Topographical Analysis of Human Enamel after Phosphoric Acid Etching and Er,Cr:YSGG Laser Irradiation

Introduction: Dental hard and soft tissues have been successfully removed by using the Er,Cr:YSGG laser, but there is a controversy about using lasers over conventional tooth surface preparation for bonding aesthetic restoration. Surface roughness and wettability in response to Er,Cr:YSGG laser irradiation are essential properties for restoration longevity. Methods: Fifty-one intact human premolars removed in orthodontic treatment were included in this study and divided into three groups (n=17). The first group (G1) was the control without surface treatment, (G2) was treated with 37% phosphoric acid for 15 seconds, and (G3) was treated with the Er,Cr:YSGG laser using the following parameters: 2 W or 3 W at 20 Hz, 10% air and water ratio using the MZ6 laser tip. The standardization of laser irradiation was accomplished by a computerized numerical control unit. The surface of the samples was evaluated by using a light microscope, profilometer, atomic force microscopy (AFM), SEM, and wettability tests. Results: The SEM examination revealed that the lased enamel surface was clean, irregular, and devoid of a smear layer, while the acid etch surface was relatively smooth and covered with a smear layer. The surface roughness of the lased enamel surface was significantly higher than that of other groups, according to the results of the profilometer as well as the AFM tests. The wettability test showed that the lased enamel surface recorded a significant reduction in the contact angle in comparison to the other groups. Conclusion: It can be concluded that the Er,Cr:YSGG laser can be used as an alternative and safe method to the acid-etching technique for surface treatment.

Clinical, Bacterial, and Prosthodontic Parameters After Implant Abutment Disinfection Using Nd:YAG, Er,Cr:YSGG, Chlorhexidine, and Conventional Steam Before Prosthesis Delivery

Objective: This 1-year prospective clinical trial was designed to assess the microbial, clinical, radiographic, and prosthetic parameters after disinfection of the implant abutment connection using Er,Cr:YSGG (erbium, chromium-doped: yttrium, scandium, gallium, and garnet) and Nd:YAG (neodymium-doped yttrium, aluminum, garnet). Materials and methods: All the patients were divided into four groups; Group I: Nd:YAG laser, Group II: Er,Cr:YSGG laser, Group III: 0.2% chlorhexidine (CHx), and Group IV: steam disinfection. Peri-implant parameters assessed included peri-implant bleeding scores (PIBS), peri-implant plaque scores (PIPS), peri-implant pocket depth (PIPD), and crestal bone loss (CBL). The peri-implant plaque samples were acquired to perform microbiological analysis to assess Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, respectively. All measurements were completed at baseline, 6 months, and 12 months postsurgery. Multiple groups were compared with the help of the Bonferroni post-hoc adjustment test (p < 0.01). Logistic regression models were utilized to assess the association between age, oral hygiene practices (brushing and flossing), and duration of implant function. Results: At the baseline level, there were no discernible differences in the peri-implant parameters between the study groups (p > 0.05). At the 6-month (p < 0.01) and 12-month (p < 0.001) follow-ups, all four study groups demonstrated a significant improvement in PIPS and PIBS, with no significant differences between the groups at baseline (p > 0.05). Based on an intergroup comparison, Group I (Nd:YAG) showed a significant decrease in PIBS when compared with the other groups. Group II showed a considerable decrease in PIPD and enhancements in CBL when compared with Groups I, III, and IV (p < 0.01). At the 6- and 12-month follow-up periods, P. gingivalis and T. denticola reduction were found to be statistically higher in Group II, whereas P. gingivalis and T. forsythia mean log CFU/mL were found to be statistically higher in Group I. Conclusions: Nd:YAG and Er,Cr:YSGG lasers both outperformed CHx and steam disinfection in terms of clinical, peri-implant, and prosthetic results when used to clean implant abutments.

Pretreatment of Root Dentin Using Photon-Induced Photoacoustic Streaming, Photodynamic Therapy, and Riboflavin with EDTA as a Final Irrigant to Improve Bond Integrity of Glass Fiber Post

Objective: To evaluate the outcome of post space disinfection using Er,Cr:YSGG laser (ECYL), riboflavin photosensitizer (RFP), and photon-induced photoacoustic streaming (PIPS) along with ethylene diamine tetra acetic acid (EDTA) as final irrigant on the bond values of glass fiber post (GFP) to the canal wall. Materials and methods: Forty human mandibular premolars were subjected to root canal treatment after decoronation till the cementoenamel junction. Post space was prepared using a Gates-Glidden drill leaving 4 mm of gutta perch at the apical third of the root section. Random allocation of samples was performed into four groups based on the post space disinfection (n = 10 each): Group 1: 1% RFP and 17% EDTA, group 2: 5.25% sodium hypochlorite (NaOCl) and 17% EDTA (control), group 3: PIPS and 17% EDTA, and group 4: ECYL and 17% EDTA. GFP was luted using Rely X Unicem. A universal testing machine and stereomicroscope were used to assess the push-out bond strength (PBS) and failure mode, respectively. Analysis of variance determined the PBS amid different experimental groups at three root levels. Multiple group comparison using means of tested groups was identified using post hoc Tukey. Results: The coronal third of group 2 (5.25% NaOCl +17% EDTA) demonstrated the highest PBS (8.83 ± 0.11 MPa). However, the lowest bond integrity (4.15 ± 0.52 MPa) was displayed in an apical third of group 1 (RFP +17% EDTA). The intergroup comparison revealed that 5.25% NaOCl +17% EDTA at all three levels demonstrated comparable outcomes of PBS with PIPS +17% EDTA and ECYL +17% EDTA specimens (p > 0.05). However, riboflavin +17% EDTA demonstrated the lowest bond strength (p < 0.05). Conclusions: Er,Cr: YSGG and PIPS in combination with 17% EDTA demonstrated comparable outcomes of bond score with those of conventional gold standard irrigation regime 5.25% NaOCl.

