Evaluation of enamel surface integrity after orthodontic bracket debonding: comparison of three different system.

OBJECTIVE: This study aimed to evaluate enamel surface integrity and time consumed during residual cement removal after bracket debonding using different adhesive removal burs with and without a dental loupe. MATERIAL AND METHODS: Sixty human-extracted premolars were collected, cleaned, mounted, and prepared for orthodontic bracket bonding. Teeth were randomly divided into three main groups (n = 20) based on the adhesive removal method: tungsten carbide system (TC), sof-lex discs system (SD), and diamond system (DB) groups. Then, each group was subdivided into two subgroups (naked eye and magnifying loupe subgroups). The brackets were bonded and then debonded after 24 h, and the Adhesive Remnant Index (ARI) was assessed. The adhesive remnants were removed by different systems, and the final polishing was performed by Silicone OneGloss. The enamel surface roughness was evaluated before bracketing (T0), after residual cement removal (T1), and finally after polishing (T2) using surface Mitutoyo SJ-210 profilometry and Scanning Electron Microscopy (SEM) to determine the Enamel Damage Index (EDI) score. The time consumed for adhesive removal was recorded in seconds. RESULTS: The Kruskal Wallis test showed a statistically significant difference in roughness values at T1 compared to T2 between subgroups (p < 0.001). When comparing EDI at T1 and T2, the Kruskal-Wallis H-test showed statistically significant differences in all subgroups. The pairwise comparisons revealed that EDI scores showed a statistically significant difference at T1 and T2 between DB vs. TC and SD (p = 0.015) but not between TC vs. SD (p = 1.000), indicating the highest roughness value observed in the DB group. The time for cement removal was significantly shorter in the magnifying loupe group than in the naked eye group and was shortest with the TC group, whereas the time was the longest with the DB group (p < 0.05). CONCLUSION: All three systems were clinically satisfactory for residual orthodontic adhesive removal. However, TC system produced the lowest enamel roughness, while the DB system created the greatest. The polishing step created smoother surfaces regardless of the systems used for resin removal.

Deep learning for virtual orthodontic bracket removal: tool establishment and application.

OBJECTIVE: We aimed to develop a tool for virtual orthodontic bracket removal based on deep learning algorithms for feature extraction from bonded teeth and to demonstrate its application in a bracket position assessment scenario. MATERIALS AND METHODS: Our segmentation network for virtual bracket removal was trained using dataset A, containing 978 bonded teeth, 20 original teeth, and 20 brackets generated by scanners. The accuracy and segmentation time of the network were tested by dataset B, which included an additional 118 bonded teeth without knowing the original tooth morphology. This tool was then applied for bracket position assessment. The clinical crown center, bracket center, and orientations of separated teeth and brackets were extracted for analyzing the linear distribution and angular deviation of bonded brackets. RESULTS: This tool performed virtual bracket removal in 2.9 ms per tooth with accuracies of 98.93% and 97.42% (P < 0.01) in datasets A and B, respectively. The tooth surface and bracket characteristics were extracted and used to evaluate the results of manually bonded brackets by 49 orthodontists. Personal preferences for bracket angulation and bracket distribution were displayed graphically and tabularly. CONCLUSIONS: The tool's efficiency and precision are satisfactory, and it can be operated without original tooth data. It can be used to display the bonding deviation in the bracket position assessment scenario. CLINICAL SIGNIFICANCE: With the aid of this tool, unnecessary bracket removal can be avoided when evaluating bracket positions and modifying treatment plans. It has the potential to produce retainers and orthodontic devices prior to tooth debonding.

Effects of the conventional, soft start, and pulse delay modes produced by light-emitting diode device on metal brackets bond strength and enamel damage: An in vitro comparative study.

