DENTAL STAINING AFTER ORTHODONTIC DEBONDING: EFFECTIVENESS OF TWO BLEACHING TREATMENT PROTOCOLS - IN VITRO STUDY

Abstract

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.