Nineteen patients with definite and suspected temporomandibular joint (TMJ) osteoarthritis participated in this study. All patients were treated by dental care including bite plane therapy. By comparing the pre-treatment clinical symptoms and TMJ tomograms with those post-treatment, efficacy of the dental treatment applied for these patients has been assessed. Since TMJ pain and limitation of mouth opening were considerably improved in almost all patients post-treatment, this suggests that the clinical prognosis of TMJ osteoarthritis can be favourable. On the other hand, radiographic changes post-treatment were variable. The longitudinal changes found in the TMJ tomograms were classified into four types. The frequency of Type 2 and Type 3, which indicate the occurrence of TMJ remodelling during the observation period, was fairy high (20 TMJs and 14 patients).