Marginal quality and wear of extended posterior resin composite restorations: Eight-year results in vivo

Abstract

AimTo evaluate wear and marginal quality of resin composite restorations over eight years of clinical service in vivo. Methods30 patients received 68 resin composite restorations (36 Grandio, 32 Tetric Ceram) in the course of a prospective clinical trial. 3-D evaluation of 36 selected teeth involving 144 epoxy replicas was carried out using a special 3-D scanning device with an accuracy of U1=2.5+L/350μm; U3=3+L/300μm. In vivo replicas were sputter-coated with gold and examined under a SEM at 200× magnification. Marginal integrity between resin composite and enamel was expressed as a percentage of the entire judgeable margin length. ResultsDuring the clinical 8-year observation period, wear significantly increased in the restored areas as well as in OCAs. RBCs under investigation showed no significant differences regarding wear (p>0.05). Localization of the restorations (premolar vs. molar or upper vs. lower) did not show a significant influence on wear rates (p>0.05). Clinically, by SEM, and by 3-D scanning distinct changes of worn contours on enamel and RBC were visible. Quantitative margin analysis revealed a change of perfect margins (58% at baseline vs. 14% at 8 years), positive step formations (15% at baseline vs. 10% at 8 years), and negative step formations (20% at baseline vs. 71% at 8 years) over time (p<0.001). Regarding the portion of gap-free margins (baseline vs. 2 years) and total margin length (baseline to 8 years), Grandio showed lower values (Mann-Whitney U-test; p<0.05). The portion of negative step formations was lower for Tetric Ceram at baseline (Mann-Whitney-U test; p<0.05). ConclusionsAfter eight years of clinical service, neither wear nor marginal quality was a critical factor for estimation and survival of extended posterior resin composite restorations.