Incorporation of Zirconium Oxide Nanoparticles in Adhesive Resin for Bonding of Brackets to Enamel Conditioned with Er,Cr:YSGG, Photodynamic Therapy, and Phosphoric Acid

Objective: To evaluate the effect of enamel conditioning methods, that is, total-etch and rinse (TER), Er,Cr:YSGG (ECYL), and photodynamic therapy (PDT) on the shear bond strength (SBS) of orthodontic metallic brackets bonded using Zirconium oxide experimental adhesive (ZOEA). Methods: Sixty human incisor buccal surfaces were cleaned and allocated into three groups based on the method of enamel surface treatment, that is, TER using 37% phosphoric acid gel, methylene blue photosensitizer activated by PDT and ECYL (n = 20 each). Each group was further divided into two subgroups (n = 10) based on the type of adhesive, that is, ZOEA and experimental adhesive (EA). Metallic brackets were seated using composite resin. Samples were placed in a universal testing machine for SBS and failure mode using the ARI index. One-way analysis of variance and post hoc Tukey were used for multiple comparisons. ARI was presented in percentages in different investigated groups. Results: TER+ZOEA (17.16 ± 0.41 MPa) displayed the highest bond integrity. However, group PDT+EA (11.34 ± 0.25 MPa) demonstrated the lowest bond scores. The intergroup comparison revealed that the TER system displayed significantly higher SBS values than the PDT and ECYL groups (p < 0.05). The intragroup comparison revealed that enamel conditioned with TER and brackets bonded with ZOEA and EA displayed comparable bond integrity (p > 0.05). Conclusions: Enamel conditioned with TER bonded to a metallic bracket displayed better bond strength than PDT and ECYL. Zirconium oxide nanoparticles incorporated in adhesive have proved to be promising in improving the bond integrity of adhesive.

Influence of Lithium disilicate pretreatment using photodynamic therapy, non-thermal plasma, and laser treatment on surface roughness and bond strength

AIMS

To assess the shear bond strength (SBS) and surface roughness (Ra) of lithium disilicate ceramic (LDC) after using different pretreatment methods i.e., Non-Thermal Plasma (NTP), self-etching ceramic primer (SECP), curcumin photosensitizer (CP), Er and Cr: YSGG lasers (ECL) in comparison to hydrofluoric acid + Silane (HF + S) MATERIALS AND METHODS: : A total of fifty LDC discs were prepared. All the discs were arbitrarily divided into five groups based on the surface conditioning used (n=10). Group 1: PDT+S, group 2: HF+ S, group 3: NTP + S, group 4: SECP, and group 5: ECL+ S. A confocal optical microscope was used to calculate Ra for each sample. A self-adhesive resin cement was applied followed by LED light curing. A universal testing machine was used to assess SBS and a stereomicroscope was used to determine the failure mode. Two-way analysis of variance (ANOVA), and a Tukey post hoc test was used to analyze data (p=0.05) RESULTS: : The highest bond integrity of resin luting bonded to conditioned LDS ceramics were presented by group 2 (HF+ S) (21.48±1.39 MPa) and lowest by group 1 (CP+S) (13.01±1.19 MPa) respectively. Intergroup comparison analysis revealed that group 1(13.01±1.19 MPa) and group 3 (14.28±0.62 MPa) displayed comparable outcomes of bond integrity(p>0.05). Similarly, it was observed that group 2 (21.48±1.39 MPa) and group 5 (21.31±1.85MPa) exhibited comparable values of bond strength(p>0.05). Specimens conditioned with HF+ S showed the highest Ra (1445.86±0.019µm). However, discs treated with SECP exhibited the lowest Ra (0139.76±0.081µm) CONCLUSION: Er, Cr: YSGG laser retains the ability to be used as an LDC surface conditioner as an alternative to HF+ S.Both the methods of pretreatment results in high surface roughness of LDC.

Removal of lithium disilicate veneers with Er,Cr:YSGGL laser: now? Or after ageing?

This study was purposed to assess the impact of ageing and resin cements polymerized with different modes on the removal time of lithium disilicate (LiSi) ceramics using Er,Cr:YSGG laser. Ninety LiSi slabs (6 × 6 × 1 mm) were cemented to freshly extracted bovine teeth using cements polymerized with different modes (light-curing (LC), dual-curing (DC), self-curing (SC)). The specimens were divided into subgroups according to ageing conditions (no thermal cycling, 5000 or 30,000 thermal cycling). After that, Er,Cr:YSGG laser was applied until LiSi slabs were debonded; the removal time was recorded. Vickers microhardness test, SEM and EDS analyses were performed for specimens with the longest exposure time to laser application in the groups. One uncemented sample was also used as a control. Data were analyzed with two-way ANOVA and Tukey post hoc test. Ageing and cement polymerization mode significantly affected the removal time of LiSi specimens. The removal time for the self-curing resin cement group (22.67 ± 12.68 s) was significantly longer than for cements polymerized with other methods (LC = 10.833 ± 7.28 s, DC = 12.0 ± 7.96 s). Removal time was significantly reduced after ageing in all polymerization modes; however, there were no significant differences between 5000 (11.83 ± 7.52 s) and 30,000 (11.83 ± 7.26 s) thermal cycling groups. Self-curing resin cements had prolonged the laser-aided removal time for LiSi ceramics. It can be concluded that Er,Cr:YSGG laser-aided removal of LiSi veneers after clinical use can be done more faster than its immediate removal.

