Pitchfork分析法评估Twin—block矫治器治疗安氏Ⅱ^1错[牙合]的硬组织疗效

Pitchfork analysis in evaluating the hard tissue change of Class II division 1 malocclusion treated by Twin-block appliance

目的应用Pitchfork分析法研究排除自然生长因素后,Twin-block矫治器治疗替牙期或恒牙早期安氏Ⅱ1错引起的硬组织改变。方法选择15例安氏Ⅱ1下颌后缩患者,观察10个月作为自然生长对照组,随后采用Twin-block矫正器治疗,平均治疗约10个月。对治疗及观察前后头颅侧位片进行Pitchfork测量分析,评价对照期和治疗期在平均功能性平面上骨骼及牙齿的位置变化的矫治疗效。结果在5.97 mm(P<0.01)的覆盖减少量和4.86 mm(P<0.01)的磨牙关系改善中,骨骼效应占41.2%和50.7%,牙齿效应分别占58.8%和49.3%,其中4.86 mm磨牙关系改善中,包括骨性改变2.46 mm、牙性改变2.40 mm,骨性改变中下颌骨贡献率约为81.7%。结论 Twin-block矫治器使发育期安氏Ⅱ1错牙患者覆盖、磨牙关系均得到较好改善,有效促进了下颌骨矢状方向上的生长发育,有利于Ⅱ类骨面型的纠正。

Objective To evaluate the skeletal and dental contribution rate to the treatment effects of Twin-block appliance excluding the influence of natural growth on patients with Class II divisionl malocclusion during mixed or early permanent dentition. Methods 15 Class II divisionl malocclusion patients in mixed or early permanent dentition were observed for 10 months and then treated by Twin-block appliance for an average of 10 months another. The cephalometric data of two groups before and after control or treatment were collected. Then Pitchfork analysis was performed to evaluate the skeletal and dental changes between these two periods. Results The treatment made 5.97 mm （P〈0.01） and 4.85 mm （P〈0.01） overjet and molar correction respectively, of which 41.2% and 50.7% due to skeletal effect, 58.8% and 49.3% was due to dental effect. Molar relationship was corrected by 4.85 mm in general, which included 2.46 mm skeletal change and 2.40 mm dental change. And within the skeletal change, the contribution ratio of lower jaw was about 81.7%. Conclusions Deep overjet and molar relation can be improved greatly by the Twin-block appliance. It can promote the mandibular growth sagitally. All these aspects contribute to correction the Class II skeletal relationship.