Yttrium Scandium Gallium Garnet Laser Research Articles

Effect of Dentin and Zirconia Surface Treatments with Laser Irradiation Versus Sandblasting on the Bonding Ability of Zirconia.

Objective: This study aimed to investigate the effects of laser irradiation applied to zirconia and tooth surfaces on shear bond strength (SBS) compared with acid etching and sandblasting. Background: The effect of laser irradiation on the bond strength between zirconia and adhesives is a controversial issue for dentin surface treatments. In addition, the effects of different combinations of surface treatments to increase adhesion on both the zirconia and dentin surfaces remain unclear. Materials and methods: A total of 90 tooth samples were assigned into groups according to various pretreatments: control group was left untreated, acid etching, and Erbium, Chromium:Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser irradiation group (15 Hz, 2 W). In addition, the zirconia specimens were separated into three groups (n = 10) according to the different surface treatments performed: sandblasting (120 μm Al2O3), Er,Cr:YSGG laser (15 Hz, 2 W), and as untreated surface. The zirconia samples were cemented to the dentin surface using dual-cure resin cement and subjected to an SBS test at a speed of 0.5 mm/min under a universal testing machine until fractures occurred in the bonding surface. Results: The highest SBS values were observed in Group tooth acid (TA)-zirconia Er,Cr:YSGG laser (ZL), followed by Group tooth Er,Cr:YSGG laser (TL)-zirconia sandblasting (ZS) and Group TA-zirconia control (ZC). The lowest SBS values were found in Group TA-ZS. Significant intergroup difference was noted between Group TA-ZL, Group tooth control (TC)-ZC, Group TL-ZS, and Group TC-ZC. However, no significant difference was noted between Group TA-ZL, Group TL-ZS, and Group TA-ZC. Conclusions: Acid etching and laser treatments applied to the dentin and zirconia surfaces were found to be effective techniques for improving the zirconia-dentin bond, respectively. Clinical Trial Registration number: 33216249-604.01.02-E.24308.

Effects of Er: YAG, Er,Cr: YSGG, and Nd: YAG laser irradiation and adhesive systems on the immediate and long-term bond strength of dentin: a systematic review and meta-analysis.

At present, lasers are increasingly used in the oral clinical field, and research and applications in dental hard tissue treatment are also increasing. The effect of laser etching dentin on the bonding strength of composite resin reported in the literature is still inconclusive. The purpose of this review was to evaluate whether laser etching can improve the immediate and long-term bonding strength of dentin and investigate the effect of different types of adhesives on the bonding strength of dentin. Two reviewers performed a literature search up from January 2012 to November 2021 in four databases: MEDLINE (PubMed), Web of Science, EMBASE, and the Cochrane Library. A total of 25 studies were included in the meta-analysis. The Cochrane Collaboration Bias Risk Assessment tool was used to evaluate the quality of the included literature, and an analysis was carried out using Review Manager Software version 5.3. The aging bond strength of dentin after erbium (Er): yttrium aluminum garnet (YAG) laser treatment was significantly lower than that of dentin in the bur group (P < 0.00001). At the same time, the bond strength of dentin immediately and aging after (Er), chromium-doped (Cr): yttrium scandium gallium garnet (YSGG) laser treatment was lower than that of dentin in the bur group (P < 0.05). There was no significant difference in the immediate and aging bonding strength among samples in the Er: YAG laser, Er, Cr: YSGG laser, and blank control groups (no laser or bur). The aging bond strength of samples after neodymium-doped (Nd): YAG laser treatment was higher than that of samples in the blank control group (P < 0.05); in addition, the performance of self-etching adhesive was slightly better than that of acid etching adhesive. Regardless of the applied surface treatment and the adhesive employed, dentin after aging showed significant bond degradation (P < 0.05). There was high heterogeneity of bond strength between different groups, and the small number of studies and the contradictory results may be the main reasons for this outcome.

