Clinical, microscopical and biochemical investigation of synovial fluid from temporomandibular joints.

The aim of this study was to investigate the relationship between pain and tenderness to palpation of the temporomandibular joint (TMJ), radiographic changes of the joint and signs of inflammation in the synovial fluid. Saline was injected into and aspirated from the TMJ of 29 patients with painful and tender TM joints and from five individuals with healthy joints. In another two patients synovial fluid could be aspirated without saline. The aspirated fluid was analyzed for inflammatory cells and for plasma proteins. A clinical examination of the stomatognathic system and a radiographic examination of the TMJ were performed before the aspiration. Besides tenderness to palpation of the TMJ, pain on mandibular movement and tenderness to palpation of the masticatory muscles were common. Erosion of the cortical outline of the joint surfaces was the most common radiographic finding. Inflammatory cells were present in the fluid of three patients but in none of the healthy individuals. Plasma proteins of inflammatory type could be detected in the fluid from seven of the patients. The results show that radiographic, cellular or biochemical signs of inflammation can frequently be found in the TMJ of patients with longstanding pain and tenderness of this joint.