Condylar position on cone-beam computed tomography images and its correlation with condylar size on panoramic radiographs

Introduction
Temporo-mandibular joint (TMJ) is a complex synovial joint located between the condylar head and mandibular fossa of the temporal bone at the base of the skull. TMJs are located bilaterally and operate simultaneously, connecting the mandible to the skull. Anatomical components of TMJ include the mandibular condyle, mandibular fossa, articular eminence of the temporal bone, soft tissue components of the articular disc, attachments, and articular space.

Objectives
This study aimed to assess the condylar position on cone-beam computed tomography (CBCT) images and its correlation with condylar size on panoramic radiographs.

Material and methods
This cross-sectional study was conducted using 35 CBCT scans and 35 panoramic radiographs of the same patients. Condylar size was measured on panoramic radiographs. Also, condylar size and angle of condyles relative to sagittal plane were assessed on CBCT axial sections. Data were analyzed with linear regression ( = 0.05).

Results
By 1-degree increase in angulation of the right and left condyles on CBCT scans, the size of the right and left condyles increased by 0.03 mm on panoramic radiographs, but this increase was not statistically significant (p = 0.33). By considering the left condyle as a reference for comparison of the effect of changing the angulation, the results showed that by each 1-degree increase in the angulation of the right condyle on CBCT scans, the size of the right condyle on panoramic radiographs increased by 0.11 mm, and this increase was statistically significant (p < 0.001).

Conclusions
No significant correlation was found between the angulation of the right and left condyles on CBCT images and the size of the right and left condyles on panoramic radiographs. However, a significant correlation was found between the condylar position on CBCT scans and the condylar size on panoramic radiographs, such that by each 1-degree increase in angulation of the right condyle on CBCT scans, the size of the right condyle increased by 0.11 mm on panoramic radiographs.