Influência da composição do primer sobre a resistência de união à microtração em sistema adesivo autocondicionante experimental

Abstract

The aim of this study was to investigate the influence of different functional monomer concentrations/HEMA in self-etching primers solvents on microtensile bond strength (μTBS) of an experimental adhesive system. Seventy bonive incisors were allocated in seven groups (n=20). Six experimental self-etching primers were synthesized with different concentratios of acidic monomer (MPF); 0, 15, 30, 50, 70 and 100 (wt %)(Groups EMa0, EMa15, EMa30, EMa50, EMa70, EMa100 respectively). Adhesive system Clearfil SE Bond (CSEB, Kuraray) was used as control. Coating adhesive resin AP-50 was prepared Seventy bovine incisors were randomized and allocate in seven groups. Vestibular enamel was grounded to expose the superficial coronal dentin, witch that was polished wet to create a standardized smear layer with 600 grit silicon paper. After rinsing, water was removed with a piece of absorbent paper, leaving the surface visibly dried. The prepared dentin surfaces were etched with primer and air-dried, after coating adhesive resin was applied and light activated with LED SDI Radii® (1400mW/cm2). The composite resin was inserted in two increments and were ligth activated for 20 s each. After storage for 24 hours, the specimens were sectioned with a refrigerated diamond saw at low-speed. To investigate immediate microtensile bond strength (μTBS) statistical analysis were performed (one-way ANOVA plus Tukey s post-hoc test, α=0.05). Fractographic analysis were performed using optical microscopy to describe failure patterns. The group EMa50 showed statistically higher (p<0.05) microtensile bond strength (55.1MPa) than others experimental groups but was similar with control (50.7MPa). Due total premature failure groups EMa0 and EMa100 were exclude form statistics. Groups EMa15, EMa30 and EMa70 were similar but different that control. Was possible conclude that concentration of acidic monomer/HEMA affects microtensile bond strength of self-etching adhesive systems. Primer composition of 50%MPF-20%HEMA- 30% water showed satisfactory microtensile bond strength as a self-etching adhesive system.