Shear Bond Strength of Enamel-Composite Resin-Zirconia Joints

Abstract

Statement of Problem: Adhesive cementation is essential to provide reliable bond strength, an improved marginal seal and esthetic performance to the zirconia fixed partial dentures. However, there are still some problems in establishment of a strong adhesive bond with zirconia, because zirconia has little or no silica content. Purpose: The aim of this study is to observe and compare the shear bond strengths of the enamel-composite resin-zirconia joints luted with different adhesive cementation protocols. Materials and Methods: Thirty pieces of zirconia discs were fabricated and divided in 3 groups. Each disc was luted to the enamel tissue of a tooth embedded in acrylic resin cylinder according to one of the following adhesive cementation protocols: 1. Hydrofluoric acid application, silanization and luting with methacrylate based composite resin cement (Group HF). 2. Silica coating, silanization and luting with methacrylate based composite resin cement (Group SC). 3. Luting with methacrylatephosphate based composite resin cement (Group PF). The shear bond strength was tested with a universal testing machine. Data were analyzed with ANOVA and multiple comparisons were made by Dunnett T3 (α =.05). Results: ANOVA revealed that the bond strengths differed significantly between all groups ( P= .00). The group SC exhibited the highest shear bond strength value, while the group HF exhibiting the lowest. Conclusions: Among the tested luting protocols, silica coating followed by silanization and luting with resin composite cement should be considered in priority for the cementation of the zirconia fixed partial dentures. Clinical Implications: Preference of the luting protocol is important to obtain long term clinical success of the zirconia fixed partial dentures.