Er:YAG laser debonding of zirconia and lithium disilicate restorations.

STATEMENT OF PROBLEM: Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) restorations of different formulations are being used increasingly in monolithic form for a range of clinical applications. Using rotary instruments to remove such restorations for any purpose is challenging, but they can be removed conservatively with erbium lasers. However, studies on how a laser penetrates different zirconias to break the cement bond between the tooth surface and the zirconia are lacking. PURPOSE: The purpose of this in vitro study was to evaluate and compare the time required for an erbium-doped yttrium-aluminum-garnet (Er:YAG) laser to remove different types of zirconia and lithium disilicate crowns. MATERIAL AND METHODS: Forty extracted premolar teeth were prepared, scanned, designed, and milled to fabricate 40 computer-aided design and computer-aided manufacturing (CAD-CAM) crowns, which were assigned to 4 groups (n=10): 3 mol% Y-TZP, 4 mol% Y-TZP, 5 mol% Y-TZP, and lithium disilicate as a control. All crowns were bonded to the teeth with a self-adhesive resin cement (Panavia SA Cement Universal). Each specimen was irradiated with an Er:YAG laser with the following parameters: 300 mJ, 15 Hz, 5.0 W, and a 50-microsecond pulse duration (supershort pulse mode). The irradiation time required for crowns to be retrieved successfully was recorded for each specimen. Data were statistically analyzed using analysis of variance and the Tukey honestly significant difference post hoc test (α=.05). The intaglio surfaces of the restorations were analyzed using scanning electron microscopy (SEM). RESULTS: The mean ±standard deviation times in minutes needed for crown debonding were 12.46 ±4.17 for the 3 mol% Y-TZP group, 10.30 ±3.33 for the 4 mol% Y-TZP group, 4.03 ±1.62 for the 5 mol% Y-TZP group, and 2.08 ±0.92 for the lithium disilicate group. A statistically significant difference (P<.05) in the debonding time was found for all investigated groups, expect between the 3 mol% and 4 mol% Y-TZP groups and between the 5 mol% Y-TZP and lithium disilicate groups. SEM analysis of the ceramic surfaces showed no visual damage associated with Er:YAG laser irradiation. CONCLUSIONS: Zirconia crown retrieval time with the Er:YAG laser was influenced by the yttria content of the zirconia, with decreasing retrieval time with increasing yttria content. Er:YAG laser debonding of zirconia crowns is a noninvasive, efficient, and rapid approach to the removal of crowns and could be applied in clinical practice.

Do erbium lasers promote changes in the tooth enamel during debonding of ceramic laminate veneers? A systematic review.

The longevity of ceramic laminate veneers can be influenced by several factors, which can result in the need for a removal process. Laser removal has emerged as a good alternative to facilitate the procedure, and its repercussions on tooth enamel have been investigated. We aimed to evaluate the efficacy of erbium lasers for debonding ceramic laminate veneers without damaging the tooth enamel. This systematic review based on the PICOS model adhered to the PRISMA statement. The PubMed/MEDLINE, Web of Science, Embase, and Scopus databases were systematically searched until December 1, 2022, and 2902 studies were retrieved. After screening, four in vitro studies that analyzed the dental morphology using scanning electron microscopy, optical analysis, stereomicroscopy, or x-ray dispersion spectroscopy were included. The risk of bias was assessed using the Cochrane Collaboration tool. Our findings suggest that erbium lasers are useful for ceramic laminate veneer removal without damaging the tooth enamel. However, the removal is influenced by the type and thickness of ceramic and type of cement used. It could be concluded that the application of Erbium laser did not promote superficial changes in the dental enamel. This effect was observed in all analysis performed.

The application of lasers in vital pulp therapy: a review of histological effects.

