristoffersen AK, et al.
J Oral Implantol. 2017;43(6):429-436.

Background:
Resolution of peri-implant inflammation and re-osseointegration of peri-implantitis affected dental implants seem to be dependent on bacterial decontamination. The aims of the study were to evaluate the antimicrobial effects of 3 different instrumentations on a micro-textured dental implant surface contaminated with an avirulent or a virulent Porphyromonas gingivalis strain and to determine alterations to the implant surface following instrumentation.
Materials and Methods:
Forty-five dental implants (Straumann SLA) were allocated to 3 treatment groups: Er:YAG laser, chitosan brush, and titanium curette (10 implants each) and a positive (10 implants) and a negative (5 implants) control. Each treatment group and the positive control were split into subgroups of 5 implants subsequently contaminated with either the avirulent or virulent P. gingivalis strain. The antimicrobial effect of instrumentation was evaluated using checkerboard DNA-DNA hybridization.
Results:
Implant surface alterations were determined using a light interferometer. Instrumentation significantly reduced the number of attached P. gingivalis ( P < .001) with no significant differences among groups ( P = .310). A significant overall higher median score was found for virulent compared with avirulent P. gingivalis strains ( P = .007); the Er:YAG laser uniquely effective removing both bacterial strains. The titanium curette significantly altered the implant surface micro-texture. Neither the Er:YAG laser nor the chitosan brush significantly altered the implant surface. The 3 instrumentations appear to have a similar potential to remove P. gingivalis. The titanium curette significantly altered the microstructure of the implant surface.
Keywords: P. gingivalis; decontamination; dental implant; laser; microstructure; surface alteration.
 Antimicrobial Effects of Three Different Treatment Modalities on Dental Implant Surfaces

41.  Decontamination of Dental Implant Surfaces by the Er:YAG Laser Beam: A Comparative in Vitro Study of Various Protocols

Nejem Wakim R, Namour M, Nguyen HV.
Dent J. 2018;6(4).

Background:
Oral rehabilitation with dental implants has revolutionized the field of dentistry and has been proven to be an effective procedure. However, the incidence of peri-implantitis has become an emerging concern. The efficacy of the decontamination of the implant surface, by means of lasers, is still controversial. Previous studies have revealed a reduction in osteoblast adhesion to carbon-contaminated implant surfaces.
Materials and Methods:
This in-vitro study aimed to evaluate the decontamination of failed implants by assessing the carbon proportion, after irradiation by low-energy erbium yttrium-aluminum-garnet laser (Er:YAG) (Fotona; 2940 nm, Ljubljana, Slovenia) for a single and for multiple passages, until getting a surface, free of organic matters; to find the appropriate procedure for dental-implant surface-decontamination. Ninety implants were used. Thirty sterile implants were kept as a negative control. Thirty failed implants were irradiated by the Er:YAG laser, for a single passage, and the other thirty, for multiple passages. The parameters used in our experiments were an irradiation energy of 50 mJ, frequency of 30 Hz, and an energy density of 3.76 J/cm2. A sapphire tip, with a length of 8 mm, was used with concomitant water spray irrigation, under air 6 and water spray 4. Super short pulse mode (SSP) was of 50 μs; irradiation speed being 2 mm/s. We used energy-dispersive X-ray spectroscopy (EDX) to evaluate the carbon proportion on the surfaces of the sterile implants, the contaminated, and the lased implants, with one (LX1) and with three passages (LX3). Statistical analysis was performed by ANOVA.
Results:
Results showed mean difference between the three groups (contaminated, LX1, and LX3) with p < 0.0001, as between LX1 and Group A (p < 0.0001), while the difference between LX3 and the control group was not statistically significant. The decontamination of the implant surfaces with a low-energy Er:YAG laser with three passages, appeared to be an encouraging approach.
 Decontamination of Dental Implant Surfaces by the Er:YAG Laser Beam: A Comparative in Vitro Study of Various Protocols

42. Influence of sodium hypochlorite concentration on cavitation effect and fluid dynamics induced by photon-induced photoacoustic streaming (PIPS): A visualization study

Cai, C., Wen, C., Guan, L., Huang, Y. & Jiang, Q.
Lasers in medical science, 2022;37(5), pp.2537–2544.

Purpose: The aim of the present study was to visualize and compare the cavitation effect and fluid dynamics induced by photon-induced photoacoustic streaming (PIPS) using sodium hypochlorite (NaOCl) with different concentrations as irrigant. Methods: Forty artificial root canals were prepared using MTWO Niti file up to size #25/.06. The canals were randomly divided into four groups (n = 10/group). High-speed camera was used to visualize and compare the cavitation effect induced by PIPS in the artificial root canals containing saline or NaOCl. Fluid velocity and Reynolds number of saline, 1%-, 2.5%- and 5.25% NaOCl irrigants induced by PIPS in the apical region were calculated using TEMA 2D software while the fluid motions were recorded. Results: Visualization profile revealed that NaOCl presented a stronger cavitation effect and fluid dynamics than saline during PIPS activation. In the apical region, 1% NaOCl group presented the highest average velocity of 3.868 m/s, followed by 2.5% NaOCl group (3.685 m/s), 5.25% NaOCl group (2.353 m/s) and saline group (1.268 m/s), corresponding to Reynolds number of 1653.173, 1572.196, 995.503 and 477.692. Statistically higher fluid velocity was calculated in 1% and 2.5% NaOCl groups compared to saline group, respectively (p < 0.05). Conclusions: The application of NaOCl and its concentration significantly influence the cavitation effect and fluid dynamics during PIPS activation. 1% and 2.5% NaOCl groups presented a more violent fluid motion in the apical region when activated by PIPS. Keywords: Cavitation Effect; Fluid Velocity; Photon-Induced Photoacoustic Streaming; Sodium Hypochlorite.
 Influence of sodium hypochlorite concentration on cavitation effect and fluid dynamics induced by photon-induced photoacoustic streaming (PIPS): A visualization study

43. In Vitro Comparison of the Wettability of a Bioceramic Root Canal Sealer on Dentin With and Without Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Irradiation

Joshi, P., Shetty, R., Banpurkar, A., Mehta, D.V., Sarode, G., Yedewar, P. & Sharma, T.
Cureus, 2022;14(3), p.e23715.

 
Introduction:
To evaluate and compare the wettability of bioceramic root canal sealer (BioRoot™ RCS, Septodont, Saint-Maur-des-Fossés, France) on dentin with and without erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation using different frequencies and energies. đ
Methods:
A hundred single-rooted tooth samples were divided into five groups of 20 samples each. Each group was treated with different methods before sealer application as follows: Group 1: Treated with 2 ml 17% ethylenediaminetetraacetic acid (EDTA) irrigant for one minute (control group); group 2: Irradiated with Er:YAG laser for one minute (8 Hz frequency and 200mJ energy); group 3: Irradiated with Er:YAG laser for one minute (8 Hz frequency and 400mJ energy); group 4: Irradiated with Er:YAG laser for one minute (16 Hz frequency and 200mJ energy); group 5: (n=20) samples irradiated with Er:YAG laser for one minute (16 Hz frequency and 400mJ energy). Bioceramic root canal sealer application was done onto the treated dentin specimen using a micropipette. The contact angle of the drop of the sealer with the dentin surface was measured after five minutes using a contact angle analyzer.
Results:
There was no significant difference in wettability between Er:YAG laser using 8Hz frequency and 200mJ energy and Er:YAG laser using 8Hz frequency and 400mJ energy. However, there was a significant difference between the other two groups of Er:YAG laser using 16Hz frequency and 400mJ energy and Er: YAG laser using 16Hz frequency and 200mJ energy.
Conclusion:
Contact angle was found to be lowest in the group that was irradiated with Er:YAG laser for one minute (16 Hz frequency and 400mJ energy) before the sealer application. The test findings demonstrated that the control group had the highest contact angle (low wettability) and it was statistically significant with all other groups.
Keywords:
frequency, contact angle, laser, root canal sealer, bioceramic
 In Vitro Comparison of the Wettability of a Bioceramic Root Canal Sealer on Dentin With and Without Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Irradiation

44. The effect of low-level laser therapy as an adjunct to non-surgical periodontal treatment

Aykol, G. et al.
Journal of periodontology, 2011,82(3), pp.481–488.

Background:
The aim of this study is to evaluate the effect of low-level laser therapy (LLLT) as an adjunct to non-surgical periodontal therapy of smoking and non-smoking patients with moderate to advanced chronic periodontitis.
Materials and Methods:
All 36 systemically healthy patients who were included in the study initially received non-surgical periodontal therapy. The LLLT group (n = 18) received GaAlAs diode laser therapy as an adjunct to non-surgical periodontal therapy. A diode laser with a wavelength of 808 nm was used for the LLLT. Energy density of 4 J/cm(2) was applied to the gingival surface after periodontal treatment on the first, second, and seventh days. Each of the LLLT and control groups was divided into two groups as smoking and non-smoking patients to investigate the effect of smoking on treatment. Gingival crevicular fluid samples were collected from all patients and clinical parameters were recorded on baseline, the first, third, and sixth months after treatment. Matrix metalloproteinase-1, tissue inhibitor matrix metalloproteinase-1, transforming growth factor-β1, and basic-fibroblast growth factor levels in the collected gingival crevicular fluid were measured.
Results:
The primary outcome variable in this study was change in gingival bleeding and inflammation. At all time points, the LLLT group showed significantly more improvement in sulcus bleeding index (SBI), clinical attachment level, and probing depth (PD) levels compared to the control group (P <0.001). There were clinically significant improvements in the laser-applied smokers’ PD and SBI levels compared to smokers to whom a laser was not applied, between the baseline and all time points (P <0.001) (SBI score: control group 1.12, LLLT group 1.49; PD: control group 1.21 mm, LLLT group 1.46 mm, between baseline and 6 months). Transforming growth factor-β1 levels and the ratio of matrix metalloproteinase-1 to tissue inhibitor matrix metalloproteinase-1 decreased significantly in both groups at 1, 3, and 6 months after periodontal therapy (P <0.001). Basic-fibroblast growth factor levels significantly decreased in both groups in the first month after the treatment, then increased in the third and sixth months (P <0.005). No marker level change showed significant differences between the groups (P <0.05).
Conclusion:
LLLT as an adjunctive therapy to non-surgical periodontal treatment improves periodontal healing.
 The effect of low-level laser therapy as an adjunct to non-surgical periodontal treatment

45. Treatment of bisphosphonate-induced osteonecrosis of the jaws with Nd:YAG laser biostimulation

Luomanen M, Alaluusua S.
Lasers Med Sci. 2011;27(1):251-255.<> 

 Treatment of bisphosphonate-induced osteonecrosis of the jaws with Nd:YAG laser biostimulation

46. Comparative evaluation of antimicrobial effects of Er:YAG, diode, and CO₂ lasers on titanium discs: an experimental study

Tosun E, Tasar F, Strauss R, Kivanc DG, Ungor C.
J Oral Maxillofac Surg. 2012;70(5):1064-1069.

 
Purpose:
This study examined carbon dioxide (CO(2); 10,600 nm), diode (808 nm), and erbium (Er):yttrium-aluminum-garnet (YAG; 2,940 nm) laser applications on Staphylococcus aureus contaminated, sandblasted, large-grit, acid-etched surface titanium discs and performed a comparative evaluation of the obtained bactericidal effects and the applicability of these effects in clinical practice.
Materials and methods:
This study was carried out in 5 main groups: Er:YAG laser in very short pulse (VSP) emission mode, Er:YAG laser in short pulse (SP) emission mode, diode laser with a 320-nm fiber optic diode laser with an R24-B handpiece, and CO(2) laser. After laser irradiation, dilutions were spread on sheep blood agar plates and, after an incubation period of 24 hours, colony-forming units were counted and compared with the control group, and the bactericidal activity was assessed in relation to the colony counts.
Results:
The CO(2) laser eliminated 100% of the bacteria at 6 W, 20 Hz, and a 10-ms exposure time/pulse with a 10-second application period (0.8-mm spot size). The continuous-wave diode laser eliminated 97% of the bacteria at 1 W using a 10-second application with a 320-μm optic fiber, 100% of the bacteria were killed with a 1-W, 10-second continuous-wave application with an R14-B handpiece. The Er:YAG laser eliminated 100% of the bacteria at 90 mJ and 10 Hz using a 10-second application in a superpulse mode (300-ms exposure time/pulse). The Er:YAG laser also eliminated 99% to 100% of the bacteria in VSP mode at 90 mJ and 10 Hz with a 10-second application.
Conclusions:
The results of this study show that a complete, or near complete, elimination of surface bacteria on titanium surfaces can be accomplished in vitro using a CO(2), diode, or Er:YAG laser as long as appropriate parameters are used.
 Comparative evaluation of antimicrobial effects of Er:YAG, diode, and CO₂ lasers on titanium discs: an experimental study

47. An evaluation of the occluding effects of Er;Cr:YSGG, Nd:YAG, CO₂ and diode lasers on dentinal tubules: a scanning electron microscope in vitro study

Gholami GA, Fekrazad R, Esmaiel-Nejad A, Kalhori KA.
Photomed Laser Surg. 2011;29(2):115-121.

Objective and background:
Dentin hypersensitivity (DH) is one of the most frequent problems causing patients’ complaints following stimulation of cervically exposed dentin. Studies have shown that different lasers have various occluding effects on dentinal tubules. This study is aimed at evaluating the occluding effects of Er;Cr:YSGG (P:0.25W,F:20Hz,Pd:140μS), Nd:YAG (P:1W,F:20Hz), CO(2) (P:1W, Pd:50μs), and 810-nm diode (P:2 W, Pd:30ms) lasers on dentinal tubules.
Materials and Methods:
Fifteen human third molars were collected and ground-sectioned vertically on the buccal and lingual surfaces to yield two dentin disks of 2-mm thickness. Then, four sites for laser irradiation and one control site were marked in the cervical areas of the dentin disks. Before laser application, specimens were exposed to a 14% EDTA solution to expose dentinal tubules and were then evaluated by scanning electron microscopy (SEM). The tubules’ entrance diameters were determined by “scale-bar” software (Phillips Scale-Bar, Phillips, Amsterdam, The Netherlands), which is specifically designed for SEM. The mean diameters for the tubules were then estimated for each site and analyzed statistically.
Results:
The mean dentinal tubule entrance diameters for Er;Cr:YSGG, 810-nm diode, CO(2), and Nd:YAG, were 1.73, 3.27, 2.10, and 1.64 microns, respectively, compared with 3.52 microns before laser irradiation. Overall, the furthest reduction in mean tubule diameter resulted from the Nd: YAG laser (53%). However, tubular diameter reduction in all laser groups (p<0.05) was found to be statistically significant. In all laser groups, melting of the peritubular dentin was the dominant observed phenomenon.
Conclusion: Our results indicate that Nd: YAG, Er; Cr: YSGG, and CO(2) lasers, through their ability to melt peritubular dentin, can occlude dentinal tubules partially or totally, and therefore reduce patients’ hypersensitivity symptoms. The 810-nm diode laser sealed tubules to a far lesser degree, with negligible effects on desensitization.
 An evaluation of the occluding effects of Er;Cr:YSGG, Nd:YAG, CO₂ and diode lasers on dentinal tubules: a scanning electron microscope in vitro study

48.  Early surgical laser-assisted management of bisphosphonate-related osteonecrosis of the jaws (BRONJ): a retrospective analysis of 101 treated sites with long-term follow-up

Vescovi, P. et al.
Photomedicine and laser surgery, 2012b; 30(1), pp.5–13.