In Vitro Study of Laser-Assisted Prefabricated Ceramic Crown Debonding as Compared to Traditional Rotary Instrument Removal

This study compared the laser and rotary removals of prefabricated zirconia crowns in primary anterior and permanent posterior teeth. Sixty-two extracted teeth were prepared for prefabricated zirconia crowns cemented with resin-modified glass-ionomer cement. Specimens underwent crown removals by a rotary handpiece, or erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. Pulpal temperatures, removal times, and scanning electron microscopy (SEM) examinations were compared. The average crown removal time for rotary and laser methods was 80.9 ± 19.36 s and 353.3 ± 110.6 s, respectively, for anterior primary teeth; and 114.2 ± 32.1 s and 288.5 ± 76.1 s, respectively, for posterior teeth (p < 0.001). The maximum temperature for the rotary and laser groups was 22.2 ± 8.5 °C and 27.7 ± 1.6 °C for anterior teeth, respectively (p < 0.001); and 21.8 ± 0.77 °C and 25.8 ± 0.85 °C for the posterior teeth, respectively (p < 0.001). More open dentinal tubules appeared in the rotary than the laser group. The rotary handpiece removal method may be more efficient than the laser with lower pulpal temperature changes. However, the laser method does not create noticeable tooth or crown structural damage compared to the rotary method.

A Novel Concept of Combined High-Level-Laser Treatment and Transcutaneous Photobiomodulation Therapy Utilisation in Orthodontic Periodontal Interface Management

This case report is aimed to demonstrate the synergetic effects of λ940 nm laser photobiomodulation (PBM) therapy in augmenting the advantages of high-level-laser treatment (HLLT)-mediated reaction orthodontic periodontal interface management. Materials and Methods: A 32-year-old female who presented with a persistent gummy smile of upper incisors and low upper midline frenum attachment post-orthodontic treatment, was seeking a better smile appearance. She had a history of delayed wound healing without underlying medical conditions; otherwise, she was fit and healthy. She underwent laser ablation of the upper midline frenum and gingivoplasty of the upper incisors region with λ940 nm and λ2780, respectively, as well as transcutaneous PBM therapy (λ940 nm) to accelerate wound healing. The laser protocols were as follows: λ2780 nm: power output—2 W, pulse width—60 μs, free running pulse (FRP), spot area—0.0016 cm², pulse repetition rate—25 pulses per second (s), 80 mJ/pulse, 90 s, λ940 nm: 1.2 W, continuous wave (CW) emission mode, 300 μm, 60 s; whereas the adjunctive λ940 nm induced-PBM parameters were as follows: power output—1.4 W, CW—120 s, single application, spot area—2.8 cm². An acceleration of the wound healing was observed on the 4th day of treatment with no immediate or post-operative complications. The results showed no functional or aesthetic relapses at a long-term follow-up of 6 months. The authors concluded that λ940 nm laser-PBM can provide a synergetic effect to HLLT in accelerating wound healing and offering a precision smile with minimal to none post-operative complications. It is safe and justifiable to utilise dual therapy over the conventional methods, which serves our patients’ needs in our daily practice and in various clinical indications. The concept and laser protocols of this clinical case report can pave the roadmap for future extensive studies.

Erbium, chromium-doped: yttrium, scandium, gallium, garnet and diode lasers in the treatment of peri-implantitis: clinical and biochemical outcomes in a randomized-controlled clinical trial

This study aims to evaluate the effects of 940 nm diode laser and 2780 nm erbium, chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser used in addition to mechanical therapy in the non-surgical treatment of peri-implantitis on clinical parameters and matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels in the peri-implant crevicular fluid. A total of 50 patients with peri-implantitis were randomized into three groups to receive peri-implant treatment. The control group (n = 17) only received conventional non-surgical mechanical therapy. The trial groups [(diode group (n = 16) and Er,Cr:YSGG group (n = 17)] received dental laser in addition to mechanical therapy. Gingival index (GI), plaque index (PI), bleeding on probing, probing depth (PD), MMP-9, and TIMP-1 levels were assessed at baseline (T0) and at 6 months after treatment (T1). The GI, PI, and PD significantly decreased in all groups at T1, compared to T0 (p < 0.05). The decrease in the PD was similar between the control and diode groups with Er,Cr:YSGG providing more reduction (1.16 ± 0.64 mm) than either method (p = 0.032). A significant intra-group decrease in MMP-9 level was only observed in the Er,Cr:YSGG group (p = 0.009). The decrease in TIMP-1 level from T0 to T1 was similar between the control and the diode groups (p > 0.05) and it was significantly lower than the decrease in the Er,Cr:YSGG group (p < 0.05). Addition of diode laser to non-surgical mechanical therapy does not provide any additional benefit for treatment outcomes. The Er,Cr:YSGG laser seems to be more efficient both at clinical and molecular levels. ClinicalTrials, ID: NCT04730687. Registered 13 April 2021. Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04730687.

Effectiveness of photodynamic therapy on bonding strength and failure modes of fiber-posts in c-shaped treated root canals

AIM

The present study aimed to assess the push-out bond strength (PBS) and failure modes of fiber-posts after photodynamic therapy (PDT) and Erbium yttrium scandium gallium garnet (Er,Cr:YSGG) in c-shaped canals.

METHODS

Sixty molars with c-shaped root configuration were studied. The endodontic prepared teeth specimen were equally randomized into four groups: i) photodynamic therapy (PDT); ii) Er,Cr:YSGG; iii) chlorhexidine and; iv) control group. Post root filling, 10 mm space was prepared for insertion of post in the root canals. The push-out bond strength was evaluated using Universal testing machine. Modes of failure were evaluated as adhesive, cohesive and admixed. Mean values were computed between groups using Kruskal-Wallis test followed by Bonferroni post hoc test. Comparison between two thirds of root sections were analyzed using Friedman test. P-value was set at 0.05 or less.

