The comparison of the marginal gaps of zirconia framework luted with different types of phosphate based-resin cements.

Abstract

Objective: Phosphase based-resin cements are known to chemically bond to zirconia ceramics. Additionally, they are the cement of choice for these materials. Therefore, the aim of this study was to evaluate the marginal gaps of zirconia frameworks luted with two types of phosphate based resin cements. Materials and methods: Thirty maxillary premolar teeth were randomly divided into two groups (n=15); a self-etch (Panavia F2.0; Kuraray Medical, Japan) and self-adhesive (Rely X U100; 3MESPE, USA) resin cements. The teeth were prepared with round shoulder and the 6° convergence angle. The zirconia frameworks were fabricated using TDS® CAD/CAM system (Total Dental Solution, Changhua, Taiwan). The marginal fits of zirconia frameworks were evaluated under a microscope (MM-11C, Nikon, Tokyo, Japan) (30x magnification) at the following sequences: before cementation, after cementation and after 20,000 thermocycles. The differences in the marginal gaps (after and before cementation: delta diff1, after thermocycling and after cementation: delta diff2) between two resin cements were analyzed with Student’s t-test and Mann Whitney U test. The differences between two processes in each group were tested with paired t-test and Wilcoxon signed-rank test (p<0.05). Results: After cementation, the marginal gaps of two resin cements were significantly higher than before cementation (p<0.001). The slight differences were found in mean of delta diff2 (self-etch: 0.88 µm, self-adhesive: 0.26 µm). The marginal gaps of zirconia frameworks cemented with self-adhesive resin cement were significantly smaller than self-etch resin cement both after cementation and after thermocycling (p<0.05). Conclusions: Long-term thermocycling had no clinical effect on the marginal fit. The type of resin cements influenced the marginal fit. The marginal gaps achieved by both resin cements were within clinically accepted standards (<120 µm).