14 January 2022

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External cervical resorption: what are the main risk factors?

Simona Chirico

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External cervical resorption (ECR) is a phenomenon often found in the clinical practice of the endodontist, but the nature of this problem is still mostly unknown. It is characterized by the loss of dental hard tissue that could be internal (within the inflamed root canal system) or external (on the external surface of a root).
The ECR defect extends horizontally toward the root canal space and vertically (apically, coronally, or both). During this dynamic process, the pulp typically remains intact, except for the latest stage of  progression when the resorption may perforate the root canal space. The etiology of ECR is not fully understood. It has been proposed that for ECR initiation the combination of an injury on the periodontal ligament and the cementum layer along with factors activating the resorbing cells are required. 

To date, there are few studies in the literature that deal with this topic. In the latest issue of Journal of Endodontics was published the study of Irinakis et al., in which they tried to analyze which local and systemic factors could determine the onset of ECR. 

Materials and methods
The current retrospective study included 76 patients who were diagnosed with ECR from 2008–2018 at the University of British Columbia (UBC) graduate endodontics clinic (Vancouver, BC, Canada). 

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 follow- up 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 shows that ECR is associated with both local and systemic risk factors. Among these, diabetes and dental trauma are the most representative.

(Photocredit: Dr. Roberto Fornara)

For additional information: External Cervical Resorption: A Retrospective Case-Control Study