Joint space measurement in centric occlusion between panoramic temporomandibular joint radiography and cone-beam computed tomography: a comparison in patients with clicking disorders

Introduction
Patients with temporomandibular disorder (TMD) commonly experience clicking. Measuring the joint space between the condyle and glenoid fossa can assist a dentist in determining potential cause of this pathological anomaly. Initial examination of temporomandibular joint (TMJ) osseous structure can be performed with panoramic temporomandibular joint radiography (PanTMJ) that has a lower radiation and cost than cone-beam computed tomography (CBCT).

Objectives
The aim of this study was to quantitatively assess the difference in joint space measurement between PanTMJ and CBCT among patients with clicking in centric occlusion.

Material and methods
The study included thirty-four patients diagnosed with clicking in at least one of the TMJs. Patients underwent PanTMJ and CBCT in centric occlusion position, following clinical examination. Anterior joint space (AJS), superior joint space (SJS), and posterior joint space (PJS) were measured. Mann-Whitney test was applied to examine differences between PanTMJ and CBCT joint space measurements, while Wilcoxon test was used to compare differences between right and left joint space.

Results
The results showed significant differences (p < 0.05) in AJS, SJS, and PJS between PanTMJ and CBCT. The width of joint space in PanTMJ tended to be underestimated compared with that in CBCT. With the exception of AJS in Pan TMJ (p < 0.05), there was no statistically significant difference between the right and left condyle space in any radiography technique (p > 0.05).

Conclusions
The results of the current study show that joint space measurements on PanTMJ cannot be compared with those on CBCT.