Microshear bonding effectiveness of different dentin regions.

Abstract

The aim of this in vitro study was to evaluate the influence of dentin surfaces with different tubule orientation on bond strength of a multimode adhesive system. Twenty human molars were selected and prepared in different ways in order to produce different dentin regions. The teeth were randomized (n = 5) according to the application modes of a multimode adhesive system (etch-and-rinse and self-etching) and to the dentin region (occlusal and proximal - 1.5 mm depth from dentinoenamel junction). Cylindrical restorations were performed on dentin with a starch tube. The samples remained immersed in distilled water for 24 h and the microshear bond strength (μSBS) test was performed. The μSBS values were expressed in MPa and analyzed with ANOVA and Tukey's test (P < 0.05). There was no significant difference in the bond strength values between the application modes of the adhesive system (P = 0.19); however, the dentin regions (P < 0.05) significantly affected the μSBS. The proximal dentin presented higher bond strength values than occlusal dentin. The dentin surfaces with different tubule orientation influenced the bonding effectiveness of the adhesive system tested.