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

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

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Effectiveness of Various Final Irrigation Techniques on Sealer Penetration in Curved Roots: A Confocal Laser Scanning Microscopy Study

BioMed Research International ◽

10.1155/2020/8060489 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Ayca Yilmaz ◽

Turgut Y. Yalcin ◽

Dilek Helvacioglu-Yigit

Keyword(s):

Confocal Laser Scanning Microscopy ◽

Laser Scanning ◽

Root Apex ◽

Laser Scanning Microscopy ◽

Confocal Laser Scanning ◽

Scanning Microscopy ◽

Confocal Laser ◽

Control Group ◽

Root Canals ◽

Curved Root Canals

Objective. To compare the efficacy of various techniques used for final irrigation on sealer penetration in the apical one-third of curved root canals. Material and Methods. Sixty-five freshly extracted maxillary first molar teeth with mesiobuccal roots having more than 20° of root curvature were used. The root canals were instrumented and randomly divided into four experimental groups and one control group. In the 4 experimental groups, 3 ml of 17% EDTA followed by 3 ml of 5.25% NaOCl was delivered with the use of the following protocols: Group 1: manual dynamic activation (MDA), Group 2: sonic irrigation (SI), Group 3: passive ultrasonic irrigation (PUI), and Group 4: conventional needle irrigation (CI). All teeth were obturated with gutta-percha and AH Plus sealer labeled with fluorescent dye. Transverse sections at 2 mm and 4 mm distance from the root apex were examined with the aid of confocal laser scanning microscopy. Total percentage (%) and maximum depth (μm) of sealer penetration were measured. Results. All the experimental groups exhibited significantly higher penetration rates than the control group at both sections (p<0.05). However, no significant differences were found in the penetration depth and percentage among the four experimental groups evaluated at both sections (p>0.05). Conclusion. PUI, SI, and MDA did not significantly improve sealer penetration in the apical portion of curved root canals when compared to conventional needle irrigation.

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Quercetin as an Auxiliary Endodontic Irrigant for Root Canal Treatment: Anti-Biofilm and Dentin Collagen-Stabilizing Effects In Vitro

Materials ◽

10.3390/ma14051178 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1178

Author(s):

Zhuo Liu ◽

Xiangli Feng ◽

Xiangyao Wang ◽

Shiyuan Yang ◽

Jing Mao ◽

...

Keyword(s):

Root Canal ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Root Canal Treatment ◽

Confocal Laser ◽

Control Group ◽

Infection Model ◽

Potential Candidate ◽

Xps Characterization ◽

Stabilizing Effect

Bacterial reinfection and root fracture are the main culprits related to root canal treatment failure. This study aimed to assess the utility of quercetin solution as an adjunctive endodontic irrigant that does not weaken root canal dentin with commitment anti-biofilm activity and bio-safety. Based on a noninvasive dentin infection model, dentin tubules infected with Enterococcus faecalis (E. faecalis) were irrigated with sterile water (control group), and 0, 1, 2, 4 wt% quercetin-containing ethanol solutions. Live and dead bacteria percentages in E. faecalis biofilms were analyzed by confocal laser scanning microscopy (CLSM). Elastic modulus, hydroxyproline release and X-ray photoelectron spectroscopy (XPS) characterization were tested to evaluate the irrigants’ collagen-stabilizing effect. The cytotoxicity was tested by CCK-8 assay. Quercetin increased the proportion of dead bacteria volumes within E. faecalis and improved the flexural strength of dentin compared to control group (p < 0.05). Quercetin-treated dentin matrix had less elasticity loss and hydroxyproline release after collagenase degradation (p < 0.05). Moreover, quercetin solutions revealed an increase in the C-O peak area under both C1s and O1s narrow-scan spectra of XPS characterization, and no cytotoxicity (p > 0.05). Quercetin exhibited anti-biofilm activity, a collagen-stabilizing effect with cytocompatibility, supporting quercetin as a potential candidate for endodontic irrigant.

