Clinical and Magnetic Resonance Imaging Findings of the Temporomandibular Joint in Patients With Rheumatoid Arthritis

BACKGROUND The aim of this study is to evaluate temporomandibular joint (TMJ) involvement in patients with rheumatoid arthritis by magnetic resonance imaging (MRI), jaw clenching force, mouth opening, and Fonseca's questionnaire, and to establish the relationship between these findings and clinical, radiologic, and laboratory activity parameters that are unique to rheumatoid arthritis. METHODS Included in the study were 30 RA patients and 30 healthy volunteers. Jaw clenching force of the entire cases was measured with Istanbul Bite Force Recorder (kg) and the mouth opening was measured with a ruler (cm). Additionally, hand grip forces of patients with rheumatoid arthritis were measured with hand dynamometer (kg). Hand and feet graphs and TMJ MRIs of patients were obtained. MRI findings were classified as normal, mild, medium, and severe. DAS28 and sharp scores of patients were estimated. Sedimentation rate (ESR), C-Reactive protein (CRP) and rheumatoid factor (RF) were checked in the patient group and Fonseca's questionnaires were filled in. RESULTS A significant difference was not observed between age, gender, and level of education of the groups. Jaw clenching force and mouth opening were established as significantly low in RA group compared to the control group (P < 0.001). A significant correlation was found between jaw clenching force, hand grip force, mouth opening, questionnaire, and MRI findings with the disease duration sharp score, DAS28, and hand grip force of the RA group (P < 0.05). However, a significant correlation was not established with ESR, CRP, and RF (P < 0.001). CONCLUSIONS Jaw clenching force, mouth opening, and Fonseca's questionnaire can be used as parameters pointing to TMJ involvement in patients with RA. Yet, further studies in which TMJ involvement is followed up since the onset of the disease are of necessity.