Evaluating the presence of IAN injury in patients with juxta-apical radiolucency after third molar surgery: a retrospective cohort study

Abstract

Background Juxta-apical radiolucency (JAR) has been presented as a radiographic sign, suggestive of the IAN injury through third molar surgery. This study aimed to evaluate the relation of JAR with IAN injury in cone-beam computed tomography (CBCT) images and to determine whether the presence of JAR is related to tooth angulation, proximity to the mandibular canal, position to the IAN, and thinning of the cortical plates. Methods Of an initial sample of 545 mandibular third molars, a total of 75 JAR+ and 75 JAR− teeth were evaluated by CBCT. We assessed the relationship between the presence of JAR in cone-beam computed tomography (CBCT) images and the presence of IAN injury after mandibular third molar surgeries. Moreover, we investigated whether the presence of IAN injury is related to tooth angulation, proximity to the mandibular canal, position to the IAN, and thinning of the cortical plates. Descriptive statistics, Chi-square test, and Fisher’s exact test were performed for statistical analysis. Results A significant relationship was found between JAR and temporary IAN injury (P = 0.036). However, there was no case of permanent IAN injury. IAN injury showed no significant relationship with the tooth angulation, position to IAN and proximity to the mandibular canal, lingual cortical plate thinning, sex, and age. Conclusions JAR is generally in contact with the mandibular canal, and some degree of cortical thinning can be found in most cases. In this study, JAR was significantly related to temporary IAN injury. JAR may increase the risk of nerve injury during the surgical removal of third molars.

Two-stage extraction by partial grinding of impacted mandibular third molar in close proximity to the inferior alveolar nerve

“…CBCT can be helpful in determining the positional relationship of the inferior alveolar nerve (IAN) with an IMM3 by providing coronal and axial views. However, the use of CBCT does not reduce the risk of damage to the IAN during IMM3 extraction[ 5 - 8 ].…”

Evaluation of Impacted Mandibular Third Molars with CBCT: A Cross-Sectional Study

“…5 The use of radiographic indicators other than computed tomography (CT) to suggest probable IAN risk is not justified due to high radiation exposure. 6 If, according to the Howe and Poyton criteria, 7 radiographic indicators (diversion of inferior alveolar canal (IAC), narrowing of IAC, and interruption of the canal's white line; darkening of the root) arise in orthopantomography that suggest a risk for nerve damage, most studies advise using CT scans because they show a clear connection between the inferior alveolar canal and the lower third molar. 7,8 Cone beam computed tomography (CBCT), a specialized CT dental imaging method, is influenced by the field of view (FOV) and voxel size.…”