Efetividade da técnica de clareamento com led violeta associada ou não a agente clareador: uma revisão sistemática e estudo in vitro

Abstract

Currently, there is great concern with aesthetics where white teeth are highly desired. Since several commercial products are launched seeking to provide greater aesthetic results in less time or with fewer adverse effects. Within this context, seeking to minimize the risk of postoperative sensitivity, the violet LED bleaching protocol was developed. Therefore, the objective of this study was to evaluate the effectiveness, morphological and structural changes of violet LED bleaching compared to bleaching with different bleaching agents. For a first study, a systematic review was carried out answering the research question: In the adult population, is violet LED an effective dental bleaching compared to bleaching with bleaching agents? Randomized clinical studies were included, there was no year nor language restriction. A search was performed in Pubmed, Cochrane Library, Latin American and Caribbean Literature in Health Sciences (LILACS), Scopus and Web of Science databases. The risk of bias (RoB 2) was obtained from the Cochrane Collaboration tool. After evaluating the articles, 5 were included for qualitative assessment, which presented a low risk of bias. In general, studies that used in-office bleaching protocols used high-concentration bleaching agents, observed little or no tooth sensitivity with the use of violet LED alone, and it was suggested that the association of violet LED with bleaching agent had greater bleaching efficacy than the bleaching agent alone. However, as it was not possible to carry out a quantitative assessment (meta-analysis), therefore more clinical studies are needed to prove whether this association is really more effective. It is suggested to carry out further randomized clinical trials with standardization of color analysis. For a second study, an in vitro evaluation of enamel microhardness and enamel mineral composition was carried out using scanning electron microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) at three periods: initial (T0), immediately after the end of the bleaching protocol (T1) and 7 days after the end of the bleaching protocol (T2); and color variation with Vita Easyshade digital spectrophotometer (ΔE1976, ΔE2000) and Whiteness Index (ΔWID) after bleaching with violet LED light in two periods: initial (T0) and 7 days after the end of the bleaching protocol (T2). To this end, 70 specimens were made in which 7 bleaching protocols were performed: violet LED (VL), 35% hydrogen peroxide (HP35), 10% carbamide peroxide (CP10), 10% hydrogen peroxide (HP10) and the association of these gels with violet LED (VL+HP35, VL+CP10 and VL+HP10). Data from the microhardness test and the color analysis were submitted to one-way ANOVA test in which the data were compared within each bleach technique. Pairwise comparisons were performed with Tukey’s test (α =0.05). Data from SEM with EDS were assessed only qualitatively. The microhardness showed a difference between the groups only immediately after the end of bleaching protocol (T1) (p<0.05), and there was a reduction in its value between TO and T1 for HP35 (p<0.01) and HP10 (p<0.05), which was reestablished in T2 (p>0.05). Regarding the SEM with EDS, we observed a reduction in the mineral percentage T1 in the VL group, however, in T2 it was reestablished. Regarding color, we observed that there was no difference between the groups evaluated for the whiteness index (p>0.05), and that, for the other indexes, only the VL+HP10 group showed a significant difference (p<0.05). From the results obtained, it can be concluded that the use of VL did not affect dental morphology and proved to be effective as bleaching agent.