Comparison of shear bonding strength for two different etching systems in canine and human dentin

Canine dentin has increased size and number of dentinal tubules compared to human dentin. With less intertubular surface area for bonding to composite material in dog teeth, bonding shear strength may be affected negatively. This study was designed to compare the shear bonding strength of canine and human dentin. It also compared bond strength of two different acid etch systems when used with the same composite resin. The shear bond strength of composite cylinders to dentin was measured in 30 extracted canine cuspid teeth and a similar number of human molar teeth. Shear bond strength was 40% greater for human compared with canine dentin. This significantly different (P < 0.05) result validates the hypothesis that dentin bond strength is positively correlated with the area of intertubular dentin. Results also indicated that shear bond strength was greater in the self-etching bond system compared with the etch and rinse system, although this difference was not significant.