TMJ static disk: correlation between clinical findings and pseudodynamic magnetic resonance images

The aim of this study was to analyze the position and mobility of the temporomandibular joint (TMJ) articular disk by means of pseudodynamic magnetic resonance imaging (MRI) and to compare: clinical features, osseus and muscular degenerative changes, the different types of static and their signs and symptoms. The study was performed on 101 patients with clinical and MRI diagnosis of TMJ internal derangement with closed lock (permanent or episodic). On the MRI survey the following was evaluated: disk displacement, disk mobility, condylar translation, bone, and muscular fatty atrophy. Pain was more frequent in static disks (SD) than in mobile disks (MD) in all types of disk displacements (p < 0.01). Condylar translation was always lower in SD than in MD, independently from the position of the articular disk (p < 0.01). Localized sclerosis was more frequent in joints with SD. There were no statistically significant differences in the incidence of fatty atrophy considering disk mobility. The results of the study indicate that clinical diagnosis of closed lock with high frequency is related to the presence of a static disk. Clinical diagnosis of SD can be confirmed with a pseudodynamic MRI survey.