A prospective, randomized, double-blind clinical trial of one nano-hybrid and one high-viscosity bulk-fill composite restorative systems in class II cavities: 12 months results.

Background: Recently, manufacturers have introduced bulk-fill composite resins that reportedly can be placed in increments of 4 mm or greater.

Objective: The purpose of this article was to report the results of 12 months prospective randomized clinical trial that evaluated the clinical performance of one high-viscosity bulk-fill composite resin in Class II cavities of posterior teeth.

Materials And Methods: Thirty-four participantshad at least two Class II cavities included the study. Class II cavities restored with either a Tetric EvoCeram bulk-fi fill or universal nano-hybrid resin composite (Tetric EvoCeram). A total of 74 restorations (37 with each material) on 34 patients were placed according to the manufacturers' instructions by one calibrated operator.

Results: Seventy restorations were evaluated after 12 months evaluation period. No postoperative sensitivity, anatomic form, retention, and secondary caries were observed after 6 and 12 months. Regarding the items color match, marginal discoloration, and marginal adaptation, the statistical analysis did not detect any statistical significance between two materials (P > 0.05).

Conclusion: After 12 months of clinical service, all restorations evaluated for both materials were classified as ideal, receiving predominantly Alfa scores for all parameters analyzed.

Clinical Relevance: This study presents that high-viscosity bulk-fill resin composites (RCs) perform just as well as nano-hybrid RCs with the 2 mm RC layering technique, therefore could be alternative to conventional nano-hybrid RCs.