Effect of Using Self-Etching Primer versus Conventional Etching Technique on Shear Bond Strength of Three Glass Ceramic Materials to Resin Cement

Introduction: The success of ceramic restorations leans on establishing a strong bond between the resin cement and ceramic materials as well as between resin cement and tooth structure. Aim: This study aimed to evaluate the effect of self-etch ceramic primer compared to the conventional technique (hydrofluoric acid + silane) on the surface morphology, wettability, and the shear bond strength of glass ceramics to resin cement. Material and methods: Twenty rectangular shaped specimens were cut form 3 glass ceramic materials (IPS e.max CAD, Vita Suprinity and Obsidian); 10 large specimens (12x14x3mm) and 10 small specimens (5x5x3mm). The specimens were divided into three groups according to ceramic type, then each group was subdivided into two subgroups according to surface treatment protocol; hydrofluoric acid + silane or self-etch ceramic primer. The large specimens were bonded to their corresponding small specimens of the same ceramic material that had the same surface treatment. The samples were thermocycled for 5000 cycles, 5-55°C, 15 secs. Shear test was performed using universal testing machine. Furthermore, the effect of the two different surface treatments on the surface topography was evaluated using SEM. Contact angle of distilled water was measured on tested glass ceramic materials after different surface treatments. For this test, 6 additional large samples were assigned, two for each glass ceramic material. Results: The samples treated with hydrofluoric acid + silane combination recorded slightly higher mean shear bond strength values to resin cement than those treated with self-etch ceramic primer within the same tested material with a statistically insignificant difference. The wettability results showed more favorable contact angles with hydrofluoric acid + silane treatment than those obtained with selfetch ceramic primer. Data were analyzed by one way ANOVA and t-Tests at p≤0.05. Conclusions: The self-etch ceramic primer can efficiently replace the conventional surface treatment method.