EFFECT OF DESENSITIZING TOOTHPASTE ON MICROTENSILE BOND STRENGTH BETWEEN RESIN COMPOSITE AND DENTIN

Abstract

The objective of this study was to evaluate and compare the effects of two desensitizing toothpastes and a regular fluoride toothpaste on microtensile bond strength of two adhesive agents to dentin. Materials and methods: The labial surfaces of forty bovine incisor crowns were ground flat, exposing dentin. The teeth were then randomly divided into four groups corresponding to the toothpaste used: 1) Sensodyne Rapid Relief (GlaxoSmithKline, UK), 2) Colgate Sensitive Pro-Relief (Colgate-Palmolive, Thailand), 3) Colgate Regular Flavor (Colgate-Palmolive, Thailand), and 4) immersed in artificial saliva (control). Each tooth in groups 1–3 was brushed with its respective dentifrice under constant loading (200 g) at 250 strokes/min for 2 minutes, twice daily for three days. Each group was then randomly divided for composite build-up using the following adhesive agents: 1) Optibond XTR (Kerr, USA), or 2) Optibond FL (Kerr, USA). After curing the adhesives, a light-cured resin composite (Premise, Kerr, USA) was used for a core build-up. The samples were sectioned into four 1± 0.1 mm thick specimens. The microtensile bond strength test was performed using a universal testing machine at a cross-head speed of 0.5 mm/min. The data were analyzed using two-way ANOVA and Tukey’s multiple comparison tests with significance set at p < 0.05. Fracture analysis of the debonded dentin surface was performed using a stereomicroscope. Results: Bond strength was significantly reduced by the application of desensitizing toothpastes (p < 0.0001). Moreover, the type of adhesive agents had a significant effect on bond strength (p < 0.0001). Conclusion: The use of desensitizing toothpaste may reduce bond strength of adhesives to dentin.