Department of Oral Health Sciences, BIOMAT Research Cluster, KU Leuven and University Hospitals Leuven, Leuven, Belgium; Private Practice, Endo Rotterdam, Rotterdam, The Netherlands.
Laboratory of Morphology, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.
J Endod. 2019 Apr;45(4):459-470. doi: 10.1016/j.joen.2018.12.013. Epub 2019 Feb 14.
Despite the fact that external cervical resorption (ECR) is a well-known and rather frequently met condition, the driving force of this phenomenon still remains unclear. Recently, hypoxia has been linked to ECR. Thus, the aim of this work was to investigate the existence of hypoxia in ECR and hypothesize on its role at the time of extraction. This work is a case study of a tooth with ECR. ECR diagnosis was based on clinical and radiographic examination with cone-beam computed tomographic imaging. The extracted tooth was further analyzed by using nanofocus computed tomographic imaging and immunohistology. To investigate the 3-dimensional extent and pattern of ECR, in vivo cone-beam computed tomographic imaging and ex vivo nanofocus computed tomographic imaging were used. Different histologic stains were used to investigate the presence of a hypoxic environment and to gain a better insight into the involved cells, neuronal structures, and remodeling process during ECR. A higher distribution of hypoxia-inducible factor 1a-positive cells was found in the apical part of the resorption area when compared with the coronal area of the resorption. In addition, a similar distribution of hypoxia-inducible factor 1a-positive odontoblasts was observed in the pulp. Three-dimensional analysis of the calcification of the pulp revealed the formation of pulp stones in areas with higher hypoxia. Histology showed that remodeling during ECR can occur according to a layered pattern. This investigation confirms the presence of hypoxia in ECR and shows that there is a gradient of hypoxia within the ECR lesion and surrounding tooth structure. The hypoxic environment within the pulp is also indicated by the formation of pulp stones.
尽管外部性颈吸收（ECR）是一种众所周知且相当常见的病症，但这种现象的驱动力仍不清楚。最近，缺氧与 ECR 有关。因此，本研究旨在探讨 ECR 中是否存在缺氧，并假设其在拔牙时的作用。这是一项关于 ECR 牙齿的病例研究。ECR 的诊断基于临床和影像学检查，包括锥形束计算机断层扫描成像。通过使用纳米焦点计算机断层扫描成像和免疫组织化学进一步分析提取的牙齿。为了研究 ECR 的 3 维范围和模式，使用了体内锥形束计算机断层扫描成像和体外纳米焦点计算机断层扫描成像。使用不同的组织学染色来研究缺氧环境的存在，并深入了解 ECR 过程中涉及的细胞、神经元结构和重塑过程。与吸收区域的冠部相比，在吸收区域的根尖部分发现缺氧诱导因子 1a 阳性细胞的分布更高。此外，在牙髓中也观察到缺氧诱导因子 1a 阳性成牙本质细胞的类似分布。牙髓钙化的 3 维分析显示，在缺氧较高的区域形成了牙髓结石。组织学显示，ECR 期间的重塑可以按照分层模式发生。本研究证实了 ECR 中存在缺氧，并表明 ECR 病变内和周围牙齿结构存在缺氧梯度。牙髓中形成的牙髓结石也表明了缺氧环境的存在。
