A Review of the Imaging Modalities Available for TMD Diagnosis

Temporomandibular disorders (TMD) affect more than 5% of the general population. Radiologic investigation of the temporomandibular joints (TMJ) and surrounding tissues offer information adding to the clinical examination, and establishing the final diagnosis. Plain radiographs are helpful as screening tools for the evaluation of bony surfaces of the TMJs. Transcranial, transpharyngeal and transmaxillary projections are used sometimes in combination. Orthopantomography or panoramic radiography is limited in functional disorders, such as hypermobility and recurrent dislocation of condyles. Tomography generates slices of the area of interest but the development of more modern imaging modalities has practically reduced its utilization. Arthrography is an invasive procedure that shows indirectly the position and the shape of the disc, as well as disc perforations or adhesions to the fossa. Computerized tomography offers advanced capabilities of imaging the hard tissues. Advancement of the equipment with cone beam CT further enhanced its diagnostic value for arthritides. Magnetic resonance imaging reproduces in detail the disc and soft tissues and provides acceptable imaging of the bone surfaces. Improvements in the technique, by using paramagnetic contrast medium intravenously or intraarticularly, render MRI the current golden standard in TMJ imaging. Ultrasound is a radiation free, non invasive and repeatable technique, recently proposed for use in TMD. Other examinations such as scintigraphy or single photon emission tomography have specific indications and restricted use in TMJ diagnostics. Finally, among the various techniques the clinician must choose the most appropriate to the kind of information needed.