Effect of thermal and mechanical loading on marginal adaptation and microtensile bond strength of a self-etching adhesive with caries-affected dentin

AIM: This study evaluated the effect of thermal and mechanical loading on marginal adaptation and microtensile bond strength in total-etch versus self-etch adhesive systems in caries-affected dentin. MATERIALS AND METHODS: Forty class II cavities were prepared on extracted proximally carious human mandibular first molars and were divided into two groups: Group I — self-etch adhesive system restorations and Group II — total-etch adhesive system restorations. Group I and II were further divided into sub-groups A (Without thermal and mechanical loading) and B (With thermal and mechanical loading of 5000 cycles, 5 ± 2°C to 55 ± 2°C, dwell time 30 seconds, and 150,000 cycles at 60N). The gingival margin of the proximal box was evaluated at 200X magnification for marginal adaptation in a low vacuum scanning electron microscope. The restorations were sectioned, perpendicular to the bonded surface, into 0.8 mm thick slabs. All the specimens were subjected to microtensile bond strength testing. The marginal adaptation was analyzed using descriptive studies, and the bond strength data was analyzed using the one-way analysis of variance (ANOVA) test. RESULTS AND CONCLUSIONS: The total-etch system performed better under thermomechanical loading.