Effects of Er,Cr:YSGG laser on repair bond strength of 5‐year water‐aged and non‐aged CAD/CAM ceramics

AbstractThe aim of this study is to examine the repair bond strength of three different 5‐year water‐aged and non‐aged computer‐aided design/computer‐aided manufacturing (CAD/CAM) ceramics (leucite‐reinforced, lithium disilicate, and feldspathic ceramic) on which four different surface treatments (bur‐grinding, sandblasting, acid‐etching, and laser irradiation) have been applied with composite resin. Note that 360 ea. samples have been attained from CAD/CAM blocks. Each CAD/CAM ceramic has been randomly separated into two sub‐groups depending on aging procedure. The designed 5‐year water‐aged and non‐aged samples have been separated into four sub‐groups. Ceramic surfaces were repaired then the samples have been placed into shear test device. Three‐way variance analysis has been used in the comparison of the repair bond strengths depending on the ceramic type, surface treatment, and aging. Results have revealed that the repair bond strength values show differences depending on CAD/CAM ceramic type, surface treatment, and the aging of the surface (p &lt; .001). While the aged and laser‐irradiated feldspathic CAD/CAM ceramics showing the highest shear bond strength, the lowest shear bond strength values were in aged and bur‐grinded feldspathic CAD/CAM ceramics. Irradiation with erbium chromium: yttrium scandium gallium garnet (Er,Cr:YSGG) laser has significantly increased the repair bond strength in leucite‐reinforced and feldspathic CAD/CAM ceramics, acid‐etching is suggested surface treatment for the lithium disilicate CAD/CAM ceramics.

Smear Layer Removal by Means of Erbium, Chromium:Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) Laser Irradiation from Apical Third of Mesial Root Canals

Smear Layer Removal by Means of Erbium, Chromium:Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) Laser Irradiation from Apical Third of Mesial Root Canals

Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser for Root Conditioning and Reduction of Postoperative Morbidity in the Treatment of Gingival Recession Defects: A Randomized Controlled Clinical Trial.

Objective: This clinical trial evaluates the effect of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) root surface biomodification and laser harvesting of de-epithelialized gingival graft (DGG) on root coverage clinical outcomes and postoperative morbidity, and compares this to the conventional blade-harvested DGG method without Er,Cr:YSGG root surface biomodification in treatment of Miller's class I, II gingival recessions (GR). Background: The application of laser technology to enhance tooth root coverage clinical outcomes as well as the impact of laser on postoperative morbidity after harvesting autogenous soft tissue grafts requires further research. Methods: This study is a randomized, single-blinded controlled trial, including 24 volunteers with isolated GR defects. They were allocated into three treatment groups to receive one of the following three interventions: blade-harvested DGG (control group: B-DGG); Er,Cr:YSGG-harvested DGG and root surface biomodified [test 1 group: L-laser-harvested DGG (L-DGG)/laser root biomodification (LRB)]; and B-DGG and Er,Cr:YSGG root surface biomodification (test 2 group: B-DGG/LRB). Clinical and radiographic parameters were recorded at baseline (1 week before surgery) and 3, 6, and 9 months postoperatively. Results: Root coverage did not show a statistically significant difference between control and test groups. Statistically significant differences were found for Visual Analog Scale on the day of surgery and day 3 and 4 postoperatively, as well as pain medication on the day of surgery favoring the L-DGG group. Conclusions: The use of Er,Cr:YSGG laser in root surface biomodification improved root coverage outcomes at 9 months. Even these changes were not statistically significant from the control group; the L-DGG technique was associated with decreased postoperative morbidity in the palatal donor site.

Fractional erbium: YSGG laser compared to the combination of fractional erbium: YSGG laser and topical autologous platelet-rich plasma for treatment of atrophic acne scars: a case report

Background: Acne scar is the most common complication in acne that occurs in about 49% of acne individuals. Fractional resurfacing lasers such as CO2 laser and erbium-doped yttrium aluminum garnet (Er: YAG) have been widely used for acne scar treatment and give satisfying results have complications such as pain, hyperpigmentation, infection, prolonged erythema, and scarring. Fractional erbium: yttrium scandium gallium garnet (Er: YSGG) laser solves previous laser techniques' disadvantages. It has an ideal wavelength of 2790 nm, which balances the epidermis layer's vaporization and thermal damage in the dermis's superficial layer. Platelet Rich Plasma (PRP) is an autologous concentration of human platelets in a small plasma volume that secreted various growth factors that can speed up the scar healing process.Case report: A-24 years old male student came with a chief complaint of acne scars on his face four years before the examination. The patient's condition is classified as moderate-severe acne scarring based on Goodman and Baron's criteria (qualitative global acne scarring system). Acne scars treatment plan was single fractional erbium: YSGG laser for the left side of the face and combined fractional Er: YSGG laser with topical autologous PRP on the right side. This procedure was performed in 2 sessions with an interval of 4 weeks, the final evaluation at 12 weeks after the first procedure. Clinical improvement of acne scars was assessed using qualitative and quantitative scales based on Goodman and Baron's, patient and observer scar assessment scale (POSAS), quartile grading scale, and patient satisfaction level.Conclusion: In the final evaluation, there was an improvement on the entire grading scale on the right side of the face (Er: YSGG laser + PRP) and the face's left side (Er: YSGG laser only). Post-treatment erythema was found on both sides of the patient's face but disappeared within three days on the face's right side and five days on the face's left side.

