Avaliação das propriedades adesivas à dentina de adesivos universais fotoativados com LEDs de terceira geração

Abstract

The aim of this study was evaluated the effect of wavelength range (violet 405nm vs blue 445 and 465 nm) emitted for a "poly-wave" LED curing-light (Valo) could affect the the microtensile bond strength (μTBS), nanoleakage (NL) and, in situ degree of conversion (DC) of universal adhesives to dentin. Two hundred and twenty human molars were randomly assigned to 6 groups, according to the following variables: adhesive system (Ambar Universal APS [ABU], Scotchbond Universal Adhesive [SBU] and Tetric n-bond Universal [TBU]) vs. adhesive strategies (self-etch and etch-and- rinse mode). During the light-curing procedure (Valo, 1400mW/cm2*10s), each quadrant of tooth corresponding to different wavelength range was demarked. After restoration, specimens were sectioned into resin-dentin bonded sticks and tested for μTBS, NL, and DC. The data from μTBS (MPa), NL (%), and DC (%) data were subjected to 3-way repeated measures ANOVA and Tukey's test (α=5%). For ABU and TBU, no significant differences were observed between different wavelength range (p > 0.05). However, for SBU, light-curing with LED 405 showed lower μTBS and DC values, as well as higher NL when compared to other LEDs (445 and 465) (p < 0.01). ABU showed better μTBS and DC values in comparison with SBU (p = 0.001). No significant differences were observed when SE and ER strategies were compared (p > 0.05). The bonding to dentin could be localized affected when universal adhesive based on the conventional camphorquinone/amine photoinitiator (Scotchbond Universal) was light-curing with poly-wave LEDS.