Juxta-apical radiolucency and relations with surrounding structures on cone-beam computed tomography

The aim of this study was to investigate the incidence of juxta-apical radiolucency (JAR) and its relations with surrounding structures using cone-beam computed tomography (CT). A total of 215 cone-beam CT images was analysed retrospectively to record the presence, site, and size of the JAR, and the relations between the JAR and the mandibular canal, buccal or lingual cortical plates, tooth position, and condition of root apex. Descriptive analyses were made, and relations between the categorical variables were tested with the chi squared test. JAR was detected in 71 (33%) (5 bilateral and 66 unilateral) of 215 patients (378 mandibular third molars) on cone-beam CT images. It was most commonly seen mesial to the tooth (43%) and above the third molars (55%), and was least common lingual to the tooth (3%) and at the distoangular third molar (3%) (p = 0.005). There was no significant relation between the JAR and the mandibular canal, but JAR was most likely to be detected superiorly to the mandibular canal (59% of cases). JAR can be seen and evaluated with cone-beam CT. It was most commonly seen mesial to the tooth and above the third molar. No significant relation was found between JAR and the mandibular canal, cortical plate, or condition of the apex. Future studies on the assessment of JAR should be done with a larger sample size as prospective cone-beam CT studies.