Sonography of the temporomandibular joint from 60 examinations and comparison with MRI and axiography.

BACKGROUND AND OBJECTIVE: Establishing a diagnosis of temporomandibular joint disorder is mainly based on clinical assessment, functional examination, nuclear magnetic resonance imaging (MRI) and axiography. Sonographic examination was compared with MRI and axiography in assessing temporomandibular joint (TMJ) function in 55 patients.

PATIENTS AND METHODS: Fifty-five patients with different TMJ problems were examined clinically, by means of axiography, sonography and some also by MRI. The range of motion was measured by sonography and axiography and the results compared using Student's t-test. Anatomical details diagnostic for disc-displacement were tested by sonography and MRI.

RESULTS: The average time required for sonography was 2 min and for axiography 20 min. The mean measurement differences for condylar movement in maximal mouth opening was 1.7 mm, for protrusion 1.6 mm and for mediotrusion 2.5 mm. The range of condylar movement as measured by sonography and axiography coincided for opening and for protrusion (statistically significant). No significance was found for lateral excursions. The concordance in diagnosis of disc dislocation, hypermobility and impaired range of motion when comparing ultrasound with MRI was 83%. All sonographic examinations were performed by one person only. Sixty repeat examinations in patients produced no complaints and showed an absolute range of difference of 0.6 mm, with a relative range of 7%. Student's t-test was significant (p<0.05) (two repetitive measurements).

CONCLUSION: Sonography proved to be a fast and reliable method for evaluating the range of movement of the TMJ. The lateral joint capsule, lateral disc, and upper condyle could be demonstrated. Pathological processes such as anterior or lateral disc displacement, disc perforation, seroma following contusion, capsular fibrosis, crystalline structures in the synovia and fracture dislocation of the condyle could be diagnosed with considerable reliability when compared with MRI. However, the medial aspect of the joint, medial disc dislocation and the angulation of the condylar slope could not be seen.