MRI-based observation of the size and morphology of temporomandibular joint articular disc and condyle in young asymptomatic adults

To investigate the size and morphology of the temporomandibular joint (TMJ) articular disc and condyle in young asymptomatic adults by using magnetic resonance imaging (MRI) and to provide a reference for clinical diagnosis and scientific study of temporomandibular disorders (TMD).Overall, 93 undergraduate volunteers without TMD were enrolled from the freshmen pool at the Qingdao University. All participants underwent MRI of the oblique sagittal and oblique coronal TMJ planes. The articular disc and condyle were subsequently measured, and their morphology was evaluated. The obtained data were then grouped and analyzed statistically. Finally, intragroup correlation coefficient (ICC) was used to evaluate the interobserver measurement reliability.We totally received 186 TMJ imaging samples. Based on our analysis, disc's anterior band in young asymptomatic adult females were thicker than males of the same age (p = 0.024). Moreover, the media-lateral dimensions of the condylar head of adult females were shorter than males of equal age (P＜0.001). The bilateral articular disc morphology was the same in 72.4% of subjects while the condylar morphology was the same in 63.4% of participants. Finally, using measurement reliability assessment, we demonstrated that our conclusions are reliable (ICC ≥0.7).The thickness of the anterior band of the disc and the media-lateral dimensions of the condylar head were gender-related. Additionally, the morphology of the bilateral articular disc and condyle was different among the subset of young asymptomatic adults.