Background data:
The management of bisphosphonate-related osteonecrosis of the jaws (BRONJ) is still controversial.
Objective: 
The purpose of this study was to compare surgical and nonsurgical approaches to the treatment of BRONJ and the possible usefulness of Nd:YAG and Er:YAG lasers.
Methods:
One hundred and twenty-eight patients (33 males, 95 females; 52 with diagnosis of multiple myeloma, 53 with diagnosis of bone metastasis, and 23 with diagnosis of osteoporosis) affected by BRONJ were evaluated at the Unit of Oral Pathology and Medicine and Laser-Assisted Surgery of the University of Parma, Italy, between January 2004 and July 2009. Overall number of BRONJ sites was 151, and number of treated sites was 101. In order to assess the efficacy of different treatments, sites were subclassified as follows: Group 1 (G1): 12 sites treated with medical therapy; Group 2 (G2): 27 sites treated with medical therapy associated with low level laser therapy (LLLT); Group 3 (G3): 17 sites treated with a combination of medical and surgical therapy; Group 4 (G4): 45 sites treated with a combination of medical therapy, surgical (including laser-assisted) therapy, and LLLT. Outcome of treatment was assessed using the staging system proposed by Ruggiero et al. Transition from a higher stage to a lower one for at least 6 months was considered as clinical improvement and suggestive of a successful treatment.
Results:
Clinical improvement was achieved in 3 out of 12 (25%) BRONJ sites in G1. Sites if G2 with an improvement were 18 out of 27 (66%). Nine out 17 BRONJ sites (53%) in G3 had a transition to a lower stage after treatment. For sites in G4, a clinical improvement was recorded in 40 out of 45 cases (89%).
Conclusions: 
In our experience, the percentage of success obtained with a combined approach based on medical therapy, surgical (including laser-assisted) therapy, and LLLT (G4) is significantly higher than the percentage of improvement obtained in G1, G2, and G3.
 Early surgical laser-assisted management of bisphosphonate-related osteonecrosis of the jaws (BRONJ): a retrospective analysis of 101 treated sites with long-term follow-up

49. Surgical approach with Er:YAG laser on osteonecrosis of the jaws (ONJ) in patients under bisphosphonate therapy (BPT)

Vescovi, P. Manfredi M, Merigo F, Meleti M, Fomaini C, Rocca JP, Nammour S. 
Lasers in medical science, 2010 ;25(1), pp.101–113.
Background:
Osteonecrosis of the jaw (ONJ) in patients on long-term bisphosphonate Therapy (BPT) has been reported with increasing frequency in literature over the past 4 years. Therapy for this condition is still a dilemma. Temporary suspension of BPT offers no short-term benefits; hyperbaric oxygen has no proven efficacy and therefore is not recommended. Intermittent or continuous antibiotic therapy with surgical debridement can be beneficial to palliate the symptoms. Er:YAG laser can be used to eliminate necrotic bone portions by partial or total resection as an alternative to conventional rotary devices.
Materials and Methods:
In our study, 91 patients affected by ONJ-BP lesion, for a total of 115 ONJ sites were observed between January 2004 and May 2008 (Department of Odontostomatology, University of Parma). Fifty-five ONJ sites were considered for this study in four different groups, retrospectively identified on the basis of treatment performed (G1-G4). G1: 13 ONJ-BP sites were treated with medical therapy (amoxicillin 1gr x 3/die per os with metronidazole 250 mg x 2/die per os) for at least 2 weeks; G2: 17 ONJ-BP sites received medical treatment in association with cycles of low-level laser therapy (LLLT) applications performed using an Nd:YAG laser (1,064 nm) once a week for 2 months; G3: 13 ONJ-BP sites were surgically treated (sequestrectomy of necrotic bone, debridement, corticotomy/surgical removal of alveolar and/or cortical bone); G4: 12 ONJ-BP sites were treated with surgical therapy performed using an Er:YAG laser (2,940 nm) in association with LLLT.
Results:
Clinical success has been defined for each treatment performed as: (a) complete mucosal healing free from signs and symptoms (classified as stage “0”) or (b) transition from a higher to a lower stage (Ruggiero staging) for at least 3 months. All the ONJ-BP sites treated with Er:YAG laser (G4 group) had a clinical improvement (100%) and 87.5% of sites had a complete mucosal healing with a mean follow-up of 13 months. The result obtained in the G4 is extremely significant in comparison with those obtained by medical treatment alone or in a traditional surgical approach. Thanks to the high degree of affinity of this wavelength for water and hydroxyapatite, both soft and bone tissues can be easily treated. This technique can also be used for conservative operations whereby necrotic bone is vaporized until healthy bone is reached. In addition, an additional advantage of the Er:YAG laser is its bactericidal and possible biostimulatory action, accelerating the healing of both soft tissues and bone tissues, in comparison to conventional treatments.
Conclusion:
In conclusion, from our experience, it is possible to observe that an early conservative surgical approach with Er:YAG laser associated with LLLT, for BP-induced ONJ could be considered as more efficient in comparison with medical therapy or other conventional techniques.
 Surgical approach with Er:YAG laser on osteonecrosis of the jaws (ONJ) in patients under bisphosphonate therapy (BPT)

50. Osteonecrosis of the jaws caused by bisphosphonates: evaluation of a new therapeutic approach using the Er:YAG laser

Angiero F, Sannino C, Borloni R, Crippa R, Benedicenti S, Romanos GE.
Lasers Med Sci. 2009;24(6):849-856.
Background:
A series of 49 patients diagnosed with osteonecrosis and all treated with latest-generation bisphosphonates was reviewed retrospectively to evaluate the use of erbium-doped: yttrium, aluminum, and garnet laser (Er:YAG) in terms of clinical outcome, and examine current trends from the clinical-therapeutic standpoint.
Materials and Methods:
Pathology reports on specimens submitted over the previous 7 years from either the mandible or the maxilla were reviewed; 49 patients were identified as having osteonecrosis of the jaws. For each of these cases, the medical history and profile were evaluated; 19 were treated with conservative therapy, 20 with radical surgery, and 10 with Er:YAG laser (2,940 nm).
Results:
Of the 20 patients treated surgically (bone baquette, curettage, sequestrectomy of the necrotic bone), some required re-treatment, which resulted in bone fracturing. None of the patients were treated successfully. The 19 cases treated conservatively produced an improvement in symptoms, but not remission of the lesions. Of the ten patients treated with Er:YAG laser, six achieved total remission of signs and symptoms, four an improvement, and re-treatment was required in one case. Our present approach is to recommend intensive prophylactic care before the administration of bisphosphonates, and great caution is advised even in simple maneuvers like curettage, because this may exacerbate the avascular process.
Conclusion:
The use of Er:YAG laser appears to be promising (within the limits of our experience). It can be concluded that at 1 year of laser surgery, the treatment led to significant improvements in clinical parameters, and may represent a valid alternative, although studies on a larger scale are needed.
 Osteonecrosis of the jaws caused by bisphosphonates: evaluation of a new therapeutic approach using the Er:YAG laser

51. En face optical coherence tomography investigation of apical microleakage after laser-assisted endodontic treatment

Todea C, Balabuc C, Sinescu C, et aL.
Lasers Med Sci. 2010;25(5):629-639.

Background:
The aim of our study was to evaluate the potential of en face optical coherence tomography (OCT) for the detection of apical microleakage after 980 nm and 1,064 nm laser-assisted endodontic treatment. Ninety, human, single-rooted teeth with one straight root canal and closed apices were used. All roots were prepared biomechanically to the working length at an apical size 30 and 0.06 taper.
Materials and Methods:
The teeth were divided into three equal groups of 30 samples each, according to the treatment to be applied to the root canal. Group I received 980 nm diode laser (3 W, 0.01 s on time, 0.01 s off time, 5 s per procedure, four procedures); group II received neodymium:yttrium-aluminum-garnet (Nd:YAG) laser (1.5 W, 15 Hz, 5 s per procedure, four procedures). In group III the root canals were approached conventionally only. In all groups the root canal filling was performed with AH Plus endodontic sealer and gutta-percha points.
Results:
An en face OCT prototype was used for the investigation of apical microleakage. According to one-way analysis of variance (ANOVA) and en face OCT, the number of defects in the laser groups was significantly lower (P < 0.005) than in the control group. No statistical differences were noted between the laser groups (P = 0.049). En face OCT imaging proved that laser-assisted endodontic treatment improved the prognosis of root canal filling and led to a reduction in apical microleakage.
 En face optical coherence tomography investigation of apical microleakage after laser-assisted endodontic treatment

52. Ex vivo evaluation of antibacterial effects of Nd:YAG and diode lasers in root canals.

Gerek M, Asci S, Yaylali DI
Biotechnol Biotechnol Equip. 2010;24(3):2031-2034.

Background:
The presence of necrotic tissue and bacteria may cause the persistence of infection in root canals. The aim of this study is to compare the antibacterial efficacy of standard irrigating procedures with 2.5% NaOCl and 17% EDTA using the laser techniques of Nd:YAG and Diode lasers on 176 extracted single-rooted teeth.
Strains of Enterococcus faecalis and Candida albicans were used. After the tests were performed, the number of colony-forming units per milliliter (CFU/ml) was counted and the results were statistically analyzed.
According to the data evaluated, although EDTA, Nd: YAG, and Diode lasers were effective as a bactericidal agent in contaminated root canals, NaOCl had a significantly higher antibacterial effect. The Nd:YAG and Diode lasers showed more antimicrobial effect than EDTA in the E. faecalis group while the Nd:YAG and Diode lasers and EDTA showed the same level of antimicrobial action in the C. albicans group.
 Ex vivo evaluation of antibacterial effects of Nd:YAG and diode lasers in root canals.

53. Treatment of large vascular lesions in the orofacial region with the Nd:YAG laser

Vesnaver A, Dovšak DA.
J Cranio-Maxillofacial Surg. 2009;37(4):191-195.

 
Introduction:
Large vascular lesions in the orofacial region are often very difficult to remove. In the 1990s, the neodymium: yttrium-aluminum-garnet (Nd:YAG) laser emerged as a new and effective mode of treatment for vascular lesions. The purpose of this paper was to determine its effectiveness and safety for the treatment of large vascular lesions in the orofacial region.
Patients and methods:
A prospective study was conducted in which 28 patients with large vascular lesions (their surface diameters being more than 3 × 3 cm) in the orofacial region were treated with the Nd:YAG laser by photocoagulation (PhC). Four different modalities of treatment were used: simple transmucosal PhC, transmucosal PhC with the use of compression, simple intralesional PhC, and ultrasound guided intralesional PhC. Follow up was conducted in all of the cases, time until complete healing was recorded, as were postoperative complications.
Results:
In all of the patients undergoing transmucosal PhC (simple or with the use of compression), tissue sloughing occured within 1–3 days, and the time until complete healing was 3–5 weeks. In patients undergoing intralesional PhC (simple or ultrasound guided), swelling was present for 1 week. There were no cases of inadvertent bleeding. Nine patients required two or more sessions of PhC. Three patients required a corrective surgical procedure as the final step. Two patients required prolonged intubation and one patient a temporary tracheostomy, all due to oedema. Two patients developed a local intraoral infection, which was controlled with broad-spectrum oral antibiotics.
Conclusion:
If used properly, the Nd:YAG laser is a safe and effective tool for the treatment of large vascular lesions.
 Treatment of large vascular lesions in the orofacial region with the Nd:YAG laser

54. Nd:YAG laser biostimulation in the treatment of bisphosphonate-associated osteonecrosis of the jaw: clinical experience in 28 cases

Vescovi, P. et al.
Photomedicine and laser surgery. 2008. 26(1), pp.37–46.

 
Objective:
To research an efficient treatment for the management of bisphosphonate-associated osteonecrosis. Background data: Necrosis of the jawbone has recently been described in association with systemic bisphosphonate therapy with drugs including zoledronic acid, pamidronate, and alendronate. The extent and clinical characteristics of bisphosphonate-associated osteonecrosis (BON) of the jaw are extremely variable, and range from the presence of fistulae in the oral mucosa or orofacial tissues, to large exposed areas of necrotic bone within the oral cavity. Clinical signs and symptoms commonly reported include pain, swelling, the presence of pus, loose teeth, ill-fitting dentures, and paresthesias of the inferior alveolar nerve when the necrosis affects the mandible. Fractures have also been reported. The treatment of BON of the jaw is still controversial since no therapy has proven to be efficacious as shown by the literature on the subject.
Materials and methods:
In this study we report results achieved with 28 patients affected by BON of the jaw, who received treatment with the Nd:YAG laser alone or in combination with conventional medical or surgical treatment. Clinical variables such as severity of symptoms, presence of pus, and closure of mucosal flaps before and after therapy were evaluated to establish the effectiveness of laser irradiation. The 28 patients with BON were subdivided into four groups: eight patients were treated with medical therapy only (antibiotics with or without antimycotics and/or antiseptic rinses), six patients were treated with medical and surgical therapy (necrotic bone removal and bone curettage), six patients were treated with medical therapy associated with laser biostimulation, and eight patients were treated with medical therapy associated with both surgical therapy and laser biostimulation.
Results:
Of the 14 patients who underwent laser biostimulation, nine reported complete clinical success (no pain, symptoms of infection, or exposed bone or draining fistulas), and three improved their symptomatology only, with a follow-up of between 4 and 7 mo. Conclusions: While the results reported in this study are not conclusive, they indicate that laser therapy has potential to improve management of BON.
 Nd:YAG laser biostimulation in the treatment of bisphosphonate-associated osteonecrosis of the jaw: clinical experience in 28 cases

55.  Histomorphometrical and radiological comparison of low-level laser therapy effects on distraction osteogenesis: experimental study.

Kan, B. et al.
Lasers in medical science, 2014; 29(1), pp.213–220.

Background:
Distraction osteogenesis (DO) is the application of traction to the callus formed between bone segments and stimulation of bone formation by creating stress on the callus with this traction. Shorten the duration of DO and increasing the capacity of bone formation is important to prevent the possible complications of DO. For this reason, it was considered that low-level laser therapy (LLLT) may affect positively DO and it can decrease the complication range by shortening the period. Unilateral mandibular distractors were applied on 16 female white New Zealand rabbit to prove this hypothesis with micro CT, plain radiograph and histomorphometric analyses. Eight rabbits were applied LLLT with GaAlAs laser on the distraction area during the distraction period. On the post-distraction 28th day, four rabbits from study group and four rabbits from control groups were sacrificed. The rest of the rabbits were sacrificed on post-distraction 56th day. As a result of this study, significant positive effects of LLLT on post-distraction 28th day were revealed with all analyses. In histomorphometrical analyses, new bone formation was significantly higher in short-term laser applied group comparing to that of short-term control group (p = 0.029). In both microCT and plain radiograph, the highest radioopacity values were observed in short-term laser group when compared with that of the controls (p = 0.043 and p = 0.025, respectively). Even though LLLT increased the healing capacity on short-term, it was not sufficient on long-term (post-distraction 56th day) healing. LLLT application on distraction period, activate healing on bone so it may decrease DO period. The result of this study should be supported with clinical studies and the most effective laser source, dose and application time should be revealed with experimental and clinical studies.
 Histomorphometrical and radiological comparison of low-level laser therapy effects on distraction osteogenesis: experimental study.

56. Comparison of Er:YAG laser and surgical drill for osteotomy in oral surgery: an experimental study

Gabrić Pandurić, D., Bago, I., Katanec, D., Žabkar, J., Miletić, I. & Anić, I.
Journal of Oral and Maxillofacial Surgery, 70(11), pp.2515–2521.

 
Purpose: 
High-energy lasers have been proposed as an alternative to the conventional surgical drill in oral and maxillofacial surgery. The aims of this study were to compare thermal changes of the bone surface, procedure time, and volume of the removed bone after drilling with an erbium (Er):yttrium-aluminum-garnet (YAG) laser versus a low-speed surgical drill. The bone sections were observed under light microscopy and examined histologically.
Material and methods: 
Thirty bone blocks were prepared from porcine ribs. On each block 2 holes (tunnel preparations) were performed using a low-speed, 1.0-mm-wide, surgical pilot drill and an Er:YAG laser (pulse energy, 1,000 mJ; pulse duration, 300 μs; frequency, 20 Hz). The temperature induced by the preparation techniques was measured using an infrared camera. The removed bone volume was calculated by a modified mathematical algorithm. The time required for the preparation was measured with a digital stopwatch and a time-measurement instrument integrated within the computer program. The cortical and spongiose surfaces of the specimens were examined microscopically and histologically under a light microscope with a high-resolution camera.
Results: 
The Er:YAG laser removed significantly more bone tissue than the drill (P < .01) in a significantly shorter time (P < .01). The temperature was statistically lower during the laser preparation (P < .01). Cavities prepared with the laser were regular with clear sharp edges and knifelike cuts. In the drill group, the preparations exhibited irregular edges full of bone fragments and fiberlike debris. Histologic examination of the laser sides showed a 30-μm-thick altered sublayer. The tissue in the drill group was covered with a smear layer without any alterations.
Conclusions:
The Er:YAG laser produced preparations with regular and sharp edges, without bone fragments and debris, in a shorter time, and with less generated heat. Thermal alterations in the treated surface were minimal.
 Comparison of Er:YAG laser and surgical drill for osteotomy in oral surgery: an experimental study

57. Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study

Vescovi, P. et al.
Medicina Oral Patología Oral y Cirugia Bucal, 2012;17(4), pp.e697–e704.

 
Objective: 
Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters.
Study Design:
Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) on a surface of 4 cm2 with a Nd:YAG laser (VSP mode, 320 micrometer fiber, defocused mode) with different parameters. Temperatures were recorded before and after laser applications and after each pause in order to evaluate also the thermal relaxation of tissues.
Results:
At submucosal level, mean thermal increase was between 1.1°C and 13.2°C, at 1 mm depth between 1.1°C and 8.5°C, at 2 mm depth between 1.1°C and 6.8°C, at 4 mm depth between 1.0°C and 5.3°C. Temperature decrease during the rest time period was variable between 0°C and 2.5°C. Conclusions: Temperatures reached during clinical procedures with parameters reported in the literature in biostimulation protocols (1.25-2 Watts) for the five minutes of application are not dangerous for biological structures. The decrease in temperature during the rest time period is less considerable in the bone in comparison to oral mucosa. Key words:Nd:YAG laser, thermal increase, thermocouple, thermal camera, low level laser therapy.
 Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study

58. Effect of low level laser therapy and zoledronate on the viability and ALP activity of Saos-2 cells

Bayram, H., Kenar, H., Taşar, F. & Hasırcı, V.
International journal of oral and maxillofacial surgery, 42(1), pp.140–146.