RESULTS

Specimens treated with PDT reported the highest mean PBS (8.56 ± 2.12 MPa), while the lowest PBS was observed in NaOCl group (6.92 ± 2.21 MPa). Thirteen failures were observed at the adhesive post interface, whereas 22 failures were found at the interface forming between the dentin surface and adhesive. Similarly, 9 failures were categorized as mixed. For PDT group, a sum of 3 failures and 4 failures were noted at the apical and cervical points.

CONCLUSION

The specimens treated with PDT showed the highest push out bond strength with least number of failures.in c-shaped root canals.

Influence of different irrigation regimens on the dentinal tubule penetration of a bioceramic-based root canal sealer: a confocal analysis study

This study aims to assess the efficacy of various irrigation protocols on the dentinal tubule penetration of a bioceramic-based endodontic sealer. Sixty-four single-rooted extracted human mandibular incisors were used. After instrumentation, teeth were randomly divided into the following four groups (n = 16 each) according to the final irrigation technique: group 1, conventional endodontic needle (CEN); group 2, EndoActivator (EA); group 3, Er,Cr: YSGG laser; group 4, XP-endo Finisher (XPF). The root canals were finally irrigated with 17% EDTA and 5.25% NaOCl for 1 min (min) respectively. The teeth were then obturated with Endosequence BC Points and rhodamine B dye-labeled BC Sealer. After 2 weeks, 1-mm-thick transverse sections were cut 2 and 5 mm from the apex, and examined by confocal laser scanning microscopy at 5 × magnification. The total percentage of sealer penetration (TPSP), sealer penetration area (SPA), and maximum sealer penetration depth (MSPD) was measured. Data were analyzed by Kruskal-Wallis, Dunn's multiple comparison, and Wilcoxon tests, with significance set at P < 0.05. At 2 mm level, no significant differences were detected among the groups (P > 0.05). At the 5 mm level, the XPF group showed significantly higher values for both TPSP and SPA in comparison with the Er,Cr: YSGG laser and CEN groups (P < 0.05), but no significant difference was observed with the EA group. The choice of different final irrigation techniques can affect dentinal tubule penetration.

Shear bond strength of metallic brackets bonded to enamel pretreated with Er,Cr:YSGG LASER and CPP-ACP

Background

Increased risk of enamel demineralization during and after orthodontic treatment raises the demand for better preventive measures including combinations of laser, CPP-ACP, and fluoride. The combination of Er,Cr:YSGG laser with CPP-ACP was proved to have a synergetic effect compared to each of them alone. Shear bond strength (SBS) of orthodontic brackets bonded to the enamel surface after being treated with preventive measures is critical. The aim of this study was to compare the SBS and failure mode of metallic brackets bonded to teeth with no pretreatment and pretreated enamel surface, either with Er,Cr:YSGG laser alone or combined with CPP-ACP.

Methods

Sixty sound extracted human premolar teeth were allocated randomly to 3 groups: In Group 1 (control), teeth were etched and bonded directly; in Group 2, laser pretreatment of the enamel surface was done followed by etching and bonding as in the control group; in Group 3, the enamel surface was lased then CPP-ACP was applied according to the manufacturer instructions, etched and bonded. SBS and Adhesive remnant index (ARI) were evaluated.

Results

No significant differences were found between the 3 groups neither in the SBS nor in the ARI scores.

Conclusions

The use of combined Er,Cr:YSGG laser with CPP-ACP as a preventive measure before bonding orthodontic brackets does not endanger the bracket’s bonding strength.

Surface treatment of RMGIC to composite resin using different photosensitizers and lasers: A bond assessment of closed Sandwich restoration

AIM

The aim of present study was to assess and compare different conditioning methods (laser, PDT and conventional) on shear bond strength (SBS) of resin modified glass ionomer cement (RMGIC) bonded to composite (sandwich technique).

MATERIAL AND METHODS

Fifty specimens were prepared from RMGIC and were packed in a teflon mould placed on glass slab. Through each of the glass slab the cement was light cured for 20 s. Now samples were randomly allocated into five groups (n = 10) according to pre-treatment protocols. In group 1 RMGIC were conditioned with MBP using PDT, Samples in group 2 treated with Er,Cr:YSGG (ECYL), group 3 pre-treated with Nd:YAG laser (NYL), samples in group 4 surface conditioned with air abrasion (AA) and group 5 conditioned with 37 % phosphoric acid (PA). Specimens after conditioning were rinsed with distilled water. Adhesive Adper Single Bond 2 was applied on treated surface of RMGIC and cured. Teflon mold was utilized to hold the composite Filtek Z250 in an incremental technique. For SBS testing all specimens were placed under shear knife edge at 1 K N at a speed of 0.5mm2 until bond failure. Optical microscope was used to evaluate failure pattern at 10x magnification. The data of SBS in Megapascal were subjected to statistical test. Analysis of variance was followed by Post hoc test with level of significance at 5 %.

RESULT

The maximum SBS was found in group 5 RMGIC conditioned with 37 % PA (16.45 ± 0.32 MPa). Whereas, group 1 (MBP, PDT) demonstrated significantly lower bond integrity (9.82 ± 1.08 MPa) compared to all experimental groups. Bond integrity of RMGIC surface treated with MBP, PDT (9.82 ± 1.08 MPa), group 3 lased with NYL (11.47 ± 0.53 MPa) and samples in group 4 conditioned with AA (11.23 ± 0.47 MPa) were comparable (p > 0.05).

CONCLUSION

ECYL has a potential to be used for conditioning of RMGIC prior to composite restoration (sandwich technique). MBP at 100 mg/L deteriorates SBS of composite to RMGIC.

