Introduction: Rheumatoid arthritis is an inflammatory chronic, disease. Rheumatoid arthritis leads to swelling, stiffness, pain, and probable loss of function in numerous joints, including the TMJ. Patients on steroid medications usually suffer from: ease of infection osteoporosis and also they have a risk of the gingival inflammation at the implant sites if the patient is unable to maintain the oral hygiene measurements to control the plaque following the treatment. Due to these problems the Dentists hesitate to perform dental implant for them. Aim of the study: To evaluate the effect on the TMJ and the bone density in patients with RA and under treatment for a long time. Material and methods: 72 patients were divided into 3 groups: group A: 24 normal patients, group B: 24 patients with rheumatoid arthritis recently discovered, group C: 24 patients with rheumatoid arthritis for at least 10 years and are on a regular treatment and follow up. The angle of the mandible was measured to determine the effect on the TMJ, and some areas were selected to measure the bone density. Results: The results for the angle measurement showed a significant difference between the measured angle in the 3 groups. The biggest angles mean was group A (the control group), while the lowest mean was group C. Regarding the measured density in the 3 groups the highest density was measured in group A, while the least was measured in group C. Conclusion: There is a high correlation between the duration of the RA and the bone density and also an effect on the TMJ which affect the mandibular angle and convert the patient occlusion into skeletal class II despite receiving a treatment.