Shear bond strength of acid and laser conditioned enamel and dentine to composite resin restorations: An in vitro study.

ObjectiveTo compare the shear bond strength of enamel or dentin conditioned with either Er,Cr:YSGG (erbium, chromium: yttrium–scandium–gallium–garnet) laser or phosphoric acid to composite resin restoration.Material and methodsForty posterior human extracted teeth were used. After mesiodistal sectioning of the teeth crowns, the samples were randomly divided into two groups—in the first group (E), bonding was performed on the enamel after roughening and in the second group (D), the enamel was removed and bonding was performed on the dentin. These groups were further randomly divided into two subgroups according to the type of etching (n = 20 each). In the acid‐etched groups (EA and DA), the surfaces were etched with 37% phosphoric acid. In the laser‐conditioned groups (EL and DL), the surfaces were conditioned with Er,Cr:YSGG laser. Total‐etch adhesive system was used to bond all the 80 specimens resin composite. The composite was vertically light‐cured, and the specimens were subjected to a shear bond strength test. Modes of bond failure were determined with a stereomicroscope.ResultsThe highest shear bond strength was observed for the DA group (16.25 ± 1.10 MPa, p < 0.0001), whereas the lowest was observed for the DL group (8.56 ± 0.67 MPa). The adhesive failure mode was the most frequently observed in all groups.ConclusionsThe shear bond strength of composite resin bonded to enamel and dentin etched with phosphoric acid was higher than when conditioned with Er,Cr:YSGG laser. Thus, laser conditioning is not recommended.

Smear Layer Removal by Means of Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er, Cr: YSGG) Laser Irradiation from Apical Third of Mesial Root Canals

<i>Aim</i>: This ex-vivo study evaluated the efficiency of an Er, Cr: YSGG laser (2780 nm) at different power settings to remove smear layer from the apical third of mesial roots of first lower molars by using SEM. <i>Materials & Methods</i>: 42 mesial root canals of first mandibular molars (type II Vertucci) were divided into 4 groups of 10 teeth each. The rest 2 teeth were used as control groups. After coronal access, all teeth were instrumented by Protaper Gold rotary files up to size F2 (25/0.08), followed an irrigation protocol with saline. Then, the experimental groups were irradiated by Er, Cr: YSGG laser. Four different output powers were tested, namely 1.25 W, 1.5 W, 2 W, 2.5 W was used to irradiate the roots in Group 1 (G1), Group 2 (G2), Group 3 (G3) and Group 4 (G4) respectively. Control group (n=2) was instrumented as experimental groups but not irradiated. Teeth were sectioned longitudinally and observed under SEM. Results were statistically analyzed with the Kruskal-Wallis Test and Mann-Whitney Test. <i>Results</i>: None of the tested groups succeeded in removing completely the smear layer from apical dentinal walls. The results showed no statistically significant differences between laser groups in removing smear layer from apical third of lower molars. Group 3 (2 W) showed better outcomes but it was not statistically significant. <i>Conclusion</i>: The outcome of the present study showed that laser-assisted smear layer removal with an Er, Cr: YSGG laser with the tested parameters is not predicable for the apical third of root canals. <i>Clinical significance</i>: The presence of chelating factor may play an important role in the mechanism of laser-assisted removal of smear layer in the apical third of root canals. Further research needs to be performed in order to find the optimal irradiation protocol.

Smear Layer Removal from the Apical Third Using the Er,Cr:YSGG Photon-induced Photoacoustic Streaming.

