目的

研究改良固定式Twin-block 功能矫治器治疗AngleⅡ类错患者的面部侧貌改变。

方法

选择18 例替牙期、恒牙早期以下颌后缩为主的AngleⅡ类错患者，均采用改良固定式Twin-block 矫治器进行Ⅰ期功能矫治，平均疗程12.3 个月。 应用X 线头影测量技术进行Holdaway 软组织头影测量分析，并对功能矫治前、后测量结果进行统计分析。

结果

功能矫治结束后，患者软组织颏部变厚（P=0.045），软组织面角增大（P=0.008），下唇突点-H 线距离变短（P=0.045）、H 角减小（P=0.042）、颏唇沟深度变浅（P=0.027）和骨骼侧面凸度减小（P=0.044）；鼻突度（P=0.051）、上唇凹深（P=0.172）、鼻下点-H 线（P=0.393）、上唇基部厚（P=0.256）、上唇厚（P=0.120）在正畸治疗前后无明显变化。

结论

改良固定式Twin-block 矫治器不依赖患者的合作，可全天戴用，制作技术简单、成本低，对下颌发育不足的AngleⅡ类错患者在替牙期、恒牙早期采用该功能矫治器能改善患者的牙矢状关系及颜面外观。

Objective

To evaluate the effects of modified fixed Twin-block appliance treatment on the profiles of Class Ⅱ patients.

Methods

Eighteen Class Ⅱ patients with mandiblular deficiency in mixed or early permanent dentition were treated with modified fixed Twin-block in the first functional phase. The effects were evaluated with Holdaway soft tissues analysis.

Results

The results showed that the thickness of soft-tissue chin increased （P=0.045）and soft-tissue facial angle increased （P=0.008）. The lower lip-H line distance decreased （P=0.045）， H angle decreased （P=0.042）， lower lip sulcus depth decreased （P=0.027） and skeletal profile convexity decreased （P=0.044）. The height of nose （P=0.051）， upper lip sulcus depth（P=0.172）， subnasale-H line（P=0.393）， the base thickness of upper lip（P=0.256）， the change of upper lip thickness （P=0.120） is statistically insignificant.

Conclusions

Modified fixed Twinblock appliance treatment was effective on improvement of facial balance in Class Ⅱpatients with mandiblular deficiency in the mixed or early permanent dentition.