Vital pulp therapy (VPT) is primarily intended to preserve the vitality of pulp tissues, which have been exposed for any reason. Various materials and techniques have been proposed to improve treatment outcomes, including the use of lasers. This study aimed to review the histological results of different dental lasers including low-level lasers, carbon dioxide (CO2), erbium-doped yttrium aluminum garnet laser (Er:YAG), neodymium-doped yttrium aluminum garnet (Nd:YAG), erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, and diode lasers for VPT. This focused review included a comprehensive electronic search of Scopus, MEDLINE, Web of Science, and Google Scholar databases from 2000 to 2022 by two independent investigators. Different combinations of keywords were used, and reference mining of related papers was done. The review included studies related to histologic evaluation of laser-assisted vital pulp therapy that stated the laser parameters that were used. Articles with radiographic or clinical assessments or articles lacking necessary data were excluded. Non-English articles were excluded unless their abstract was in English and encompassed the necessary data. Most studies indicated the efficacy of lasers for reduction of inflammation, acceleration of healing, and increasing the thickness of dentinal bridge. According to the evidence, lasers used in combination with pulp capping agents are beneficial to enhance the success rate of VPT.

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.

Efficacy of antibacterial agents combined with erbium laser and photodynamic therapy in reducing titanium biofilm vitality: an in vitro study.

BACKGROUND AND OBJECTIVE: The emergence of peri-implant diseases has prompted various methods for decontaminating the implant surface. This study compared the effectiveness of three different approaches, chlorhexidine digluconate (CHX) combined with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser, photodynamic therapy (PDT), and CHX only, for reducing biofilm vitality from implant-like titanium surfaces. STUDY DESIGN/MATERIALS AND METHODS: The study involved eight volunteers, each receiving a custom mouth device containing eight titanium discs. The volunteers were requested to wear the device for 72 h for biofilm development. Fluorescence microscopy was used to evaluate the remaining biofilm with a two-component nucleic acid dye kit. The vital residual biofilm was quantified as a percentage of the surface area using image analysis software. Sixty-four titanium discs were assigned randomly to one of four treatment groups. RESULTS: The percentage of titanium disc area covered by vital residual biofilm was 43.9% (7.7%), 32.2% (7.0%), 56.6% (3.6%), and 73.2% (7.8%) in the PDT, Er:YAG, CHX, and control groups, respectively (mean (SD)). Compared to the control group, the treatment groups showed significant differences in the area covered by residual biofilm (P < 0.001). CHX combined with Er:YAG laser treatment was superior to CHX combined with PDT, and CHX only was better than the control. CONCLUSION: Within the current in vitro model's limitations, CHX combined with Er:YAG laser treatment is a valid method to reduce biofilm vitality on titanium discs.

Efficacy of Smear Layer Removal at the Apical One-Third of the Root Using Different Protocols of Erbium-Doped Yttrium Aluminium Garnet (Er:YAG) Laser.

Background and Objectives: Smear layer forms during cleaning and shaping can obstruct the entry of both irrigant and sealant into the dentinal tubules, resulting in the accumulation of the bacteria and their byproducts. To ensure effective adhesion and better periapical healing, it is strongly advised to remove the smear layer before proceeding with root canal obturation. This study was designed to compare the efficiency of laser-activated irrigation (LAI) in removing the smear layer and debriding the most apical third of the root canal. Materials and Methods: Sixty-five extracted human teeth with straight single roots were randomly and equally divided into four laser and one control groups. Root canals in all samples were shaped using prime size TruNatomy rotary files. During preparation, each canal was irrigated with 3 mL of 3% NaOCl and 3 mL of 17% EDTA alternately, followed by the irrigation with 10 mL of distilled water to avoid the prolonged effect of EDTA and NaOCl solutions. Final irrigation of 5 mL of 17% EDTA of the root canal was done to eliminate the smear layer and was subsequently activated by an endodontic ultrasonic tip for 20 s three times (control group), a flat-end laser tip (test groups 1 and 3) or a taper-end laser tip (test groups 2 and 4) for two cycles. The time of each cycle activation was 10 s (groups 1 and 2) or 20 s (groups 3 and 4) in which the Er:YAG laser of 2940 nm was used. The laser operating parameters were 15 Hz and 50 µs pulse duration. The samples were then split longitudinally and subjected to scanning electron microscopy (SEM). Results: The remaining smear layer at the apical part of the root canals was statistically significant between the control group and the laser groups 1 (p = 0.040) and 2 (p = 0.000). Within the laser groups, the exposed tubules count was greater in the laser with the flat tip as compared with the tapered tip (Laser 1 > Laser 2 and Laser 3 > Laser 4). Finally, no significant differences in the count of debris between the laser groups and control group were observed, except for laser 4 (p < 0.05), which had the highest count of debris. Conclusion: LAI to remove debris and smear layer at the apical third of the root canal is inferior to the current ultrasonic technique. However, when using the Er:YAG LAI, it is recommended to use a flat tip design for 10 s for two cycles to ensure maximum debridement of the apical dentin surface.