Background:
A limited number of clinical studies indicate the supportive role of low level laser therapy (LLLT) on medical and/or surgical approaches carried out in treatment modalities for bisphosphonate related necrosis of jaws (BRONJ), the most common side effect of bisphosphonates used to inhibit bone resorption. The purpose of this study was to investigate the effects of LLLT on cell proliferation and alkaline phosphatase (ALP) activity of human osteoblast-like cells (Saos-2) treated with different doses of zoledronate, the most potent bisphosphonate. Saos-2 cells were treated with different concentrations of zoledronate and were irradiated with diode laser (wavelength 808 nm, 10 s, 0.25 or 0.50 W). Cell numbers and ALP activity of the cells were determined. LLLT mildly increased the proliferation rate or ALP activity, while zoledronate reduced both. When applied together, LLLT lessened the detrimental effects of zoledronate and improved cell function and/or proliferation. Based on the results of this study, it was concluded that LLLT has biostimulative effects on Saos-2 cells, even after treatment with zoledronate. LLLT may serve as a useful supportive method for BRONJ treatment through enhancement of healing by osteoblasts.
 Effect of low level laser therapy and zoledronate on the viability and ALP activity of Saos-2 cells

59. Bisphosphonate-related osteonecrosis: laser-assisted surgical treatment or conventional surgery?

Atalay B, Yalcin S, Emes Y, et al.
Lasers Med Sci. 2011;26(6):815-823.

 
Background:
Bisphosphonates (BSPs) are used for the treatment of multiple myeloma, metastatic breast and lung cancer, Paget’s disease, osteoporosis, hypercalcemia due to malignancy, and many other skeletal diseases. BSPs reduce osteoclastic functions, which result in bone resorption. Bisphosphonates-related osteonecrosis of jaws (BRONJ) is a newly developed term that is used to describe the significant complication in patients receiving bisphosphonates. BSPs are known to exhibit an anti-angiogenetic effect that initiates tissue necrosis of the hard tissue. There is currently no consensus on the correct approach to this issue.
Aim:
The aim of this retrospective study is to compare the effects of laser surgery with biostimulation to conventional surgery in the treatment of BSP-induced avascular bone necrosis on 20 patients who have been treated in our clinic. BRONJ was evaluated in patients with lung, prostate, and breast cancer under intravenous BSP treatment. Twenty patients in this study developed mandibular or maxillary avascular necrosis after a minor tooth extraction surgery or spontaneously. Bone turnover rates were evaluated by serum terminal C-telopeptide levels (CTX) using the electrochemiluminescence immunoassay technique and patients were treated with laser or conventional surgical treatments and medical therapy.
Materials and Methods:
Ten patients were treated with laser surgery and biostimulation. An Er:YAG laser (Fotona Fidelis Plus II® Combine laser equipment, Slovenia) very long pulse (VLP) mode (200 mJ, 20 Hz) using a fiber tip 1.3 mm in diameter and 12 mm in length was used to remove the necrotic and granulation tissues from the area of avascular necrosis. Biostimulation was applied postoperatively using an Nd:YAG laser. Low-level laser therapy (LLLT) was applied to the tissues for 1 min from 4 cm distance using an Nd:YAG laser (Fotona-Slovenia) with a R24 950-µm fiber handpiece long-pulse (LP) mode, 0.25-W, 10 Hz power/cm(2) from the mentioned distance the spot size was 0.4 cm(2), and power output was 2.5 J. Energy density from the mentioned distance was calculated to be 6.25 J/cm(2). The other ten patients were treated with conventional surgery. Treatment outcomes were noted as either complete healing or incomplete healing.
Results:
There were no statistically significant differences between laser surgery and conventional surgery (p > 0.05). CTX values also did not affect the prognosis of the patients. Treatment outcomes were significantly better in patients with stage II osteonecrosis than in patients with stage I osteonecrosis. Our findings suggest that dental evaluation of the patients prior to medication is an important factor in the prevention of BRONJ. Laser surgery is a beneficial alternative in the treatment of patients with this situation. Further randomized studies with larger patient numbers may also improve our understanding of treatment protocols for this situation. Similar articles
 Bisphosphonate-related osteonecrosis: laser-assisted surgical treatment or conventional surgery?

60.  Nd:YAG laser photocoagulation of benign oral vascular lesions: a case series

Medeiros Jr R, Silva IH, Carvalho AT, Leão JC, Gueiros LA.
Lasers Med Sci. 2015;30(8):2215-2220.

Background:
Vascular anomalies of the head and neck are common lesions usually associated with functional and/or aesthetic limitations. The aim of the present paper was to report a case series of oral vascular malformations treated with Nd:YAG laser photocoagulation, highlighting the clinical evolution and post-surgical complications. Fifteen patients diagnosed with oral vascular malformations were treated with Nd:YAG laser followed by three sessions of biostimulation. None of the patients presented post-surgical pain, but 6 of 15 patients (40%) experienced minimal post-surgical complications. All cases presented complete resolution of the lesions after laser treatment. More importantly, 12 out of 15 (80%) resolved after a single session. Low morbidity, minimal patient discomfort, and satisfactory aesthetic results point Nd:YAG laser photocoagulation as a promising option for the management of benign oral vascular lesions.
Keywords: Laser surgery; Nd-YAG lasers; Nonablative laser treatment; Vascular malformations.
 Nd:YAG laser photocoagulation of benign oral vascular lesions: a case series

61.  Er:YAG Laser Versus Cold Knife Excision in the Treatment of Nondysplastic Oral Lesions: A Randomized Comparative Study for the Postoperative Period

Broccoletti R, Cafaro A, Gambino A, Romagnoli E, Arduino PG.
Photomed Laser Surg. 2015;33(12):604-60.
Objective:
The aim of this prospective study was to estimate the effects of Erbium substituted: Yttrium Aluminium Garnet (Er:YAG) laser, compared with traditional scalpel, on the early postoperative sequelae of nondysplastic oral lesion removal.
Background data:
There is limited evidence that laser surgery could exhibit advantages over scalpel in oral mucosal surgery.
Methods:
The investigators studied a cohort of 344 patients; 394 lesions were randomized and treated. Outcome statistically evaluated variables were: age, gender, the site and size of investigated lesions, visual analogue score (VAS) of pain, the Oral Health Impact Profile questionnaire (OHIP-14) and the Quality of Life test (QOL), and number of analgesics taken in the 1st week after surgery.
Results:
Significant differences were found if considering the surgical time, VAS, and QOL and OHIP-14 questionnaires; regarding those data,the Er:YAG laser appeared to be faster and less painful than traditional scalpel (p < 0.05). For bigger lesions, patients statistically took more painkillers if they had undergone traditional surgery. Considering the site of the treated lesions, Er:YAG laser was less painful, especially in the gingiva and palate (p < 0.05).
Conclusions:
This is the first randomized controlled surgical trial reported for the management of nondysplastic oral lesions with the use of an Er:YAG laser. With many limitations, the present report identifies significant difference in the immediate postoperative surgical period between the two treatments, meaning that the Er:YAG laser seemed to be less painful, and better accepted by patients, than traditional scalpel.
 Er:YAG Laser Versus Cold Knife Excision in the Treatment of Nondysplastic Oral Lesions: A Randomized Comparative Study for the Postoperative Period

62. Use of an Er:YAG Laser for Pulpotomies in Vital and Nonvital Primary Teeth

Kotlow L.
J Laser Dent,2008; 16(2): 75-79.

Background:
Pulp therapy for vital and nonvital primary teeth usually involves the use of chemical agents, such as formocresol, or electrocautery. This article reviews the results of using the Er:YAG laser to achieve similar results. Clinical and radiographic evidence indicates that using the Er:YAG laser results in safe, successful treatment of pulpotomies in primary teeth, similar to the successful treatment of other modalities.
 Use of an Er:YAG Laser for Pulpotomies in Vital and Nonvital Primary Teeth

63. Effect of different laser-assisted irrigation activation techniques on apical debris extrusion

Doğanay Yıldız E, Dinçer B, Fidan ME
Acta Odontol Scand. 
2020;78(5):332-336.
 
Objective:
The aim of this study was to compare apical debris extrusion when neodymium-doped yttrium aluminium garnet (Nd:YAG) lasers, erbium-doped yttrium aluminium garnet (Er:YAG) or photon-induced photoacoustic streaming (PIPS) are used for irrigation activation.
Materials and methods:
A total of 60 extracted human mandibular premolar teeth have similar dimensions were included and the samples were split into four groups according to the irrigation technique (n = 15): conventional needle irrigation, PIPS, Er:YAG and Nd:YAG. ProTaper Universal system up to F4 was used for root canal instrumentation. Bidistilled water was used as an irrigation solution during instrumentation and irrigation activation. Apically extruded debris was collected into preweighed Eppendorf tubes during instrumentation and irrigation activation procedures. The tubes were then kept in an incubator at 70 °C for 5 days. The initial weight of the tube was subtracted from the final weight and the result was recorded as the weight of dry extruded debris. The data were evaluated statistically using a one-way ANOVA test followed by least significant difference post hoc test (p < .05).
Results:
Conventional needle irrigation caused significantly less debris extrusion than laser-assisted irrigation activation groups (p < .05). Laser-assisted irrigation activation groups caused statistically similar debris extrusion (p > .05).
Conclusion: Laser-assisted irrigation activation techniques caused more debris extrusion when compared to conventional needle irrigation.
Keywords: Irrigation; debris; laser-assisted irrigation activation.
 Effect of different laser-assisted irrigation activation techniques on apical debris extrusion

64. Comparison of apical irrigant solution extrusion among conventional and laser-activated endodontic irrigation

Vidas J, Snjaric D, Braut A, et al.
Lasers Med Sci. 2020;35(1):205-211.

 
Background:
The aim of this study was to determine the amount of extruded endodontic irrigant among needle-syringe irrigation (NSI) and laser-activated irrigation (LAI) regimens.
Materials and Methods:
Twenty extracted maxillary central incisors were prepared utilizing GT professional rotary files (size 40, taper 0.06). Irrigation was performed with two 27 G irrigation needles (notched open ended (ON) and single side vented (SV)) each at two different irrigant volumetric flow rates (VFR)-0.05 ml/s (3 ml/min) and 0.10 ml/s (6 ml/min). LAI was performed with Er:YAG (erbium-doped yttrium aluminum garnet) using different fiber types (X-Pulse-14/400 cylindrical tip, Preciso- 14/300 flat cylindrical tip, PIPS- 14/400 quartz tapered tip). The Er:YAG laser with a wavelength of 2940 nm (Lightwalker AT, Fotona, Ljubljana, Slovenia) was used according to the following protocol: 10 mJ per pulse, 15 Hz, pulse duration 50 μs. Irrigation time was 60 s for all protocols. Precision syringe pump (PSP) maintained constant irrigant volumetric flow rate. Apically extruded irrigant was collected and net weighed for each protocol (N = 10). Data were analyzed by t tests and Kruskal-Wallis. All LAI regimens had statistically significant lower irrigant extrusion compared with NSI except for the SV 27 G needle used with 0.05 ml/s VFR when compared with the Preciso fiber tip (p = 0,230).
Results:
The largest amount of extruded irrigant was with the ON 27 G needle at the 0.10 ml/s VFR, while the smallest was after LAI with PIPS fiber tip. The lower quantity of apically extruded irrigant during LAI (X-Pulse and PIPS) points out a safer endodontic irrigation method compared with conventional irrigations.
Keywords: 
Endodontics; Er YAG laser; Laser-activated irrigation; Root canal irrigants; Sodium hypochlorite.
 Comparison of apical irrigant solution extrusion among conventional and laser-activated endodontic irrigation

65. Micro-CT study on the removal of accumulated hard-tissue debris from the root canal system of mandibular molars when using a novel laser-activated irrigation approach

Yang Q, Liu MW, Zhu LX, Peng B.
Int Endod J. 2020;53(4):529-538.

Aim: 
To compare the efficacy of ultrasonically activated irrigation (UAI), photon-induced photoacoustic streaming (PIPS) and shock wave enhanced emission photoacoustic streaming (SWEEPS) activation for the removal of accumulated hard-tissue debris (AHTD) from the root canal system of mandibular molars when assessed using microcomputed tomography (micro-CT).
Methodology: 
A total of 30 mandibular first and second molars with joining mesial root canals containing an isthmus and a single distal canal were subjected to three micro-CT scans (before and after canal instrumentation and after final irrigation) at a resolution of 15 μm. Mesial canals were prepared up to a ProTaper F3 rotary file, and distal canals were prepared up to a ProTaper F4 rotary file. Teeth were randomly assigned to three groups according to the irrigant activation method (n = 10): the UAI group, the PIPS group and the SWEEPS group. The final irrigation procedures were performed using a total of 15.5 mL of 1% NaOCl for each tooth with an activation time of 3 × 30 s. After three-dimensional model reconstruction and volumetric measurement of root canals, the percentage reduction (%Rd) of AHTD was calculated. The %Rd of AHTD was analysed statistically using one-way analysis of variance and nonparametric tests at a significance level of 5%.
Results: 
There were no significant differences between the three groups in terms of canal volume before or after instrumentation, or the volume of debris after canal preparation (P > 0.05). In the mesial canals, irrigation with SWEEPS reduced the overall debris by 84.31%, which was significantly more than the reduction associated with PIPS and UAI (58.79% and 50.27%, respectively). In the distal canals, the %Rd of AHTD was significantly different between PIPS and SWEEPS and between UAI and SWEEPS (P < 0.05), but was not significantly different between PIPS and UAI groups (P > 0.05). The SWEEPS was associated with a greater %Rd of AHTD than the PIPS and UAI groups.
Conclusions: 
SWEEPS was associated with significantly less debris compared than PIPS and UAI, especially in isthmus-containing mesial roots. None of the activation techniques completely removed debris from root canal systems.
Keywords: hard-tissue debris; irrigation; photoacoustic streaming; ultrasonic.
 Micro-CT study on the removal of accumulated hard-tissue debris from the root canal system of mandibular molars when using a novel laser-activated irrigation approach

66. Does the Photon-Induced Photoacoustic Streaming Activation of Irrigation Solutions Alter the Dentin Microhardness?

Akbulut MB, Terlemez A. 
Photobiomodulation, photomedicine, laser Surg. 2019;37(1):38-44.

 
Objective:
The aim of this in vitro study was to evaluate the efficacy of photon-induced photoacoustic streaming (PIPS) activation of sodium hypochlorite (NaOCl), chlorhexidine (CHX) or ethylenediaminetetraacetic acid (EDTA) on the dentin microhardness and to assess the compositional changes of root dentin.
Background data:
It is still unclear whether PIPS activation of irrigants alters the dentin microhardness and mineral content of dentin.
Materials and methods:
 Root canals of 72 extracted single-rooted teeth were prepared and teeth were fixed in microcentrifuge tubes with silicone impression material. After setting of the silicone, teeth were removed and split longitudinally in buccolingual direction. One half was used as control (pretreatment) while the other was placed into the tube (posttreatment). Then specimens were divided into six test groups (three with and three without PIPS activation). The irrigants tested were 2.5% NaOCl, 17% EDTA, and 2% CHX. Experimental tooth specimens were irrigated with 6 mL of test solution, with additional PIPS activation applied to the PIPS groups. Then specimens were subjected to Vickers microhardness testing. Percentage change of microhardness was calculated. Energy dispersive X-ray spectroscopy (SEM-EDX) was performed to measure element content.
Results:
Among the irrigant-alone groups, NaOCl and CHX did not alter the dentin microhardness, whereas statistically lower microhardness values were obtained in EDTA group. Chemical composition of dentin was affected from all irrigants used. PIPS activation led to no additional alteration in dentin microhardness. PIPS significantly increased the phosphorus level in NaOCl group.
Conclusions: Dentin microhardness was significantly affected by the irrigation solution, not by the PIPS activation.
 Does the Photon-Induced Photoacoustic Streaming Activation of Irrigation Solutions Alter the Dentin Microhardness?

67. Does the Photon-Induced Photoacoustic Streaming Activation of Irrigation Solutions Alter the Dentin Microhardness?

Akbulut MB, Terlemez A.
Photobiomodulation, photomedicine, laser Surg. 2019;37(1):38-44.

Objective:
The aim of this in vitro study was to evaluate the efficacy of photon-induced photoacoustic streaming (PIPS) activation of sodium hypochlorite (NaOCl), chlorhexidine (CHX) or ethylenediaminetetraacetic acid (EDTA) on the dentin microhardness and to assess the compositional changes of root dentin.
Background data:
It is still unclear whether PIPS activation of irrigants alters the dentin microhardness and mineral content of dentin.
Materials and methods:
 Root canals of 72 extracted single-rooted teeth were prepared and teeth were fixed in microcentrifuge tubes with silicone impression material. After setting of the silicone, teeth were removed and split longitudinally in buccolingual direction. One half was used as control (pretreatment) while the other was placed into the tube (posttreatment). Then specimens were divided into six test groups (three with and three without PIPS activation). The irrigants tested were 2.5% NaOCl, 17% EDTA, and 2% CHX. Experimental tooth specimens were irrigated with 6 mL of test solution, with additional PIPS activation applied to the PIPS groups. Then specimens were subjected to Vickers microhardness testing. Percentage change of microhardness was calculated. Energy dispersive X-ray spectroscopy (SEM-EDX) was performed to measure element content.
Results:
Among the irrigant-alone groups, NaOCl and CHX did not alter the dentin microhardness, whereas statistically lower microhardness values were obtained in EDTA group. Chemical composition of dentin was affected from all irrigants used. PIPS activation led to no additional alteration in dentin microhardness. PIPS significantly increased the phosphorus level in NaOCl group.
Conclusions: Dentin microhardness was significantly affected by the irrigation solution, not by the PIPS activation.
 Does the Photon-Induced Photoacoustic Streaming Activation of Irrigation Solutions Alter the Dentin Microhardness?

