Characteristics of Juxta-apical Radiolucency as Risk Factor of Inferior Alveolar Injury

Juxta-apical radiolucency (JAR) is introduced as a new risk factor for inferior alveolar nerve (IAN) injury; following the removal of the third molar. Thus, the aim of the present study was to examine the relationship of JAR to IAN, cortical plates, and its position with regards to IAN and tooth angulation.

The present case-control study comprising a sample of 545 Cone Beamed CT scans of mandibular third molars examined 75 JAR cases and 75 control teeth. The relationship of JAR to IAN, its position with regards to IAN, lingual cortical plate thinning, teeth position and angulation were investigated. Descriptive analyses, chi-square and fisher exact tests were performed with a value of 0.05 considered significant.

Mesioangularteeth were the most common in both groups. Based on tooth angulation, no significant difference was detected between case and control groups (p value = 0.346). There was no significant difference between the two groups, with regards to JAR and tooth proximity to IAN (p value = 0.578). Although, the most prevalent position in the JAR group was lingual and superior in the control group, but no significant difference was observed between them (p value = 0.122). Most cases of JAR (84.0%) and most cases of control group (77.3%) showed some degree of cortical thinning. Based on this, no significant difference was present between the JAR and control groups (p value = 0.626).

JAR is generally in contact with mandibular canal and some degree of corticalthinning manifest in most of these cases. These findings suggest a possible increase in the risk of nerve injury during surgical removal of third molars.