Metal–ceramic crowns cemented with two luting agents: short-term results of a prospective clinical study

A prospective, randomized, controlled, split-mouth trial was performed to evaluate the cementation modes for metal–ceramic crowns. A total of 40 fully veneered metal–ceramic crowns were delivered in the posterior jaw segments of 20 patients using either a self-adhesive resin cement (RelyX Unicem Aplicap, 3M ESPE; n = 20) or a zinc oxide phosphate cement (Hoffmann's Cement, Hoffmann; n = 20). Thirteen parameters related to the abutment teeth and their periodontal status were evaluated. A visual analog scale was used to assess the sensitivity of the abutment teeth by patient-based outcomes. Data were statistically analyzed by a single-classification ANOVA (α = 0.05) and logistic regression analysis. The results presented were obtained after a mean observation period of 1.8 years. The dropout rate was 0%. None of the abutment teeth exhibited secondary caries at the restoration margins. No significant differences were demonstrated between the luting agents based on visual analog scale (p > 0.05), hypersensitivity (OR = 1.31), abutment mobility (p > 0.05), or probing depths (p > 0.05). Based on the sulcus fluid flow rates, a significantly greater mean difference was obtained with zinc oxide phosphate cement than with self-adhesive resin cement (9.2 units; p = 0.0006). Significant differences between the baseline examination and the follow-up examinations for sulcus bleeding index (p = 0.0013) and plaque index (p < 0.0001) were observed regardless of the luting agent used. The two cement types showed scarcely any differences between the parameters investigated. The outcomes of cementing fully veneered metal–ceramic crowns were equally good with self-adhesive resin cement as with the clinically proven zinc oxide phosphate cement.