Microtensile bond strength of etch-and-rinse and self-etch adhesive systems to demineralized dentin after the use of a papain-based chemomechanical method

Purpose: To evaluate the in vitro microtensile bond strength (mu TBS) of etch-and-rinse and self-etch adhesive systems to demineralized dentin after the use of a papain-based chemomechanical method. Methods: 36 demineralized human dentin slabs were randomly distributed into two groups according to the method of caries removal: (1). Mechanical removal with manual excavators; (2) Chemomechanical removal with a papain-based gel (Papacarie). Subsequently, three adhesive systems were applied (n=6): (a) an etch-and-rinse adhesive system (Single Bond); (b) a two-step self-etch adhesive system (AdheSE); (c) a one-step self-etch adhesive system (Adper Prompt). The slabs were restored with a microhybrid resin composite and each resin-dentin block was sectioned into 1.0 mm(2) thick slabs, which were kept in receptacles containing distilled water at relative humidity, for 24 hours, at 37 C. After that, they were subjected to tensile stress in a universal testing machine at a speed of 0.5 mm/minute. Data were submitted to two-way ANOVA and Tukey's test at a 0.05 level of significance. The fractured specimens were observed under a stereomicroscope to assess the failure mode. Results: The application of both chemomechanical and mechanical methods on demineralized dentin yielded mu TBS values that were statistically similar among them, regardless of the adhesive system used. Caries removal with a chemomechanical papain-based method did not interfere in the adhesion of the tested adhesive systems to demineralized dentin. (Anz J Dent 2010;23:23-28).