Improvement in the Tensile Bond Strength between Resin Cement and Dentin Surfaces after Temporary Cement Application

Purpose: The aim of this study was to evaluate the efficacy of three tooth conditioners in restoring the reduced bond strength between resin cement and teeth resulting from remaining temporary cement. Materials and Methods: Ethyl dihydrogen phosphate, methacryloxyethyl dihydrogen phosphate, and 2-methacryloxyethyl hydrogen maleate were evaluated as conditioners. After eliminating the temporary cement with a curette from the bovine dentin surface, the conditioners were applied onto the surface of the specimen and a resin cement was adhered. Stepwise scanning electron microscopic observation and tensile bond strength measurement were carried out. Results: Granular substances were present on the dentin surface even when the temporary cement was carefully eliminated with a curette. When primer and resin cement were applied on this surface without conditioner application, no resin tag or hybrid layer was observed and the mean bonding strength between tooth and adhesive resin cement was 1.8 MPa. In contrast, resin tag and hybrid layer were observed after primer and resin cement application when the dentinal surface was treated with conditioner. Mean tensile bone strength values increased to 6.2 MPa for specimens treated with 20% methacryloxyethyl dihydrogen phosphate for 60 seconds. Conclusion: The authors recommend methacryloxyethyl dihydrogen phosphate as it provides high tensile bond strength values and requires no additional rinse step.