Shear Bond Strength of Self-Adhesive Versus Conventional Flowable Composites: An In Vitro Study

Aim: As an emerging yet underexplored innovation in dentistry, self-adhesive flowable composites (SAFCs) represent a promising and enduring advancement in the dental material technology. Our study aims to evaluate the shear bond strength of two SAFCs and the bonding of conventional flowable composite (CFC) to permanent dentin. Materials and Methods: Thirty-six teeth were embedded in acrylic blocks, with the occlusal third removed to expose the underlying dentin. A cylindrical mold was positioned on the treated dentin surface and filled with the composite resin material to be evaluated. The prepared permanent dentin surfaces were randomly assigned to three groups based on the following application protocols: Group 1: Axo Uni Flow (AXIMACK, India); Group 2: Constic (DMG, Germany); and Group 3: 37% phosphoric acid etchant + Single Bond Universal + Filtek Z350 XT (3M ESPE, USA). The shear bond strength of the prepared specimens was measured by using a universal testing machine. The data were analyzed with Kruskal-Wallis one-way analysis of variance, followed by Dwass-Steel-Critchlow-Fligner pairwise comparisons. Results: Filtek Z350 XT (3M ESPE, USA) demonstrated higher shear bond strength values when compared to Constic (DMG, Germany) and Axo Uni Flow (AXIMACK, India). A significant difference was found between these materials. However, the shear bond strength of the two SAFCs tested did not differ significantly. Conclusion: The investigation's findings suggest that the SAFCs exhibited inferior shear bond strength compared with CFCs when bonded with permanent dentin.