Clinical Performance Of All-Ceramic Inlays: Complications And 5-Year Survival

Objective: This randomized clinical trial evaluated complications and survival of two systems of all-ceramic inlays depending on the type of composite used for luting. Methods: 32 patients were treated with 220 copy-milled (Celay, Cy) and heat pressed (IPS Empress, Em) all-ceramic inlays by randomized pairwise assignment to homologous teeth (modified split mouth design). All inlays were adhesively luted under rubberdam by using dual-curing resin luting agent. Each patient was assigned to either low-viscosity (Variolink 2) or high-viscosity (Variolink Ultra) modification by additional randomization. All patients were prospectively followed in a systematic recall including a modified CDA ranking by one examiner (not involved into treatment). Examiner and patients were unaware of therapy assignment. Survival and complication rate were estimated by time to event analysis. Results: The median observation time of all 32 patients was 6.25 years (range: 1 to 10y). 169 inlays (24 patients) were followed at least 5 years. Survival was estimated at 96.7% after 5 years. 3.9% of the inlays experienced failure or complication. The therapy strata showed only minor variations. Neither restoration system nor type of luting material showed statistically significant influence on survival or complication rate. Complication rate varied according to inlay extension: no complication (1 surface), 2.9% (2 surfaces), 6.7% (3 or more: 3+), but ChiSq (2 vs. 3+) was >0.05. Only inlays in contact with a neighbouring tooth (proximal surface) were affected by complications or failure: 5.3% over 5 years. This finding was statistically significant (ChiSq<0.03). Conclusion: It is concluded that good clinical performance of adhesively luted all-ceramic inlays might obviously not primarily depend on the restorative systems or materials used. The extension of the inlay seems to have some influence. But, having proximal surfaces is supposed to be its true underlying risk factor for success and survival.