A prospective randomized clinical trial of one bis-GMA-based and two ormocer-based composite restorative systems in class II cavities: Five-year results.

OBJECTIVES Ormocer composites, consisting of a silicon-based polymer, have been developed recently as a tooth-colored restorative material. The purpose of this prospective randomized clinical trial was to evaluate the performance of two small-particle hybrid ormocer-based restorative systems (AD, Admira/Admira Bond, VOCO; DE, Definite/Etch & Prime 3.0, Dentsply) and one small-particle hybrid bis-GMA-based composite restorative system (TC, Tetric-Ceram/Syntac, Ivoclar-Vivadent) in class II cavities. METHODS From 128 occlusal-proximal restorations (44 AD, 43 DE and 41 TC) placed in 32 adult patients, eventually 77 (22 AD, 29 DE and 26 TC) remained available for evaluation after 5 years. Their clinical performance was scored according to the USPHS criteria and evaluation of bite-wing radiographs. RESULTS After 5 years, eight AD, six DE and seven TC restorations had failed (p=0.10, log-rank test). The main reason was fracture or marginal gap formation, while secondary caries accounted for four failures. In all restorations the quality of surface, margins and contact point decreased significantly compared to baseline. DE had a significant poorer color match (p<0.01). Statistical evaluation using the KW test showed that failures were concentrated on specific patients. CONCLUSIONS In a group of class II restorations, there was no significant difference in failures after 5 years between ormocer-based and bis-GMA-based restorative systems.