68. A Comparative Analysis Regarding the Osseointegration of Immediate Loaded Implants Using Two Different Implant Site Preparations: Erbium:Yttrium-Aluminum-Garnet Laser Versus Surgical Conventional Way-An In Vivo and Histological Animal Study

Semez, G., Cescato, A., Luca, R.E., Tonetti, L. & Todea, D.C.
Photobiomodulation, photomedicine, and laser surgery, 39(1), pp.70–80.

 
Objective:
The aim of the study is to evaluate the possibility of preparing the implant site using the erbium:yttrium-aluminum-garnet (Er:YAG) laser scanner prototype and to reduce and/or eliminate time between primary (mechanical) stability and secondary (biological) stability, looking to the immediate occlusal loading in a single implant. Background: A prerequisite for successful osseointegration is the establishment of direct bone-to-implant contact without interposition of nonbone or connective tissue. In recent years, the use of laser radiation was presented as an alternative/adjunctive treatment for bone tissue ablation due to vaporization of the tissues in the absence of a smear layer.
 Methods:
The experimental protocol included six minipigs, which underwent tooth extraction, followed (after 2 months) by implant bed preparation in two methods: using a conventional bur kit and using an Er:YAG laser scanner (X runner) protocol. Four implants were placed in positions 34, 37, 44, and 47 on each animal. The animals underwent the second surgical procedure for bone sample collection (including the implant) before their sacrifice at 45-60-90-120 days. The newly formed bone was evaluated on the bone samples using histological examination and quantitative evaluations of different histological parameters based on microscopical analysis.
Results: The results that we obtained allow some interesting comparison in terms of different bone composition, depending on the method of implant site preparation and on healing periods. Moreover, it was possible to compare the bone composition, at different time stages, of implant sites prepared in the same way.
Conclusions:
Our research allowed us to demonstrate that the use of Er:YAG laser compared with traditional drill leads to the presence of a greater share of lamellar bone and a lower necrotic share in the implant site. We also showed the possibility of applying immediate occlusal loading on an in vivo animal model.
Keywords: Er:YAG laser; biological stability; bone-to-implant contact; osseointegration; primary stability.
 A Comparative Analysis Regarding the Osseointegration of Immediate Loaded Implants Using Two Different Implant Site Preparations: Erbium:Yttrium-Aluminum-Garnet Laser Versus Surgical Conventional Way-An In Vivo and Histological Animal Study

69. Evaluation of the shear bond strength of resin cement to enamel after bleaching with Er: YAG and diode laser

Ceyda, A., Müjde, S., Yusuf, O.O. & Neslihan, C.
Advanced Composites Letters, 2020;29, pp.1–7.

Objective:
The shear bond strength (SBS) of composite resin cement and color change to enamel bleached with two different concentrations of hydrogen peroxide (HP) bleaching agents in combination with two different laser applications was evaluated.
Materials and Methods:
The Er: YAG laser (λ = 2940 nm) and diode laser (λ = 940 nm) were used with the bleaching agent consisting of 40% HP opalescence (Opalescence Xtra Boost, Ulgen, South Jordan, UT, USA) and 35% HP whiteness (Whiteness HP Blue, FGM Dental Products, Joinville, SC, Brazil). Seventy-two human extracted teeth were randomly divided into two groups: For the 40% HP treatment, 36 specimens were divided into three subgroups: (1) HP agent with no laser treatment, (2) HP agent treated with Er: YAG laser, and (3) HP agent treated with diode laser. The same protocol was performed for the 35% HP. The color change was analyzed using the Commission Internationale de l’ Eclairage (CIE) L*a*b* system and surface roughness was analyzed by an atomic force microscope. The specimens were bonded with resin cement and a shear bond test was performed at 0.5 mm/min. The failure surfaces were evaluated using scanning electron microscope analysis.
Results:
ΔE value of the 40% HP + Er: YAG group was significantly higher than the other groups while diode groups showed the lower SBS values than the control groups (p < 0.05).
Conclusion:
The Er: YAG laser with 40% HP may be effective for the brighter teeth and the use of Er: YAG laser produced higher adhesion between enamel and resin cement than diode laser.
 Evaluation of the shear bond strength of resin cement to enamel after bleaching with Er: YAG and diode laser

70. Removal of Composite Restoration from the Root Surface in the Cervical Region Using Er: YAG Laser and Drill-In Vitro Study

Zakrzewski, W., Dobrzynski, M., Kuropka, P., Matys, J., Malecka, M., Kiryk, J., Rybak, Z., et al.
Materials (Basel, Switzerland), 2020;13(13).

Background: 
Recently, the defects of the tooth surface in the cervical region are often restored using composite filling materials. It should meet the needs of the patients regarding esthetics and material stability. The aim of the study was to analyze the tooth root surface at the cervical region after the removal of the composite filling material by means of the Erbium-doped Yttrium Aluminium Garnet (Er: YAG) laser or drill using the scanning electron microscopy (SEM) and fluorescence microscopy.
Materials and methods: 
For the purposes of this study, 14 premolar teeth (n = 14) were removed due to orthodontic reasons. The rectangular shape cavities with 3 mm in width and 1.5 mm in height were prepared with a 0.8 mm bur on high-speed contra-angle in the tooth surface just below cemento-enamel junction (CEJ) and filled with the composite material. The composite material was removed with the Er: YAG laser at a power of 3.4 W, energy 170 mJ, frequency 20 Hz, pulse duration 300 μs, tip diameter 0.8 mm, air/fluid cooling 3 mL/s, and time of irradiation: 6 sec, at a distance from teeth of 2 mm (G1 group, n = 7) or a high-speed contra-angle bur (G2 group, n = 7). After the removal of composite material, the surfaces of teeth were examined using the scanning electron microscopy (SEM) and fluorescence microscopy.
Results: 
The Er: YAG irradiation allowed to remove completely the composite material from the tooth cavity. The study confirmed, that the ends of collagen fibers were only partially denatured after the Er: YAG laser application.
Conclusion: 
It has been proved that using the Er: YAG laser is an effective and safe method of composite removal for the dentin surface.
Keywords: Er: YAG laser; cervical root surface; laser ablation; smear layer; vaporization.
 Removal of Composite Restoration from the Root Surface in the Cervical Region Using Er: YAG Laser and Drill-In Vitro Study

71. Treatment with Nd:YAG Laser Irradiation Combined with Sodium Hypochlorite or Hydrogen Peroxide Irrigation on Periodontal Pathogens: An In Vitro Study

Grzech-Leśniak, K., Belvin, B. R., Lewis, J. P., & Golob Deeb, J.
An In Vitro Study, 39(1), 46–52.

Objective:
The purpose of this study was to evaluate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser with low concentrations of hydrogen peroxide (H2O2) or sodium hypochlorite (NaOCl) on viability of oral bacteria.
Materials and methods:
Bacterial species Streptococcus gordoniiPorphyromonas gingivalis, and Fusobacterium nucleatum were grown in an anaerobic chamber at 37°C. Samples were irradiated with the Nd:YAG laser (1064 nm, 300 μm Varian tip) using parameters: 150 mJ, 20 Hz, 3 W, 50 sec, and 100 μs short pulse duration in contact mode. Treatment groups included (1) control, (2) Nd:YAG, (3) 0.5% H2O2, (4) Nd:YAG and 0.5% H2O2, (5) 0.5% NaOCl, and (6) Nd:YAG with 0.5% NaOCl. Viable colonies were counted, calculated into colony forming unit/mL, and converted into log form for statistical analysis using a two-tailed paired t-test.
Results:
The combined treatment with the Nd:YAG and H2O2 showed the greatest reduction in all bacterial viability compared with other treatment groups (p < 0.001). Antiseptic solutions and laser were most effective against P. gingivalis, least effective against S. gordonii but improved significantly in combination with laser irradiation (p < 0.001). Laser alone was effective against all of three bacterial species, however, it was not significant.
Conclusions:
Combination treatment with Nd:YAG laser and an oxidative disinfectant (0.5% NaOCl or H2O2) resulted in more effective reduction of bacterial viability than monotherapies.
 Treatment with Nd:YAG Laser Irradiation Combined with Sodium Hypochlorite or Hydrogen Peroxide Irrigation on Periodontal Pathogens: An In Vitro Study

72. Penetration depth of irrigants into root dentine after sonic, ultrasonic and photoacoustic activation

Galler KM, Grubmüller V, Schlichting R, et al. 
Int Endod J. 2019;52(8):1210-1217.

Aim:
To compare penetration depths of endodontic irrigants into the dentinal tubules of extracted teeth when using several activation methods.
Methodology: 
The root canals of 90 extracted human teeth were prepared to size 40, .06 taper. The straight and round-shaped root canals were distributed randomly into six groups, and final irrigation was performed with EDTA and sodium hypochlorite as follows: (I) manual dynamic activation, (II) Ultrasonic, (III) Sonic, (IV) PIPS (photon-induced photoacoustic streaming, (V) SWEEPS (shock-wave enhanced emission photoacoustic streaming) and (0) control without final irrigation or activation. Subsequently, methylene blue was inserted into the canals and activated according to the groups (I-V). Teeth were sectioned horizontally, imaged under a light microscope, and dye penetration depths were measured in six sections per tooth and 24 points on a virtual clock-face per section. Data were analysed statistically by nonparametric tests for whole teeth and separately for coronal, middle and apical thirds.
Results: 
Penetration of dye into the dentinal tubules was lowest for the controls. Median penetration depths amounted to 700-900 μm for groups I-V with differences in the apical thirds between group I and the other test groups. Minimum penetration depths were significantly greater for PIPS in the apical thirds (P ≤ 0.046).
Conclusions: 
Greater penetration depths occurred in the apical thirds for ultrasonic, sonic and laser-induced activation compared to manual dynamic activation. PIPS was associated with deeper penetration of irrigants. The novel SWEEPS mode did not increase irrigant penetration.
Keywords: EDTA; disinfection; laser; root canal; sodium hypochlorite; ultrasonic.
 Penetration depth of irrigants into root dentine after sonic, ultrasonic and photoacoustic activation

73. Efficacy of sonically, ultrasonically and laser-activated irrigation in removing a biofilm-mimicking hydrogel from an isthmus model

Swimberghe RCD, De Clercq A, De Moor RJG, Meire MA.
Int Endod J. 2019;52(4):515-523.

Aim: 
To evaluate the efficacy of sonically, ultrasonically and laser-activated irrigation (LAI) in removing a biofilm-mimicking hydrogel from the isthmus in a root canal model.
Methodology: 
Transparent resin blocks containing two standardized root canals (apical diameter of 0.3 mm, 6% taper, 16 mm long, with a coronal reservoir) connected by an isthmus (0.15 mm wide, 2 mm high) were used as the test model. The isthmus was filled with a hydrogel-containing dentine debris. The canals were filled with irrigant, and the models were randomly assigned to the following activation groups (n = 20): EndoActivator (EA), Eddy, ultrasonically activated irrigation (UAI) with an Irrisafe 25 mm length, size 25 file and LAI with a 2940 nm Er:YAG-laser (20 Hz, 50 μs, 20 mJ, PIPS tip at the canal entrance). All protocols were executed for 3 × 20 s. Needle irrigation (NI) with a 27G needle served as the control. Standardized images of the isthmus were taken before and after irrigation, and the amount of removed hydrogel was determined using image analysis software and compared across groups using Welch anova (P ≤ 0.05).
Results: 
Hydrogel removal was greatest in the LAI group (90.2%) and was significantly greater than that with UAI, EA and NI (P ≤ 0.014), but not significantly different from Eddy (P = 0.498). Hydrogel removal with Eddy (85.9%) was significantly greater than that with NI and EA (P < 0.05), but not significantly different from UAI (P = 0.07). There was no significant difference between the NI and EA groups (P = 1).
Conclusions: 
Laser-activated irrigation and Eddy resulted in the greatest hydrogel removal and performed better than EA and UAI. The effect of LAI was also not dependent on deep intracanal tip placement.
Keywords: Eddy; biofilm; erbium laser; isthmus; root canal irrigation; sonic activation.
 Efficacy of sonically, ultrasonically and laser-activated irrigation in removing a biofilm-mimicking hydrogel from an isthmus model

74. Comparison of the micro-tensile bond strengths of four different universal adhesives to caries-affected dentin after ER:YAG laser irradiation

Donmez, N., Gungor, A.S., Karabulut, B. & Siso, S.H
Dental materials journal, 38(2), pp.218–225.

Background:
The micro-tensile bond strengths (micro-TBSs) of four universal adhesive systems, applied in two different bonding techniques, to carries-affected dentin after Er:YAG laser irradiation were investigated. Twenty-four extracted human molars were divided into four groups, according to the adhesive systems used. Each group was subdivided into two subgroups, depending on the bonding method used: the etch-and-rinse procedure or self-etch procedure. The carious lesions were irradiated using an Er:YAG laser. Resin composites were used to restore the adhesive-treated dentin surfaces. After 2,500 thermal cycles, the vertical composite resin-dentin sticks obtained were subjected to micro-TBS tests. One tooth in each group was examined using scanning electron microscopy (SEM). There were statistically significant differences (p<0.001) in micro-TBS values between universal adhesives. The results of this study suggested that universal adhesives applied both with self and total etch technique can be used for adhesive restorations to caries-affected dentin after Er:YAG laser irradiation. If lasers are preferred as a caries removal method, choosing a dentin bonding agent containing MDP may be recommended in clinical practice due to the property of increasing the bonding strength.
Keywords: Caries-affected dentin; Er:YAG laser; Microtensile bond strength; Universal adhesive.
 Comparison of the micro-tensile bond strengths of four different universal adhesives to caries-affected dentin after ER:YAG laser irradiation

75.  Medication-Related Osteonecrosis of the Jaw: An Autofluorescence-Guided Surgical Approach Performed with Er:YAG Laser

Vescovi P, Giovannacci I, Otto S, et al.
Photomed Laser Surg. 2015;33(8):437-442.
Objective: 
The aim of this study was to propose an autofluorescence (AF)-guided surgical approach performed with Er:YAG laser and Nd:YAG low-level laser therapy (LLLT).
Background data: 
Medication-related osteonecrosis of the jaw (MRONJ) therapy remains an unresolved problem. The proposed conservative and surgical treatment regimens are associated with contradictory success rates. However, the increased experience with MRONJ management suggests that surgical therapy can halt disease progression, and can allow a histology-based diagnosis of osteonecrosis. Surgical approach with Er:YAG laser is associated with significantly better results compared with medical treatment and traditional surgical approaches. One of the difficulties encountered during surgical removal of a MRONJ is the precise individuation of necrotic bone margins.
Patient and methods: 
A case of Stage III maxillary osteonecrosis treated with a new surgical approach is presented.
Results: 
After 7 months of follow-up, complete mucosal healing was evident, and the patient was free of symptoms. Such a technique allowed a highly accurate and minimally invasive approach through the selective ablation of the non-/hypofluorescent areas.
Conclusions: 
Taking into account the advantages of laser therapy and the possible effectiveness of AF in highlighting surgical margins, this approach would probably achieve excellent outcomes.
 Medication-Related Osteonecrosis of the Jaw: An Autofluorescence-Guided Surgical Approach Performed with Er:YAG Laser

76. Circulatory leukotriene changes during bone healing following osteotomies prepared with Er:YAG laser and piezosurgery: an animal study

Hadzi-Petrushev, N., Gjorgievska, E., Gabric, D., Dinescu, S., Mitrokhin, V. & Mladenov, M.
Biotechnology and Biotechnological Equipment, 2020;33(1), pp.325–330.

Background:
Among high-energy lasers, the short-pulsed infrared erbium-doped yttrium aluminium garnet (Er:YAG) laser has shown the best potential for precise cutting and rapid osseous healing. The objective of the present study was to analyse the healing of the bone tissue treated with short-pulsed infrared erbium-doped yttrium aluminium garnet laser in contact and non-contact mode and piezosurgery in relation to the circulatory leukotriene B4 and cysteinyl leukotrienes.
Materials and Methods:
Twenty-four 10-week-old adult male Wistar rats were used. Three osteotomies on the medial part of the tibia were performed on each animal: one on the right tibia and two ones on the left tibia. After surgery, six animals were immediately euthanized and the others were euthanized after 1, 2 and 3 weeks. The bone healing after osteotomy was analysed by a laser-based profilometry. After euthanasia, blood samples were taken from the abdominal aorta and collected for further analysis of the circulatory leukotriene B4 and cysteinyl leukotrienes.
Results:
A decrease in the osteotomy volume resulted from bone healing during the 3-week period. After the third week, there was almost complete healing of the prepared osteotomies. The circulating levels of both LTB4 and Cys-LTs at 7 and 14 days after osteotomy, were significantly reduced in comparison with the initial levels (p < 0.001 for LTB4 and p < 0.05 for Cys-LTs). On the 21st day after surgical treatment, only the circulating levels of LTB4 were significantly decreased compared to those on day 7 (p < 0.001) and day 14 (p < 0.05). All osteotomies healed through a significant decrease in both examined circulatory LTs.
 Circulatory leukotriene changes during bone healing following osteotomies prepared with Er:YAG laser and piezosurgery: an animal study

77. Qualitative evaluation of hybrid layer formation using Er:YAG laser in QSP mode for tooth cavity preparations

Kallis A, Tolidis K, Gerasimou P, Dionysopoulos D.
Lasers Med Sci. 2019;34(1):23-34.

