External Cervical Resorption: A Retrospective Case-Control Study

Introduction: The current retrospective case-control study examined the potential systemic and local risk factors in relationship to external cervical resorption (ECR). The study hypothesis stated that both local and systemic risks are associated with higher ECR rates. Methods: The ECR group included data about 76 patients (98 teeth) diagnosed with ECR at the university graduate endodontics clinic from 2008-2018. An equivalent comparative control group without ECR was composed of the same pool of patients and matched with cases by sex and age. Information about dental and medical history, including potential local risk factors (bruxism, trauma, eruption disorders, extraction of an adjacent tooth, orthodontics, and restorations) and systemic risk factors (medical conditions, medication, and allergies), was collected for both groups. Data were analyzed at tooth and patient levels. The chi-square test or Fisher exact test compared proportions between the 2 study groups. Results: The overall ECR prevalence among endodontic patients during the 10-year followup was 2.3%. ECR was most frequent in maxillary anterior teeth (31.6%), and the Heithersay class 2 was the most frequent (38.8%) ECR diagnosis. Diabetes was the only significant systemic risk factor (P < .05). Trauma, as a local risk factor, was significantly (P < .05) more frequently reported in cases than in controls. Conclusions: The study hypothesis stating that both systemic and local risk factors were associated with higher ECR rates was partly confirmed, as one systemic (diabetes) and one local (trauma) risk factor were associated with higher ECR rates.