Evaluation of the effect of 3 bonding protocols on the micro-tensile bond strength of self-adhesive composite to enamel and dentin

Objectives: To investigate the micro tensile bond strength (µTBS) of self-adhesive bulk-fill composite (Surefil One) to enamel and dentin bonded without bonding agent, with an additional phosphoric acid etch, and with the use of a bonding agent in etch and rinse mode. Methods: 90 sound extracted wisdom teeth were used in this study. Surefil One (Dentsply Sirona, Konstanz, Germany), Prime&Bond Universal (Dentsply Sirona, Konstanz, Germany) and Detrey Conditioner 36 Etch Gel (Dentsply Sirona, Konstanz, Germany) were tested. Teeth were divided in 6 groups of 15 teeth, according to tooth substrate (enamel and dentin) and bonding protocols (no bonding agent, bonding with 36% phosphoric acid etch, bonding in etch and rinse mode using a universal adhesive). µTBS was tested using a universal testing machine and micromorphological observation of the interface was investigated using a magnifier. Data were analyzed using STATA version 15.0. Different bonding protocols were compared using appropriate statistical tests including ANOVA, Kruskal Wallis, Mann-Whitney, and Fisher’s exact tests (p < 0.05). Results: Surefil One bonded on enamel using etch and rinse mode with a universal adhesive yielded the highest µTBS values compared to control and with phosphoric acid etching. Additional phosphoric acid etching significantly increased µTBS on enamel. On dentin, etch and rinse mode also recorded the highest µTBS and there was a significant difference between control group and with additional phosphoric acid etching. Control groups showed the lowest µTBS in all experimental groups. Conclusions: Bonding Surefil One in etch and rinse mode with a universal adhesive is recommended on both enamel and dentin.