Background:
The purpose of this study was to evaluate the thickness and qualitative characteristics of the hybrid layer after two cavity preparation methods, using Er:YAG laser in QSP mode and conventional carbide burs. Additionally, two different adhesive techniques were investigated using etch-and-rinse and self-etch adhesive systems.
Materials and Methods:
Sixty sound human third molars were used and were randomly divided into four groups (n = 15). In the first two groups, large (4 mm length, 3 mm wide, and 3 mm deep) class I cavities were prepared using Er:YAG laser (2.94 μm) in QSP mode, while in the other two groups, the cavities were prepared using carbide burs. After cavity preparations, two different adhesive techniques with GLUMA® 2 Bond (etch-and-rinse) and Clearfil™ Universal Bond Quick (self-etch) were applied. For the qualitative evaluation of the formed hybrid layer, photomicrographs were taken using SEM, and elemental semi-quantitative analysis was performed using EDS to confirm the extent of the hybrid layer.
Results:
One-way ANOVA was applied to verify the existence of statistically significant differences, followed by Tukey test for post hoc comparisons (Bonferroni corrected), and the level of significance was set at a = 0.05. The laser-treated groups exhibited higher hybrid layer thickness than bur-treated groups (p < 0.001). Between the laser-treated groups, etch-and-rinse technique presented higher hybrid layer thickness than self-etch technique (p < 0.001), while between the bur-treated groups, no significant differences were detected (p = 0.366). Er:YAG laser cavity preparations in QSP mode may be advantageous for adhesion of composite restorations, but more data are necessary to confirm its clinical effectiveness.
Keywords: Energy dispersive X-ray spectroscopy; Er:YAG; Hybrid layer; Quantum square pulse mode; Scanning electron microscopy.
 Qualitative evaluation of hybrid layer formation using Er:YAG laser in QSP mode for tooth cavity preparations

78. Investigation of the antibacterial effect of laser irradiation and chemical agent on human oral biofilms contaminated titanium discs.

Birang E, Birang R, Narimani T, Tolouei A, Fekrazad R.
Photodiagnosis Photodyn Ther. 2019;25:259-264.

Introduction:
A main challenge in treatment of peri-implant disease is the effective decontamination of the implant surface. This challenge has always been a problem, associated with the treatment of these diseases with regard to the difficulty in removing and eliminating bacterial biofilm from the surface of dental implants, especially rough surfaces. The aim of this in-vivo study was to evaluate the effect of five different antimicrobial methods in reducing bacteria adhering to titanium surfaces.
Materials and methods:
In the present in-vivo study, the contaminated discs, except for the negative control group, randomly underwent one of five treatments: Erbium: Yattrium Aluminum Garnet (Er-YAG) laser, plastic curette, 0.12% chlorhexidine, aPDT, and 810 nm diode laser. A pectrophotometer was used to measure Optical Density (OD) in case of aerobic microorganisms. Colony-Forming Units (CFUs) were used for anaerobic bacteria. Then, all the analyses were carried out at a significance level of α = 0.05 through SPSS software.
Findings:
One-way analysis of variance (ANOVA) of aerobic bacteria showed a significant difference among 6 groups in terms of OD variations during a 0-24 h time interval (P < 0.001). The results of Kruskal-Wallis test were used to investigate the effect of study methods on anaerobic bacteria after 48 h, and the results showed a significant difference among 6 groups in terms of CFUs (P < 0.001).
Conclusion:
The results of the present study showed that all five mechanicals (plastic curette), chemical (CHX), laser (810 nm diode and Er: YAG), and aPDT methods could reduce oral biofilms from roughed surfaces of titanium discs. Er: YAG laser and plastic curette had the highest and the lowest effects respectively.
 Investigation of the antibacterial effect of laser irradiation and chemical agent on human oral biofilms contaminated titanium discs.

79. Low-level laser irradiation modulates the proliferation and the osteogenic differentiation of bone marrow mesenchymal stem cells under healthy and inflammatory condition

Wang, L., Wu, F., Liu, C., Song, Y., Guo, J., Yang, Y. & Qiu, Y.
Lasers in medical science, 34(1), pp.169–178.

Background:
The aim of this in vitro study was to evaluate the effects of low-level laser therapy (LLLT) at different energy intensities on proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) under healthy and inflammatory microenvironments. Human BMSCs and BMSCs from inflammatory conditions (i-BMSCs, BMSCs treated with tumor necrosis factor α; TNF-α) were subject to LLLT (Nd:YAG;1064 nm) at different intensities.
Materials and Methods:
We designed one control group (without irradiation) and four testing groups (irradiation at 2, 4, 8, and 16 J/cm2) for both BMSCs and i-BMSCs. Cell proliferation was measured using colony-forming unit fibroblast assay and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay. Osteogenic capacity of cells was determined by alkaline phosphatase (ALP) staining, ALP activity assay, Alizarin Red S staining and the mRNA transcript levels of genes runt-related transcription factor 2 (Runx2), ALP, and osteocalcin. Moreover, the effects of LLLT on secretion of TNF-α in BMSCs and i-BMSCs were measured by enzyme-linked immunosorbent assay.
Results:
Our results demonstrated LLLT could significantly promote BMSC proliferation and osteogenesis at densities of 2 and 4 J/cm2. LLLT at density of 8 J/cm2 could promote the proliferation and osteogenesis of i-BMSCs. However, LLLT at 16 J/cm2 significantly suppressed the proliferation and osteogenesis of BMSCs both in healthy and in inflammatory microenvironment. Moreover, we also found that the expression of TNF-α was obviously inhibited by LLLT at 4, 8, and 16 J/cm2, in an inflammatory microenvironment. Considering these findings, LLLT could improve current in vitro methods of differentiating BMSCs under healthy and inflammatory microenvironments prior to transplantation.
Keywords: Bone marrow mesenchymal stem cells (BMSCs); Inflammation; Low-level laser therapy (LLLT); Osteogenesis; Proliferation.
 Low-level laser irradiation modulates the proliferation and the osteogenic differentiation of bone marrow mesenchymal stem cells under healthy and inflammatory condition

80. Evaluation of the effect of dentin surface treatment by air abrasion and Er:YAG laser on the retention of metal crowns luted with glass ionomer cement in teeth with reduced crown height: An in vitro study

Chauhan, S., Mahajan, N., Sethuraman, R. & Naveen, Y.G.
Journal of Indian Prosthodontic Society, 19(2), pp.141–148.

Aim and objectives:
The purpose of this study was to investigate the effect of dentin surface treatment with aluminum oxide air abrasion and Er:YAG laser on tensile bond strength of metal crowns. Metal crowns were luted with conventional glass ionomer cement (GIC) in the teeth with reduced crown height, where preparation geometry did not provide optimal retention form.
Materials and methods: 
Forty-eight human premolars were prepared to receive metal crowns and were randomly divided into four groups for tensile bond strength testing. Group A: Untreated dentin luted with self-adhesive composite resin cement as positive control; Group B: Untreated dentin luted with GIC as negative control; Group C: Surface treatment with 50 μm aluminum oxide air abrasion and luted with GIC; Group D: Surface treatment with Er:YAG laser (λ =2.94 mm) with a total energy 84.88 J/cm2 of (60 mJ/pulse, 10 Hz, 60 pulses, and 100 μs pulse width) and luted with GIC. The cemented specimens were thermocycled and later subjected to axial load in a universal testing machine at 0.5 mm/min cross-head speed for tensile testing. Scanning electron microscopic evaluation of dentin surface treatment and cement-dentin interface was also done in representative specimens.
Results: 
One-way analysis of variance showed statistically significant difference among/within the groups (P < 0.001). Tukey’s post hoc test presented significant increased tensile bond strength of Er:YAG laser group. Air abrasion group showed no significant increase in tensile bond strength values (P = 0.033).
Conclusion: 
Dentin surface treatment with Er:YAG laser significantly improved the tensile bond strength of luting GIC compared to air-abraded and untreated dentin.
Keywords: Air abrasion; Er:YAG laser; complete metal crown; glass ionomer cement; reduced crown height; tensile bond strength.
 Evaluation of the effect of dentin surface treatment by air abrasion and Er:YAG laser on the retention of metal crowns luted with glass ionomer cement in teeth with reduced crown height: An in vitro study

81. 1064 nm Nd:YAG laser light affects transmembrane mitochondria respiratory chain complexes

Ravera, S., Ferrando, S., Agas, D., De Angelis, N., Raffetto, M., Sabbieti, M.G., Signore, A., et al.
Journal of biophotonics,2019; 12(9), p.e201900101.
Background:
Photobiomodulation (PBM) is a non-plant-cell manipulation through a transfer of energy by means of light sources at the non-ablative or thermal intensity. Authors showed that cytochrome-c-oxidase (complex IV) is the specific chromophore’s target of PBM at the red (600-700 nm) and NIR (760-900 nm) wavelength regions. Recently, it was suggested that the infrared region of the spectrum could influence other chromospheres, despite the interaction by wavelengths higher than 900 nm with mitochondrial chromophores was not clearly demonstrated. We characterized the interaction between mitochondria respiratory chain, malate dehydrogenase, a key enzyme of Krebs cycle, and 3-hydroxyacyl-CoA dehydrogenase, an enzyme involved in the β-oxidation (two mitochondrial matrix enzymes) with the 1064 nm Nd:YAG (100mps and 10 Hz frequency mode) irradiated at the average power density of 0.50, 0.75, 1.00, 1.25 and 1.50 W/cm2 to generate the respective fluences of 30, 45, 60, 75 and 90 J/cm2 . Our results show the effect of laser light on the transmembrane mitochondrial complexes I, III, IV and V (adenosine triphosphate synthase) (window effects), but not on the extrinsic mitochondrial membrane complex II and mitochondria matrix enzymes. The effect is not due to macroscopical thermal change. An interaction of this wavelength with the Fe-S proteins and Cu-centers of respiratory complexes and with the water molecules could be supposed.
Keywords: adenosine triphosphate (ATP); cytochrome c oxidase; infrared light; low-level laser therapy (LLLT); photobiomodulation.
 1064 nm Nd:YAG laser light affects transmembrane mitochondria respiratory chain complexes

82. Effects of Nd:YAG laser irradiation on the growth of Candida albicans and Streptococcus mutans: in vitro study

Grzech-Lesniak, K. et al.
Lasers in medical science, 2019; 34(1), pp.129–137.

Background:
The purpose of this study was to evaluate the effects of Nd:YAG laser with flat-top handpiece on the in vitro growth of Candida albicans and Streptococcus mutans. The incidence of C. albicans (opportunistic commensal) and S. mutans (facultatively anaerobic) infections is increasing, despite available treatments. Cultures of Streptococcus mutans and Candida albicans were irradiated using Nd:YAG laser (LightWalker, Fotona) with flat-top handpiece (Genova, LightWalker, Fotona) at the following parameters: group G1: 0.25 W, 10 Hz, 15 s, 3 J and group G2: 1 W, 10 Hz, 60s, 59 J. The results were evaluated directly and 24 h after irradiation using a quantitative culture method (estimation of colony-forming units in 1 ml of suspension, cfu/ml), and microscopic analysis with Janus green stain and compared with control group in which laser was not applied. C. albicans was reduced by 20 up to 54% for G1, and for G2 by 10 up to 60% directly after the application. The cfu/ml values for S. mutans decreased by 13% (p = 0.1771) for G1 and 89% (p < 0.0001) for G2. In both test groups 24 h after the application, the number of colony-forming units decreased by 15-46% for G1 and by 15-64% for G2. The arrested cell division, increasing the surface area and increasing the number of metabolically inactive cells, were observed in morphometric analysis. Macroscopic and microscopic analyses revealed a reduction in cell number and a significant decrease of cell metabolism after laser application for both C. albicans and S. mutans.
Keywords: Biofilm; Cell metabolism; Flat-top handpiece; LLLT; Neodymium laser.
 Effects of Nd:YAG laser irradiation on the growth of Candida albicans and Streptococcus mutans: in vitro study

83. A Novel Protein Testing Model to Assay the Efficacy of Multiple Irrigation Activation Techniques for Removal of Ex Vivo Biomolecular Film

Dönmez Özkan H, Metin K, Bakir ZB, Yiğit Özer S.
Photomed Laser Surg. 2018;36(9):493-498.

Objective: 
This study aimed to compare the debris removal efficacies of irrigation activation techniques using ex vivo biomolecular film.
Materials and methods: 
Root canals of 50 human mandibular premolars were prepared, and freshly prepared collagen solutions were applied into the root canals using a peristaltic pump. Specimens were randomly divided into the five groups and irrigated with 3 mL of 5.25% sodium hypochlorite (NaOCl): G1 (needle irrigation and control group): a 27-gauge notched-tip irrigation needle (Endo-Eze; Ultradent, South Jordan, UT); G2, Vibringe sonic irrigation system (VSS) (Vibringe B.V. Corp., Amsterdam, Netherlands); G3, EndoActivator sonic irrigation system (EA) (Dentsply Tulsa Dental Specialties, Tulsa, OK); G4, passive ultrasonic irrigation (PUI) (EMS, Nyon, Sweden); and G5, photon-induced photoacoustic streaming (PIPS) (Fotona, Ljubljana, Slovenia). Postirrigation solution was collected in beakers containing 3% sodium thiosulfate by which NaOCl solution was neutralized. Residual protein levels in NaOCl solution were evaluated by the Bradford method. Data were analyzed using ANOVA with Duncan post hoc tests (α = 0.05).
Results: 
PIPS (laser-activated irrigation) method removed more artificial collagen than other experimental groups (EA, PUI, VSS) or the control group (p ≤ 0.05). There were no statistical differences among the EA, PUI, and VSS groups. The PIPS, PUI, and EA groups were superior compared with the conventional irrigation (p ≤ 0.05); however, there were no significant differences between VSS and the conventional irrigation groups.
Conclusions: 
Although all the methods and techniques examined in this study were suitable in extruding the ex vivo biomolecular film, the PIPS method was found significantly more effective than all the other tested groups (p ≤ 0.05).
Keywords: biofilm; collagen; photon-induced photoacoustic streaming; sodium hypochlorite; sonic; ultrasonic.
 A Novel Protein Testing Model to Assay the Efficacy of Multiple Irrigation Activation Techniques for Removal of Ex Vivo Biomolecular Film

84. Antibacterial and Smear Layer Removal Efficacy of Er:YAG Laser Irradiation by Photon-Induced Photoacoustic Streaming in Primary Molar Root Canals: A Preliminary Study

Korkut E, Torlak E, Gezgin O, Ozer H, Sener Y.
Photomed Laser Surg. June 2018. doi:10.1089/pho.2017.4369

Objective: 
The objective of this study was to compare antibacterial and smear layer removal efficacy of the erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation by photon-induced photoacoustic streaming (PIPS), neodymium:yttrium-aluminium-garnet (Nd:YAG), and diode lasers and conventional irrigation agent in primary molar root canals.
Background: 
The selection, application, and activation of the irrigant are important factors affecting the success of the endodontic treatment.
Materials and methods: 
Distal root canals of human primary mandibular molar teeth used for antimicrobial efficacy evaluation were first inoculated with Enterococcus faecalis (n = 25). Smear layer removal efficacy was evaluated on the noninoculated specimens (n = 20). The root canals in the first treatment groups were irrigated with a conventional technique using 5% sodium hypochlorite (NaOCl). In the laser groups, the root canals were irradiated with either Nd:YAG (1064 nm) or diode lasers (940 nm) followed by NaOCl irrigation agent. In the fourth groups, the NaOCl irrigation agent was activated with an Er:YAG laser (2940 nm) by PIPS tip using nonablative settings. Antibacterial efficacy was determined by viable counts of E. faecalis after treatments. The treated root canals were examined by scanning electron microscopy to determine the smear layer removal efficacy of treatments.
Results: 
Statistically significant (p < 0.05) reductions in the number of E. faecalis were achieved in Nd:YAG and diode laser groups and Er:YAG laser by PIPS-activated irrigation groups compared to the NaOCl group. Er:YAG laser by PIPS-activated irrigation resulted in more cleaning of the root canal walls and a higher quantity of open tubules.
Conclusions: These findings suggest that Er:YAG laser by PIPS-activated irrigation can be considered as an effective irrigant agitation technique in pediatric endodontics.
Keywords: bacterial reduction; irrigation; lasers; photon-induced photoacoustic streaming; primary molar root canals; smear layer.
 Antibacterial and Smear Layer Removal Efficacy of Er:YAG Laser Irradiation by Photon-Induced Photoacoustic Streaming in Primary Molar Root Canals: A Preliminary Study

85. Efficacy and Safety of Photon Induced Photoacoustic Streaming for Removal of Calcium Hydroxide in Endodontic Treatment

Laky M, Volmer M, Arslan M, Agis H, Moritz A, Cvikl B.
Biomed Res Int. 2018;2018:2845705.