The purpose was to study the influence of Erbium,Chromium:Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser at short pulse duration on smear layer removal from apical root third. Twenty-four single-rooted mandibular premolars were used. The roots length was cut to 14 mm and instrumented using the Protaper Gold system to size 40/0.06. The samples were divided into four groups (n=6) as follows: (A) conventional irrigation with 5 mL of 17% Ethylenediaminetetraacetic acid ( EDTA), (B) passive ultrasonic irrigation with 5mL of 17% EDTA, (C) Er,Cr:YSGG induced photoacoustic streaming (PIPS) with 5 mL of 17% EDTA and (D)Er,Cr: YSGG induced PIPS with 5 mL of 5.25% sodium hypochlorite (NaOCl). After final irrigation with normal saline and drying, the roots were painted with nail varnish externally, and 2%methylene blue dye was injected into the canal. The tooth split horizontally at the fourth millimetres. The picture was taken by a professional Digital SLR camera. The dye penetration was measured using analytical software (measure picture CAD-KAS Kessler Germany). Dunnett's test was used to compare control group against experimental groups. After the statistical test, the highest mean percentage was presented in the laser group with 17% EDTA (Group C=85.9804) followed by the laser group with 5.25% NaOCl (Group D=69.7817) and ultrasonic group (Group B=34.5453) respectively and the lowest mean percentage was in the control group (Group A=20.7969). Based on this in vitro study, PIPS technique using Er,Cr:YSGG pulse laser (0.5 W,5 Hz, air and water off) at short pulse duration and 17% EDTA proved effectively in smear layer removal, while the PIPS proved an acceptable result when the laser is used alone assisted by NaOCl.

Clinical effectiveness of Er,Cr:YSGG lasers in non-surgical treatment of chronic periodontitis: a meta-analysis of randomized controlled trials.

The meta-analysis aimed to systematically evaluate all the available pieces of evidence concerning the clinical effectiveness of Er,Cr:YSGG lasers (erbium, chromium, yttrium scandium gallium garnet laser) in the non-surgical treatment of patients with chronic periodontitis, and provide guidance for clinicians about the application of Er,Cr:YSGG lasers during the process of non-surgical periodontal treatments. The meta-analysis was conducted with data extracted from 16 randomized controlled clinical trials (RCTs) that compare Er,Cr:YSGG lasers adjunct/substitute to scaling and root planing (SRP) with SRP alone for the treatment of chronic periodontitis published in English or Chinese from January 2000 to January 2020. The weighted mean differences (WMDs) and 95% confidence intervals (CIs) were counted for probing depth (PD) reduction, clinical attachment level (CAL) gain, and visual analogue scale (VAS) score. Heterogeneity of each study was evaluated with the Q test. The publication bias was measured using Begg's adjusted rank correlation test. Sixteen RCTs with 606 patients were included in the meta-analysis. There were statistically significant differences between Er,Cr:YSGG lasers adjunct/substitute to SRP and SRP alone in the PD reduction at 1-month follow-up (WMD = ‑0.35, 95% CI [- 0.63, ‑0.07], P =0.013), 3-month follow-up (WMD = - 0.342, 95% CI [- 0.552, - 0.132], P = 0.001), CAL gain at 3-month follow-up (WMD = - 0.17, 95% CI [- 0.31, 0.03], P = 0.017), and VAS score (WMD = - 2.395, 95% CI [- 3.327, - 1.464], P = 0.000) immediately after treatment. There were no significant differences of PD reduction and CAL change at 6-month follow-up. The present meta-analysis indicated that Er,Cr:YSGG lasers provided additional effectiveness in PD reduction and CAL gain at short-term follow-ups and there was less pain compared with SRP alone.

Efficacy of Er,Cr Laser incision Corticotomy in Rapid Maxillary Canine Retraction: A Split-Mouth Randomized Clinical Trial.