OBJECTIVES: This study aimed to compare the bond strength and enamel damage following debonding of metal brackets cured by different light-curing modes: conventional, soft start, and pulse delay modes. MATERIAL AND METHODS: Sixty extracted upper premolars were randomly divided into three groups according to the used light-curing mode. Metal brackets were bonded with a light-emitting diode device employing different modes. Group 1: conventional mode (10s mesial+10 s distal); group 2: soft start mode (15s mesial+15s distal); group 3: pulse delay mode (3s mesial+3s distal, followed by 3min of no photoactivation, then 9s mesial+9s distal). Radiant exposure was the same in all study groups. Shear bond strengths of the brackets were tested with a universal testing machine. A stereomicroscope was used to determine the number and length of enamel microcracks. One-Way ANOVA and Kruskal-Wallis tests were used to detect significant differences in shear bond strength and microcracks number and length among groups. RESULTS: The soft start and pulse delay modes produced significantly greater shear bond strength than the conventional mode (19.46±4.90MPa; 20.47±4.97MPa; 12.14±3.79MPa, respectively, P<0.001). However, there was no significant difference between the soft start and pulse delay groups (P=0.768). The number and length of microcracks increased significantly after debonding in all study groups. The change in microcracks length was not different among study groups. CONCLUSION: The soft start and pulse delay modes produced greater bond strength than the conventional mode without predisposing enamel to higher risk of damage. Conservative methods for debonding are still required.

Evaluation of enamel roughness after orthodontic debonding and clean-up procedures using zirconia, tungsten carbide, and white stone burs: an in vitro study.

BACKGROUND: The main goal of orthodontic debonding is to restore the enamel surface as closely as possible to its pretreatment condition without iatrogenic damage. This study aimed to compare the effects of different adhesive removal burs; zirconia burs, tungsten carbide burs, and white stone burs on enamel surface roughness. MATERIALS AND METHODS: Total sample of 72 extracted premolars was randomly divided into three equal groups (n = 24) depending on the method of adhesive removal: zirconia burs (ZB); tungsten carbide burs (TC); and white stones (WS). The metal brackets were bonded using Transbond XT orthodontic adhesive (3 M Unitek, Monrovia, CA, USA) and debonded after 24 h using a debonding plier, then the ARI was assessed. The adhesive remnants were removed using the different burs and Final polishing was performed using Sof-lex discs and spirals. Thirteen samples from each group were evaluated using a Mitutoyo SJ-210 profilometer to determine average surface roughness (Ra) and three samples from each group were examined under Scanning Electron Microscopy (SEM) to determine EDI score. The evaluations were performed at three time points; before bonding (T0), after adhesive removal (T1) and after polishing (T2) and the time consumed for adhesive removal by burs was recorded in seconds. The data were analyzed statistically by ANOVA, Tukey's test and Kruskal-Wallis H-test. RESULTS: Kruskal-Wallis H-test showed no statistically significant difference of ARI in all studied groups (p = 0.845) and two-way mixed ANOVA revealed that all burs significantly increased surface roughness at T1 compared to T0 (p < 0.001) in all groups with the lowest Ra values were observed in the ZB group, followed by the TC group, and WS group. The fastest procedure was performed with WS, followed by ZB, then TC bur (p < 0.001). After polishing (T2), Ra values showed no significant difference in ZB group (P = 0.428) and TC group (P = 1.000) as compared to T0, while it was significant in WS group (p < 0.001). CONCLUSION: zirconia bur was comparable to tungsten carbide bur and can be considered as alternative to white stone which caused severe enamel damage. The polishing step created smoother surface regardless of the bur used for resin removal.

Fluorescence-aided identification technique using a low-cost violet flashlight and rotatory instruments for dental trauma splint removal.

BACKGROUND/AIM: Removing resin composites used for bonding dental trauma splints may result in irreversible damage to the enamel. This in vitro study evaluated the influence of additional violet illumination and different bur types on damage caused to tooth enamel. MATERIALS AND METHODS: Fifteen maxillary models with four bovine incisor teeth were prepared. All models were scanned using a laboratory scanning system (s600 ARTI; Zirkonzahn). Six experimental groups (n = 10) were generated by two study factors: lighting type (three levels), (1) low-cost (5-7 US$) violet LED flashlight (LUATEK, LT 408); (2) VALO Cordless light curing unit (Ultradent) with black lens; or (3) without additional illumination; and rotatory instrument (two levels), (1) diamond bur or (2) multifluted tungsten-carbide bur. New scanning was performed after splint removal, and the generated files were superimposed on the initial scans using Cumulus software. The light emitted by both violet light sources was characterized by using integrating sphere and beam profile. A qualitative and quantitative analysis of enamel damage and two-way ANOVA followed by Tukey's post hoc was used at an α = 0.05. RESULTS: The use of low-cost violet flashlight that emitted the violet peak light at 385 nm and VALO Cordless with black lens at 396 nm resulted in significantly lower damage to the enamel surface than those in the groups without additional violet light (p < .001). An interaction between rotatory instruments and lighting was found. When no additional violet lighting was used, the diamond bur presented higher mean and maximum depth values. CONCLUSIONS: Fluorescence lighting facilitated the removal of remnant resin composite dental trauma splints, leading to less invasive treatment. The diamond bur resulted in higher enamel damage than that affected by the multifluted bur when no violet lighting was used. A low-cost violet flashlight is a useful fluorescence-aided identification technique for removing resin composite dental trauma splints.

