Methods: MBII, TOKUYAMA M-bond (TMB) (Tokuyama Dental Corp.) and C&B-Metabond (CBM) (Sun Medical) were used in this study. TBS; the surfaces of bovine dentin (n=8) were ground (600-grit), bonded to stainless steel rods according to manufacturers' instructions, stored in distilled water (37°C, 24hours), thermo-cycled (10,000 times, between 4°C and 60°C). TBS was measured using a universal testing machine (UTM) (cross-head speed 2.0mm/min). Flexural tests; each cement was cured in the Teflon mold (25mm x 2mm x 2mm) (37°C, 60min), stored in distilled water (37°C, 24hours), polished (1500-grit). Energy (tenacity) at the breaking point or 5.5mm displacement was calculated by three point flexural tests using a UTM (cross-head speed of 1.0mm/min). Color change (Δ b*) of cured cement stored in distilled water (37°C, one year) was analyzed using automatic color analyzer.
Results: After 10,000 thermo-cycles, TBS using MBII, TBM and CBM were 19.1±3.5MPa, 16.0±3.0MPa and 12.9±3.9MPa respectively. Energy of MBII and CBM at 5.5mm displacement was 96.6±4.6mJ and 77.6±4.0mJ respectively and those of TMB at the breaking point was 5.7±1.2mJ. Δ b* of MBII, TMB and CBM were 2.3, 10.3 and 0.5 respectively.
Conclusion: Because of the chemical polymerization initiator system (borate derivative), TBS, tenacity and color of MBII were satisfactory.