Influence of photodynamic therapy and different lasers Er,Cr:YSGG and Er,YAG on dentin conditioning bonded to conventional and bioactive cement

AIM

The aim of the present study was to evaluate the bond integrity of bioactive cement (BA_c) in contrast to conventional cement Calibra (C) after dentin treated with different surface conditioners (PDT, EYL, ECL) MATERIALS AND METHODS: Sixty non-carious permanent mandibular molars were disinfected and embedded in acrylic resin till cement-o-enamel junction. For homogeneity the buccal surface were grounded and polished. Samples were categorized into three main groups based on conditioning technique. Samples in group 1 and 2 dentin conditioned with Er,Cr:YSGG (ECL), group 3 and 4 surface treated with Er:YAG (EYL) and group 5 and 6 treated with photodynamic therapy (PDT).On conditioned surface bonding agent was applied and light cured. Samples from group 1,3,5 were bonded to Calibra (C). Whereas, specimens in group 2,4,6 were conditioned with bioactive cement (BA_c) and subjected to ageing followed by shear bond strength testing (SBS) in universal testing machine. To detect significance difference between means of different groups analysis of variance (ANOVA) was performed followed by Tukey's post-hoc tests.

RESULTS

The maximum SBS was displayed in group 1, dentin conditioned with ECL and bonded to C (20.23 ± 0.47 MPa). Whereas, group 6, PDT of dentin to BA_c demonstrated lowest bond integrity among experimental groups (12.97 ± 0.25 MPa). Bond strength of group 1, ECL-C (21.55 ± 3.08 MPa) and group 3 EYL-C (19.11 ± 0.65 MPa) were comparable (p > 0.05). Group 5 samples treated with PDT, MB-C (13.41±0.32 MPa) and group 6, MB-BA_c (12.97 ± 0.25 MPa) were also comparable (p > 0.05) CONCLUSION: BAc bonded to dentin after surface conditioning with ECL, EYL and PDT presented lower SBS in comparison to conventional cement C. Further studies are required to extrapolate the current findings.

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.

Does Er,Cr:YSGG reduce the microleakage of restorations when used for cavity preparation? A systematic review and meta-analysis

Background

As the member of erbium laser family, Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) has obtained the approval for caries removal and cavity preparation by Food and Drug Administration (FDA). However, there is still controversy over the beneficial effects of Er,Cr:YSGG preparations on microleakage. The present study is the first systematic review and meta-analysis to compare the microleakage of cavities prepared by Er,Cr:YSGG lasers with that by traditional burs. In addition, the effect of acid etching on the adhesive potential of self-etch and etch-and-rinse adhesives was assessed after laser preparation.

Methods

An electronic search was performed in Pubmed, EBSCO, Embase, and the Cochrane Controlled Register of Trials (CENTRAL).

Results

Totally, 357 articles were identified. Finally, 13 met the inclusion criteria, of which 11 were selected for meta-analysis. All the included studies exhibited a moderate risk of bias. Based on the meta-analysis, no significant difference was observed between the Er,Cr:YSGG and traditional bur groups in terms of the incidence of microleakage. Self-etch adhesives, in combination with prior acid etching, showed less microleakage than those without acid etching in the laser-prepared cavities.

Conclusions

Current studies do not support the beneficial effects of Er,Cr:YSGG preparations on microleakage. Additional acid etching with self-etching adhesives is recommended after Er,Cr:YSGG preparations. Further high-quality studies are needed to draw a convincing conclusion in the future.

Bond assessment of resin modified glass ionomer cement to dentin conditioned with photosensitizers, laser and conventional regimes

AIM

To assess different conditioning regimes on shear bond strength (SBS) of resin modified glass ionomer cement (RMGIC) bonded to dentin MATERIAL AND METHODS: Fifty non carious intact maxillary molars were cleaned, isolated and randomly divided into five groups (n = 10). Before randomization, dentin surface was exposed and finished. Samples in group 1 were conditioned with methylene blue photosensitizer (MBP) 50 mg/l and activated by photodynamic therapy (PDT), Group 2: surface treated with Er,Cr:YSGG (ECL), Group 3: surface conditioned with polyacrylic acid (PAA) (control), Group 4: surface conditioned with 17 % Ethylenediaminetetraacetic acid (EDTA), Group 5: surface conditioned with total etch (Optibond solo Plus). For SBS testing the samples were placed in universal testing machine. Fracture analysis of debonded surfaces were evaluated using stereomicroscope at 40x magnification. Means and standard deviations were calculated using analysis of variance (ANOVA) and Tukey's post hoc test at a significance level of (p < 0.05).

RESULTS

The maximum bond strength was found in group 5 conditioned with Optibond solo plus total etch (23.15 ± 3.21 MPa). Whereas, the lowest bond values were observed in group 1 treated with MBP (15.25 ± 1.54 MPa). Moreover, samples in group 2, group 3 and group 4 resulted in comparable bond strength (p > 0.05).

CONCLUSION

MBP at 50 mg/l is not recommended to condition dentin prior to RMGIC application. Moreover, ECL has a potential to be suggested for dentin conditioning compared to PAA.

Debris and Smear Layer Removal in Curved Root Canals Using the Dual Wavelength Er,Cr:YSGG/Diode 940 nm Laser and the XP-Endoshaper and Finisher Technique

Objective: To validate the capability of the dual wavelength laser (Er,Cr:YSGG and diode 940 nm) and the XP-Endoshaper and finisher in removing the smear layer from curved canals. Methods: Forty curved root canals were prepared using the R25 file of the Reciproc^® system. The teeth were randomly divided into five groups: G1: negative control irrigated with distilled water, G2: positive control irrigated with EDTA 17% and a final rinse of NaOCl 3%, G3: XP-Endoshaper and finisher with EDTA 17%, G4: dual wavelength Er,Cr:YSGG (1.25 W, 50 Hz, 50 μs) and diode 940 nm (2 W, 50% DC), and G5: dual wavelength Er,Cr:YSGG (2 W, 20 Hz, 50 μs) and diode 940 nm (2 W, 50% DC). Laser scanning microscope images (1000 × ) were scored with the Hülsmann scoring system. Results: Superior smear layer removal was observed in G5 in comparison with G4, especially in the apical third of the canal. Furthermore, the XP-Endoshaper and finisher exhibited positive results in all parts of the canal. Conclusions: The higher power output of the Er,Cr:YSGG in the dual wavelength laser may be a suitable approach to remove the smear layer from the apical third of curved canals. Moreover, the XP-Endoshaper and finisher with EDTA could expose the dentinal tubules, however, the negative side effects of applying EDTA 17% for longer periods must be taken into consideration. This work is clinically significant as it addresses the main aim of endodontic treatment and provides a suitable method to remove the debris, smear layer, and bacterial remnants from the clinically challenging curved root canals.