Erbium, chromium:Yttrium-scandium-gallium-garnet (Er, Cr:YSGG) laser versus diode laser in the treatment of pericoronitis.

Background: There are limited number of studies about the lasers used for the treatment of pericoronitis infection. Aim: To compare the Er, Cr:YSGG laser and diode laser applications clinically in the treatment of pericoronitis infection. Patients and Methods: Sixty patients with pericoronitis infection were divided into three groups using block randomization: Er, Cr:YSGG + antibiotic group, n = 20 (mean age: 24.20 ± 6.13; 14 females, 6 males); diode group + antibiotic, n = 20 (mean age: 23.45 ± 2.96; 14 females, 6 males); and antibiotic, n = 20 (mean age: 22.45 ± 3.02; 11 females, 9 males). In addition, laser application was performed for patients in the Er, Cr:YSGG and diode laser groups on the 1st and 2nd days until the extraction day. Tooth extractions were performed on the 3rd day for all patients. Patients' pain (with visual analog scale [VAS]), lymphadenopathy, and local edema were clinically evaluated in the first 3 days and on the 7th day of treatment. Results: Pain score on the 2nd day of treatment was determined to be significantly lower in the Er, Cr:YSGG + antibiotic laser group as compared with the other two groups (P = 0.019). Although regression of lymphadenopathy on the 3rd day was highest (P = 0.025) in the Er, Cr:YSGG group, there was no significant difference between the groups regarding local edema. Conclusion: Er, Cr:YSGG laser improved the healing process in the treatment of pericoronitis and made an important contribution to the treatment.

Laser therapy for treating hypertrophic and keloid scars.

