Tensile bond strength of self-adhering flowable composite on dentin surface (An in vitro study)

This study evaluated the effect application microtensile bond strength (μTBS) on the self-adhering flowable composite resin to dentin surface. Occlusal surfaces of human adult premolars and deciduous molars were ground to obtain flat dentin surfaces with a water-cooled diamond saw. Each of the following adhesive systems were applied to dentin surface of the tooth, following manufacturers’ instructions: Self-adhesive flowable resin composite: (Vertiseflow), Self-etch adhesive system (optibond). Buildups were then made on the bonded surfaces and incrementally light-cured for 20 s. with Two light curing resin composite resin: Herculite resin composite and Self-adhesive flowable resin composite. The restored teeth were stored in water at 37^oC for 24 h, three months and six months. Each tooth quarter was serially cut in a longitudinal direction in order to obtain several bonded sticks (0.9-mm2 in cross-section). Maximal microtensile stress (in MPa) at failure was recorded using a universal testing machine. Data were analyzed by two-way ANOVA and Tukey’s test at 5% significance level. The result revealed that self-adhesive flowable composite showed the lowest tensile bond strength in comparison with the obti bond all-in-one adhesive or Vertise flow as adhesive. In conclusion, Optibond adhesive has higher bond strength than Vertise flow adhesive composite, etching dentin surface with acid etchant phosphoric acid 37% enhance bond strength for self-adhesive flowable composite, Tensile bond strength in permanent dentin higher than deciduous dentin and the storage time has adverse effect on the bond strength.