Method: The protocol followed the CONSORT statement for clinical trials. Thirty-five patients, with at least four NCCLs, participated in this randomized, double blind, parallel clinical study. After sample size calculation, 180 restorations were assigned to one of the following groups: OFL – Optibond FL (3-step etch&rinse); OSP – Optibond Solo Plus (2-step etch&rinse); XTR – Optibond XRT (2-step self-etch); and AIO – Optibond All-in-One (1-step self-etch). The composite resin Filtek Supreme Ultra (3M ESPE) was placed incrementally. The restorations were evaluated at baseline and after 18 months using both the FDI and the USPHS criteria. Statistical analyses were performed with Friedman repeated measures ANOVA by rank and McNemar test for significance in each pair (α=0.05).
Result: Ten restorations (2 for OFL, 2 for OSP, 3 for XTR and 3 for AIO) were lost at 18 months (p > 0.05 for either criteria). Marginal staining was observed in eight restorations using the FDI criteria (p > 0.05); and 5 restorations using the USPHS-modified criteria with no difference between materials (p > 0.05). Twenty-one restorations (5 for OFL, 4 for OSP, 6 for XTR, and 6 for AIO) were classified as Bravo for marginal adaptation (USPHS; p > 0.05). However, 64 restorations were considered as Bravo using the FDI criteria (14 for OFL, 13 for OSP, 16 for XTR, and 21 for AIO; p > 0.05).
Conclusion: The four bonding strategies showed similar clinical behavior at 18-months. The FDI evaluation criteria tend to be more sensitive than the USPHS criteria