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Quercetin as an Auxiliary Endodontic Irrigant for Root Canal Treatment: Anti-Biofilm and Dentin Collagen-Stabilizing Effects

10.20944/preprints202101.0481.v1 ◽

2021 ◽

Author(s):

Zhuo Liu ◽

Xiang-li Feng ◽

Xiang-yao Wang ◽

Shi-yuan Yang ◽

Jing Mao ◽

...

Keyword(s):

Root Canal ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Root Canal Treatment ◽

Confocal Laser ◽

Control Group ◽

Infection Model ◽

Potential Candidate ◽

Xps Characterization ◽

Dentin Collagen

(1) Background: Bacterial reinfection and root fracture are the main culprits related to root canal treatment failure. This study aimed to assess the utility of quercetin solution as an adjunctive endodontic irrigant that strengthen root canal dentin with commitment anti-biofilm activity and bio-safety. (2) Methods: Based on a noninvasive dentin infection model, dentin tubules infected with Enterococcus faecalis (E. faecalis) were irrigated with sterile water (control group), and 0, 1, 2, 4 wt% quercetin-containing ethanol solutions. The live and dead bacteria proportions within E. fae-calis biofilms were analyzed using confocal laser scanning microscopy (CLSM). Elastic modulus and hydroxyproline release and X-ray photoelectron spectroscopy (XPS) characterization was tested on irrigant-treated demineralized dentin to evaluate irrigants’ biostability. The cytotoxicity of irrigants was tested by CCK-8 assay. (3) Results: Quercetin increased the proportion of dead bacteria volumes within E. faecalis, and improved the flexural strength of dentin collagen com-pared to control group. The XPS characterization revealed an increase in C-O peak area under both C1s and O1s narrow-scan spectra. The CCK-8 assay confirmed no cytotoxicity of quercetin solutions. (4) Conclusions: Quercetin exhibited anti-biofilm activity, collagen-stabilizing effect as well as cytocompatibility, supporting quercetin as a potential candidate for endodontic irrigant.

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Use of electromagnetic stimulation on an Enterococcus faecalis biofilm on root canal treated teeth in vitro

Scientific Reports ◽

10.1038/s41598-021-87922-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Beatriz H. D. Panariello ◽

Justin K. Kindler ◽

Kenneth J. Spolnik ◽

Ygal Ehrlich ◽

George J. Eckert ◽

...

Keyword(s):

Enterococcus Faecalis ◽

Root Canal ◽

Laser Scanning ◽

Confocal Imaging ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Microscopy Imaging ◽

Electromagnetic Stimulation ◽

Root Canal Disinfection

AbstractRoot canal disinfection is of utmost importance in the success of the treatment, thus, a novel method for achieving root canal disinfection by electromagnetic waves, creating a synergistic reaction via electric and thermal energy, was created. To study electromagnetic stimulation (EMS) for the disinfection of root canal in vitro, single rooted teeth were instrumented with a 45.05 Wave One Gold reciprocating file. Specimens were sterilized and inoculated with Enterococcus faecalis ATCC 29,212, which grew for 15 days to form an established biofilm. Samples were treated with 6% sodium hypochlorite (NaOCl), 1.5% NaOCl 1.5% NaOCl with EMS, 0.9% saline with EMS or 0.9% saline. After treatments, the colony forming units (CFU) was determined. Data was analyzed by Wilcoxon Rank Sums Test (α = 0.05). One sample per group was scored and split for confocal laser scanning microscopy imaging. There was a significant effect with the use of NaOCl with or without EMS versus 0.9% saline with or without EMS (p = 0.012 and 0.003, respectively). CFUs were lower when using 0.9% saline with EMS versus 0.9% saline alone (p = 0.002). Confocal imaging confirmed CFU findings. EMS with saline has an antibiofilm effect against E. faecalis and can potentially be applied for endodontic disinfection.