Introduction: This study sought to evaluate the efficacy of lasercision corticotomy for the acceleration of canine movement. Our secondary objectives were assessing the canine rotation, the rate of anchorage control, the level of pain, and the gingival index (GI). Methods: Twelve orthodontic patients (9 females and 3 males) referring to the School of Dentistry and one dental clinic from May 2019 to September 2019 participated in this split-mouth randomized clinical trial. The allocation of the test and control sides was performed by flipping a coin. The mean age of patients was 18.91±3.87 years (range 15-30 years). The treatment plan included maxillary first premolar extraction. Following the initial leveling and alignment phase, an initial impression was made. Corticotomy was carried out with the erbium, chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser (3.5 W, 30 Hz, 40% air, 80% water) in one maxillary quadrant (the laser side). Canine retraction was immediately initiated following surgery using nickel-titanium closed-coil springs with 150 g force. The impression was repeated 1 month after the onset of retraction. The casts were scanned, and the distance between the canine cusp tip and the rugae line was measured to quantify the amount of anteroposterior canine movement. The molar anchorage control was also evaluated by measuring the distance between the mesial contact of the permanent first molar and the rugae line. Gingival health was evaluated using the GI. The modified McGill pain questionnaire was used to assess the level of patients' pain. Results: Lasercision corticotomy accelerated canine retraction with no adverse effect on gingival health. Anchorage loss in the posterior teeth and pain scores were not significantly different between the control and laser sides. Conclusion: Laser corticotomy can effectively accelerate canine retraction with no complications or discomfort for the patients.

Lasers to prevent dental caries: a systematic review

ObjectiveTo assess the effectiveness of lasers (at sub-ablative parameters) in reducing caries incidence compared with traditional prophylactic interventions (TPIs) when used alone or together with other TPIs such as pits...

Evaluation of Smear Layer Removal by Activation Ethylene Diamine Tetra Acetic Acid 17% with Erbium Chromium: Yttrium Scandium Gallium Garnet and Diode Laser: Scanning Electron Microscopy

Background and Objectives: Activation of ethylene diamine tetra acetic acid (EDTA) with diode laser and Erbium Chromium: Yttrium Scandium Gallium Garnet (Er, Cr: YSGG) proposed as a promising adjuvant to conventional protocols but, its effectiveness has been seldom addressed. The purpose of this study was to evaluate the effect of laser-activated irrigations using the diode laser and the Er, Cr: YSGG laser on removing smear layer (SL) from the root canal wall. Materials and Methods: SL was generated by preparing the root canals of extracted human teeth to a #35/0.05 two shape instrument. The SL then received treatments of one of the following: Group 1, 5 ml, 5.25% NaOCl + 5 ml, 17% EDTA Each for 60 s, Group 2 5 ml, Group 2, 5.25% NaOCl 60 s + 5 ml, 17% EDTA 40 s + Diode laser 980 nm 20 s 5 ml, and Group 3, 5.25% NaOCl 60 s + 17% EDTA 35 s + Er, Cr: YSGG with RFT-2 tip for five cycles of 5 s. Results: The activation of EDTA with diode laser 980 nm shows to be most effective in the SL in the apical and coronal third could be very useful adjutant in endodontic treatment due to its compactness.

Microshear Bond Strength of a Self-adhesive Composite to Erbium Laser-Treated Primary Enamel.

Introduction: Advances have been made in the composition of flowable composites in recent years and self-adhering composites, which do not require a bonding agent, have recently been introduced to the market. This study aimed to assess the microshear bond strength (µSBS) of a self-adhering flowable composite (Vertise) to primary enamel treated with a graphite disc with silicon carbide particles (SIC) and laser irradiation, the result of which was compared to that of a conventional flowable composite (Premise). Methods: In this in vitro, experimental study, 72 samples of sound primary enamel were evaluated. A smooth enamel surface was obtained using a graphite disc. Next, the erbium chromium yttrium scandium gallium garnet (Er,Cr:YSGG) laser was used for enamel surface treatment in half of the samples (n=36). All the samples were then randomly divided into 4 groups of (i) Premise flowable composite (PF) without laser (n=18), (ii) Vertise flowable composite (VF) without laser (n=18), (iii) PF with laser (n=18), and (iv) VF with laser (n=18). The teeth were then incubated at 37°C for 24 hours and were then subjected to thermocycling. The µSBS of samples was measured using a universal testing machine and reported in megapascal (MPa). Data were analyzed using SPSS via the two-way ANOVA and independent-samples t test at P<0.05. Results: The mean µSBS of VF was significantly higher to the laser-treated samples (13.60±5.47) compared with the non-treated samples (5.89±2.42) (P<0.001). However, no significant difference was noted in the µSBS of PF to the laser-treated (13.18±3.45) and non-treated samples (16.06±3.52) (P=0.058). Conclusion: The µSBS of the conventional flowable composite is higher than that of the self-adhering flowable composite to the enamel of primary teeth. Enamel surface treatment with laser irradiation increases the µSBS of self-adhering flowable composites.