The influence of age and orthodontic debonding on the prevalence and severity of enamel craze lines.

BACKGROUND: Craze lines may cause esthetic concerns, especially when noted on the incisors. Various light sources with additional recording apparatus have been proposed to visualize craze lines, but a standardized clinical protocol is yet to be determined. This study aimed to validate the application of near-infrared imaging (NIRI) from intraoral scans to evaluate craze lines and to determine the influence of age and orthodontic debonding on their prevalence and severity. METHODS: The NIRI of maxillary central incisors from a full-mouth intraoral scan and photographs from an orthodontic clinic (N = 284) were collected. The prevalence of craze lines and influence of age and orthodontic debonding history on severity were evaluated. RESULTS: Craze lines were detected reliably as white lines distinguishable from dark enamel using the NIRI from intraoral scans. The craze line prevalence was 50.7%, which was significantly higher in patients 20 years or older than in patients younger than 20 years (P < .001), with more frequent severe craze lines for those 40 years or older than in patients younger than 30 years (P < .05). Prevalence or severity was similar between patients with and without an orthodontic debonding history regardless of the type of appliance. CONCLUSION: The prevalence of craze lines in the maxillary central incisor was 50.7%, with a higher prevalence in adults than in adolescents. Orthodontic debonding did not affect the severity of craze lines. PRACTICAL IMPLICATIONS: Craze lines were reliably detected and documented by means of applying NIRI from intraoral scans. Intraoral scanning can provide new clinical information on enamel surface characteristics.

Comparative evaluation of three methods of adhesive remnant removal after orthodontic bracket debonding.

OBJECTIVE: This study aimed to assess the effects of three methods of adhesive remnant removal (carbide bur and low speed handpiece, carbide bur and high speed handpiece, and zircon-rich glass fiber reinforced composite bur), after orthodontic bracket debonding, on tooth color and enamel surface roughness. METHODS: Ninety sound premolar teeth were selected. The baseline tooth color was assessed using Vita spectrophotometer. The teeth were subjected to bracket bonding processes and then randomly divided into three equal groups. In each group, composite remnant was removed by one of the three methods of adhesive removal, and the teeth were then subjected to color assessment again. To measure the surface roughness, a scanning electron microscope (SEM) with x400 magnification was used. RESULTS: ANOVA showed that the effect of the three methods of adhesive remnant removal on ∆L, ∆b and ∆E was statistically significant (p=0.01), but without significant effect on ∆a. Comparison of the means showed that composite bur and high speed carbide bur yielded the highest ∆E (p=0.05), and had a significant difference when compared to carbide bur and low speed handpiece. The highest ∆L and ∆b values belonged to samples approached with composite bur and carbide bur with high speed handpiece, respectively. SEM analysis showed that the composite bur created a very smooth surface, compared to the other two methods. CONCLUSION: Zircon-rich glass fiber reinforced composite created the smoothest enamel surface and highest color change, when compared to the other two methods.

Effects of a flash-free system on dental plaque accumulation and bonding-debonding process: A clinical study.

