Effect of Feldspathic Ceramic Surface Treatments on Bond Strength to Resin Cement

Objective: The objective of this study was to evaluate the shear bond strength of resin cement to feldspathic ceramic with various surface treatments. Background Data: Application of adhesive techniques is well established in restorative dentistry, yet the influence of surface treatments on the bond strength of resin cement to ceramic materials prior to luting or repair procedures remains unclear. Methods: One hundred samples made of a feldspathic ceramic were divided into 10 groups (n = 10): (1) control (no treatment); (2) 10% hydrofluoric acid (HF); (3) 37% phosphoric acid (H₃PO₄); (4) 1.23% acidulated phosphate fluoride acid (APF); (5) diamond bur; (6) air abrasion with Al₂O₃; (7) Al₂O₃ + HF; (8) CoJet-Sand; (9) Er:YAG laser, and (10) Al₂O₃ + Er:YAG laser. Afterwards, silane was applied and a resin cement cylinder was built. After 24 hours at 37°C, the prepared specimens were submitted to a shear bond strength test and stereoscopic evaluation to determine the type of failure after rupture. Results: Bond strength means were statistically different for the different surface treatments. The highest bond strengths were obtained with HF, CoJet-Sand, and Al₂O₃. The groups treated with Al₂O₃ + Er:YAG laser, diamond bur, and Al₂O₃ + HF had moderate bond strengths. The lowest bond strengths were obtained with H₃PO₄, APF, Er:YAG laser, and the control group. Conclusions: The HF, CoJet-Sand, and Al₂O₃ techniques were the most effective surface treatments. The null surface treatment proposed with the Er:YAG laser showed low bond strength, and seems to be inadequate for clinical use with the parameters tested.