Clinical performance and wear resistance of two compomers in posterior occlusal restorations of permanent teeth: six-year follow-up

This study evaluated the clinical performance and wear resistance of compomer restorations placed in the occlusal cavities of posterior permanent teeth after six years. In 1999, 72 Class I restorations were placed by a single operator in 33 patients. Eighty-two percent of these restorations were located in molars. Each patient received at least two restorations, one with F2000 (3M ESPE) and another with Dyract AP (Dentsply). The finished and polished restorations that were free of any failure were considered the baseline. The restorations were clinically evaluated at baseline and at one-, two- and six-year intervals using modified USPHS criteria for color mismatch, marginal discoloration, surface roughness, marginal adaptation, anatomic form and secondary caries. Polyvinylsiloxane impressions (Express, 3M ESPE) were also taken, and models were obtained for indirect wear assessment (Leinfelder scale) at the same intervals. After six years, 11 patients attended the recall. Twenty-seven compomer restorations (11 with Dyract and 16 with F2000) were reevaluated. Data were submitted to the Friedman's test, ANOVA with repetitive measures, Tukey's test (clinical data), Wilcoxon and Kruskal-Wallis tests and the Spearman's correlation test (wear evaluation), all at a significance level of p < 0.05. When comparing the materials, F2000 and Dyract presented similar clinical performance and occlusal wear at the end of the clinical trial. The two compomers showed a significant increase in wear at the six-year follow-up, and a positive correlation (r2 = 0.65) was detected between wear and evaluation time (p < 0.001). Despite the decrease in restoration quality and the increase in occlusal wear, nearly all restorations were considered acceptable after the six-year evaluation.