Relevance of Adhesive Systems Evolution on Microleakage of Composite Restorations

Objectives: This study evaluated the microleakage on the cementum and enamel surfaces in Class II restorations using different kinds of etch & rinse and self-etch adhesive systems from the same label. Methods: Eighty box-type Class II standardized cavities were prepared on both proximal surfaces of previously extracted sound human molars with the cervical margin located 1mm above or below the cemento-enamel junction (CEJ). Teeth were randomly assigned to four groups (n=10) and restored, following manufacturer's instructions (Kerr), as follows: Group I, OptiBond FL, three-step etch & rinse adhesive; Group II, OptiBond Solo Plus, two-step etch & rinse adhesive; Group III, OptiBond Solo Plus Self-Etch Primer, two-step self-etch adhesive; Group IV, OptiBond All-In-One, one-step self-etch adhesive. Premise nanocomposite was incrementally inserted as the final restoration. The teeth were thermocycled at 5C/55C for 1000 cycles and immersed in 0.5% basic fuchsine solution for 24 hours. The specimens were cut into three slices approximately equal distance from the end wall of the restoration. Each section was observed under 40x stereomicroscope. The enamel and cementum margin leakage was evaluated using an ordinal scale (0-3). Data were analyzed using Mann-Whitney test at a p<0.05 level of significance. Results: For enamel, significantly more microleakage was recorded for Group III (median=3) compared to Group I (median=0), Group II (median=2) and Group IV (median=1), (p<0.05). At the cementum margin, microleakage values for Group I and IV (median=1) were significantly lower than for Group II and III (median=3), (p<0.05). Conclusion: Significantly less microleakage was associated with the use of three-step etch & rinse and the one-step self-etch adhesives compared to the other two groups at both enamel and cementum margins; however just the three-step etch & rinse adhesive system performed significantly better at the enamel than at the cementum margin.