INTRODUCTION: The objectives of this study were to evaluate the effects of a flash-free (FF) System on (1) the amount of plaque accumulation around the braces on buccal surfaces of the teeth, (2) the time required for the placement of brackets, including the clean-up of the flash, (3) the amount of adhesive left on the tooth after debonding, and (4) time required for adhesive remnant clean-up. METHODS: Thirty-six patients (aged 19.96 ± 5.74 years) were randomly distributed to receive adhesive precoat (APC)-FF and APC-Plus ceramic brackets on the maxillary right or left anterior 6 teeth. Bonding and debonding time were measured per segment in milliseconds. A plaque revealer agent was applied to discolor the dental plaque, and a modified plaque accumulation index was used to evaluate the amount of plaque at 2 different time points. An adhesive residue index was used after the debonding. RESULTS: The mean bonding times were 138.87 seconds (8332.47 milliseconds) and 77.82 seconds (4669.31 milliseconds) for APC-Plus and APC-FF, respectively. The difference was statistically significant (P ≤0.001). The difference between the mean debonding times was not statistically significant. A significant difference was found between the adhesive residue index scores of the 2 systems (P ≤0.001). There was no statistically significant difference between plaque accumulation scores at first- and second-time points for both adhesive systems. APC-Plus score (0.94 ± 0.98) was higher than the APC-FF score (0.50 ± 0.91) on the incisal side at the second time point (P ≤0.05). CONCLUSIONS: FF adhesives can be a good alternative to reduce chair time in bonding appointments.

Flash-free and conventional adhesive ceramic brackets in patients undergoing orthodontic treatment: A systematic review and meta-analysis.

To investigate whether flash-free adhesive ceramic brackets (FFA) have a better clinical performance than conventional adhesive ceramic brackets (CVA) in patients undergoing multi-bracket orthodontic treatment. PubMed, CENTRAL, Web of Science, Scopus, Embase, CNKI and Grey-literature were searched without restrictions up to January 2022. Both randomized controlled trials (RCTs) and controlled clinical trials (CCTs) were included. Risk of bias assessment was performed using the RoB 2.0 and ROBINS-I cochrane risk of bias tools. Eight articles, for seven studies, were included in this systematic review, and four split-mouth trials (SMT) were included in the meta-analysis. A random-effects meta-analysis found a statistically significant faster bonding time with FFA (mean difference [MD] = -93.85 seconds/quadrant, P = .002, 2 SMT), and no statistically significant difference regarding bracket failure rate at 6 months (risk ratio [RR] = 1.05; P = .93, 3 SMT), adhesive removal time (MD = -18.26 seconds/quadrant, P = .50, 2 SMT), and amount of remnant adhesive (MD = -0.13/bracket, P = .72, 2 SMT) between FFA and CVA. No difference (P > .05, 3 SMT) was found in enamel demineralization and periodontal measurements. CVA showed a statistically significant higher debonding pain score (P = .004, 1 SMT). Both flash-free and conventional adhesive ceramic brackets had a similar clinical performance, except for the faster bonding with FFA. Further, well-designed clinical trials are still required.

[Clinical comparative study of efficacy of Er:YAG laser for debonding different veneers].

PURPOSE: To compare the debonding time of IPS e.max CAD lithium disilicate glass-ceramic veneers in different thickness and transparency using Er:YAG laser, and evaluate the effect of Er:YAG laser on the surface topography of the veneers and the underlying tooth. METHODS: A total of twelve maxillary first premolar teeth were collected and prepared, then veneers were made by computer aided design and computer aided manufacture(CAD/CAM) system. The veneers were divided into four groups according to different thicknesses and transparency: e.max HT with 0.5 mm and 1.0 mm thickness, e.max LT with 0.5 mm and 1.0 mm thickness. Three veneers of each group were cemented to prepared premolar with resin cement and then stored in normal saline solution at room temperature for 7 days. All veneers were debonded with Er:YAG laser and the debonding time of all-ceramic veneers of all groups was recorded. Scanning electron microscopy(SEM) observation was performed to detect the surface topography of the veneers and the underlying tooth. SPSS 19.0 software package was used for statistical analysis. RESULTS: The debonding time of 1.0 mm-thick groups were longer than 0.5 mm-thick groups. When the veneer thickness was 0.5 mm, the average debonding time of e.max LT group was longer than e.max HT. Consistent with the finding of 0.5 mm, the longer debonding time was found in the e.max LT group of 1.0mm. No cracks and crater structure were found in SEM observation of veneers after Er:YAG laser irradiation. Teeth surface was covered with bonding cement with no signs of ablation or damage of the enamel. CONCLUSIONS: Er:YAG laser can completely debond lithium disilicate glass-ceramic veneers, and the debonding time depends on the transparency and thickness of the veneers. The lower translucent porcelain veneers (e.max LT) and thicker ones (1.0 mm-thick) had a longer debonding time. Moreover, Er:YAG laser does not damage the morphology and topography of the veneer and the teeth surface.

