Effect of Resin Coating on Microtensile Bond Strength between Dentin and Dental Composite Materials

Objective The objective of this study was to investigate the effect of a thin film resin coating on the microtensile bond strength between human dentin and an indirect composite resin (CeraSmart, CER) and a polymer infiltrated ceramic network (Vita Enamic, VIT). Materials and Methods Forty extracted human third molars were sectioned and randomly assigned to four groups (n ¼ 10 teeth per group): (1) CER with Bio Coat Ca, (2) CER without Bio Coat Ca, (3) VIT with Bio Coat Ca, and (4) VIT without Bio Coat Ca. All specimens were bonded using Super-Bond C&B resin cement. The bonding procedure was performed according to the manufacturer’s instructions. The bonded specimens were sectioned longitudinally to obtain bar-shaped specimens with an approximate surface area of 1 1 mm². A total of 6 to 8 specimen sticks in the central area of each tooth were used for the microtensile test and the mean microtensile bond strength (µTBS) was used to represent the bond strength of each tooth. The µTBS data were statistically analyzed using two-way analysis of variance at α ¼ .05. Results The mean µTBS of group 1 to group 4 were 25.6 9.1, 25.9 3.3, 24.9 6.1, and 30.1 4.1 MPa, respectively. The mean µTBS of specimens with and without Bio Coat Ca were not significantly different for both CER and VIT (p > 0.05). The most frequent type of failure observed in every group were cohesive within a resin cement and mixed failure through dentin and cement. An adhesive failure was observed 6 to 12% in nonresin-coated groups and 0% in coated specimens. Conclusion The microtensile bond strength of all groups was not significantly different, which indicated that a resin coating was not detrimental and a potential shift toward more favorable failure patterns when bonding with a thin resin coating was observed.