Two-year follow-up study of repairs using conventional resins and bulk-fill in proximal restorations. A double-blind randomized clinical trial

Abstract

Introduction: Currently, composite resins (CRs) are the material of choice for direct restorations, and in cases of partial deterioration, repair is often recommended, as it significantly increases their lifespan. Bulk-fill resins (BFRs), on the other hand, are restorative materials that can be applied in single increments, thereby simplifying the procedure and reducing clinical time. The objective of this study was to evaluate the two-year clinical performance of repairs of proximal posterior composite resin restorations performed using BFRs and conventional nanohybrid CRs.
Materials and Methods: Thirty-six volunteer patients from the clinic of the Faculty of Dentistry at the Universidad de Chile participated in this study. It had an experimental, controlled, randomized, double-blind clinical design, in which the experimental unit was the repair of proximal CR restorations. The groups evaluated were as follows: Group 1, repair with Tetric EvoCeram Bulk Fill® resin (TEVO); and Group 2, repair with Filtek Z350 XT® resin (Z350). Repairs were evaluated at baseline and at 24 months using the FDI World Dental Federation evaluation system (1: clinically excellent/very good, 2: clinically good, 3: clinically sufficient/satisfactory, 4: clinically unsatisfactory, 5: clinically poor) for the following clinical properties: marginal integrity (MI), surface texture (ST), marginal staining (MS), sensitivity (S), fracture and retention (RT), proximal and occlusal anatomy (AN), and caries (C).
Results: A total of 72 restorations were followed up. Excellent clinical performance was observed in the following parameters: MI: Z350 86.1% and TEVO 83.3%; ST: Z350 77.8% and TEVO 80.6%; MS: Z350 63.9% and TEVO 66.6%. For both fracture and retention (RT) and anatomy (AN), excellent performance was observed for Z350 (86.1%) and TEVO (88.8%). For sensitivity (S) and caries (C), both groups showed 100% excellent outcomes. No statistically significant differences were found between the two groups (p>0.05).
Conclusion: There were no statistically significant differences in two-year clinical performance between repairs of proximal posterior composite resin restorations performed using BFR and conventional composite resin.