A short- and long-term shear bond strength study using acids of varying dilutions on bovine dentine

Objectives: The purpose of this study was to evaluate the short-(24 h) and long-(180 day) term shear bond strengths of resin to bovine dentine etched with varying dilutions of aqueous solutions of phosphoric and maleic acids. Methods: Bovine dentine surfaces were prepared using water irrigated #600 grit SiC paper. The dentine surfaces were etched in groups of 10 teeth using various dilutions of phosphoric or maleic acid. Using the Scotchbond Multipurpose System (SBMP; 3M Co., MN, USA) and a wet technique the etched surfaces were primed and unfilled bonding resin (UBR) was applied to the dentine surface within the confines of a gelatin cylinder. A cylinder of filled resin (Z 100; 3M Co., MN, USA) was then photocured and the specimens were then stored in water for 24 h or 180 days prior to shear bond testing to failure. Results: The results showed that high bond strengths were recorded using acids which were more dilute than those commercially available. There were also indications that phosphoric acid is not the etching acid of choice for the SBMP system. Conclusions: The results of this study showed that high bond strengths can be achieved in dentine using etching acids which are more dilute than those commercially available. Maleic acid appears to be the etchant of choice for the SBMP system.