- 作者：Athina M. Mavridou ; DDS ; MSc&lowast ; ; &dagger ; ; athimavridou@gmail.com" class="auth_mail" title="E-mail the corresponding author ; Esther Hauben ; MD ; PhD&Dagger ; ; Martine Wevers ; PhD§ ; ; Evert Schepers ; DDS ; PhD&lowast ; ; Lars Bergmans ; DDS ; MSc ; PhD&lowast ; ; Paul Lambrechts ; DDS ; PhD&lowast ;
- 关键词：Cone-beam computed tomography ; external cervical resorption ; hypoxia ; nanofocus computed tomography ; reparative mineralized tissue
- 刊名：Journal of Endodontics
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：42
- 期：12
- 页码：1737-1751
- 全文大小：10868 K
Methods
Twenty-seven cases of vital permanent teeth displaying ECR were investigated. ECR diagnosis was based on clinical and radiographic examination with cone-beam computed tomographic imaging. The extracted teeth were further analyzed by using nanofocus computed tomographic imaging, hard tissue histology, and scanning electron microscopy.
Results
All examined teeth showed some common characteristics. Based on the clinical and experimental findings, a 3-stage mechanism of ECR was proposed. At the first stage (ie, the initiation stage), ECR was initiated at the cementum below the gingival epithelial attachment. At the second stage (ie, the resorption stage), the resorption invaded the tooth structure 3-dimensionally toward the pulp space. However, it did not penetrate the pulp space because of the presence of a pericanalar resorption-resistant sheet. This layer was observed to consist of predentin, dentin, and occasionally reparative mineralized (bonelike) tissue, having a fluctuating thickness averaging 210 μm. At the last advanced stage (ie, the repair stage), repair took place by an ingrowth and apposition of bonelike tissue into the resorption cavity. During the reparative stage, repair and remodeling phenomena evolve simultaneously, whereas both resorption and reparative stages progress in parallel at different areas of the tooth.
Conclusions
ECR is a dynamic and complex condition that involves periodontal and endodontic tissues. Using clinical, histologic, radiographic, and scanning microscopic analysis, a better understanding of the evolution of ECR is possible. Based on the experimental findings, a 3-stage mechanism for the initiation and growth of ECR is proposed.