Avaliação in vitro da cor da estrutura dentária submetida a diferentes fontes de luz associadas à peróxidos de hidrogênio ou carbamida

Abstract

Objectives: to evaluate, in vitro, using ΔE and commercial color (VITA) the optical effect promoted by the type of dye associated with hydrogen peroxide and different commercial bleaching agents in different concentrations, photoactivated by two types of light sources, in the whitening of the human tooth structure. Methods: One hundred forty human third molars extracted for therapeutic indication had their coronary portion cut in half in the mesiodistal direction followed by a cut in the longitudinal direction, thus obtaining two equal parts. Two types of light were used, one being the blue LED (Radii cal, SDI, 1000mW/cm²,440nm-480nm) and the other violet (Whitening Plus, DMC, 450mW/cm², 405nm+/-10nm), five types of manipulated hydrogen peroxide: no dye (PSC), lilac peroxide (PL), red peroxide (PV), blue peroxide (PAZ) and yellow peroxide (PAM) and six types of commercial bleaching agents: Whiteclass (PH7), Potenza Bianco (PH35) Boost(PH38), Power Bleaching(PC37), Whitening Blue HP (PC35) and Opalescence (PC10). The samples were randomly divided into 35 groups (n=8 for each group), varying for each bleaching agent the application of a type of light (blue or violet) or the absence of light. The whitening gels were applied once a week to the tooth surface, in a 2mm thick layer, for 15 minutes 3 times or two hours according to the percentage for 3 weeks. In the groups where a light source was applied, the irradiation protocol was 1 minute of light exposure, followed by a 30-second pause. An Easyshade 5.0 spectrophotometer (Vita) was used to measure ΔE (l* a* b*) and commercial color. The samples had their color measured on a black background at the following times: 1) before the application of the bleaching agent; 2) after the application of each session of the groups described in table 2; 3) after 1 week of the finalized whitening treatment. The results were submitted to the Shapiro Wilk test, ANOVA for repeated measures and Tukey test with a confidence level of 95%. Results: According to the ANOVA test, the groups PC10, PH35, PH7, PC35, PL, PV, PAZ showed no statistical difference between the subgroups without light, blue LED and violet LED. In the PH38 group, the subgroup without light, presented the highest ΔE00 (6,19), whereas in the PC37 group, the blue LED subgroup presented the smallest variation of ΔE00 (1,34). In the PSC group, the blue LED subgroup presented the smallest variation of ΔE00 and in the PAM group, the subgroups light-activated by blue or violet LED presented the highest ΔE00 (9,06 e 7,04). Conclusion: The association of blue or violet led to 40% hydrogen peroxide (Boost) significantly reduced ΔE00. The association of blue or violet LED with hydrogen peroxides at concentrations of 7.5%, 35%, 40% or 10%, 35% and 37% carbamide did not promote greater color variation ΔE00. The association of 35% hydrogen peroxide and yellow dye promoted higher values of ΔE00 when associated with blue LED or violet light.