Practical evaluation of the lateral temporomandibular joint radiograph.

The reevaluation of the lateral transcranial radiograph is needed because of the confusion that surrounds the diagnosis and treatment of TMJ dysfunction-pain. The lack of universal acceptance of the validity of the lateral TMJ radiograph contributes to the lack of progress of TMJ dysfunction-pain treatment and improved methods for the treatment of prosthodontic patients. The lateral transcranial TMJ radiograph was reevaluated for its duplicability (+/- 0.2 mm). The image was found to be a cross section of the lateral third of the condyle rather than a composite view of the condyle made at an angle. The condylar position in the fossa can be correctly evaluated in transcranial radiographs, because the relative condylar position in the fossa is similar in all sagittal views and the image is always of the same sagittal plane (lateral third). Soft tissue within or lining the fossa does not affect the evaluation of condylar position. Chronic osteoarthritic TMJ pathology can exist without subjective pain; therefore, routine use of initial TMJ radiographs with subsequent radiographs at 5-year intervals is suggested for all patients. Because condylar repositioning may be indicated before subjective pain symptoms appear, condylar repositioning should be contemplated whenever extensive prosthodontic treatment is needed. In addition, if chronic osteoarthritic lesions are observed initially, radiographs are indicated at more frequent intervals and anti-inflammatory agents should be considered for routine use depending on the rate and extent of the pathologic development. The existence of osteoarthritic lesions was confirmed by serial radiographs over 5 to 10 years. If an osteoarthritis is present, condylar repositioning (when condylar displacement is present) or changes in occlusion should be considered. There is some clinical evidence that condylar displacement is associated with pathologic remodeling and/or osteoarthritic lesions of the condyle and that condyle repositioning arrests the pathologic process. The principle of condylar concentricity , previously established for the treatment of TMJ dysfunction-pain syndrome and for functional centric relation in prosthodontics, was formulated by associating condylar position in the fossa with TMJ dysfunction-pain in many patients. This article suggests the value of the lateral TMJ radiograph as an important practical aid in the diagnosis and treatment of TMJ dysfunction pain and in the establishment of functional centric relation in prosthodontics.