BACKGROUND: Hypertrophic and keloid scars are common skin conditions resulting from abnormal wound healing. They can cause itching, pain and have a negative physical and psychological impact on patients' lives. Different approaches are used aiming to improve these scars, including intralesional corticosteroids, surgery and more recently, laser therapy. Since laser therapy is expensive and may have adverse effects, it is critical to evaluate the potential benefits and harms of this therapy for treating hypertrophic and keloid scars. OBJECTIVES: To assess the effects of laser therapy for treating hypertrophic and keloid scars. SEARCH METHODS: In March 2021 we searched the Cochrane Wounds Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL EBSCO Plus and LILACS. To identify additional studies, we also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses, and health technology reports. There were no restrictions with respect to language, date of publication, or study setting. SELECTION CRITERIA: We included randomised controlled trials (RCTs) for treating hypertrophic or keloid scars (or both), comparing laser therapy with placebo, no intervention or another intervention. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, extracted the data, assessed the risk of bias of included studies and carried out GRADE assessments to assess the certainty of evidence. A third review author arbitrated if there were disagreements. MAIN RESULTS: We included 15 RCTs, involving 604 participants (children and adults) with study sample sizes ranging from 10 to 120 participants (mean 40.27). Where studies randomised different parts of the same scar, each scar segment was the unit of analysis (906 scar segments). The length of participant follow-up varied from 12 weeks to 12 months. All included trials had a high risk of bias for at least one domain: all studies were deemed at high risk of bias due to lack of blinding of participants and personnel. The variability of intervention types, controls, follow-up periods and limitations with report data meant we pooled data for one comparison (and only two outcomes within this). Several review secondary outcomes - cosmesis, tolerance, preference for different modes of treatment, adherence, and change in quality of life - were not reported in any of the included studies. Laser versus no treatment: We found low-certainty evidence suggesting there may be more hypertrophic and keloid scar improvement (that is scars are less severe) in 585-nm pulsed-dye laser (PDL) -treated scars compared with no treatment (risk ratio (RR) 1.96; 95% confidence interval (CI): 1.11 to 3.45; two studies, 60 scar segments). It is unclear whether non-ablative fractional laser (NAFL) impacts on hypertrophic scar severity when compared with no treatment (very low-certainty evidence). It is unclear whether fractional carbon dioxide (CO2) laser impacts on hypertrophic and keloid scar severity compared with no treatment (very low-certainty evidence). Eight studies reported treatment-related adverse effects but did not provide enough data for further analyses. Laser versus other treatments: We are uncertain whether treatment with 585-nm PDL impacts on hypertrophic and keloid scar severity compared with intralesional corticosteroid triamcinolone acetonide (TAC), intralesional Fluorouracil (5-FU) or combined use of TAC plus 5-FU (very low-certainty evidence). It is also uncertain whether erbium laser impacts on hypertrophic scar severity when compared with TAC (very low-certainty evidence). Other comparisons included 585-nm PDL versus silicone gel sheeting, fractional CO2 laser versus TAC and fractional CO2 laser versus verapamil. However, the authors did not report enough data regarding the severity of scars to compare the interventions. As only very low-certainty evidence is available on treatment-related adverse effects, including pain, charring (skin burning so that the surface becomes blackened), telangiectasia (a condition in which tiny blood vessels cause thread-like red lines on the skin), skin atrophy (skin thinning), purpuric discolorations, hypopigmentation (skin colour becomes lighter), and erosion (loss of part of the top layer of skin, leaving a denuded surface) secondary to blistering, we are not able to draw conclusions as to how these treatments compare. Laser plus other treatment versus other treatment: It is unclear whether 585-nm PDL plus TAC plus 5-FU leads to a higher percentage of good to excellent improvement in hypertrophic and keloid scar severity compared with TAC plus 5-FU, as the certainty of evidence has been assessed as very low. Due to very low-certainty evidence, it is also uncertain whether CO2 laser plus TAC impacts on keloid scar severity compared with cryosurgery plus TAC. The evidence is also very uncertain about the effect of neodymium-doped yttrium aluminium garnet (Nd:YAG) laser plus intralesional corticosteroid diprospan plus 5-FU on scar severity compared with diprospan plus 5-FU and about the effect of helium-neon (He-Ne) laser plus decamethyltetrasiloxane, polydimethylsiloxane and cyclopentasiloxane cream on scar severity compared with decamethyltetrasiloxane, polydimethylsiloxane and cyclopentasiloxane cream. Only very low-certainty evidence is available on treatment-related adverse effects, including pain, atrophy, erythema, telangiectasia, hypopigmentation, regrowth, hyperpigmentation (skin colour becomes darker), and depigmentation (loss of colour from the skin). Therefore, we are not able to draw conclusions as to how these treatments compare.  AUTHORS' CONCLUSIONS: There is insufficient evidence to support or refute the effectiveness of laser therapy for treating hypertrophic and keloid scars. The available information is also insufficient to perform a more accurate analysis on treatment-related adverse effects related to laser therapy. Due to the heterogeneity of the studies, conflicting results, study design issues and small sample sizes, further high-quality trials, with validated scales and core outcome sets should be developed. These trials should take into consideration the consumers' opinion and values, the need for long-term follow-up and the necessity of reporting the rate of recurrence of scars to determine whether lasers may achieve superior results when compared with other therapies for treating hypertrophic and keloid scars.

Effect of different types of adhesive systems on the bond strength and marginal integrity of composite restorations in cavities prepared with the erbium laser-a systematic review.

