Effect of Ceramic Surface Treatment on Tensile Bond Strength to a Resin Cement

Purpose: The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-treated ceramic surfaces produce the highest tensile bond strength to resin cements, independent of the ceramic microstructure and composition; and (2) the tensile bond strength test is appropriate for analysis of interfacial adhesion for ceramic-bonded-toresin systems. Materials and Methods: Ceramic specimens were polished with 1-µm alumina abrasive and divided into four groups of 10 specimens for each of seven ceramic types. One of the following surface treatments was applied: (1) 10% ammonium bifluoride (ABF) for 1 minute; (2) 9.6% HF for 2 minutes; (3) 4% acidulated phosphate fluoride (APF) for 2 minutes; and (4) a silane coupling agent. The surface-treated areas were coated with an adhesive resin and bonded to a resin cement. Specimens were loaded to failure in tension using a testing machine. Tensile bond strength data were statistically analyzed, and fracture surfaces were examined to determine the mode of failure. Results: Silane-treated surfaces showed statistically higher mean tensile bond strength values than surfaces treated with any etchant (HF, ABF, APF). HF produced statistically higher mean tensile bond strengths than ABF and APF. All failures occurred in the adhesion zone. Conclusion: The tensile bond strength test is adequate for analysis of the adhesive zone of resin-ceramic systems. The chemical adhesion produced by silane promoted higher mean bond strength values than the micromechanical retention produced by any etchant for the resin-ceramic systems used in this study.