In vitro evaluation of dental bleaching effectiveness using hybrid lights activation Avaliação in vitro da eficácia da fotoativação no clareamento dental utilizando a técnica em consultório

Methods: From 60 extracted bovine incisor teeth, specimen sizes were standardized and dentin was conditioned by immersion in 38% phosphoric acid for 15 s. Following this procedure, the samples were placed in a water bath with ultrasound for 20 min and then immersed in a 25% coffee solution for a two-week period. The dentin was polished with a felt disc and aluminum oxide paste and finally sealed with colorless nail polish. Specimens were randomly divided into five groups, and their original color was measured using the EasyShade (VITA) spectrophotometer. All specimens received three applications of the bleaching agent Opalescence Xtra-Boost (Ultradent) during a period of 15 min each. Group 1 did not receive light activation, Group 2 was activated with a Halogen light (15 min), Group 3 was activated with a blue hybrid LEDs and a laser (15 min), Group 4 was activated with light from a green LED and a laser (15 min) and Group 5 was activated with a red laser (15 min). Tooth color was measured again after performing the various bleaching techniques on all specimens. The resulting data on color variations ΔE, Δa*, Δb* and ΔL*, and the color variations referenced on the Vita Classical scale were subjected to ANOVA, Tukey and Dunn tests (α=5%).