Efeito das proantocianidinas na longevidade de restaurações adesivas: ensaio clínico aleatorizado e duplo-cego

Abstract

Proanthocyanidins (PAs) are natural agents capable of crosslinking dentin collagen, inhibit collagenase proteolytic activities and have shown positive effects on the resistance to biodegradation, mechanical properties and structural stability of dentin in vitro. This thesis consists of two chapters that aimed to evaluate in vivo the effect of PAs on the longevity of adhesive restorations of non-carious cervical lesions (NCCLs) in a randomized, double-blind clinical trial. Chapter 1 evaluated the PA, as an aqueous solution, applied to the dentin prior to the application of the adhesive system and after the acid etching, at concentrations of 2% (PA2) and 5% (PA5) (by weight). Chapter 2 evaluated the PA incorporated in the adhesive system at concentrations of 2% (EX2) and 5% (EX5) (by weight). For both, 45 patients with 3 lesions each were selected, giving a total of 135 NCCLs per study. A simplified conventional commercial adhesive system, applied according to the manufacturer's recommendations, was used as the control group in the studies. NCCLs from both studies were restored with composite resin and the restorations were evaluated after polishing and in the 6 and 24-month periods using modified United States Public Health Service (USPHS) criteria and the International Federation of Dentistry (FDI). For the two studies, differences in assessments between the three groups after 6 and 24 months were tested with the Friedman variance analysis of repeated measures by category ( = 0.05) and differences in the assessments of each group in the initial period and after 6 and 24 months were evaluated using the Wilcoxon test ( = 0.05). The results of chapter 1 showed that there was a statistically significant reduction in the retention rate for the PA5 group in the evaluation after 6 (17%) and 24 (30%) months (p = 0.03). The three groups showed a significant worsening in marginal adaptation over time for the FDI criterion, but no restoration was considered to have a clinically relevant discrepancy. Regarding the marginal discoloration, for the FDI criterion, a significant difference was observed between the initial evaluation and the 24-month evaluation for all groups. The results of chapter 2 showed that the EX5 group had a significant drop in the retention rate (15%) after 6 months. After 24 months, both the EX2 group (27%) and the EX5 group (29%) had a significantly lower retention rate than the control group. Regarding the marginal adaptation, all groups presented significant discrepancy over time, only for the FDI criterion. All groups presented increased marginal pigmentation over time for the two criteria evaluated, but only the EX5 group presented statistical difference when compared to the other groups in the periods of 6 and 24 months. In both studies, no restoration showed postoperative sensitivity or recurrence of caries. In this way, it was concluded that PA applied previously or incorporated into the adhesive system did not present clinical advantages after 24 months of evaluation.