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.

Enamel surface roughness evaluation after bracket debonding: Comparison between light cure and self cure adhesive resin 3-Dimensional profilometric study.

Introduction: After fixed orthodontic treatment, following bracket removal, the debonding procedure should lead to restitutio ad integrum of the enamel or, at least, restore the enamel surface as closely as possible to its pretreatment condition. Adhesion of brackets in orthodontics is that they should be strong enough to prevent failure during all treatment but also low enough, so that enamel damage would be minimal during bracket removal after treatment. Material and Methods: A total of 60 premolars were collected and stored in distilled water. The extracted teeth were divided into two groups of 30 each, group A was to be bonded with self-cure adhesive while group B light cure adhesive was to be used. A standardised protocol was followed for adhering the brackets to the tooth surfaces. All the teeth were bonded with metal brackets (3M Unitek, Gemini Twin Brackets 0.022 slot). In group A, bonding adhesive (3M Unitek self cure adhesive primer) was applied. In group B, the bonding adhesive (3M Unitek light cure adhesive primer) was photopolymerized for 10 seconds after application. Results: Surface roughness of enamel as assessed by profilometry shows that light cure adhesive creates more roughness as compared to self cure adhesive. To conclude, self cure adhesive is clinically better than light cure adhesive. Discussion: In the present study enamel surface roughness were compared after debonding. Enamel surface roughness after bracket debonding depends on a host of factors, which include - brackets, adhesive used and method of remnant removal.

Dental staining after orthodontic debonding: effectiveness of two bleaching treatment protocols - in vitro study

Objective: The aim of this study was to compare the effectiveness of two bleaching treatment protocols to treat dental staining after orthodontic debonding. Materials and Methods: Twenty four bovine teeth were submitted to orthodontic bracket (Morelli, Edgewise Prescription, Slot 22) bonding (Transbond XT, 3M) and debonding, which were divided into three groups according to the bleaching protocol: hydrogen peroxide 10% (Whiteness, FGM) simulating home bleaching protocol (Home Bleaching Group), hydrogen peroxide 35% Whiteness, FGM) simulating dental office bleaching protocol (Office Bleaching Group) and Control Group, which was not exposed to any dental bleaching protocol, and stored in distilled water at 37°C. The specimens were submitted to the following processes: aging of resin remaining tegs by ultraviolet (UV), staining with coffee solution and tooth bleaching with 10% hydrogen peroxide (G1) and 35% hydrogen peroxide (G2). The color stability analysis (CIE color space L* a* b* was performed with Vita Easyshade Compact spectrophotometer before bonding (T0), after aging and staining processes (T1) and after bleaching treatment (T2). All teeth were stored in distilled water at 37°C between experimental times. The comparison between the groups and time effect evaluation were performed using ANOVA / Tukey ( =0.05) and ANOVA-MR with Bonferroni correction ( =0.016), respectively. Results: The color stability parameters L *, a * and b * indicated, with the exception of GC, a tendency of increase in T1 (G1 - L *: 76.72 ± 13.39; a *: 6.68 ± 3.71; b *: 43.14 ± 4.04 / G2: - L *: 75.78 ± 4.66; a *: 8.13 ± 2.75; b *: 43.42 ± 8.87), which reflected the tendency to decrease brightness in T1, followed by a tendency to return to T0 values (G1 - L *: 82.92 ± 12.16; a *: 4.25 ± 3.68; b *: 39.40 ± 9.49 / G2: - L *: 83.76 ± 8.02; a *: 8.76 ± 4.08; b *: 47.90 ± 5.88). Significant differences were observed in G2 in a * (T1: 8.13 ± 2.75, T2: 8.76 ± 4.08) and b * (T1: 43.42 ± 8.87; T2: 47.90 ± 5.88), indicating that this group did not return to the values presented in T0 (a *: 1.81 ± 1.70; b *: 35.40 ± 5.08) (p <0.05). Conclusion: Based on the results of this study, it can be concluded that home bleaching protocol presented better performance for dental surface whitening in an eventual staining after orthodontic debonding.

