Boundary-Lubricating Ability and Lubricin in Synovial Fluid of Patients With Temporomandibular Joint Disorders

PurposeThis study was conducted to measure the boundary-lubricating ability and lubricin concentration of synovial fluid (SF) from patients with different stages of temporomandibular joint disorders (TMDs) and establish relationships between them.Patients and MethodsAccording to the imaging and clinical findings, TMD patients were divided into 3 subgroups: displaced disc with reduction, displaced disc without reduction, and osteoarthritis. The boundary-lubricating ability of SF was determined by the coefficient of friction (COF) of SF in vitro with a friction apparatus. The lubricin concentrations were quantified by enzyme-linked immunosorbent assays.ResultsThe COF of SF in TMD patients was significantly higher than that of healthy control subjects, but no observed difference was found among patient subgroups. Furthermore, a significant decline in lubricin concentrations was found in the group with osteoarthritis, whereas there was no significant change in the other groups. However, a significant correlation was not found between the COF and the lubricin concentrations in our study.ConclusionsThese findings showed that distinct changes in lubricin and boundary-lubricating ability in the SF occurred with different stages of TMDs.