Bond to dentin-glass ceramic: effect of neutralization and mechanical cycling

Objectives::to evaluate the hypothesis that a process of hydrofluoric acid precipitate neutralization (APN) and fatigue load cycling (FLC) performed on human premolars restored with ceramic inlays had an influence on micro-tensile bond strength testing (MTBS).Methods: MOD inlay preparation were performed in forty pre-molars (its root were embedded into acrilyc resin). Forty ceramic restorations made with glass-ceramic (IPS Empress) were confectioned. The restoration inner surfaces were submitted to 2 surface treatment methods (N=20): (control): etched (60s) with 10% hydrofluoric acid (HF) + rinse (60s) + drying + application of silane; (experimental) HF + APN + rinse + drying. Later all the restorations were silanized, and adhesively cemented (Multilink). Ten premolars from each group were submitted to aging (mechanical cycling/10⁶ cycles / 50N,37°C). Afterwards the samples were sectioned into beams specimens (vestibular dentin – restoration – lingual dentin set) and submitted microtensile test.Results: bond strength was significantly affected by the surface treatment (P < .0001) (control>experimental) and mechanical cycling (P < .0001) (NC > C) (2-way ANOVA and tukey tests, alpha=.05) Conclusion: hydrofluoric acid precipitate neutralization appears damage significantly the resin bond to glass-ceramic. The clinical simulation of the specimens by using mechanical cycling is important to evaluate the bond ceramic-dentin.