143 - Bonding and wear properties of self-adhesive flowable resin composites.

The aim of this study is to evaluate the bonding and wear properties of self-adhesive flowable resin composites. The four self-adhesive flowable resin composites used in this study were: 1) Constic (CO, DMG), 2) FitSA F03 (FS, Shofu), 3) Fusio (FU, Pentron Clinical), 4) Vertise Flow (VF, Kerr). Two hundred and eighty bovine mandibular incisors were used for shear bond strength testing to both enamel and dentin, and the teeth were mounted in self-cure acrylic resin. The labial surfaces of the coronal central portion were ground using P120- and P400-grit silicon carbide papers. A mold insert was clamped against the specimens and filled with self-adhesive flowable resin composite. After storage at 37°C for 24 h, shear bond strength testing was carried out using a universal testing machine. Twelve specimens of each of the four self-adhesive flowable resin composites were prepared for simulated localized wear testing. An Alabama wear testing machine with a four-station plastic water bath in which stainless steel ball bearings served as the wear antagonists was used. Load of up to 78.5 N was applied over 400,000 cycles at 2 Hz. Scanning electron microscopy observation of bonding interfaces and wear facets was conducted. Bond strength to dentin ranged from 1.3 MPa to 4.2 MPa, while bond strength to ground enamel ranged from 6.5 MPa to 12.2 MPa, and bond strengths to etched enamel ranged from 23.7 to 32.5 MPa. The rank order for bond strength to dentin and ground enamel was FS = CO > FU = VF, and for etched enamel was FU = CO ≥ VF > FS. There was significant variation in wear between the materials, from 0.099 mm3 to 0.367 mm3 in volume loss, and 148.6 µm to 327.4 µm in facet depth. The rank order for both measures of wear was FS > CO > FU = VF. The bonding performance and occlusal wear resistance of self-adhesive flowable resin composites is still weaker than resin composites with adhesive systems, but selective enamel etching can improve bonding performance. In addition, the relationship of the rank orders for the results may indicate that bonding to ground enamel and dentin relies more on chemical bonding, while bonding to etched enamel relies more on the mechanical properties of the materials. [ABSTRACT FROM AUTHOR]