Microtensile bond strength of restorative composite bonded with self-adhesive resin cements to enamel and dentin

Abstract

PURPOSE: To determine the microtensile bond strength (µTBS) of composite restorations when bonded with self-adhesive resin-cements. METHODS: Thirty caries-free extracted molars were sterilized, and divided into 5 equal groups according to adhesive used: SBMP (Scotch-Bond-Multipurpose, total-etch 3-step adhesive, 3M/ESPE), PAN (PanaviaF-2.0, resin-cement with self-etch primer, Kuraray), RXU (RelyX-Unicem, self-adhesive resin-cement, 3M/ESPE), BRZ (Breeze, self-adhesive resin-cement, Pentron) and MON (Monocem, self-adhesive resin-cement, Shofu). Each group was divided into 2 subgroups (dentin or enamel). Bonding agents, used according to manufacturers’ directions, or a thin layer of resin cement was applied onto teeth flat surfaces. Six mm-thick Filtek-Z250 (3M/ESPE) composite build up was made in three increments. Teeth were sectioned to obtain rectangular specimens which were subjected to tensile force until failure. Specimens were subjected to 1,000 thermo-cycles between 5oC-55°C. Means and standard deviation (SD) were calculated and statistically-analyzed with ANOVA and Tukey’s t-test. Specimens’ failure modes were reported. RESULTS: SBMP showed the highest µTBS results with enamel (24.6(6.1) MPa), PAN showed high µTBS with enamel (12.1(3.9)MPa) and dentin (11.6(4.7)MPa) compared to the other self-adhesive cements. Failure modes were adhesive and mixed for self-adhesive resin-cements. MON subgroups and BRZ enamel subgroup underwent premature failure. CONCLUSION: self-adhesive resin-cements showed low µTBS compared to SBMP.