Background:
Calcium hydroxide removal from the root canal by photon induced photoacoustic streaming (PIPS) compared to needle irrigation and irrigation using sonic activation was investigated. Additionally, safety issues regarding apical extrusion were addressed. In endodontic treatment temporary intracanal medication like calcium hydroxide should be completely removed for long term success.
Materials and Methods:
For analysis, 60 artificial teeth were prepared, filled with calcium hydroxide, and divided into four groups. The teeth were assigned to needle irrigation, irrigation using a sonic device, PIPS with a lower energy setting (10 mJ, 15 Hz), or PIPS with a higher energy setting (25 mJ/40 Hz). For comparison the weight of each tooth was measured before and after calcium hydroxide incorporation, as well as after removing calcium hydroxide using the four different methods. Regarding safety issues another 24 samples were filled with stained calcium hydroxide and embedded in 0.4% agarose gel. Color changes in the agarose gel due to apical extrusion were digitally analysed using Photoshop.
Results:
No significant differences were found for calcium hydroxide removal between the two laser groups. Sonic assisted removal and needle irrigation resulted in significant less calcium hydroxide removal than both laser groups, with significantly more calcium hydroxide removal in the ultrasonic group than in the needle irrigation group. For apical extrusion the higher laser (25 mJ/40 Hz) group resulted in significant higher color changes of the periapical gel than all other groups. PIPS with the setting of 10 mJ/15 Hz achieved almost complete removal of calcium hydroxide without increasing apical extrusion of the irrigation solution.
 Efficacy and Safety of Photon Induced Photoacoustic Streaming for Removal of Calcium Hydroxide in Endodontic Treatment

86.  Characteristics of the Irrigant Flow in a Simulated Lateral Canal Under Two Typical Laser-Activated Irrigation Regimens

Su Z, Li Z, Shen Y, et al.
Lasers Surg Med. September 2020.
Background and objectives: 
Photon-induced photoacoustic streaming (PIPS) and shockwave-enhanced emission photoacoustic streaming (SWEEPS) are two promising laser-activated irrigation (LAI) methods for root canal irrigation. Their performance in driving irrigant flush in a complex root canal system will be evaluated by microscale particle image velocimetry (μPIV) measurement and will be compared with that of ultrasonic-activated irrigation (UAI).
Study design/materials and methods: 
A μPIV system with 7 μm fluorescent tracer particles was adopted to measure two-dimensional (2D) velocity fields around the junction region, with a size of 1.8 mm × 1.5 mm, between one main canal and one lateral canal in an endodontic training block, which was driven by SWEEPS (Er:YAG laser) operating at 15 Hz and 20 mJ. The flow field driven by PIPS (Er:YAG laser) at the same frequency and energy, as well as by UAI (with non-cutting insert) operating at 40% unit power, was also measured for a direct comparison.
Results: 
It was found that both SWEEPS and PIPS can activate a so-called “breath mode” during the irrigation. Namely, the induced irrigant flush presented a back-and-forth oscillation along both the main canal and the lateral one. The maximum flow speed in the lateral canal was observed to be up to 10 m/s in the SWEEPS modality, while reduced to around 7 m/s in the PIPS modality. The penetration length in the lateral canal in both modalities was estimated to be larger than 1 mm. In comparison, the flow field induced by UAI was characterized as irregular vortical structures, the maximum flow speed in the lateral canal was 0.15 m/s and significantly lower than LAI (P < 0.01), and the penetration length was less than 300 μm and lower than LAI (P < 0.05).
Conclusion: 
Compared to UAI, PIPS, and SWEEPS are more capable of delivering the irrigant deeper into the lateral canal. Furthermore, the back-and-forth flush in the breath mode is ideal for removing debris during irrigation. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.
Keywords: lateral canal; microscale particle image velocimetry; photon‐induced photoacoustic streaming; shockwave‐enhanced emission photoacoustic streaming; ultrasonic‐activated irrigation.
 Characteristics of the Irrigant Flow in a Simulated Lateral Canal Under Two Typical Laser-Activated Irrigation Regimens

87.  Real-time intracanal temperature measurement comparing mechanically and laser-activated irrigation to syringe irrigation

Donnermeyer D, Schäfer E, Bürklein S.
Aust Endod J  J Aust Soc  Endodontology Inc. November 2020.

Abstract:
Antibacterial activity and tissue dilution of sodium hypochlorite (NaOCl) are improved by moderately heating the irrigant. Temperature can be risen by preheating or intracanal activation. To assess intracanal temperature development of NaOCl during irrigation activation and syringe activation (SI) in a closed system at 37°C, Type-K thermocouples were inserted close to the root canal of one human single-rooted maxillary canine at the apex and 5 and 10 mm from the apical foramen via drilled holes. The root was positioned in a plastic vial filled with alginate simulating surrounding biological structures. Experiments were performed in a closed environment at 37°C (n = 14): EA: EndoActivator (Dentsply Sirona), EDDY: EDDY (VDW), PUI: passive ultrasonic irrigation, PIPS: Photon-induced photoacoustic streaming (Fotona), S60: SI of 60°C-NaOCl, S45: SI of 45°C-NaOCl, and S20: SI of 20°C-NaOCl. S45, PUI and EDDY lead to minor intracanal temperature increases. EA and PIPS did not influence the intracanal temperature. SI with 60°C-NaOCl resulted in higher intracanal temperatures than activation systems. Temperature dissipation into simulated tissues buffered intracanal temperature changes.
Keywords: EDDY; EndoActivator; PIPS; passive ultrasonic irrigation; photon-induced photoacoustic streaming; sodium hypochlorite.
 Real-time intracanal temperature measurement comparing mechanically and laser-activated irrigation to syringe irrigation

88.  Evaluation of Microleakage in Resin Composites Bonded to an Er:YAG Laser and Bur-Prepared Root and Coronal Dentin Using Different Bonding Agents

Shirani F, Birang R, Ahmadpour E, et al.
J Lasers Med Sci. 2021;12:e74.
Introduction: This study was conducted to assess the microleakage in Er: YAG laser-ablated and burprepared root and coronal dentin cavities using self-etch and total-etch adhesive systems.
Methods: Sixty extracted caries-free human third molars were sectioned for dentin exposure. Then, two standard class V cavities were prepared in the root and coronal dentin of each tooth and allocated to one of the following conditioning groups randomly (n=12/Group): G1: Diamond bur for cavity preparation and single bond (BESB) etch-and-rinse adhesive for bonding, G2: Er: YAG laser (160 MJ, 20 Hz, 29.88 J/cm2) and SB (LESB), G3: Er: YAG laser and SB without acid etching (LSB), G4: Diamond bur and Clearfil SE Bond (BCSE) self-etch system, and G5: Er: YAG laser and Clearfil SE Bond (LCSE). The cavities were filled with Z100 composite resin. Dye penetration was assessed after thermocycling. Data analysis was done by Kruskal–Wallis and Mann–Whitney U tests. Statistical significance was set at P<0.05.
Results: The results showed there were no statistically significant differences in microleakage between the two preparation methods (bur and laser) or the bonding agents applied (P>0.05). Regardless of the cavity preparation method, dye penetration was significantly higher in coronal dentin than in root dentin (P<0.05).
Conclusion: The Er: YAG laser had the same efficacy as the conventional method for cavity preparation, and microleakage did not depend on the bonding agent. Microleakage was significantly higher in coronal restorations than in root restorations.
Keywords: Dentin, Er, YAG laser, Microleakage, Composite Resin, Self-etching primer
 Evaluation of Microleakage in Resin Composites Bonded to an Er:YAG Laser and Bur-Prepared Root and Coronal Dentin Using Different Bonding Agents

89.  Comparison of three irrigation methods: SWEEPS, ultrasonic, and traditional irrigation, in smear layer and debris removal abilities in the root canal, beyond the fractured instrument

Vatanpour, M., Toursavadkouhi, S. & Sajjad, S.
Photodiagnosis and photodynamic therapy,2021; 37, p.102707.

 
Background: :This study compared the effectiveness of three irrigation methods in removing smear layer and debris in the presence of the fractured instrument. The three compared irrigation methods were conventional syringe irrigation, passive ultrasonic irrigation, and SWEEPS (Shock wave enhanced emission photoacoustic streaming) irrigation.
Methods and materials: Sixty-three permanent mandibular molars with moderate curvature were included in this experimental study. Mesiobuccal root canals were prepared with Race files (FKG Dentaire. Switzerland) up to #25, 4%. A #30, 6% Race file was used to simulate file fracture 3 mm short of working length. The prepared samples, randomly divided into three groups, and final irrigation was separately done in each group. Group 1 conventional syringe irrigation (CSI) as the control group, Group 2 passive ultrasonic irrigation (PUI), and Group 3 Shock wave enhanced emission photoacoustic streaming or SWEEPS Irrigation (SI). Smear layer and debris removal beyond separated file scored with scanning electron microscope(SEM) images. Data were analyzed using the nonparametric tests to compare the smear layer and debris scores.
Result: SWEEPS and passive ultrasonic irrigation significantly removed smear layer and debris, better than conventional syringe irrigation (p<0.001). The smear layer and debris removal efficiency between passive ultrasonic Irrigation and SWEEPS were not significantly different (p = 0.629).
Conclusion: In the face of the irretrievably broken instrument in the root canal, passive ultrasonic irrigation and the SWEEPS method can enhance smear layer and debris removal compared to conventional syringe irrigation.
Keywords: Laser; SWEEPS; Scanning electron microscopy; Smear layer; Syringe irrigation; Ultrasonic.
Copyright © 2021. Published by Elsevier B.V.
 Comparison of three irrigation methods: SWEEPS, ultrasonic, and traditional irrigation, in smear layer and debris removal abilities in the root canal, beyond the fractured instrument

90.  Laser v/s Conventional – Comparison of Shear Bond Strength of Orthodontic Brackets Bonded Using Various Etching Techniques

Srivastava VK, Mahajan S, Mehta SC, Singh I, Singh A, Saxena T.
audi J Oral Dent Res. 2021;6(9):398-404.

Background/Objectives: 
The following study was performed to test and compare the shear bond strength and of the orthodontics brackets bonded to extracted human premolar teeth using various etching procedures and also to determine the brackets / adhesive failure mode.
Materials/Methods: 
The teeth were acid-etched using 37% orthophosphoric acid, laser-etched with Er: YAG (Fotona Lares, wavelength, 2 940 nm) and both acid etching followed by laser etching. Orthodontic brackets were bonded to all the teeth using Transbond XT paste (3M Unitek).
Results:
Shear bond strength of all teeth of each group was determined by using Universal testing machine. Data obtained were compared by Kruskal Wallis analysis of variance (ANOVA) and chi-square (χ2 ) test was used to compare the adhesive remnant index (ARI) scores for all the three groups.
Conclusions: 
The study found laser-etched procedure more effective than acid-etched procedure and both acid and laser-etched procedures in the management of orthodontics. Keywords: Orthodontic brackets, Acid etching, Laser therapy, Er: YAG laser, Bond strength
 Laser v/s Conventional – Comparison of Shear Bond Strength of Orthodontic Brackets Bonded Using Various Etching Techniques

91.  The antibacterial efficacy of photon-initiated photoacoustic streaming in root canals with different diameters or tapers

Wen, C., Yan, L., Kong, Y., Zhao, J., Li, Y. & Jiang, Q.
BMC Oral Health, 2021b;21(1), p.542.

Background:
In recent years, the concept of minimally invasive endodontics has been proposed, which could be described as preventing or treating diseases by preserving more dental tissue and creating minimal damage. In the process of root canal preparation, it was recommended to use instruments with a smaller taper to preserve more tooth tissue and improve the preservation rate of the affected teeth. Photon-induced photoacoustic streaming (PIPS) was a new type of laser-activated irrigation technology, which was now widely used in endodontic treatment. The purpose of this article was to evaluate the bactericidal effect of PIPS with NaOCl in root canals with different widths or tapers.
Materials and Methods:
Twenty-three maxillary first molars with three independent root canals were included in this study. The mesiobuccal (MB), distobuccal (DB), and palatal (P) root canals were prepared at sizes of #10/.02, #25/.02, and #25/.06, respectively. After being incubated with a bacterial suspension for 4 weeks, the specimen were irrigated with 2% NaOCl activated by conventional needle irrigation (CNI) (n = 10) or PIPS (n = 10). Three specimen were not treated (control group). Before and after irrigation, the presence of bacteria was assessed with an adenosine 5′-triphosphate (ATP) assay kit and biofilms were assessed using confocal laser scanning microscopy and scanning electron microscopy.
Results:
In specimen prepared using PIPS irrigation, the ATP was reduced by more than 98%. When the root canal taper was 0.02, the size #25 root canals had a higher percentage of dead bacteria than the size #10 root canals in all regions (P < 0.05) in the PIPS group. When the root canal width was #25, the 0.02 taper group had a higher percentage of dead bacteria than the 0.06 taper group in the apical region (P < 0.05), except coronal and middle regions (P > 0.05). PIPS irrigation results in a greater percentage of dead bacteria and reduction of ATP in size #10/.02 root canals than CNI in size #25/.06 root canals in three regions (P < 0.05).
Conclusion:
Increasing the width from #10 to #25 improves the bactericidal effect of PIPS in the root canal. Increasing the taper of the root canal from 0.02 to 0.06 at size #25 did not affect the bactericidal effects of PIPS. PIPS resulted in more dead bacteria in specimen with smaller tapers and root canal widths than CNI. PIPS can be used to clean the smear layer in the coronal region and open the dentin tubules.
Keywords: Photon-induced photoacoustic streaming, Diameter, Taper, Root canal
 The antibacterial efficacy of photon-initiated photoacoustic streaming in root canals with different diameters or tapers

92.  Photoacoustic removal of Enterococcus faecalis biofilms from titanium surface with an Er:YAG laser using super short pulses

Terlep S, Hympanova M, Dogsa I, Pajk F, Stopar D. 
Lasers Med Sci. 2021 Feb 22.

Background:
Biofilms that grow on implant surfaces pose a great risk and challenge for the dental implant survival. In this work, we have applied Er:YAG photoacoustic irrigation using super short pulses (Er:YAG-SSP) to remove biofilms from the titanium surfaces in the non-contact mode. Mature Enterococcus faecalis biofilms were treated with saline solution, chlorhexidine, and hydrogen peroxide, or photoacoustically with Er:YAG-SSP for 10 or 60 s. The number of total and viable bacteria as well as biofilm surface coverage was determined prior and after different treatments. Er:YAG-SSP photoacoustic treatment significantly increases the biofilm removal rate compared to saline or chemically treated biofilms. Up to 92% of biofilm-covered surface can be cleaned in non-contact mode during 10 s without the use of abrasives or chemicals. In addition, Er:YAG-SSP photoacoustic irrigation significantly decreases the number of viable bacteria that remained on the titanium surface. Within the limitations of the present in vitro model, the ER:YAG-SSP seems to constitute an efficient therapeutic option for quick debridement and decontamination of titanium implants without using abrasives or chemicals.
Keywords: Biofilm control; Dental implants; Enterococcus faecalis; Er:YAG laser; Er:YAG-SSP; Photoacoustic irrigation; Titanium surface.
 Photoacoustic removal of Enterococcus faecalis biofilms from titanium surface with an Er:YAG laser using super short pulses

93.  Evaluation of bond strength of resin cement to Er:YAG laser-etched enamel and dentin after cementation of ceramic discs

Ismatullaev A, Taşın S, Usumez A. 
Lasers Med Sci. 2021;36(2):447-454.

 
Background:
The purpose of this study was to investigate the shear bond strength (SBS) of ceramic discs luted to differently etched enamel and dentin surfaces.
Materials and Methods:
Occlusal surfaces of 64 carious-free human molars and vestibule surfaces of 64 first maxillary incisors were ground to get flat superficial dentin and flattened enamel respectively. After generating 4 groups according to the surface etching method (37% orthophosphoric acid, Er:YAG laser-contact handpiece/scanning handpiece (1 or 2 times of scanning)), ceramic discs were luted to the surfaces with adhesive resin cement (Variolink N, Vivadent Ets., Schaan/Liechtenstein). After etching and cementation, thermocycling of 5000 cycles (Sd Mechatronık Gmbh, Feldkirchen-Westerham, Germany) and SBS test (Servopulser EHFFD1; Shimadzu, Kyoto, Japan) were performed respectively.
Results:
The surface morphologies of 2 specimens, etched enamel and dentin, prepared for each group were examined with SEM analysis. Failure modes were determined under a USB digital microscope. Data were analyzed with one-way analysis of variance (ANOVA) and Tukey HSD test (α = 0.05). SBS values in dentin surfaces showed statistically significant differences (p < 0.05) among tested groups. The highest SBS among dentin groups was determined in the group which had 2 times etching by Er:YAG laser (11.42 MPa) by a scanning handpiece. No statistical differences were observed in the other dentin or enamel groups.
Conclusions:
Laser etching seems to be a viable alternative to acid etching on both enamel and dentin surfaces while double etching of dentin with a scanning handpiece can improve the adhesion.
Keywords: Dentin; Enamel; Er:YAG laser; IPS e-max Press ceramic; Shear bond strength; Surface treatment.
 Evaluation of bond strength of resin cement to Er:YAG laser-etched enamel and dentin after cementation of ceramic discs

94.  Comparison of Er:YAG modalities (PIPS-SWEEPS) on eliminating of Enterococcus faecalis populations.

Arıcıoğlu, B., Hatipoğlu, F.P., Hatipoğlu, Ö. & Bahçeci, İ.
Selcuk Dental Journal, 2021; 8(3), pp.750–757.

