正畸治疗骨性Ⅲ类错(牙合)对下颌平面角小的成年女性患者颞下颌关节的影响

目的：分析正畸矫治前后成年女性骨性Ⅲ类错[牙合]低角患者颞下颌关节的变化，探讨非手术正畸治疗对成年骨性Ⅲ类错[牙合]低角患者颞下颌关节的影响。方法：选取16例成年女性骨性Ⅲ类错[牙合]低角患者，18～23岁，采用OPA-K滑动直丝弓技术矫治，矫治前后拍摄双侧闭口矫正许勒位片和头颅侧位X线片，进行颞下颌关节间隙测量和头影测量分析。对矫治前后的测量数据进行配对t检验。结果：与矫治前相比，矫治后关节前间隙线距和面积分别增加0．27mm（P〈0．001）、0．70mm^2（P〈0．01），关节后间隙线距和面积分别减小0．24mm、0.67mm^2（P〈0．001）,线性百分比由22．13％减少为9．64％（P〈0．001），关节后前间隙面积之比由1．56减小为1.19（P〈0.01），关节前间隙与关节后间隙趋于相等。头影测量发现，与矫治前相比，矫治后点Co、Ar、Go及Pg相对前颅底均明显后移（P〈0.05）。结论：成年骨性Ⅲ类错[牙合]低角患者非手术矫治后髁突由下前位向后向上移至中位，关节结构趋于协调和稳定，有利于颞下颌关节紊乱病症状的缓解。

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

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 1.19 (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 low-angle patients with skeletal class III malocclusion.