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.