Background and purpose: 
To determine the effectiveness of novel two Er:YAG lasers, photon-initiated photoacoustic streaming (PIPS\SSP) and shock wave-enhanced emission photoacoustic streaming (SWEEPS\AutoSWEEPS) in terms of removal Enterococcus faecalis (E. faecalis) with or without antimicrobial agents (NaOCl and chlorhexidine gluconate).
Materials and Methods:
Forty-two extracted single-rooted mandibular premolars were prepared, sterilized, and then inoculated with E. faecalis for 4 weeks, and randomly divided into to two main and three subgroups (n= 7). Group Ia ( PIPS + distilled water), Group Ib (PIPS + 5% NaOCl), Group Ic (PIPS + CHX), and Group IIa (SWEEPS + distilled water), Group IIb (SWEEPS + 5% NaOCl), and Group IIc (SWEEPS + CHX). Following incubation for 48 hours at 37°C, the colonies formed (CFU) were counted.
Results:
NaOCl and CHX activated with PIPS\SSP or SWEEPS\AutoSWEEPS modalities showed significantly higher reduction rates than distilled water activated with both laser-activated methods (p<0.05), but no significant differences were detected between the NaOCl and CHX groups. Besides, in all groups, no significant difference was detected between PIPS\SSP and SWEEPS\AutoSWEEPS performances in the reduction of CFU counts (p>0.05).
Interpretation: 
Even novel laser activation methods or modalities are not sufficient alone to adequately reduce bacterial load and using antimicrobial agents with laser activation is necessary for the best reduction for microbial elimination. Novel SWEEPS\AutoSWEEPS modalıty with the conical 600μm tip showed no increased efficacy compared with PIPS\SSP mode. Besides, smaller fiber tip may increase the success of applications for minimally invasive access cavities and preparation.
 Comparison of Er:YAG modalities (PIPS-SWEEPS) on eliminating of Enterococcus faecalis populations.

95.  Effect of femtosecond and ER:YAG laser systems on shear bond strength of enamel surface and morphological changes

Özüdoğru S, Kahvecioğlu F, Tosun G, Gündoğdu Y, Kılıç HŞ. 
Lasers Dent Sci. 2021;5(4):199-205.

Purpose
The present study aimed to investigate the impact of a femtosecond laser and Er:YAG laser as an alternative to orthophosphoric acid etching on the shear bond strength.
Materials and Methods:
Thirty permanent mandibular teeth were assigned to one of three groups based on the treatment performed on their buccal/lingual surfaces. Group I, 37% orthophosphoric acid etching; Group II, Er:YAG laser; Group III, femtosecond laser. A 3 × 3 mm diameter bonding area was demarcated on the enamel. Fissure sealant material was applied to the test areas and cured for 20 s in all groups. The shear bond strength of all the specimens was determined using an Instron universal testing machine.
Results:
After testing, the fracture surfaces were analyzed using a stereomicroscope, and the fracture modes of each sample were categorized according to the adhesive remnant index.ResultsThe results revealed no significant differences in terms of shear bond strength of the femtosecond laser (7.55 ± 0.6 MPa), Er:YAG laser (7.26 ± 0.6 MPa), and acid etching groups (6.61 ± 0.5 MPa) (p > 0.05).Conclusion The present in vitro study showed that the bond strength of the enamel surface following treatment with femtosecond and Er:YAG laser systems alone was sufficient when compared with that after acid etching.Clinical significanceIt is possible to use femtosecond lasers for bonding fissure sealant to enamel surfaces as an alternative to acid etching.
 Effect of femtosecond and ER:YAG laser systems on shear bond strength of enamel surface and morphological changes

96.  Disinfection of Root Canals with Laser-Activated Irrigation, Photoactivated Disinfection, and Combined Laser Techniques: An Ex Vivo Preliminary Study

Olivi M, Raponi G, Palaia G, Berlutti F, Olivi G, Valentini E, Tenore G, Del Vecchio A, Romeo U.
Photobiomodulation, Photomedicine, and Laser Surgery. 
2021 Jan 1;39(1):62-9.
Objective:
 This study aimed to evaluate the efficacy of laser-activated irrigation using photon-induced photoacoustic streaming (PIPS®) and photoactivated disinfection (PAD) techniques and their combination to improve penetration and activation of toluidine blue in the endodontic space of teeth experimentally infected with Enterococcus faecalis.
Materials and methods:
Twenty-seven extracted single-root teeth were instrumented, sterilized, and infected with E. faecalis and divided into seven groups of three teeth each: Group A [sodium hypochlorite (NaClO) 5% hand irrigation], Group B [NaClO 5% hand irrigation+ethylenediaminetetraacetic acid (EDTA)+NaClO 5% activated by PIPS], Group C (EDTA+NaClO 5% activated by PIPS), Group D (toluidine blue activated by PAD), Group E (toluidine blue activated by PIPS and PAD), Group F (NaClO 5% hand irrigation+toluidine blue activated by PAD), and Group G (NaClO 5% hand irrigation+toluidine blue activated by PIPS and PAD). Finally, positive and negative group controls were prepared. The presence of biofilms after the treatments was assessed by the BioTimer assay. PIPS was performed with an Er:YAG laser (2940 nm, LightWalker, Fotona® d.o.o., Slovenia) at 20 mJ, 15 Hz, 0.3 W, and 50-μs pulse duration. PAD was performed with a 635 nm diode laser (Smart M, Lasotronix®, Poland) at 400 mW in continuous wave (CW).
Results: When NaClO was used, significant decontamination (p ≤ 0.05) was obtained in all experimental groups with respect to the positive control, other than Group G. Irrigation with EDTA+NaClO activated by PIPS produced a higher level of decontamination than Group A (p ≤ 0.05). Significant results in reducing biofilm load compared with the control and Group A were observed when NaClO was coupled with toluidine blue activated by PAD (p ≤ 0.05).
Conclusions: Disinfection of root canals can be obtained using a combination of different irrigants, photosensitizers, and activation protocols. EDTA+NaClO using the PIPS protocol and toluidine blue activated by PAD (both preceded by NaClO irrigation) can be considered effective tools. The possibility of replacing NaClO with toluidine blue, whatever the method of activation, should be further investigated.
Keywords: BioTimer assay; Enterococcus faecalis; endodontic infection; laser activated irrigation; photo activated disinfection; photon induced photoacoustic streaming.
 Disinfection of Root Canals with Laser-Activated Irrigation, Photoactivated Disinfection, and Combined Laser Techniques: An Ex Vivo Preliminary Study

97.  SEM Evaluation of Tooth Surface after a Composite Filling Removal Using Er:YAG Laser, Drills with and without Curettes, and Optional EDTA or NaOCl Conditioning

Kiryk J, Matys J, Grzech-Leśniak K, et al. S
Materials (Basel). 2021;14(16):1-10.

Background:
This study aimed to evaluate the microporosity of the tooth surface structure adjacent to the cemento-enamel junction (CEJ) after the removal of composite fillings with a drill in comparison with removal by an Er:YAG laser and after cleaning with a periodontal curette, chemical EDTA and NaOCl (sodium hypochlorite) conditioning.
Materials and Methods: 
The research material consisted of 30 extracted premolars with cervical composite fillings. The teeth were divided into six groups according to the method of tooth preparation: group G1 (n = 5)—a diamond drill; group G2 (n = 5)—a diamond drill + curette; group G3 (n = 5)—a diamond drill + 24% EDTA (PrefGel, Straumann, Switzerland); group G4 (n = 5)—an Er:YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) set with the following parameters: power: 1.65 W (composite removal, CR), 1.2 (tooth conditioning, TC), energy: 110 mJ (CR), 80 mJ (TC), frequency: 15 Hz, pulse duration: 50 μs, tip diameter: 1 mm, air/fluid cooling: 4, distance 1.5 mm, energy density: 14.01 J/cm2 (CR), 10.19 J/cm2 (TC); group G5 (n = 5)—an Er:YAG laser + 2% sodium hypochlorite (NaOCl); group G6 (n = 5)—an Er:YAG laser + 5.25% NaOCl. In each tooth, three cavities were made and subjected to analysis. The dentin surface was evaluated using a scanning electron microscope (SEM).
Results: 
Groups G1 and G2 exhibited mechanical damage to the tooth surface structure caused by the rotary motion of a diamond drill. The SEM image showed a smear layer that could only be removed chemically using 24% EDTA gel (group G3). The tooth surfaces prepared with the Er:YAG laser (groups G4–G6) revealed a homogeneous structure without damage along with open dentinal tubules (without smear layer) and visible denaturation of collagen fibers. The sodium hypochlorite (NaOCl) conditioning did not increase the visibility of dentinal tubules. (4)
Conclusions: 
Dentin surfaces have open dentinal tubules after removal of the composite filling using the Er:YAG laser and therefore do not require additional NaOCl conditioning.
Keywords: CEJ, collagen fibers, dentinal tubules, gingival recession, smear layer
 SEM Evaluation of Tooth Surface after a Composite Filling Removal Using Er:YAG Laser, Drills with and without Curettes, and Optional EDTA or NaOCl Conditioning

98.  Effect of Nd:YAG and Er:YAG laser tooth conditioning on the microleakage of self-adhesive resin cement

Kaviani A, Khansari Nejad N.
Biomater Investig Dent. 2021;8(1):152-159.
Statement of problem: 
Recently, the application of lasers in restorative dentistry has been considered for cavity preparation and surface conditioning of enamel and dentin. However, the beneficial effects of cavity surface conditioning by laser irradiation on microleakage are still controversial.
Purpose: 
This study aimed to compare the microleakage of self-etch adhesive resin cement with Nd:YAG and Er:YAG laser tooth surface conditioning to evaluate the capabilities of these lasers as a reliable replacement for etching cavities.
Materials and methods: 
Fifty-four class V cavities were prepared on the buccal and lingual surfaces of 27 sound human premolar teeth. The samples were randomly divided into three groups (n = 18): group 1: no conditioning; group 2: conditioned with Er:YAG laser (2940 nm, 10 Hz, 1.2 W); group 3: conditioned with Nd:YAG laser (1064 nm, 1.5 W, 10 Hz). All the cavities were filled with self-adhesive resin cement. After curing and polishing, the samples were immersed in 2% methylene blue solution for 24 h, and after being embedded in acrylic resin, they were sectioned longitudinally and examined under a stereomicroscope. The data were submitted to Kruskal-Wallis and Dunn tests (α = 0.05).
Results: 
The lowest microleakage mean rank was observed in the Er:YAG group (19.19), and the highest mean rank was noted in the Nd:YAG group (33.08), with significant differences between the three groups (P-value = .01). Pairwise comparisons demonstrated significant differences between the Er:YAG and Nd:YAG groups (P-value = .004) as well as Er:YAG and no conditioned groups (P-value =.022).
Conclusion: 
The irradiation of the Er:YAG laser (2940 nm, 10 Hz, 1.2 W) on cavity surface resulted in less marginal microleakage of self-etch adhesive resin cement restorations compared to Nd:YAG (1064 nm, 1.5 W, 10 Hz) and no conditioning groups.
Keywords: Er:YAG; Nd:YAG laser; laser; microleakage; self-adhesive resin cement.
 Effect of Nd:YAG and Er:YAG laser tooth conditioning on the microleakage of self-adhesive resin cement

99.  Dental Aerosol as a Hazard Risk for Dental Workers

Matys J, Grzech-Leśniak K.
Materials (Basel). 2020;13(22):1-13.

Abstract:
Standard dental procedures, when using a water coolant and rotary instruments, generate aerosols with a significantly higher number of various dangerous pathogens (viruses, bacteria, and fungi). Reducing the amount of aerosols to a minimum is mandatory, especially during the new coronavirus disease, COVID-19. The study aimed to evaluate the amount of aerosol generated during standard dental procedures such as caries removal (using dental bur on a high and low-speed handpiece and Er:YAG laser), ultrasonic scaling, and tooth polishing (using silicon rubber on low-speed handpiece) combined with various suction systems. The airborne aerosols containing particles in a range of 0.3-10.0 μm were measured using the PC200 laser particle counter (Trotec GmbH, Schwerin, Germany) at three following sites, manikin, operator, and assistant mouth, respectively. The following suction systems were used to remove aerosols: saliva ejector, high volume evacuator, saliva ejector with extraoral vacuum, high volume evacuator with extraoral vacuum, Zirc® evacuator (Mr.Thirsty One-Step®), and two customized high volume evacuators (white and black). The study results showed that caries removal with a high-speed handpiece and saliva ejector generates the highest amount of spray particles at each measured site. The aerosol measurement at the manikin mouth showed the highest particle amount during caries removal with the low and high-speed handpiece. The results for the new high volume evacuator (black) and the Zirc® evacuator showed the lowest increase in aerosol level during caries removal with a high-speed handpiece. The Er:YAG laser used for caries removal produced the lowest aerosol amount at the manikin mouth level compared to conventional dental handpieces. Furthermore, ultrasonic scaling caused a minimal aerosol rise in terms of the caries removal with bur. The Er:YAG laser and the new wider high volume evacuators improved significantly suction efficiency during dental treatment. The use of new suction systems and the Er:YAG laser allows for the improvement of biological safety in the dental office, which is especially crucial during the COVID-19 pandemic.
Keywords: COVID-19; Er:YAG laser; biological safety; high volume evacuator.
 Dental Aerosol as a Hazard Risk for Dental Workers

100. The effect of different irrigation solutions and activation techniques on the expression of growth factors from dentine of extracted premolar teeth

Hancerliogullari, D., Erdemir, A. & Kisa, U.
International Endodontic Journal, 54(10), pp.1915–1924.

Aim: 
To evaluate in a laboratory study, the effect of different canal irrigant solutions and activation techniques on transforming growth factor (TGF-β1), insulin growth factor-1 (IGF-1), bone morphogenetic protein-7 (BMP-7) and vascular endothelial growth factor-A (VEGF-A) release levels from the dentine of extracted premolar teeth.
Methodology: 
Seventy premolar teeth with single root and canal were used. The lengths of the root segments were standardized to 12 mm, and the root canals were prepared up to size 100 with hand files. All surfaces of the teeth were covered with nail polish except the inner root canal surface. The root canals were irrigated with 1.5% NaOCl. Ten teeth were allocated to the control group. The remaining sixty teeth were divided into 2 main groups according to the chelating agent used (17% EDTA, 10% Citric acid; CA) and 3 subgroups (n = 10) according to irrigation activation technique (conventional syringe irrigation (CSI), passive ultrasonic irrigation (PUI) and Er:YAG laser activation). After the activation procedure, the root segments were placed into eppendorf tubes containing 1 mL of phosphate-buffered saline solution and kept at 37℃. TGF-β1, IGF-1, BMP-7 and VEGF-A release levels from dentine were measured using the enzyme-linked immunosorbent assay (ELISA) method at 24 h and at day 7. The volume of root canals was calculated using cone-beam computed tomography. The growth factor levels were calculated in ng/mL except VEGF-A (pg/ml). Normality analysis of the data was evaluated with the Kolmogorov-Smirnov test. Statistical analysis was performed using the Mann-Whitney-U and Wilcoxon tests.
Results: 
Regardless of the activation type and sampling time, EDTA caused significantly more IGF release than did CA, whereas EDTA and CA were equally effective for the release of the other growth factors. For either EDTA or CA, the lowest and highest growth factor release levels were observed in the CSI and Er:YAG laser groups, respectively (p < .05). All of the growth factors were released significantly more at 24 h than on day 7 (p < .05).
Conclusions: 
Irrigation activation techniques with EDTA or CA increased the release levels of all growth factors from the dentine of canal walls in extracted premolar teeth.
Keywords: EDTA; Er:YAG laser; citric acid; growth factors; regenerative endodontics; ultrasonic.
 The effect of different irrigation solutions and activation techniques on the expression of growth factors from dentine of extracted premolar teeth

101. Effect of Optimized Irrigation With Photon-Induced Photoacoustic Streaming on Smear Layer Removal, Dentin Microhardness, Attachment Morphology, and Survival of the Stem Cells of Apical Papilla

Wu L, Jiang S, Ge H, Cai Z, Huang X, Zhang C. 
Lasers Surg Med. 2021;53(8):1105-1112.

Background and objectives: 
This study aimed to evaluate the effect of optimized irrigation with photon-induced photoacoustic streaming (PIPS) activation of different irrigants (distilled water or ethylenediaminetetraacetic acid [EDTA]) on smear layer removal, dentin microhardness, attachment morphology, and survival of stem cells of the apical papilla (SCAP) in an organotypic root canal model.
Study design/materials and methods: 
A total of 144 standardized root segments were randomly allocated into 6 groups for irrigation: (i) NaOCl group, (ii) NaOCl + EDTA group, (iii) NaOCl + PIPS (distilled water) group, (iv) NaOCl + PIPS (EDTA) group, (v) NaOCl + EDTA + PIPS (distilled water) group, and (vi) NaOCl + EDTA + PIPS (EDTA) group. Each group was divided into four subgroups for assessment: (i) dentin cleanliness; (ii) dentin microhardness; (iii) cell attachment morphology; and (iv) viable SCAP quantification.
Results: 
Compared with the control groups, the NaOCl + EDTA + PIPS (EDTA) group showed higher efficiency in smear layer removal and in increasing SCAP viability with more stretched cellular morphology. There were no statistically significant differences in either smear layer removal effect, dentin microhardness, attachment morphology, or survival of SCAP among the other groups when optimized with PIPS (distilled water or EDTA) (P > 0.05).
Conclusions: 
Our findings indicated that irrigation optimized with PIPS activation of EDTA for 40 seconds was conducive to smear layer removal without additional dentin microhardness decrease. Additionally, this irrigation created more cell-friendly dentin conditioning than other approaches, which was beneficial for the attachment and survival of SCAP. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.
Keywords: cell attachment; photon-induced photoacoustic streaming; regenerative endodontics; smear layer; stem cells of apical papilla.
 Effect of Optimized Irrigation With Photon-Induced Photoacoustic Streaming on Smear Layer Removal, Dentin Microhardness, Attachment Morphology, and Survival of the Stem Cells of Apical Papilla

102. Efficacy of Er:YAG laser-assisted direct pulp capping in permanent teeth with cariously exposed pulp: A pilot study

Wang, M., Ma, L., Li, Q. & Yang, W.
Australian endodontic journal : the journal of the Australian Society of  Endodontology Inc, 2020;46(3), pp.351–357.