There are inconclusive results regarding etching and bonding protocol to achieve optimal bond strength and marginal integrity of adhesive composite resin restorations in erbium laser prepared cavities. This systematic review aimed to consider which adhesive system protocol may be optimal in achieving the bond strength and marginal integrity in erbium laser-prepared cavities, comparable to that obtained with conventional method of cavity preparation. This review was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement with literature search based on all publications during the period January1, 2000-October 10, 2020, in three databases: MEDLINE, Google Scholar and ScienceDirect. The necessary information was extracted by two independent authors. The search resulted in 139 articles from all databases, and a total of thirty-one articles met the inclusion criteria. The results indicated that the selection of adhesives depending on their pH and composition and the laser pulse duration and pulse energy used plays an important role in predicting the adhesion and marginal integrity. The 10-MDP containing moderate self-etch adhesives has demonstrated predictable outcomes. Longer pulse durations used for cavity preparations may indicate the use of etch-and-rinse (EnR) or moderate self-etch adhesives (SEA) to allow better resin infiltration in deep craters formed due to laser irradiation. However, further studies with more standardizations in relation to adhesives and laser parameters are needed.

Improvement of apical papilla cell attachment after erbium, chromium-doped yttrium, scandium, gallium, and garnet laser application: a study in an ex vivo immature tooth model.

The purposes of this study were (1) to investigate the direct effect of an Er,Cr:YSGG laser on human apical papilla cell (APC) proliferation and mineralization and (2) to examine the effect of Er,Cr:YSGG laser, when applied to an ex vivo immature tooth model, on APC attachment. An Er,Cr:YSGG laser at various power outputs (0.1, 0.5, and 1 W) was used at different positions (2, 5, or 8 mm from the cells) to irradiate cultured APCs. APC proliferation and mineralization were assessed at various intervals. For the cell attachment evaluation, ex vivo tooth models containing dentin samples were irrigated with either EDTA or normal saline solution (NSS) and supplemented with laser activation. Fibronectin-positive-staining cells were counted and analyzed. The number of APCs was significantly greater when power outputs of 0.1 W and 0.5 W were used than when 1 W was used (P < 0.05). The close contact of laser application, at 2 and 5 mm, exerted a negative effect on cell proliferation at 24 and 48 h. The application at 8 mm did not show the deterioration effect. APC mineralization was reduced after laser irradiation, regardless of the power and the tip positioning, at 21 days. APC attachment in all laser-activated groups was significantly greater than in the groups without laser. The use of Er,Cr:YSGG laser significantly promoted APC attachment on the root canal dentin.

The effect of Er,Cr:YSGG laser on periodontopathic bacteria elimination: an in vitro study.

In vitro bacterial elimination using the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser against periodontopathic bacteria was investigated. Bacterial suspensions of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were spread on agar plates and the Er,Cr:YSGG laser was applied at 40 mJ pulse energy for durations of 30 s, 60 s, and 90 s. The agar plates were incubated, and growth inhibition zones were assessed. Optimal laser irradiation durations to achieve maximal bacterial elimination were evaluated using laser ablation on the bacterial colonies. The remaining viable bacteria were determined by the colony-forming unit (CFU) counting method. Growth inhibition zones were observed at all irradiation durations for both A. actinomycetemcomitans and P. gingivalis. Mean logarithmic values of CFU/ml after bacterial colony irradiation for 0 s (control), 12 s × 1 lap, 24 s × 1 lap, 48 s × 1 lap, and 24 s × 2 laps were 8.82 ± 0.35, 7.31 ± 0.94, 6.32 ± 0.61, 3.17 ± 2.90, and 0.00, respectively, for A. actinomycetemcomitans and 9.83 ± 0.50, 9.42 ± 0.11, 6.90 ± 1.60, 2.33 ± 3.19, and 0.00 for P. gingivalis. Significant differences were found between the control group and the two irradiated groups 48 s × 1 lap and 24 s × 2 laps (p < 0.05), and also between irradiated groups 12 s × 1 lap and 24 s × 2 laps (p < 0.05). An Er,Cr:YSGG laser with power setting 1.5 W and 30 Hz frequency showed potential for bacterial elimination against A. actinomycetemcomitans and P. gingivalis in vitro. Significant bacterial elimination (> 99.99%) was observed after 48 s of irradiation.

Erbium lasers in non-surgical periodontal therapy: an umbrella review and evidence gap map analysis.

