Descriptive Analysis of Factors Associated with External Cervical Resorption.

INTRODUCTION: The aim of this study was to perform a descriptive analysis of the occurrence of external cervical resorption (ECR) in relation to the patients' characteristics (sex, age, and tooth type) and the potentially involved predisposing factors. METHODS: This study includes data on 284 patients (337 teeth with evidence of ECR) referred to the University Hospital Leuven (Leuven, Belgium) and Endo Rotterdam (Rotterdam, the Netherlands) for diagnosis and treatment from 2010 to 2015. The medical history, existing radiographs, and dental records were available for evaluation. Each patient was then interviewed followed by a thorough clinical and radiographic examination. Intraoral pictures using a dental operating microscope and digital camera were taken during clinical examination. The radiographic examination consisted of digital periapical radiography and/or cone-beam computed tomographic imaging. A review of existing literature provided a potential predisposing factor checklist for ECR. The clinical data were correlated with the dental and medical history of each patient in an attempt to identify some potential predisposing factor(s) that could contribute to ECR. The frequency of the occurrence of ECR was correlated with tooth type, sex and age of the patient, and each 1 of the recorded potential predisposing factor(s). RESULTS: From the examined teeth (337) with ECR, 175 (54%) were found in male patients and 162 (46%) were found in female patients. In 59% of the cases, more than 1 potential predisposing factor was identified. Most ECR cases were observed on maxillary central incisors (29%) followed by maxillary canines (14%), mandibular molars (14%), and maxillary premolars (11%). In addition, most ECR cases were observed on maxillary teeth (72%). The most frequently appearing factor was orthodontics (45.7%). Other frequently observed factors were trauma (28.5%), parafunctional habits (23.2%), poor oral health (22.9%), malocclusion (17.5%), and extraction of a neighboring tooth (14%). CONCLUSIONS: The data indicate that ECR is not related to patient sex. ECR occurs most often in the maxillary central incisor. In the majority of the cases, more than 1 potential predisposing factor was identified, indicating that ECR may be mainly multifactorial. The most frequently appearing factors were orthodontics, iatrogenic or accidental trauma, and poor oral health. This information may be helpful in diagnosing ECR at an early stage when screening patients presenting with these predisposing factors.

Understanding External Cervical Resorption in Vital Teeth.

INTRODUCTION: The aim of this study was to investigate the 3-dimensional (3D) structure and the cellular and tissue characteristics of external cervical resorption (ECR) in vital teeth and to understand the phenomenon of ECR by combining histomorphological and radiographic findings. 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.