Effect of mechanical cycling on microtensile bond strength between dentin and pressed ceramic restoration cemented by different strategies.

Abstract

Introduction: Hot pressed ceramics is usually used in prosthodontics as restorative material, being important to evaluate which cementation strategy generates better union between this ceramic and dental structure.

Aim: To evaluate the effect of mechanical cycling on bond strength between a hot-pressed glass-ceramic and dentin, using different cementation strategies. Materials and Methods: Sixty molar teeth with flat oclusal dentin surface were allocated in six groups: Gr1-Self-adhesive resin cement; Gr2-Self-adhesive resin cement + Mechanical Cycling(MC); Gr3-Total etch adhesive + conventional resin cement; Gr4-Total etch adhesive + conventional resin cement + MC; Gr5-Self-etching adhesive + resin cement with MDP; Gr6-Self-etching adhesive + resin cement with MDP + MC. Sixty hot-pressed leucite-based all-ceramic restorations were cemented as recommended by manufacturers. Bar-shaped samples of 1 mm² of cross-sectional bonding area were obtained and the microtensile test were conducted. Data were submitted to ANOVA-two way and Tukey test (?=0.05). Results: Mechanical cycling did not influence the results (p=0.1576), but cementation strategy (p=0.0419) affected. RelyX U100 showed the lowest values (7.0±5.0), RelyX ARC showed highest values (10.6±4.5) and Panavia F showed intermediary values (8.5±5.1). Conclusion: 2.10⁶ million cycles are not able to damage the union between resin cement and dentin; conventional adhesive cementation strategy promoted the more stable interfaces between restoration and dentin.