A 24-month randomized clinical study of flowable bulk-fill resin composites in Class III cavities

Background: The 24-month clinical performance of 3 commercially available flowable bulk-fill resin composites in Class III restorations was evaluated. Materials and Methods: Forty-two patients, 27 females (64.3%) and 15 (35.7%) males, received at least 3 Class III restorations that never exceeded 4 mm depth and width. One hundred thirty-eight teeth, divided up into three groups (n=46), were randomly restored with Admira Fusion x-base (AFB), Estelite Bulk Fill Flow (EBF) and SDR flow+ (SDR) in one single increment. A 2-step self-etch adhesive system Clearfil SE Bond (C-SE) with selective enamel etching was used for all restorations. The restorations were clinically evaluated using a slightly modified USPHS criteria at the baseline and every 6 months for 24 months. Success rates of each material between the baseline and at 24 months were compared with the McNemar test. At each timepoint, the comparison of the clinical performance among materials in terms of the ratings of the considered criteria was analyzed by using the Friedman and Cochran’s Q tests. Results: At the end of the 24-month follow-up, the overall clinical success rate was 100% for each tested material. However, significant differences among the composites were highlighted for several criteria involving the marginal adaptation, marginal discoloration, surface texture, surface staining and color match. Conclusions: The flowable bulk-fill resin composites tested showed an overall good effectiveness for Class III restorations after the 24 months, although significant rating differences among the materials emerged for some specific clinical criteria.