Effects of orthodontic treatment on temporomandibular joint in adult female low-angle patients with skeletal class Ⅲ malocclusion

Abstract:

Objective To investigate the effects of orthodontic treatment on temporomandibular joint （TMJ） in adult low-angle patients with skeletal class Ⅲ malocclusion. Methods Sixteen adult female low- angle patients with skeletal class Ⅲ malocclusion were included in the study. All patients were treated with OPA-K straight wire technique. Lateral cephalometric and corrected transcranial projection films were taken before and after treatment. Cephalometric analysis was carried out. All data were analyzed statistically. Results After orthodontic treatment, the linear measurement and area of anterior space in TMJ increased by 0. 27 mm（ P 〈 0. 001 ） and 0. 70 mm^2 （ P 〈 0. 01 ）, respectively, while the posterior space decreased by 0. 24 mm and 0. 67 mm^2,respectively（P 〈0. 001 ）. Linear ratio decreased from 22. 13% to 9. 64% （P 〈0. 001 ）, and area proportion decreased from 1.56 to l. 19（P 〈0. 01 ）. Anterior space became equal to the posterior space. Cephalometric analysis showed that point Co, Ar, Go and Pg were all retruded （P 〈 0. 05 ）. Conclusions After orthodontic therapy, the condyle moved posteriorly to normal concentric position, which would be helpful in alleviating temporomandibular disorders（TMD） symptom in adult lowangle patients with skeletal class Ⅲ malocclusion.[天津医科大学口腔医院口腔正畸科赵艳红