Abstract
Purpose: In daily clinical treatment, the crown restoration was dislodged from root dentin with the cast post. With regard to the cause of this dislodgment, morphology of the post or stress distribution have been evaluated. However, adhesion to the tooth was evaluated only a little, and furthermore, the evaluation of the adhesion is only to the crown dentin. In this study, to elucidate the cause of the dislodgment of post cores from the tooth, differences between the adhesion of resin cements to the crown dentin and that to the root dentin were evaluated.
Method: Human teeth were extracted and frozen. The human teeth were allowed to thaw before use, and the crown dentin and tooth root dentin were polished with #1000 water-resistant paper. In the adhesion test, 4 types of commercially available resin cements were used. Furthermore, the conditions of resin after treatment by preliminary treatment materials and resin tags after adhesion by resin cements were observed with a scanning electron microscope.
Results: Tooth crown dentin showed greater adhesion than tooth root dentin in all 4 types of resin cements. Removal of smeared layers by preliminary treatment materials was marked in tooth crown dentin. Furthermore, the presence of longer resin tags in tooth crown dentin was confirmed.
Conclusion: It was suggested that to improve the adhesion of resin cement to tooth root dentin, it was necessary to perform the treatment of smeared layers in tooth root dentin on the same level as in tooth crown dentin.