Objetivo: O objetivo deste estudo foi comparar a eficácia de dois protocolos de tratamento clareador para manchas dentárias causadas após a descolagem ortodôntica. Materiais e Métodos: Vinte e quatro dentes bovinos foram submetidos à colagem e descolagem de braquetes ortodônticos (Morelli, Prescrição Edgewise, Slot 22") (Transbond XT, 3M), que foram divididos em três grupos de acordo com o protocolo de clareamento: peróxido de hidrogênio 10% (Whiteness, FGM) simulando protocolo de clareamento caseiro (grupo clareamento caseiro), peróxido de hidrogênio 35% Whiteness, FGM) simulando protocolo de clareamento de consultório (grupo clareamento de consultório) e Grupo Controle, que não foi exposto a nenhum protocolo de clareamento dental, armazenado em água destilada a 37ºC. Os corpos de prova foram submetidos aos seguintes processos: envelhecimento das resinas remanescentes por ultravioleta (UV), manchamento em solução de café e clareamento dental com peróxido de hidrogênio 10% (G1) e peróxido de hidrogênio 35% (G2). A análise de estabilidade de cor (sistema CIE L* a* b*) foi realizada com espectrofotômetro Vita Easyshade Compact antes da colagem (T0), após os processos de envelhecimento e manchamento (T1) e após o tratamento clareador (T2). Todos os dentes foram armazenados em água destilada a 37 °C entre os tempos experimentais. A comparação entre os grupos e a avaliação do efeito do tempo foram realizadas utilizando ANOVA/Tukey ( =0,05) e ANOVA-MR com correção de Bonferroni ( =0,016), respectivamente. Resultados: Os parâmetros de estabilidade de cor L *, a* e b* indicaram, com exceção do GC, tendência de aumento em T1 (G1 - L*: 76,72 ± 13,39; a*: 6,68 ± 3,71; b*: 43,14 ± 4,04 / G2: - L* : 75,78 ± 4,66; a*: 8,13 ± 2,75; b*: 43,42 ± 8,87), o que refletiu a tendência de diminuição do brilho em T1, seguido de uma tendência de retorno aos valores de T0 (G1- L*: 82,92 ± 12,16 ; a*: 4,25 ± 3,68; b*: 39,40 ± 9,49 / G2: - L*: 83,76 ± 8,02; a*: 8,76 ± 4,08; b*: 47,90 ± 5,88). Foram observadas diferenças significativas no G2 em a* (T1: 8,13 ± 2,75, T2: 8,76 ± 4,08) e b* (T1: 43,42 ± 8,87; T2: 47,90 ± 5,88), indicando que esse grupo não retornou aos valores apresentados em T0 (a*: 1,81 ± 1,70; b*: 35,40 ± 5,08) (p<0,05). Conclusão: Com base nos resultados deste estudo, pode-se concluir que o protocolo de clareamento caseiro apresentou melhor desempenho para o clareamento da superfície dentária em um eventual manchamento após a descolagem ortodôntica.

Do different orthodontic pliers used in bracket debonding have different effects on pain and sensitivity? A prospective split-mouth study.

OBJECTIVES: The assessment of whether different orthodontic pliers used in bracket debonding have different effects on pain and sensitivity experience. MATERIALS AND METHODS: Thirty-three patients (17 females, 16 males) with metal brackets were included in the study. Compressed air and freshly melted ice water were applied to each tooth (6-6) in upper and lower arch before bracket debonding (T0), just after debonding (T1), and 1 week after debonding (T2). Bracket remover plier (BRP) and Weingart plier (WP) were used to debond brackets. A numeric rating scale (NRS) was used to assess sensitivity for each tooth at T0, T1, and T2. Tooth pain was assessed for each tooth using NRS during bracket debonding. RESULTS: Statistically higher pain scores were found in teeth U4 (upper first premolar) (p = 0.017) and L6 (lower first molar) (p = 0.026) in Weingart plier group. No statistically significant difference was found during debonding in the other teeth between groups. Statistically high sensitivity score was found at T1 time point in tooth U3 (upper canine) by applying air stimulus in Weingart plier group (p = 0.024). There was no statistically significant difference between the sensitivity scores measured at T2 time point by applying air and cold stimuli between groups. CONCLUSIONS: Although the debonding pain scores were statistically significant in two teeth and the sensitivity score in one tooth, there was no clinical significance between the two pliers in terms of pain and sensitivity. CLINICAL RELEVANCE: Both debonding pliers gave clinically similar results in terms of pain and sensitivity.