The literature on the efficacy of erbium lasers for nonsurgical periodontal therapy is inconsistent. The objective of the umbrella review was to collate the information available in the systematic reviews to provide a comprehensive synthesis of clinical and patient reported outcomes following the use of erbium lasers for non-surgical periodontal therapy. An electronic database search was carried out, and systematic reviews/meta-analyses which assessed the efficacy of erbium lasers as monotherapy or as an adjunct to scaling and root planing were included. The methodological quality and reporting quality of the included studies were assessed. 15 Systematic reviews/meta-analyses were obtained after title, abstract, and full text search. The meta-analyses data revealed a clinical attachment level gain, reduction in probing pocket depth at 1 and 3-month follow-up, and no additional benefit at ≥ 6-month follow-up in the erbium laser group. The evidence gap map revealed lack of clinical outcome data at > 6-month follow-up and dearth in studies assessing patient reported outcome measures and adverse events. Erbium lasers may provide short-term clinical benefits, and further studies with standardized laser parameters evaluating long-term follow-up, patient-reported outcome measures, and adverse events are needed.

Comparison of Er:YAG laser and ultrasonic in root canal disinfection under minimally invasive access cavity.

The disinfection of root canal through minimally invasive access cavity remains questionable. This in vitro study compared the effectiveness of three disinfection measures including conventional irrigation, ultrasonic assisted irrigation, and erbium:yttrium-aluminum-garnet (Er:YAG) laser assisted irrigation through conventionally or minimally invasive access. Sixty-six extracted maxillary first molars were randomly divided into group 1 conventionally invasive access group (CIA) and group 2 computer-guided minimally invasive access group (MIA). Each group was further randomly divided into three subgroups, (A) conventional irrigation (CI), (B) passive ultrasonic agitation (PUI), and (C) Er:YAG laser activated irrigation (LAI). Enterococcus faecalis (E. faecalis) infection model was established inside all root canals after instrumentation was performed up to ProTaper Universal F2. After various disinfection methods, microbial samples were collected from root canals by paper tip method and cultured, and colony forming units (CFU) values of each sample were calculated. Then the root canals were enlarged to the size of F3, after which dentin debris was collected from the F3 file. After dilution and culturing, the CFU value was calculated for each group. Two-way analysis of variance (ANOVA) was performed to test the interaction. The results revealed a significant antagonism (F = 3.394, P = 0.043). The bacterial CFU counts of group B and group C were significantly less than that of group A (P < 0.05), and there was no significant difference between group B and C (P > 0.05). Additionally, group 2A was better than group 1A (P < 0.05); there was no significant difference between group 1B and group 2B, group 1C and group 2C (P > 0.05). Comparison of the bacterial CFU counts in dentin debris after disinfection, the results revealed a significant antagonism (F = 7.224, P = 0.002), and group C had the least. The disinfection effect of Er:YAG laser or ultrasonic assisted computer-guided minimally invasive access is similar to conventionally invasive access, and Er:YAG laser is better than ultrasonic in removing bacteria from dentinal tubules and is easy to operate, which is more suitable for minimally invasive root canal treatment.

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.

Effects of diode and erbium lasers as an adjunct to scaling and root planing on clinical and immunological parameters in non-surgical periodontal treatment: a split-mouth randomized controlled clinical trial-"effects of lasers on immunological parameters".