Er,Cr:YSGG Laser Performance Improves Biological Response on Titanium Surfaces.

Porphyromonas gingivalis infection is one of the causes of implant failures, which can lead to peri-implantitis. Implant surface roughness is reportedly related strongly to P. gingivalis adhesion, which can lead to peri-implantitis and, later, cell adhesion. Our aim was to evaluate the effects of Er,Cr:YSGG laser on titanium (Ti) disc surfaces and its interaction with bacterial adhesion and fibroblast viability. Ti discs underwent two treatments: autoclaving (control) and erbium, chromium-doped yttrium scandium gallium garnet (Er,Cr:YSGG) laser treatment (test). Ti disc surfaces were examined with scanning electronic microscope (SEM), Energy-dispersive spectrometry (EDX), X-ray photoelectron spectroscopy (XPS). The surface roughness same as wettability were also investigated. Fibroblast viability was assessed with the water-soluble tetrazolium 1 (WST-1) test, and osteoblast differentiation was assessed with the alkaline phosphatase (ALP) assay. Bacterial structure and colony formation were detected with scanning electron microscopy and Gram stain. In comparison to control discs, the test discs showed smoother surfaces, with 0.25-µm decrease in surface roughness (p < 0.05); lower P. gingivalis adhesion (p < 0.01); less P. gingivalis colonization (p < 0.05); and increased fibroblast viability and osteoblast differentiation (p < 0.05). Er,Cr:YSGG laser treatment improved disc surfaces by making them slightly smoother, which reduced P. gingivalis adhesion and increased fibroblast viability and osteoblast differentiation. Er,Cr:YSGG laser treatment can be considered a good option for managing peri-implantitis. Further investigations of laser-assisted therapy are necessary for better guidelines in the treatment of peri-implantitis.

Evaluation the effect of different laser powers on the Enterococcus faecalis infected root canals: An in vivo study

Aim: To assess in vivo the immediate and delayed disinfecting efficacy of erbium,chromium:yttrium scandium gallium garnet (Er,Cr:YSGG) laser against Enterococcus faecalis at the output powers 1, 1.5, and 2 W with a 20s period of time. Materials and Methods: Study criteria include 45 single-rooted teeth. Patients were randomly divided into three groups (gps) (n = 15/gp) according to the output powers selected in this study. After access opening, first microbiological samples (S1) were collected immediately before Er,Cr:YSGG laser treatment. Second microbiological samples (S2) were taken immediately after instrumentation and laser disinfection at the output powers 1, 1.5, and 2 W with 20s period of exposure time. Third samples (S3) were collected after 1 week of irradiation. The obtained samples were transferred to an agar plate and incubated for 48h at 37°C. The colonies of E. faecalis formed were then counted. The collected data were analyzed using one-way analysis of variance (ANOVA) analysis and Duncan multiple range tests at level P ≤0.05. Results: The result showed no significant difference between number of bacteria before laser treatment and after 1 week of laser application at the output power 1 W. However, significant difference was detected immediately after laser application. At 2 W a significant difference was observed between number of bacteria before laser treatment and after treatment with no difference between number of bacteria immediately after treatment and after 1 week of irradiation. Conclusion: Er,Cr:YSGG laser at high output power (2 W) detected a maximum reduction of E. faecalis in the infected root canals, but bacteria were not eliminated completely.

Calculus Removal and Root Surface Roughness When Using the Er:YAG or Er,Cr:YSGG Laser Compared with Conventional Instrumentation Method: A Literature Review.

