Effects of desensitizing treatments on composite bond strength to dentin

Objective: The aim of this study was to evaluate the bond strength of composite resin to dentin mediated by a self-etch adhesive following the application of various dentin desensitizing treatments and artificial saliva storage. Methods: Buccal cervical areas of 24 extracted human third molars were ground flat to expose cervical dentin. The dentin surfaces were polished with 1200-grit SiC paper and then the teeth were randomly assigned to 6 groups, five desensitizing treatment and one control: Group I- VivaSens; Group II- Fluor Protector; Group III- Isodan; Group IV- Futura Bond NR; Group V- Nd:YAG laser and Group VI- Control (without any application of desensitizing agent). After applying the desensitizing treatments and storage in artificial saliva for 14 d at 37 C degrees, Futura Bond NR was employed to bond resin composite to dentin. TPH composite build-ups were constructed incrementally to a height of 5mm. The teeth were sectioned to obtain bonded slices of 0.7 mm thick each which contained the resin-composite joint. They were then trimmed into an hourglass shape and subsequently subjected to the microtensile test at a crosshead speed of 1 mm/min. Data were analyzed using Kruskal-Wallis analysis and multiple comparisons test. Results: The control and Futura Bond NR self-etch treatment (group IV) group, yielded statistically significant higher bond strength values than the other desensitizing treatment groups tested (p < 0.005). While pretreatment of dentin surfaces with desensitizing agents (Fluor Protector, VivaSens and Isodan) and laser (Nd:YAG) reduced the bond strength values of composite resin, higher bond strengths were achieved with the use of a self-etch adhesive (Futura Bond NR). Conclusion: Desensitizing treatments, except self-etch adhesive, might have an adverse effect on the bond strength of a composite resin to dentin mediated by a self-etching primer.