Risk determination of inferior alveolar nerve injury after mandibular third molar extraction

Abstract

Introduction. Extraction of impacted molars may be accompanied by complications, including inferior alveolar nerve (IAN) injury, with an incidence of up to 8.4% [3]. Among the risk factors for IAN trauma is the relationship between the molar and the mandibular canal (MC). The aim of the study is to evaluate the difficulty of extraction of impacted M3M and the risk of NAI injury based on radiological clichés. Materials and methods. A retrospective descriptive study was performed, including 25 molars. OPGs, and CBCTs of the patients were evaluated. Age, sex of patients; degree of inclusion according to Pell & Gregory; angulation of molars; Rood & Shehab signs were studied. Results. According to the degree of difficulty of the intervention, we obtained: low difficulty — 2 cases; medium — 21 cases; high — 2 cases. 84% of cases showed an association between more than one signs proposed by Rood & Shehab. The most common were loss of white line (33%), followed by MC narrowing and root darkening (22% each). The incidence of NAI injury was 8.3%. Conclusions. Risk prediction is useful in planning and facilitates decision making regarding the extraction technique of the impacted M3M.