This study evaluated the effects of diode and erbium lasers, as an adjunct to scaling and root planing (SRP), on clinical and immunological parameters in non-surgical periodontal therapy. In this split-mouth randomized controlled clinical trial, 17 participants with at least one periodontally involved tooth in each quadrant received oral hygiene instruction and full-mouth SRP. At baseline, probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP), and full-mouth plaque index (FMPI) were measured, and gingival crevicular fluid (GCF) sampling was performed. Next, one random quadrant in each participant received 940 nm diode laser (1 W, continuous-wave), and another quadrant received 2780 nm Er,Cr:YSGG laser (1.5 W, 30 Hz) irradiation. The GCF levels of interleukin (IL)-10 and matrix metalloproteinase (MMP)-13 were measured at baseline, and after 2 and 6 months using ELISA. The clinical parameters were also measured. Data were analyzed by repeated measures ANOVA. Significant clinical improvement was noted in all groups (P < 0.05). CAL in the control group was higher at 6 months than 2 months. The increase in IL-10 in erbium group was significantly greater than that in other groups (P < 0.001). The MMP-13 level was significantly lower in laser groups with greater reduction in erbium group (P < 0.001). Application of 940 nm diode and 2780 nm Er,Cr:YSGG lasers as an adjunct to SRP significantly decreased the GCF level of MMP-13, with no significant clinical advantage over SRP monotherapy. Application of 2780 nm Er,Cr:YSGG laser in addition to SRP increased the GCF level of IL-10.Trial registration numbers: IRCT20140318017053N11 and IRCT20140318017053N9.

Erbium laser-assisted ceramic debonding: a scoping review.

PURPOSE: Removal of ceramic restorations and appliances can be time consuming, invasive, and inconvenient. Erbium lasers offer an alternative noninvasive method for debonding of ceramic appliances. This paper aims to provide a comprehensive review of current literature on the effectiveness of erbium lasers for removal of ceramic restorations and appliances from natural teeth and dental implants. METHODS: A comprehensive search of 7 databases, including Medline (Ovid), Embase, Dentistry and Oral Sciences Source (DOSS), Web of Science, Cochrane Library, and ProQuest Dissertations and Theses was performed. The inclusion and exclusion criteria were agreed prior to the literature search. Two reviewers independently screened the title and abstract. A third reviewer then broke the tie, if any. The selected articles then underwent full text review and the data was extracted. RESULTS: The search identified 4117 unique articles published through June 10, 2021. Studies were assessed and categorized based on the type of restoration/appliance, type of abutment, type of laser, laser settings, efficacy of debonding, and pulpal temperature rise. Thirty-eight full-text articles were reviewed for inclusion. Time for ceramic debonding varies depending on the type of restorations and materials. Removal of zirconia crowns from teeth and implant abutments requires a longer period of time compared to lithium disilicate crowns. Temperature increases were reported as 5.5 degrees or less. Laser setting and laser type affect the debonding time and the increase in temperature. Examinations of debonded ceramics demonstrated no known structural damages resulting from laser applications. CONCLUSIONS: Erbium lasers are effective noninvasive tools to remove all ceramic restorations/appliances from natural teeth and implant abutments without causing harm to abutments. Laser-assisted debonding should be considered as a viable alternative to rotary instrumentation for ceramic crowns; however, clinical studies of erbium-assisted ceramic retrieval are needed.

Effects of Er:YAG laser irradiation of different titanium surfaces on osteoblast response.

The aim of this in vitro study was to evaluate the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation on titanium surface topography and the proliferation and differentiation of osteoblasts using standard clinical treatment settings. Er:YAG laser irradiation at two levels ((1): 160 mJ, pulse at 20 Hz; (2): 80 mJ, pulse at 20 Hz) was applied to moderately rough and smooth titanium disks before MG-63 osteoblast-like cells were cultured on these surfaces. Titanium surface and cell morphology were observed by scanning electron microscopy. Cell proliferation/viability was measured by CCK-8 test. Gene expression of alkaline phosphatase (ALP), osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), and collagen type 1 was measured by qPCR, and OPG and OC protein production was determined by enzyme-linked immunosorbent assay. Treatment with Er:YAG laser at 160 mJ/20 Hz markedly caused heat-induced fusion of titanium and cell condensation on moderately rough surfaces, but not in smooth surfaces. MG-63 proliferation/viability decreased after 5 days in moderately rough surfaces. The expression of ALP, OC, OPG, and collagen type 1 was unaffected by laser treatment at 160 mJ/20. Laser irradiation at 80 mJ/20 Hz enhanced RANKL gene expression after 5 days in moderately rough surfaces. Study results suggest that Er:YAG laser irradiation at clinically relevant setting has no essential effect on osteogenic gene and protein expression of osteoblasts. However, surface structure, cell attachment, and proliferation are influenced by both treatment protocols, which implies that caution should be taken in the clinical treatment of peri-implant diseases when Er:YAG laser is used.

