Two-year clinical evaluation of proanthocyanidins added to a two-step etch-and-rinse adhesive

Objective: To compare the clinical behavior of Proanthocyanidins (PA)-free and PA-containing two-step etch-and-rinse adhesive used underneath resin composite restorations in non-carious cervical lesions (NCCLs) over a 6- (6 M) and 24-month (24 M) period. Methods: 135 restorations were randomly placed in 45 subjects. The NCCLs were conditioned (37% phosphoric acid for 15 s) and distributed into 3 groups: Control (EX0) - ExciTE F (Ivoclar Vivadent) adhesive applied following the manufacturer's recommendations; EX2 and EX5 – 2 wt% and 5 wt% of PA were added to ExciTE F, respectively, and applied as in EX0. Resin composite was placed incrementally and light-cured. The restorations were evaluated at baseline, 6 M and 24 M, using FDI and USPHS criteria. Statistical analyses were performed using Friedman and Wilcoxon tests (α = 0.05). Results: The retention rates were 98% (95% confidence interval 88–99%) for EX0, 92% (80–97%) for EX2; and 85% (72–93%) for EX5 at 6 M. A significant difference was found only for EX5 at 6 M when compared with the respective baseline findings (p = 0.03) and when compared with EX0 and EX2 (p = 0.001) at 6 M. After 24 M, the retention rates were 98% (88–99%) for EX0, 73% (59–84%) for EX2, and 71% (56–82%) for EX5. Only EX0 did not result in significant difference in retention rate at 24 M when compared with baseline but showed a significant higher retention rate when compared with those of EX2 and EX5 (p = 0.001). Conclusion: Adding proanthocyanidins to the adhesive solution jeopardized the retention of composite resins restorations in non-carious cervical lesions after 24 months. Clinical relevance: In spite of being user-friendlier than when used separately, the incorporation of proanthocyanidins into the adhesive solution impairs the longevity of composite restorations.