Adhesion of 4-META/MMA-TBB resin to heated dentin: effects of pre-treatments with FeCl3 and/or HEMA.

The purpose of this study was to compare the tensile bond strengths (TBSs) and failure mode of 4-META/MMA-TBB resin to 60 degrees C-heated and unheated bovine dentin, especially to investigate the influence of ferric chloride contained in citric acid pre-conditioning. In addition, the effect of HEMA priming for heated dentin was also evaluated. The TBSs to heated dentin were significantly lower than those to unheated dentin. Adhesive failures were observed in most specimens of the heated and HEMA-non primed group. HEMA application to heated dentin significantly increased the TBSs in each acid conditioning, which were also significantly higher than those of the unheated and ferric chloride-contained citric acid-conditioned group. It was clarified that heating dentin decreased the bond strength without HEMA priming even if the dentin surfaces were acid conditioned with 10-3, while HEMA priming after acid conditioning recovered the bond strength.