Methods: 18 human central incisors were selected for this study. 14 teeth were divided into two groups of 7 in each control or experimental group. 4 central incisor teeth were used to assess the histomorphologic view of dentin of crowns. After endodontic treatment in the experimental group, the roots were cut in both experimental and control group. The filling materials inside the canal including gutta-percha and sealer were removed by pluggers. Root samples were cut from cervical and middle part of root with diamond disc. Also, 4 crown samples were cut into two halves by diamond disc to assess the dentin from upper and lateral view. The samples were assessed by scanning electron microscope. The photographs were taken from one third of apical, one third of middle of root canal, and the sections of crowns to calculate the percentage of area occupied by dentinal tubules using Adobe Photoshop software.
Results: The Mann-Whiteny test in analysis of dentinal tubule surface in different parts of dentin surfaces showed statically significant difference (P=0.005).
Conclusions: It can be concluded that in treated teeth that a suitable substrate for bonding is not available due to the presence of debris and residual of filling materials.