Objective: The purpose of this literature review was to evaluate the effectiveness of using Er:YAG (erbium-doped yttrium/aluminum/garnet) laser or Er,Cr:YSGG (erbium, chromium-doped yttrium/scandium/gallium/garnet) laser on calculus removal and their effect on the topography and roughness of root surface in comparison with the conventional instruments in the nonsurgical periodontal therapy. Background data: One of the most challenging problems in treatment of periodontal disease is the elimination of plaque and calculus, leaving a clean and smooth root surface to decrease plaque and calculus retention, and for good gingival reattachment. Materials and methods: PubMed and Google Scholar were searched for available literature. The electronic search was limited to articles published in the period between January 2007 and April 2017, in the English language. Results: A total of 47 publications fulfilled the inclusion criteria of this systematic review and screened according to the research questions. Calculus removal using the ultrasonic instrument showed remaining calculus compared with the hand instrument, whereas, on the contrary, erbium lasers revealed no remaining calculus or smaller amounts compared with the conventional instruments when used in appropriate settings. The results of this review showed that ultrasonic instrumentation produced effects on the root surface almost similar to that of hand instrumentation. Er:YAG laser and Er,Cr:YSGG laser clarify a little more surface roughness when compared with conventional instruments. Conclusions: The present systematic review indicates that a combination of scaling and root planing (SRP) using the erbium lasers as an adjunctive therapy at certain parameters can be appropriate to remove residual debris from the root surface and at the same time have little or no negative thermal effect on the root surface. The Er:YAG laser also seems to be the most suitable for nonsurgical periodontal therapy. Additional new good-designed studies are needed to evaluate the effectiveness of erbium lasers with SRP in nonsurgical periodontal therapy.

Fracture resistance of root-filled teeth after cavity preparation with conventional burs, Er: YAG and Er,Cr: YSGG lasers.

The aim of the present study is to compare the fracture resistance of teeth after access cavity preparation with conventional rotary burs, Erbium-doped yttrium aluminum garnet laser (Er:YAG) and Erbium, cromium: yttrium scandium gallium garnet laser (Er,Cr:YSGG) lasers. Fifty five intact mandibular molars were divided into 3 negative groups (groups 1, 2, 3; n=5 for each), 3 study groups (groups 4, 5, 6; n=10 for each) and 1 positive control group (intact teeth; n=10). Access cavities of groups 1, 2 and 3 were prepared with conventional burs, Er:YAG laser and Er,Cr:YSGG laser respectively. After root canal obturation, their coronal portions were left non-restored. Access cavities of groups 4, 5 and 6 were prepared by using the same equipment but their coronal portions were restored with composite resinafter root canal obturation. Following thermocycling, fracture strength was evaluated with a Universal Testing Machine. Mean force at which each sample is fractured was recorded in Newton unit and statistically analyzed. Fracture resistance of group 7 (intact teeth) was significantly higher than all other groups (p<0.001). Differences among the fracture resistance values of groups 4, 5 and 6 were not significantly different but they were significantly higher than those of groups 1, 2 and 3 (p<0.001). No significant difference was found between Groups 1, 2 and 3. Preparing access cavities with either laser or bur has no effect on the fracture resistance of teeth with root canal treatment.

PR387: Clinical and immunological evaluation of the efficacy of an erbium, chromium: yttrium scandium gallium garnet laser for non‐surgical periodontal therapy

PR387: Clinical and immunological evaluation of the efficacy of an erbium, chromium: yttrium scandium gallium garnet laser for non‐surgical periodontal therapy

Effect of Laser-Activated Irrigations on Smear Layer Removal from the Root Canal Wall.

The purpose of this study was to evaluate the effect of laser-activated irrigations (LAI) by using the Erbium: Yttrium Aluminum Garnet (Er:YAG) laser and the Erbium Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser on removing smear layer (SL) from the root canal wall. LAI has been proposed as an adjuvant to conventional protocols of endodontic treatment to enhance the disinfection, which is a promising protocol for SL removal. SL was generated by preparing the root canals of extracted human teeth to a #35/.04 M3 instrument. The SL then received treatments of one of the following: (A) NaOCl, 5.25% sodium hypochlorite (NaOCl) for 60 sec; (B) EDTA, 17% ethylenediamine tetraacetic acid (EDTA) for 60 sec; (C) NaOCl+EDTA, NaOCl, and EDTA for 30 sec each; (D) LAI+NaOCl, LAI with NaOCl for 60 sec; (E) LAI+EDTA, LAI with EDTA for 60 sec; and (F) LAI+NaOCl+EDTA, LAI with NaOCl, and EDTA for 30 sec each. Efficacies of SL removal were evaluated by using a five-grade scoring system under scanning electron microscopy. The laser activations significantly enhanced the effect of the NaOCl, EDTA, and NaOCl+EDTA irrigations in removing SL. The efficacies of SL removal were presented in a descending order of LAI+NaOCl+EDTA, LAI+EDTA>LAI+NaOCl, NaOCl+EDTA>EDTA>NaOCl. Among the treatments, the LAI+NaOCl+EDTA was the most effective protocol in removing SL from the entire root canal wall, which may be effective for root canal treatment.