Dentin bond strength of bioactive cement in comparison to conventional resin cement when photosensitized with Er,Cr:YSGG Laser

Objective:

The purpose of the present study was to assess dentin shear bond strength (SBS) and mode of bond failure of bioactive cement (BA) in comparison to conventional resin cement when photosensitized by Er,Cr: YSGG Laser (ECL).

Methods:

The present in-vitro study was carried out from March 2019 to May 2019. Sixty permanent non-carious, intact, non-fractured molars were isolated and mounted vertically in acrylic resin. Buccal surface of each molar tooth was ground, polished and surface treated with ECL. Ketac conditioner was applied on the surface washed and air dried surface. Tetric -N-Bond adhesive was applied on forty-five samples and light cured. The specimens were allocated into four groups (n=15) according to the type of cement used i.e., Calibra (C), BA, Variolink II (V) and Maxcem-Elite (ME). For SBS testing was performed using the universal testing machine. Eight samples from each group were assessed for modes of failure. Means and standard deviations were compared using analysis of variance (ANOVA) and Tukey’s post hoc test at a significance level of p < 0.05.

Results:

The highest mean SBS was observed in group ECL-C (21.55±3.08). The lowest mean SBS was displayed in group ECL-ME (14.25±3.55). Mean SBS values for group ECL-C (21.55±3.08) and group ECL-V (20.74±4.15) were comparable (p <0.05). Similarly, SBS values of group ECL-BA (15.48±3.62) and group ECL-ME (14.25±3.55) were comparable (p <0.05).

Conclusion:

Dentin surface conditioned with Er,Cr: YSGG and bonded to C and V cements exhibit favourable bond strength values.

Influence of photobio-modulation with an Er,Cr: YSGG laser on dentin adhesion bonded with bioactive and resin-modified glass ionomer cement

METHODS

One hundred and twenty extracted human molars were allocated in eight groups (n = 15) based on surface conditioning and cement type. Specimens of groups 2 and 6 were conditioned with ECL whereas, groups 3 and 7 were treated with ECL + ethylenediamine tetra acetic acid (EDTA). Specimens in groups 4 and 8 were surface conditioned by ECL + EDTA + Tetric-N-Bond, and groups 1 and 5 were considered as control (non-surface treated). Cement build-ups were performed on the surface-treated dentin with BAC (groups 1-4) and RMGIC (groups 5-8). A universal testing machine was used to measure the SBS and the mode of failure was evaluated using a stereomicroscope. Statistical analysis was performed using an analysis of variance and Tukey's post hoc test, at a significance level of p < 0.001.

RESULTS

The highest SBS values were observed in group 8, ECL + EDTA + Tetric-N-Bond + RMGIC (21.54 ± 3.524 MPa) and the lowest SBS values were displayed by group 1, with no surface treatment and BAC application (11.99 ± 0.821 MPa). The majority of failures were found to be mixed in lased dentin-treated dentin surfaces. BAC when bonded to dentin surfaces conditioned with ECL showed lower SBS in comparison to RMGIC.

CONCLUSION

Conditioning of dentin with ECL and a bonding agent (Tetric-N-bond) improved bond strength scores for BAC and RMGIC. Use of EDTA improved bond strength values when bonded to BAC and RMGIC; however, this improvement was not statistically significant.

Lithium di silicate ceramic surface treated with Er,Cr:YSGG and other conditioning regimes bonded to orthodontic bracket

Aim

To assess bond integrity and modes of failure of metallic brackets to lithium disilicate ceramics (LDC) conditioned with Er,Cr:YSGG laser (ECL).

Material and methods

Sixty LDC were arbitrarily allocated into six groups (n = 15) according to the type of ceramic surface conditioning treatment. Group 1 surface treated with silane (S) only, group 2 surface etched with hydrofluoric acid (HF)+ S, group 3 surface conditioned with HF+ ultrasonic bath (UB)+ S, group 4 sand blasting (SB) of glass ceramic surface with 50 µm Al₂O₃, group 5 surface conditioned with self-etch ceramic primer (SECP) and in group 6 surface treated with ECL + S. After conditioning, the specimens were positioned in a universal testing device for shear bond strength (SBS) testing. Adhesive Remnant Index (ARI) was used to determine sites of bond failure. Among experimental groups analysis of variance (ANOVA) and Tukey multiple comparison test was used at a significance level of (p < 0.05).

Results

The highest SBS values were observed in group 3 HF+ UB + S (18.21 ± 1.241) and the lowest SBS values were displayed group 1 surface treated with S only (5.21 ± 0.23). Specimens surface conditioned in group 2 with HF+ S (17.85 ± 1.25), group 3 HF+ UB + S (18.21 ± 1.241) and group 6 ECL + S (17.09 ± 1.114) unveiled comparable SBS values (p > 0.05).

Conclusion

LDC conditioned with ECL at (4.5 W and 30 Hz) has a potential to be used in clinical settings alternate to HF acid.