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Bactericidal compounds controlling growth of the plant pathogen pseudomonas syringae pv. actinidiae, which forms biofilms composed of a novel exopolysaccharide

10.26686/wgtn.12597797 ◽

2020 ◽

Author(s):

S Ghods ◽

Ian Sims ◽

MF Moradali ◽

BHA Rehma

Keyword(s):

Pseudomonas Syringae ◽

Chlorine Dioxide ◽

Laser Scanning ◽

Extracellular Polymeric Substances ◽

Virulent Strain ◽

Bactericidal Effect ◽

Cell System ◽

Laser Scanning Microscopy ◽

Base Layer ◽

Confocal Laser

© 2015, American Society for Microbiology. Pseudomonas syringae pv. actinidiae is the major cause of bacterial canker and is a severe threat to kiwifruit production worldwide. Many aspects of the disease caused by P. syringae pv. actinidiae, such as the pathogenicity-relevant formation of a biofilm composed of extracellular polymeric substances (EPSs), are still unknown. Here, a highly virulent strain of P. syringae pv. actinidiae, NZ V-13, was studied with respect to biofilm formation and architecture using a flow cell system combined with confocal laser scanning microscopy. The biofilm formed by P. syringae pv. actinidiae NZ V-13 was heterogeneous, consisting of a thin cellular base layer 5 μm thick and microcolonies with irregular structures. The major component of the EPSs produced by P. syringae pv. actinidiae NZ V-13 bacteria was isolated and identified to be an exopolysaccharide. Extensive compositional and structural analysis showed that rhamnose, fucose, and glucose were the major constituents, present at a ratio of 5:1.5:2. Experimental evidence that P. syringae pv. actinidiae NZ V-13 produces two polysaccharides, a branched α-D-rhamnan with side chains of terminal α-D-Fucf and an α-D-1,4-linked glucan, was obtained. The susceptibility of the cells in biofilms to kasugamycin and chlorine dioxide was assessed. About 64 and 73% of P. syringae pv. actinidiae NZ V-13 cells in biofilms were killed when kasugamycin and chlorine dioxide were used at 5 and 10 ppm, respectively. Kasugamycin inhibited the attachment of P. syringae pv. actinidiae NZ V-13 to solid surfaces at concentrations of 80 and 100 ppm. Kasugamycin was bacteriostatic against P. syringae pv. actinidiae NZ V-13 growth in the planktonic mode, with the MIC being 40 to 60 ppm and a bactericidal effect being found at 100 ppm. Here we studied the formation, architecture, and composition of P. syringae pv. actinidiae biofilms as well as used the biofilm as a model to assess the efficacies of bactericidal compounds.

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Susceptibility of Mature Staphylococcus Biofilms to Chinese Herbal Decoction Sanhuang Jiedu: An In Vitro Study

BioMed Research International ◽

10.1155/2020/7473942 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Shaoe Zhang ◽

Xiao Wang ◽

Xiaotao Shi ◽

Honglue Tan ◽

Himanshu Garg

Keyword(s):

Laser Scanning ◽

Multidrug Resistant ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Control Group ◽

Antibiofilm Activity ◽

Dependent Manner ◽

Chinese Herbal ◽

Titanium Surfaces

Background. External socking and washing with the Chinese herbal Sanhuang Jiedu decoction (SHJD) can effectively control local limb infections with bone and implant exposure. However, the antibiofilm activities of this decoction in vitro have not yet been investigated. Therefore, the aim of this study was to examine the effects and characteristics of SHJD on the mature biofilms of multidrug-resistant staphylococci on a titanium surface. Methods. Biofilm-forming methicillin-resistant Staphylococcus epidermidis ATCC 35984 and S. aureus ATCC 43330, and non-biofilm-forming S. epidermidis ATCC 12228 were selected as the experimental strains. The mature biofilms were prepared on titanium surfaces. The five experimental groups were based on dilution concentrations (DC) of SHJD: the control group (biofilm incubated with 0.85% NaCl solution), the SHJD (DC:1/8) group (initial SHJD solution was diluted 1/8), the SHJD (DC:1/4) group, the SHJD (DC:1/2) group, and the SHJD (DC:1/1) group (initial SHJD solution). The effects of SHJD on the mature biofilms were observed with the bacterial spread plate method, crystal violet (CV) staining, scanning electron microscopy, and confocal laser scanning microscopy. Results. After culture in tryptic soy broth for 72 h, ATCC 43300 and ATCC 35984 produced mature biofilms and ATCC 12228 did not. The optical density value of ATCC 12228 was 0.11 ± 0.02 , significantly lower than that of ATCC 35984 ( 0.42 ± 0.05 ) or ATCC 43300 ( 0.41 ± 0.03 ) ( P < 0.05 ). The mature biofilms of ATCC 43300 and ATCC 35984 clearly disintegrated when incubated for 12–24 h with SHJD (DC:1/1) or SHJD (DC:1/2), showing only scattered bacterial adhesion. In the SHJD (DC:1/4) group, although many residual bacterial colonies still clustered together, presenting a biofilm structure, it was very looser than that in the SHJD (DC:1/8) group in which the biofilm was similar to that in the control group. For ATCC 12228, only colony adhesion was observed, and the number of colonies decreased as the concentration of SHJD or the culture period increased. The quantitative results for the bacterial spread plate and CV staining showed significant differences between the SHJD groups ( P < 0.05 ). Conclusion. SHJD has antibiofilm activity against multidrug-resistant Staphylococcus strains. It weakens or disrupts already-formed mature biofilms on titanium surfaces in a concentration- and incubation time-dependent manner.