Construction of an In Vivo Debonding Device and Comparison of Bracket Failure Rate and Debonding Force for Indirect Orthodontic Bonding.

AIM: A major limitation of indirect bonding is incomplete penetration of the curing light through transfer trays, leading to inadequate curing of light-cure adhesive resin, causing bracket bond failure. Dual-cure adhesive resin is both light and chemically cured, which reduces the requirement of light for curing of the composite. Comparative evaluation of bracket failure rate and bond strength between dual-cure composite and light-cure composite for indirect orthodontic bonding of brackets. MATERIALS AND METHODS: A split-mouth randomized clinical study was carried out in 51 patients (30 females and 21 males). Indirect orthodontic bonding using Erkogum as adhesive to attach the bracket to cast and glue gun material was utilized to form a transfer tray. Conventional light-cure and dual-cure adhesive resins were compared with regard to their bracket failure rate, adhesive remnant index score, and in vivo clinical bond strength. RESULTS: Kolmogorov-Smirnov test was employed to test the normality of data. Mann-Whitney U test and Chi-square test were performed for the quantitative variables and it was observed that both the groups showed similar results for the parameters being measured. The mandibular arch showed more bracket failure, the dual-cure composite group showed more bracket failure, however, the adhesive remnant index (ARI) score for both the groups was similar. No statistically significant difference was seen concerning the clinical bond strength between the two adhesive resins. CONCLUSION: Dual-cure adhesive system can be used for indirect bonding in orthodontics. The mandibular arch had a higher bond failure in the second premolar region. The sequence of bond failure was concordant among both the adhesive groups. However, dual-cure adhesive invariably showed more bracket failure. The highest bond strength was observed for the maxillary canine brackets in the light-cure group, and mandibular canine brackets in the dual-cure group. Whereas, the weakest bond strength in the light-cure group was observed for the mandibular second premolar brackets and for maxillary second premolar brackets in the dual-cure group. There was no significant difference between the in vivo clinical bond strength between the two adhesive systems. On debonding, majority of the adhesive was observed to be on the tooth surface. CLINICAL SIGNIFICANCE: This study signifies that both light-cure and dual-cure resins can be used for indirect bonding procedures but light-cure composite resin shows a lower bracket failure rate as compared to dual-cure composite resin.

Influence of pulse duration and water/air cooling ratio on the efficiency of Er:YAG 2940 nm laser in debonding of porcelain laminate veneers: An in vitro study.

OBJECTIVE: To determine the effectiveness of different pulse durations (PD) and the water/air (W/A) cooling ratio of the Er:YAG 2940 nm laser that are required for debonding porcelain laminate veneers (PLV), by investigation of the needed time for PLV debonding (DT) and the changes in dental pulp temperature. MATERIALS AND METHODS: Thirty-six extracted noncarious human maxillary premolars were prepared for receiving PLV. Samples were randomly assigned to six different groups, based on PD and the W/A ratio: Groups A (50 µs, 1:1), B (50 µs, 3:3), C (100 µs, 1:1), D (100 µs, 3:3), E (300 µs, 1:1), and F (300 µs, 3:3). Veneers were debonded using laser irradiation by the same parameters (270 mJ, 15 Hz) with noncontact application mode. RESULTS: All 36 veneers were debonded. Samples of the 50 and 100 µs PDs showed significantly shorter DT (7.4-17 s) than that of the 300 µs which showed significantly the longest DT (104 s) among all other groups (p < .001). However, the highest elevation of pulp temperature was observed in Group E (300 µs, 1:1) which reached (3.4°C). CONCLUSION: Using the 50 or 100 µs PD of the Er:YAG laser was more efficient than 300 µs in reducing DT of PLVs with minimal change in pulp temperature. W/A cooling ratio had minimal influence on the DT of PLV.

Assessment of chemical, ultrasonic, diode laser, and Er:YAG laser application on debonding of ceramic brackets.

