The influence of different placement techniques on the clinical success of bulk-fill resin composites placed in Class II cavities: a 4-year randomized controlled clinical study.

OBJECTIVE: The purpose of this double-blind and split-mouth randomized controlled clinical trial was to evaluate the clinical success of the placement technique (bulk-filling and incremental techniques) of a bulk-fill resin composite in Class II carious lesions. MATERIALS AND METHODS: Two different bulk-fill resin composites, X-tra fil (Voco) and Filtek Bulk Fill (3M ESPE), were used in the bulk-filling and incremental techniques for 20 patients. The study was carried out in 4 groups, with 20 restorations in each group. Restorations were appraised at baseline, 6-month, 2-year, and 4-year recall. World Dental Federation (FDI) and the US Public Health Service (USPHS) criteria were used in the evaluations. The Friedman, Kruskal-Wallis, and Mann-Whitney U tests were used for the statistical analysis. RESULTS: At the end of year 4, there was no loss of restoration in any group. According to the USPHS and FDI criteria, there was a difference in the baseline and 4-year in marginal adaptation and marginal discoloration of the restorations (P < 0.05). When Filtek-Bulk was placed as an incremental technique, there was a minor fracture in four restorations (P > 0.05). In addition, Filtek-Bulk showed a color change according to the results based on both the USPHS and FDI criteria (P < 0.05). The difference between the two placement techniques of each resin composite was not significant at the year 4 recall when all criteria were evaluated (P > 0.05). CONCLUSIONS: The 4-year clinical success of the evaluated bulk-fill composites is not dependent on the placement technique used. CLINICAL RELEVANCE: This study can help clinicians choose which technique (bulk fill and incremental techniques) bulk-fill composites can be used. TRIAL REGISTRATION: US National Library of Medicine, www. CLINICALTRIALS: gov , ID: NCT04565860 Registered on 10/09/2020. Clinical Evaluation of Bulk-fill resin Composites in Class II Restorations.