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The Penetration Ability of Calcium Silicate Root Canal Sealers into Dentinal Tubules Compared to Conventional Resin-Based Sealer: A Confocal Laser Scanning Microscopy Study

Materials ◽

10.3390/ma12030531 ◽

2019 ◽

Vol 12 (3) ◽

pp. 531 ◽

Cited By ~ 4

Author(s):

Yemi Kim ◽

Ban-Suk Kim ◽

Yong-Min Kim ◽

Donghee Lee ◽

Sin-Young Kim

Keyword(s):

Root Canal ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Intensity Level ◽

Single Cone ◽

Penetration Ability ◽

Ah Plus ◽

Root Canal Sealers ◽

Apical Area

The purpose of this study was to compare the penetration ability of calcium silicate root canal sealers and conventional resin-based sealer using confocal laser scanning microscopy (CLSM). A total of 60 recently extracted single-rooted human premolars were used in this study. The root canals were prepared to a size 40/0.06 taper with ProFile rotary instruments and irrigated with NaOCl and EDTA. After drying all canals, the specimens were randomly divided into three experimental groups (n = 20): Group 1, gutta-percha (GP)/AH Plus with continuous wave compaction; group 2, GP/BioRoot RCS with a single-cone technique; and group 3, GP/Endoseal MTA with a single-cone technique. All experimental samples were sectioned perpendicular to their long axis using a low-speed diamond wheel at the apical, middle, and coronal third levels. The penetration abilities of all samples were evaluated using CLSM. A Kruskal–Wallis analysis and a series of Mann–Whitney U post hoc tests were performed. A higher intensity level was found in the coronal area and a lower intensity level in the apical area in all the experimental groups. The AH Plus group showed higher sum fluorescence intensity in the apical and coronal thirds compared with the BioRoot RCS and Endoseal MTA groups, whereas the BioRoot RCS group showed a higher intensity level in the middle third, similar to the AH Plus group. The maximum sealer penetration depth was low in the apical area and high in the coronal area in the AH Plus and Endoseal MTA groups. In the BioRoot RCS group, maximum sealer penetration was observed in the middle third. In conclusion, there were significant differences in sealer penetration pattern and distance according to the root level and sealer type.

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Percentage of Gutta-Percha-, Sealer-, and Void-Filled Areas in Oval-Shaped Root Canals Obturated with Different Filling Techniques: A Confocal Laser Scanning Microscopy Study

European Journal of Dentistry ◽

10.1055/s-0040-1701543 ◽

2020 ◽

Vol 14 (01) ◽

pp. 008-012

Author(s):

Vinicio Hidemitsu Goto Hirai ◽

Ricardo Machado ◽

Maria Carolina Lucato Budziak ◽

Lucila Piasecki ◽

Alexandre Kowalczuck ◽

...