The effects of using erbium, chromium-doped:yttrium-scandium-gallium-garnet laser on the surface modification, bacterial decontamination, and cell adhesion on zirconia discs: an in vitro study.

The use of zirconia for implants and abutments has become more prevalent in implant dentistry as an alternative to the commonly used titanium implants, and peri-implant disease can still affect them. The erbium, chromium-doped:yttrium-scandium-gallium-garnet (Er, Cr:YSGG) laser has emerged as a promising treatment modality. The purposes of this in vitro study were to (1) determine the effects of the laser on the surface roughness of zirconia discs; (2) determine the extent of removal of a single species biofilm, E. coli, on the zirconia discs after applying the laser; (3) determine the amount of cell adhesion and proliferation utilizing fibroblasts on zirconia discs after treatment with the laser. All treatments will be compared with the commonly used ultrasonic instrumentation and hand scalers. For the first aim, gross examination revealed noticeable surface damage on the discs when using ultrasonic and scalers but not for the laser group. For surface roughness, the mean roughness was Pa= 0.623±0.185 µm, 0.762±0.421 µm, 0.740±0.214 µm, and 0.724±0.168 µm for control discs, and discs treated with either the Er,Cr:YSGG laser, ultrasonic instrumentation, and hand scalers respectively. There was no statistical significance among the groups (p=0.628). For bacteria decontamination, there was a statistical significance among the groups (p< 0.0001). Statistical significance was seen between the control group and each of the three treatment groups, favoring the treatment groups (p< 0.0001). Statistical significance was seen when comparing ultrasonic instrumentation and hand scalers (p= 0.000) as well as when comparing the Er,Cr:YSGG laser to hand scalers (p= 0.007), favoring both the ultrasonic instrumentation and Er,Cr:YSGG laser. No significance between the Er,Cr:YSGG laser group and the ultrasonic instrumentation group was noted (p =0.374). When comparing the cell attachment following treatment in each of the three groups and also without treatment (control), there was a statistical significance among the groups (p<0.0001) in terms of total cell count, favoring the control and the laser groups. Further evaluations with SEM showed differences in cell morphology indicating more adherent cells on Er,Cr:YSGG laser-treated surfaces. In conclusion, gross examination of the discs show clear surface changes when using ultrasonic instrumentation and hand scalers compared to the Er,Cr:YSGG laser group. The Er,Cr:YSGG laser was able to effectively ablate bacteria from zirconia disc. Fibroblast attachment on the surfaces of the zirconia discs shows more adherence when treated with Er,Cr:YSGG laser.

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.

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. CLINICAL TRIAL REGISTRATION: ISRCTN registry #ISRCTN32132076.

Luminescent Ink Based on Upconversion of NaYF4:Er,Yb@MA Nanoparticles: Environmental Friendly Synthesis and Structural and Spectroscopic Assessment.

NaYF4:Er,Yb upconversion luminescent nanoparticles (UCNPs) were prepared by hydrothermal methods at 180 °C for 24 h. The X-ray diffraction (XRD) and TEM (transmission electron microscopy) images show that the resulting 60 nm UCNPs possess a hexagonal structure. In this work, maleic anhydride (MA) was grafted on the surface of UCNPs to induce hydrophilic properties. The photoluminescence spectra (PL) show upconversion emissions centered around 545 nm and 660 nm under excitation at 980 nm. The luminescent inks, including UCNPs@MA, polyvinyl alcohol (PVA), deionized water (DI), and ethylene glycol (EG), exhibit suitable properties for screen printing, such as high stability, emission intensity, and tunable dynamic viscosity. The printed patterns with a height of 5 mm and a width of 1.5 mm were clearly observed under the irradiation of a 980 nm laser. Our strategy provides a new route for the controlled synthesis of hydrophilic UCNPs, and shows that the UCNPs@MAs have great potential in applications of anti-counterfeiting packing.