Bond strength of a universal adhesive system to bovine vs. human primary teeth

Abstract

To compare the bond strength of a universal adhesive system to bovine primary and human primary enamel and dentin. Flat enamel and dentin surfaces from 28 sound human primary molars and 28 bovine primary incisors were bonded with Scotchbond Universal Adhesive applied in etch-and-rinse and self-etch mode (n = 7). Composite resin cylinders (0.72 mm 2 ) were built on the adhesive area. The specimens were submitted to a microshear bond strength test, and the bond failure mode was evaluated. Bond strength data (MPa) were analyzed using two-way ANOVA and Tukey's test (α = 0.05). Energy-dispersive X-ray spectroscopy (EDS) was carried out to identify the levels of calcium and phosphorus in each type of teeth. Higher bond strength values were found to bovine primary enamel compared to human enamel (p = 0.04). No statistically significant differences were found between bovine and human primary dentin (p = 0.09). The universal adhesive applied in self-etch mode to enamel resulted in lower bond strength values (p < 0.05). EDS analysis showed significantly lower calcium content in bovine primary dentin (p = 0.01), but no significant differences were found between bovine and human primary enamel. Bovine primary teeth can only reliably replace human teeth in bonding studies when dentine is the focused substrate. Bovine primary enamel promotes higher bond strength values compared to human primary enamel.