Abstract:
Direct pulp capping is a minimally invasive method to preserve pulp integrity. We evaluated the treatment efficacy of Er:YAG laser irradiation combined with direct pulp capping for pulp exposure due to caries. A total of 21 patients with 22 teeth were enrolled in the conventional group (calcium hydroxide), and 24 patients with 25 teeth were enrolled in the laser-assisted group (Er:YAG laser irradiation at settings of 10 Hz, 50 mJ; combined with calcium hydroxide). The cumulative success rate of the conventional group and the laser-assisted group was 68.2% and 91.7% at 12 months, respectively. Results showed that the laser-assisted procedure increased the survival time (β = 0.04, OR = 0.07), while proximal-occlusal cavities in molars decreased the survival time (β = 0.03, OR = 12.5). Er:YAG lasers improve the effectiveness of conventional direct pulp capping (using Dycal) with limited side-effects and can be applied clinically.
Keywords: calcium hydroxide; dental pulp capping; dental pulp exposure; lasers; pilot projects
 Efficacy of Er:YAG laser-assisted direct pulp capping in permanent teeth with cariously exposed pulp: A pilot study

103. Thermal Evaluation by Infrared Thermography Measurement of Osteotomies Performed with Er:YAG Laser, Piezosurgery and Surgical Drill—An Animal Study

Gabrić, D., Aumiler, D., Vuletić, M., Gjorgievska, E., Blašković, M., Mladenov, M. & Pavlić, V.
Materials, 2021;14, p.3051

Background:
The bone healing process following osteotomy may vary according to the type of surgical instrumentation. The aim of the present in vivo study was to determine thermal changes of the bone tissue following osteotomies performed by Er:YAG laser ablation in contact and non-contact modes, piezoelectric surgery, and surgical drill using an infrared thermographic camera. For each measurement, the temperature before the osteotomy-baseline (Tbase) and the maximal temperature measured during osteotomy (Tmax) were determined. Mean temperature (ΔT) values were calculated for each osteotomy technique. The significance of the difference of the registered temperature between groups was assessed by the ANOVA test for repeated measures. Mean baseline temperature (Tbase) was 27.9 ± 0.3 °C for contact Er:YAG laser, 29.9 ± 0.3 °C for non-contact Er:YAG laser, 29.4 ± 0.3 °C for piezosurgery, and 28.3 ± 0.3 °C for surgical drill. Mean maximum temperature (Tmax) was 29.9 ± 0.5 °C (ΔT = 1.9 ± 0.3 °C) for contact Er:YAG laser, 79.1 ± 4.6 °C (ΔT = 49.1 ± 4.4 °C) for non-contact Er:YAG laser, 29.1 ± 0.2 °C (ΔT = −0.2 ± 0.3 °C) for piezosurgery, and 27.3 ± 0.4 °C (ΔT = −0.9 ± 0.4 °C) for surgical drill. Statistically significant temperature changes were observed for the non-contact laser. The results of the study showed beneficial effects of the osteotomy performed by the Er:YAG laser used in the contact mode of working as well as for piezosurgery, reducing the potential overheating of the bone tissue as determined by means of infrared thermography.
Keywords: Er:YAG laser, piezoelectric surgery, animal model, osteotomy, thermography
 Thermal Evaluation by Infrared Thermography Measurement of Osteotomies Performed with Er:YAG Laser, Piezosurgery and Surgical Drill—An Animal Study

104. Explaining the working mechanism of laser-activated irrigation and its action on microbial biofilms: A high-speed imaging study

Swimberghe, R.C.D., Tzourmanas, R., De Moor, R.J.G., Braeckmans, K., Coenye, T. & Meire, M.A.
International endodontic journal, 2022;55(12), pp.1372–1384.

Aim: 
Laser-activated irrigation (LAI) using pulsed erbium lasers has been studied with regard to canal cleaning, but its working mechanism remains poorly understood. This study sought to unravel the method of action of LAI and to assess its effect on bacterial biofilms in a root canal model, by means of high-speed imaging.
Methodology: 
A root canal model consisting of dentine and glass walls was used. Visualization of the canal space during activation was achieved with a high-speed camera, capturing 20-s activation series at 50 000 frames per second. Recordings were made of canal models filled with water, models filled with water containing glass microspheres, and models with a biofilm (an undefined biofilm originating from oral samples, a 1-week-old Enterococcus faecalis biofilm or a 11-day-old multispecies biofilm) grown on the dentine walls. LAI parameters were 2940 nm, 15 Hz, 50 μs, 20 mJ and 400 μm conical tip held at orifice level. Quantitative (measurement of size, life time and timing of cavitation bubbles; velocity and amplitude of root canal content movement) and qualitative (descriptive) analysis of the intracanal events was performed using imaging software.
Results: 
During the implosion of the primary bubble, smaller cavitation bubbles emerged throughout the entire canal. This process began in the coronal canal part and continued in the apical direction. Expansion of these bubbles was followed by an implosion, and this volumetric change over a time span of a few 100 μs resulted in a very rapid vertical movement of the canal content with a mean amplitude of 900 μm. The succession of these movements with every pulse, resulted in biofilm detachment from the root canal walls and the gradual displacement of fragments coronally, until their complete removal. The pattern of the biofilm removal was the same for all groups. LAI was able to remove biofilm from the root canal models.
Conclusions: 
The hydrodynamic effect of LAI is based on the generation of small cavitation bubbles throughout the entire canal, far from the primary bubble. Their volumetric oscillation results in a small yet very fast vertical movement of the root canal content and local liquid streaming on each pulse, resulting in biofilm detachment and coronal displacement.
Keywords: biofilm; cavitation; erbium laser; high-speed imaging; irrigation; root canal.
 Explaining the working mechanism of laser-activated irrigation and its action on microbial biofilms: A high-speed imaging study

105. FESEM evaluation of smear layer removal from conservatively shaped canals: laser activated irrigation (PIPS and SWEEPS) compared to sonic and passive ultrasonic activation—an ex vivo study

Mancini, M., Cerroni, L., Palopoli, P., Olivi, G., Olivi, M., Buoni, C. & Cianconi, L.
BMC Oral Health,  2021; 21: 81.

Background:
Irrigation of the pulp space is a mandatory step to get rid of all its organic and inorganic content. Activation of the irrigants play a key role in the era of minimally invasive endodontics. The aim of this study was to assess the effectiveness of different irrigants activation methods in removing the smear layer at 1, 3, 5 and 8 mm from the apex from conservatively shaped canals.
Materials and Methods;
Eighty-five human mandibular premolars were selected. Specimens were shaped to TruShape 25/.06 and divided into 5 groups (1 control and 4 test groups) according to the final activation technique (EndoActivator, EA), Ultrasonic (EndoUltra, PUI) and Laser (PIPS and SWEEPS). EDTA (Ethylenediaminetetraacetic acid) followed by NaOCl (Sodium Hypochlorite) and again EDTA were activated for each test group. Specimens were then split longitudinally and observed by Field Emission Scanning Electron Microscopy (FESEM). Blinded evaluation of the presence of smear layer was performed at 1000X magnification, according to a 5-score index system. Comparison between groups were analysed statistically using the Kruskal–Wallis non-parametric analysis of variance. Bonferroni multiple comparison tests were used.
Results:
At 1 mm only PIPS and SWEEPS performed better than the control group. At 3, 5 and 8 mm from the apex, every activation technique showed statistically significant reduction of smear layer when compared to the control group. PIPS and SWEEPS obtained better cleanliness result compared to EA, while only PIPS was superior to PUI in terms of cleanliness.
Conclusions:
PIPS and SWEEPS showed the best results in conservative canal preparations. Nowadays, contemporary rotary instruments allow fast and minimally invasive shaping of the endodontic space. In this scenario irrigants’ activation may be regarded as a mandatory step to a favourable clinical outcome.
Keywords: Smear layer removal, Conservative canal shaping, Sonic activation, PUI, PIPS, SWEEPS
 FESEM evaluation of smear layer removal from conservatively shaped canals: laser activated irrigation (PIPS and SWEEPS) compared to sonic and passive ultrasonic activation—an ex vivo study

106. Comparison of Gingival Troughing by Laser and Retraction Cord

Tao X, Yao J-W, Wang H-L, Huang C.
Int J Periodontics Restor Dent.2018;38(4):527-532.

Abstract
This study was aimed at comparing the most common two methods for gingival troughing: presaturated cord and lasers (including diode, Nd:YAG, and Er:YAG). A total of 108 anterior teeth (58 maxillary and 50 mandibular) in 50 patients were included in this study. Gingival treatment was carried out in the following four groups: presaturated cord, diode laser, Nd:YAG laser, and Er:YAG laser. The gingival width and gingival recession (GR) were measured at different times (at the time of treatment, after 1 week, and after 4 weeks). The presaturated cord resulted in significantly higher (P < .05) GR than lasers and narrower gingival sulci. Er:YAG laser resulted in the quickest and most uneventful wound healing when compared to diode and Nd:YAG lasers.
 Comparison of Gingival Troughing by Laser and Retraction Cord

107. Efficacy Comparison of Nd:YAG laser, diode laser and dentine bonding agent in dentine hypersensitivity reduction: a clinical trial

Tabatabaei MH, Chiniforush N, Hashemi G, Valizadeh S.
Laser Ther. 2018;27(4):265-270.

Purpose
Dentin hypersensitivity is characterized by short, sharp pain arising from exposed dentin in response to external stimuli. Several modalities have been suggested for treatment of this condition such as low-level laser therapy (LLLT) and application of dentin bonding agents. The aim of this study was to compare the clinical efficacy of diode laser, Nd:YAG laser and dentin bonding agent for treatment of dentin hypersensitivity.
Materials and methods
In this study, 135 teeth of 22 patients diagnosed with dentin hypersensitivity were divided into three groups: In group 1, the teeth were irradiated by diode laser with 810 nm wavelength for 30 seconds and in group 2, the teeth were irradiated by Nd:YAG laser with 1064 nm wavelength for 40 seconds. CLEARFIL SE BOND was applied on teeth in group 3. LLLT was carried out in 3 sessions with 7-day intervals between sessions, during a period of 3 consecutive weeks. Hypersensitivity was assessed by cold test according to the criteria proposed by Uchida at baseline, immediately after treatment and at 1, 3 and 6 months, postoperatively.
Results
Reduction of dentin hypersensitivity was observed at 3 and 6 months following the use of Nd:YAG laser (p < 0.001). Reduction in dentin hypersensitivity was observed immediately after treatment in all groups. Statistically significant differences in level of dentin hypersensitivity were found between groups at 3 and at 6 months (p ≤ 0.001). The reduction in dentin hypersensitivity by Nd:YAG laser was significantly superior to that in other groups at this time.
Conclusion
The efficacy of Nd:YAG laser in reduction of dentin hypersensitivity was significantly superior to that of other modalities at 3 and 6 months.
 Efficacy Comparison of Nd:YAG laser, diode laser and dentine bonding agent in dentine hypersensitivity reduction: a clinical trial

108. Postoperative evaluation of Er:YAG laser, piezosurgery, and rotary systems used for osteotomy in mandibular third-molar extractions

Civak, T., Ustun, T., Yilmaz, H.N. & Gursoy, B.
Journal of Cranio-Maxillofacial Surgery, 2020; 49(1), pp.64–69.

Objective
This study compared patient postoperative pain, swelling, and trismus after usage of rotary instruments, piezosurgery, and Er:YAG lasers in mandibular third-molar extraction.
Materials and methods
This prospective study was executed with class II and position B vertically impacted mandibular third molars. Patients were divided into three groups according to the osteotomy system used to remove retentive bone: rotary instruments, piezosurgery, and Er:YAG laser. Postoperative pain was evaluated using VAS questionnaires at 12 h, 24 h, 48 h, and 7 days after procedures. Trismus was evaluated by measuring the distance between the maxillary and mandibular incisors at maximum mouth opening, and comparing preoperative measurements with those for postoperative days 2 and 7. Analyses of swelling were carried out via a stereophotogrammetry system. Operation times were measured using a digital stopwatch from the initial incision to the final suture.
Results
There were no statistically significant differences between the groups in terms of pain, trismus, or swelling (p > 0.05). Pain persisted more in the rotary instrument group 24 h later (0 ± 1.3; p = 0.001). The pain scores obtained after 48 h for the piezosurgery (1.81 ± 2.29) and rotary (2.2 ± 2.12) groups were observed at 24 h in the laser group (2.19 ± 1.52). The mean operation time was highest using the laser (19.1 ± 3.85 min; p = 0.001) and lowest using rotary instruments (9.88 ± 2.97 min; p = 0.001).
Conclusion
Piezosurgery and Er:YAG laser are good alternatives to rotary instrument systems in third-molar extraction, but both systems are slower than traditional rotary instruments.
 Postoperative evaluation of Er:YAG laser, piezosurgery, and rotary systems used for osteotomy in mandibular third-molar extractions

109. Aesthetic treatment outcomes of capillary hemangioma, venous lake, and venous malformation of the lip using different surgical procedures and laser wavelengths (Nd:Yag, er,cr:Ysgg, co2, and diode 980 nm)

Nammour, S., Mobadder, M. El, Namour, M., Namour, A., Arnabat-Dominguez, J., Grzech-Leśniak, K., Vanheusden, A.
Journal of Environmental Research and Public Health, 2020; 17(22), pp.1–17.

Abstract
Different approaches with different clinical outcomes have been found in treating capillary hemangioma (CH), venous lake (VL), or venous malformations (VM) of the lips. This retrospective study aims to assess scar quality, recurrence rate, and patient satisfaction after different surgeries with different laser wavelengths. A total of 143 patients with CH or VM were included. Nd:YAG laser was used for 47 patients, diode 980 nm laser was used for 32 patients (treatments by transmucosal photo-thermo-coagulation), Er,Cr:YSSG laser was used for 12 patients (treatments by excision), and CO2 laser was used for 52 patients (treatments by photo-vaporization). The Manchester scar scale was used by practitioners to assess the scar quality. The recurrence rate and patients’ satisfaction were noted at different follow-ups during 12 months. Our retrospective study showed that laser-assisted aesthetic treatment of vascular lesions (CH, VL, and VM) of the lips can be considered effective regardless of the wavelength used (Er,Cr:YSGG, CO2, Nd:YAG, and diode 980 nm) or the treatment procedure (transmucosal photo-thermo-coagulation, photo-vaporization, and surgical excision). There was no significant difference in patient and practitioner satisfaction with aesthetic outcome at 6 months follow-up. Furthermore, the treatments of lip vascular lesions performed using Er,Cr:YSGG and CO2 lasers did not show any recurrence during the 12 months of follow-up, while recurrence rates of 11% ± 1.4% and 8% ± 0.9% were seen in the diode and Nd:YAG groups, respectively.
 Aesthetic Treatment Outcomes of Capillary Hemangioma, Venous Lake, and Venous Malformation of the Lip Using Different Surgical Procedures and Laser Wavelengths (Nd:YAG, Er,Cr:YSGG, CO2, and Diode 980 nm)

110. Evaluation of upper labial frenectomy: A randomized, controlled comparative study of conventional scalpel technique and Er:YAG laser technique

Sarmadi, R., Gabre, P. & Thor, A.
Clinical and experimental dental research, 2020.

Objectives
Abnormalities in the maxillary frenum may lead to esthetic or functional limitations and need to be corrected with a surgical intervention called frenectomy. The aim of the study was to compare frenectomies performed using Er:YAG laser technology with those using a conventional scalpel technique. Comparisons were of patients’ experiences, treatment times, bleeding during treatment and wound healing.
Material and methods
The trial was performed as a prospective, randomized and controlled, single-blind investigation. A total of 40 patients requiring frenectomy were randomly assigned to groups which underwent either conventional or Er:YAG laser treatment. Patients’ experiences, treatment time, bleeding and wound healing were evaluated immediately after surgery and 5 days, 12 days and 3 months after surgery.
Results
Significant increase in time spent in surgery and bleeding was seen with conventional scalpel surgery. Directly after surgery the wound area was significantly larger in the laser group but at the 5-day evaluation no difference could be observed between the groups. Finally, patients were satisfied with both methods, giving them the same assessments.
Conclusion
In the frenectomy procedure, laser surgery is faster and causes less bleeding and may be advantageous in frenectomies.
 Evaluation of upper labial frenectomy: A randomized, controlled comparative study of conventional scalpel technique and Er:YAG laser technique