Objective To investigate effects of non- surgical treatment on temporal mandibular joint（TMJ）of adult low- angle subjects with severe skeletal Class Ⅲ deformity. Methods Thirteen low- angle patients with severe skeletal Class Ⅲ malocclusion（male 5, female 8）were included in the study. The average age was 21.3 years old. They were treated with OPA- K straight wire technique. Helkimo index evaluation was made before and after treatment. Lateral cephalometric films and corrected TMJ lateral cephalometric radiograghs were taken before and after treat - ment, and linear and area measurement were observed. All data were analyzed with SPSS 12.0 software. Results After non- surgical treatment, Helkimo indexes of all patients redistributed. The line distance and area of anterior space in TMJ increased while the posterior space decreased. Linear percent decreased from 20.81% to 8.04%, and area proportion decreased from 1.62 to 1.01. Anterior space was the same as the posterior. Condyles and mandibles were retruded. Conclusion After non- surgical therapy in adult low- angle subjects with severe skeletal Class Ⅲ malocclusion, condyles remove posteriorly from more anterior position to normal concentric position, and temporomandibular disorders symptom is relieved and cured effectively