BACKGROUND: Risk of enamel damage that often accompanies ceramic brackets debonding raises the demand of finding an optimal method for debonding of them without adverse effects. Different techniques were proposed in an attempt to facilitate their debonding. Comparison of these techniques is crucial. The aim of this study was to evaluate and compare different techniques for debonding of ceramic brackets in terms of shear bond strength and adhesive remnant index. MATERIALS AND METHODS: A total of 100 extracted premolars were randomly allocated into 5 groups. Ceramic brackets were then bonded to teeth using light cure composite resin. Among test groups; group I: served as control, group II: chemical aided debonding via peppermint oil, group III: ultrasonic aided debonding, group IV: diode laser aided debonding, and group V: Er:YAG laser aided debonding. Brackets were shear tested using universal testing machine followed by ARI assessment and evaluation of enamel microstructure was performed using scanning electron microscopy. RESULTS: A significantly lower shear bond strength was found in ultrasonic, diode, and Er:YAG laser groups. However, no significant difference was found in the chemical group. A significantly higher adhesive remnant index was found solely in Er:YAG laser group with minimal enamel microstructure alterations. CONCLUSIONS: Er:YAG laser is a promising tool in debonding ceramic brackets. Ultrasonic and diode laser significantly reduced shear bond strength. Yet, adhesive remnant index in both groups revealed no difference. Chemical aided debonding had little effect and hence, it cannot be recommended without further development.

Effect of different resin removal methods on enamel after metal and ceramic bracket debonding : An in vitro micro-computed tomography study.

PURPOSE: The aim of this study was to conduct an in vitro evaluation of the effects of different adhesive debonding and polishing techniques performed after metal and ceramic bracket removal on enamel using micro-computed tomography (micro-CT). METHODS: This study was performed on 42 extracted maxillary first premolars divided into 2 main groups and 6 subgroups as follows: metal (group 1) or ceramic (group 2) brackets were bonded to the teeth, then, after debonding, one of three different methods was used to remove the residual adhesive: tungsten carbide burs with pumice (A), fiber-reinforced composite burs and polishing paste (B), or Sof-Lex discs (C; 3M Dental, St Paul, MN, USA). The samples were evaluated by micro-CT before bracket bonding (T0) and after resin removal (T1). Demineralization area, demineralization depth, demineralization volume, mineral density, and mineral volume were measured. RESULTS: At T1, demineralization area was significantly larger in groups 1A and 2A compared to groups 1B, 1C, 2B, and 2C (P = 0.001). Group 2A (ceramic bracket/tungsten carbide-pumice) had the highest demineralization volume (P = 0.001). When the groups were compared in terms of change from T0 to T1, groups 1A and 2A showed significantly larger changes in demineralization area compared to the other 4 groups (P = 0.001). The increase in demineralization volume was larger in group 2A compared to all other groups (P = 0.001). CONCLUSION: All resin removal methods damaged the enamel surface to varying degrees. Regardless of bracket type, the use of tungsten carbide and pumice should be avoided when cleaning the tooth surface after debonding. Use of composite burs and Sof-Lex discs in particular after the debonding of ceramic brackets will help minimize damage.

Use of nano-hydroxyapatite serum and different finishing/polishing techniques to reduce enamel staining of debonding after orthodontic treatment : A randomized clinical trial.

PURPOSE: The aim of this study was to assess the effect of nano-hydroxyapatite serum and different finishing, polishing techniques on color alterations of enamel caused by debonding procedures after comprehensive orthodontic treatment by use of a spectrophotometer. METHODS: This randomized clinical trial recruited 20 participants with previous non-extraction orthodontic treatment and acceptable hygiene to evaluate enamel staining after orthodontic debonding. The usage of a carbide bur alone, as the conventional method, and the combination use of carbide burs and Sof-Lex discs (3M™ ESPE, St. Paul, MN, USA) were compared to each other followed by 10 days application of nano-hydroxyapatite after debonding. Then the enamel staining was evaluated by a reflectance spectrophotometer in three periods: immediately, and 2 and 4 months after debonding. RESULTS: The comparison of the groups showed a significant interaction between Sof-Lex groups and the control side after the first interval of the study (p = 0.042). Application of nano-hydroxyapatite demonstrated no significant difference in color parameters between upper and lower arches of the participants at all intervals of this study (p > 0.05). The mean total color change (ΔE) in all groups and between all intervals had been clinically perceptible (ΔE > 3.3). CONCLUSIONS: The applied concentrations of nano-hydroxyapatite had no significant effect in reducing tooth color changes after debonding in orthodontic treatment. Sof-Lex discs can significantly reduce tooth color changes in a short time.