The Effect of Er,Cr:YSGG and Diode Laser Applications on Dental Implant Surfaces Contaminated with Acinetobacter Baumannii and Pseudomonas Aeruginosa

Treatment of peri-implantitis through several implant surface decontamination techniques have been reported, however, some of them can negatively alter the implant surface or enhance more bacterial resistance. The aim of this in vitro study was to evaluate implant surface decontamination by means of Er,Cr:YSGG and diode lasers. Fifty micro-textured (MTX) dental implants were contaminated with Acinetobacter baumannii (n = 25) and with Pseudomonas aeruginosa (n = 25). All implants were then divided into five groups for the decontamination procedure. In group I (GI), decontamination was done with an Er,Cr:YSGG laser (2780 nm), while in group II (GII) decontamination was performed using photodynamic therapy (a 650 nm diode laser). In Group III (GIII) decontamination was performed with photodynamic therapy (an 808 nm diode laser), and in group IV (GIV) decontamination was performed with 0.12% chlorhexidine. Group V (GV) was the control group with no decontamination. After decontamination, colony forming units (CFU) were counted and implants were prepared for SEM analysis. A significant difference (p < 0.001) was observed for GI compared to the other groups, and also for GIV compared to both GII and GIII. The Er,Cr:YSGG laser (GI) showed the best results in decontaminating the implant surface. Chlorhexidine (GIV), proved to be better in decontaminating the implant surface than photodynamic therapy GII and diode laser GIII. No significant difference was found between group GII and GIII. The SEM analysis showed no significant change in the implant surface topography. The results of this study suggest that the Er,Cr:YSGG laser can be considered as an effective technique for reducing bacteria contamination on implant surfaces.

Comparison of Er:YAG and Er,Cr:YSGG Laser in the Treatment of Oral Leukoplakia Lesions Refractory to the Local Retinoid Therapy

Objective: The aim of this study was to compare the efficacy of Er:YAG and Er,Cr:YSGG laser in the treatment of oral leukoplakia refractory to conventional retinoid therapy. Materials and methods: The study sample consisted of 54 patients (16 men and 38 women) who were histopathologically diagnosed with oral leukoplakia that was refractory to conventional retinoid therapy. Patients were randomly allocated into two groups according to the type of the laser used for treatment of oral leukoplakia: Group 1. Er:YAG laser; Group 2. Er,Cr:YSGG laser. Patients were recalled at 6 months and 1 year after treatment to evaluate possible recurrence and assess the patients' postoperative quality of life. Results: After initial ablation, the degree of residual lesion was significantly greater in the Er:YAG laser group (74.1%), compared with the Er,Cr:YSGG group (18.5%) (p = 0.0001). Six months and 1 year after the second ablation, there was no lesion recurrence in either laser group. Fourteen days after the initial ablation, the visual analog scale (VAS) pain rating and the total oral health impact profile score fell significantly in both groups (p < 0.0001). However, in the Er,Cr:YSGG laser group, the average value of the VAS rating was significantly lower than in the Er:YAG laser group (p = 0.039). Conclusions: The Er:YAG and Er,Cr:YSGG lasers showed similar efficacy in the treatment of oral leukoplakia and resulted in full postoperative recovery without recurrence after 1 year of follow-up.

Effect of Er,Cr:YSGG on Remineralization Using CPP - ACPF (MI - Paste Plus) after Enamel Erosion Caused by Carbonated Soft Drink in Primary Teeth: In-Vitro Study

BACKGROUND:

Erosion is a widespread phenomenon with higher predilection in primary dentition.

AIM:

The aim of the present study is to assess the remineralising effect of Er,Cr:YSGG laser application combined with CPP-ACPF after erosive demineralisation by Coca-Cola in primary teeth.

METHODS:

Fifty teeth (n = 10) were divided into; Group I: Artificial saliva, (Saliva natural, Medac, UK), Group II: CPP-ACPF (MI Paste Plus, GC Corp, USA), Group III: Er,Cr:YSGG (Waterlase iPlus, USA), Group IV: CPP-ACPF + Er,Cr:YSGG, Group V: Er,Cr:YSGG + CPP-ACPF. Teeth were immersed in Coca-Cola for 10 min, 5 times/day for 5 days. DIAGNOdent (DD) measurements were taken before and after the experiment.

RESULTS:

There was a significant increase in DD readings after erosive-treatment cycles in all test groups. The highest reading was in samples immersed in artificial saliva, and the lowest was in those subjected to combined CPP-ACPF and Er,Cr:YSGG laser application, regardless of the sequence used. There was no significant difference between samples immersed in artificial saliva, and after CPP-ACPF application. Similarly, there was no significant difference between samples treated by combined treatment of CPP-ACPF and Er,Cr:YSGG application. However, there was a significant difference between samples immersed in artificial saliva or treated with CPP-ACPF application and those subjected to combined treatment CPP-ACPF along with Er,Cr:YSGG.

CONCLUSION:

Combining Er,Cr:YSGG laser and CPP-ACPF paste significantly increased enamel remineralisation, regardless of the sequence implemented. Saliva naturally and CPP-ACPF application had a comparable effect on remineralisation.

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

Purpose

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.

Materials and methods

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.

Results

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.

Conclusion

Preparing access cavities with either laser or bur has no effect on the fracture resistance of teeth with root canal treatment.