Keyword(s):

Confocal Laser Scanning Microscopy ◽

Laser Scanning ◽

Continuous Wave ◽

Laser Scanning Microscopy ◽

Confocal Laser Scanning ◽

Scanning Microscopy ◽

Confocal Laser ◽

Root Canals ◽

Gutta Percha

Abstract Objective This study compared different obturation techniques, analyzing percentage of areas filled with gutta-percha, sealer, and voids (PGFA, PSFA, and PVFA, respectively) in oval-shaped root canals. Materials and Methods A total of 60 extracted human mandibular central incisors were decoronated, instrumented, and irrigated using the same protocol. After drying, the root canal was filled with AH Plus labeled with 0.1% rhodamine B dye using a Lentulo spiral. The filling procedure was performed by dividing the teeth into four groups according to the respective technique: G1, cold lateral condensation; G2, continuous wave of condensation; G3, modified cold lateral condensation using an F3 master cone; and G4, modified continuous wave of condensation using an ISO (International Organization for Standardization) sized 30 gutta-percha cone. Then, slices measuring 1.5 mm in thickness were obtained 3 and 6 mm from the apex and evaluated by confocal laser scanning microscopy to determine PGFA, PSFA, and PVFA. Statistical Analysis The data were analyzed statistically with analysis of variance and Games-Howell’s tests (p = 0.05). Results The groups showed no significant differences in the apical third (3 mm from the apex). In the middle third (6 mm from the apex), G3 and G1 showed higher PGFA and PVFA, respectively. G3 showed lower PSFA than G2 and G4. Both cold techniques (G1 and G3) promoted lower PSFA than both warm techniques (G2 and G4). Conclusions Notwithstanding the limitations of this in vitro study, PGFA, PSFA, and PVFA ranged significantly only in the middle third, as observed by the different filling techniques. Higher PGFA and PVFA values were obtained for G3 and G1, respectively. Both cold techniques promoted lower PSFA than both warm techniques.

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Evaluation of four final irrigation protocols for cleaning root canal walls

International Journal of Oral Science ◽

10.1038/s41368-020-00091-4 ◽

2020 ◽

Vol 12 (1) ◽

Author(s):

Qiang Li ◽

Qian Zhang ◽

Xiaoying Zou ◽

Lin Yue

Keyword(s):

Root Canal ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Smear Layer ◽

Confocal Laser ◽

Bacterial Survival ◽

Bacterial Inhibition ◽

Layer Removal ◽

Significant Difference ◽

Canal Systems

Abstract The aim of this study was to compare the efficiency of four final irrigation protocols in smear layer removal and bacterial inhibition in root canal systems. Thirty roots inoculated with Enterococcus faecalis were prepared with ProTaper Universal files. The teeth were disinfected by conventional needle irrigation, sonic agitation using the EndoActivator device, passive ultrasonic irrigation, or an M3 Max file. Teeth with no root canal preparation served as blank controls for the establishment of the infection baseline. Teeth with preparation but no final irrigation served as a post-instrumentation baseline. After the final irrigation, the teeth were sectioned in half. One half of each tooth was examined by scanning electron microscopy (SEM) to assess smear layer removal using a five-point scale. The other half was examined by confocal laser scanning microscopy (CLSM) using the LIVE/DEAD BackLight bacterial viability kit to evaluate the depth of bacterial survival in dentinal tubules. SEM analysis revealed no significant difference in smear layer removal throughout the whole canal among the EA, PUI, and M3 Max groups (P > 0.05). CLSM revealed that PUI achieved the greatest bacterial inhibition depth in the coronal ((174.27 ± 31.63) μm), middle ((160.94 ± 37.77) μm), and apical ((119.53 ± 28.49) μm) thirds of the canal (all P < 0.05 vs. other groups). According to this comprehensive SEM and CLSM evaluation, PUI appears to have the best infection control ability in root canal systems.

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Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets

BioMed Research International ◽

10.1155/2016/7276287 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Ruo-qiao Han ◽

Kai Yang ◽

Ling-fei Ji ◽

Chen Ling

Keyword(s):

Bond Strength ◽

Shear Bond Strength ◽

Laser Scanning ◽

Er:Yag Laser ◽

Statistical Significance ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Control Group ◽

Test Machine ◽

Ceramic Brackets

Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets.Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy.Results. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p<0.05), but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket.Conclusion. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods.

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