A 24-month clinical evaluation of composite resins with different viscosity and chemical compositions: a randomized clinical trial

Objectives: To evaluate the clinical performance of two methac-rylate-based flowable composites and an ormocer-based flow-able composite in noncarious cervical lesions (NCCLs) in adult participants. Method and materials: In total, 183 restorations were performed on NCCLs. All cavities were restored using a universal adhesive system (Futurabond U, Voco) with selective enamel etching and with one of the three evaluated flowable composites (n = 61): low-viscosity methacrylate-based composite (GrandioSO Flow, LV), high-viscosity methacrylate-based composite (GrandioSO Heavy Flow, HV), and an ormocer-based flow-able composite (Admira Fusion Flow, ORM). All restorations were evaluated using FDI and USPHS criteria after24 months. Kruskall-Wallis analysis of variance rank (a =.05) was used for statistical analysis. Results: After 24 months of clinical evaluation, 16 restorations were lost (LV = 3, HV= 10, ORM =3) and the retention rates (95% confidence interval) were 95.0% for LV, 82.2% for HV, and 95.0% for ORM, with statistical differences observed between HV and LV as well as HV and ORM (P < .05). When secondary parameters were evaluated, no significant differences between groups were observed (P>.05). Thirty-three restorations (LV = 8, HV= 13, ORM = 12) showed minor marginal staining, 71 restorations (LV = 26, HV = 20, ORM =25) presented small marginal adaptation defects, and one restoration for HV presented recurrence of caries. Conclusion: The universal adhesive associated with the ormocer-based and methacrylate-based flowable composite showed promising clinical performance after 24 months. However, the heavy-flow restorations showed significantly more failures.