Effects of Erbium Family Laser on Shear Bond Strength of Composite to Dentin After Internal Bleaching

Introduction: The aim of this study was to assess the effect of surface treatment with erbium: yttrium-aluminum-garnet (Er:YAG) and erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers on shear bond strength of composite resin to recently bleached dentin. Methods: In this study, 40 extracted human premolars were selected. The teeth were cut 4 mm apical to the cusp tip and were randomly divided into four groups (n=10 in each group) for shear bond strength testing. For bleaching, 35% hydrogen peroxide (H2 o2 ) gel (Opalescence Endo, Ultradent, South Jordan, UT, USA) was applied to dentin surfaces of all specimens for 10 days. Before etching and bonding, in Er,Cr:YSGG and Er:YAG laser groups, dentin surfaces were irradiated with Er,Cr:YSGG and Er:YAG lasers, respectively. In Er,Cr:YSGG group, Er:YAG group and control group, composite restoration was performed immediately after bleaching while in common procedure group, composite restoration was performed after seven days. The teeth were then subjected to shear bond strength testing machine. The data were statistically analyzed using analysis of variance (ANOVA) and Tukey test. Results: The mean and standard deviation (SD) of shear bond strength was 4.3 ± 1.4 MPa for control group, 6.7 ± 2.0 Mpa for Er,Cr:YSGG group, 14.4 ± 3.7 Mpa for Er:YAG group and 19.4 ± 2.6 Mpa for common procedure group. Conclusion: The shear strength of composite to Er:YAG laser-treated bleached dentin was significantly higher than control group while significantly lower than common procedure.

Evaluation of the Effects of Er,Cr:YSGG Laser, Ultrasonic Scaler and Curette on Root Surface Profile Using Surface Analyser and Scanning Electron Microscope: An In Vitro Study

Introduction: The periodontal therapy is primarily targeted at removal of dental plaque and plaque retentive factors. Although the thorough removal of adherent plaque, calculus and infected root cementum is desirable, it is not always achieved by conventional modalities. To accomplish more efficient results several alternative devices have been used. Lasers are one of the most promising modalities for nonsurgical periodontal treatment as they can achieve excellent tissue ablation with strong bactericidal and detoxification effects. Methods: Thirty freshly extracted premolars were selected and decoronated. The mesial surface of each root was divided vertically into four approximately equal parts. These were distributed into four group based on the root surface treatment. Part A (n = 30) was taken as control and no instrumentation was performed. Part B (n = 30) was irradiated by Erbium, Chromium doped Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser. Part C (n = 30) was treated by piezoelectric ultrasonic scaler. Part D (n = 30) was treated by Gracey curette. The surface roughness was quantitatively analyzed by profilometer using roughness average (Ra) value, while presence of smear layer, cracks, craters and melting of surface were analyzed using scanning electron microscope (SEM). The means across the groups were statistically compared with control using Dunnett test. Results: Among the test groups, Er,Cr:YSGG laser group showed maximum surface roughness (mean Ra value of 4.14 μm) as compared to ultrasonic scaler (1.727 μm) and curette group (1.22 μm). However, surface with smear layer were found to be maximum (50%) in curette treated samples and minimum (20%) in laser treated ones. Maximum cracks (83.34%) were produced by ultrasonic scaler, and minimum (43.33%) by curettes. Crater formation was maximum (50%) in laser treated samples and minimum (3.33%) in curette treated ones. 63.33% samples treated by laser demonstrated melting of root surface, followed by ultrasonic scaler and curettes. Conclusion: Er,Cr:YSGG laser produced maximum microstructural changes on root surface that can influence the attachment of soft periodontal tissues as well as plaque and calculus deposition. In vivo studies are needed to validate these results and to evaluate their clinical effects.

Effect of the lasers used in periodontal therapy on the surfaces of restorative materials

The present study aimed to reveal potential damage of the lasers, which are used as an alternative to manual instruments in periodontal therapy, might cause to the surface of restorative materials. Four different restorative materials were used: a glass-ionomer cement (GIC), a flowable composite (FC), a universal composite (UC) and an amalgam. Ten cylindrical samples (8 mm × 2 mm) were prepared for each restorative material. Two laser systems were used in subgingival curettage mode; an 940 nm diode laser (Epic Biolase, Irvine, CA) and an Er,Cr:YSGG laser (Waterlase iPlus, Biolase, Irvine, CA). After laser irradiation, roughness of the sample surfaces was measured using a profilometer. Additionally, atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses were performed to evaluate the morphology and surface deformations of the restorative materials and surfaces. The laser irradiation did not affect the surface roughness of any restorative materials relative to that of the control group (p > 0.05) except for the Er,Cr:YSGG treatment on GIC (p < 0.05). SEM and AFM images verified the results of the surface roughness tests. Within the limitations of the present study, it was demonstrated that Er,Cr:YSGG and diode lasers, aside from the Er;Cr:YSGG treatment on GIC, caused no harmful surface effects on adjacent restorative materials. SCANNING 38:227-233, 2016. © 2015 Wiley Periodicals, Inc.

Minimally Invasive Periodontal Treatment Using the Er,Cr: YSGG Laser. A 2-year Retrospective Preliminary Clinical Study

Minimally invasive surgery (MIS) using the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser (Waterlase MD, Biolase, Irvine, CA) to treat moderate to advanced periodontal disease is presented as an alternative to conventional therapies. To date, there are few short- or long-term studies to demonstrate the effects of this laser in treating and maintaining periodontal health. Electronic clinical records from 16 patients – total of 126 teeth, with pocket depths ranging from 4 mm to 9 mm – were treated with the same protocol using the Er,Cr:YSGG laser. The mean baseline probing depths (PD) were 5 mm and clinical attachment levels (CAL) were 5 mm in the 4 - 6 mm pretreated laser group. The mean baseline probing depths were 7.5 and 7.6 mm for PD and CAL respectfully in the 7 – 9 mm pretreatment laser group. At the 2 year mark, the average PD was 3.2 ± 1.1 mm for the 4-6 mm pocket group and the 7-9 mm pocket group had a mean PD of 3.7 ± 1.2 mm. mean CAL was 3.1 ± 1.1 mm for the 4-6 mm group and 3.6 ± 1.2 for the 7-9 mm group with an overall reduction of 1.9 mm and 4.0 mm respectively. At one and two years, both groups remained stable with PD comparable to the three-month gains. The CAL measurements at one and two years were also comparable to the three-month gains.