下唇挡与 Twin block 联合矫治对下牙弓的影响

The study of effects on the mandibular arch resulted by the application of Mandibular Lip Bumper combined with Twin Block

目的观察下唇挡与 Twin block 联合矫治Ⅱ类Ⅰ分类错(牙合)对下牙弓的影响。方法选择16例伴下颌后缩的Ⅱ类Ⅰ分类错(牙合)患者,替牙(牙合)期或恒牙(牙合)早期,随机分成二组,每组8例,一组为对照组,采用常用型 Twin block 治疗,另一组为治疗组,采用下唇挡与 Twin block 联合矫治。经过8～10个月的矫治,双侧后牙基本正常建(牙合),对每组患者治疗前后 X 线头影片及牙(牙合)模型进行测量、对比。结果治疗组下牙弓长度、周长的增长明显大于对照组(P＜0．05),且下颌第一磨牙明显远中移动(P＜0．05)。结论下唇挡与 Twin block 联合矫治Ⅱ类Ⅰ分类错(牙合),具有推磨牙向后、扩大下牙弓的作用,对下颌后缩伴下牙弓拥挤、下磨牙前移的患者尤为适宜。

Objective To observe the effects of mandibular arch resulting from the application of Mandibular Lip Bumper combined with Twin Block to treat Class Ⅱ division Ⅰ malocclusion. Methods 16 cases with Class Ⅱ division Ⅰ malocclusion were selected who were in the period of mixed or early permanent dentition with mandibular retrusion. The cases were divided randomly into two groups, 8 in each. One group was designed as controlled group treated with Twin block, the other group was treated group treated with Mandibular Lip Bumper combined with Twin Block. Two group cases were treated for 8-10 months till the normal occlusion on both sides were basically established. Then the cephalometric X- ray films and dental casts before and after treatment for each group case were measured, compared and analysed. Results The increases of lower length and circumference in the treated group were more significant than those in the controlled group （P〈0.05）, and the distalization of lower first molar was obvious in the treated group （P〈0.05）. Conclusion Mandibular Lip Bumper combined with Twin Block to treat Class Ⅱ division Ⅰ malocclusion has the effects of distalization of lower molars, and enlargement of lower arch which can be widely used in clinical practice, especially for the mandibular retrusion case with lower arch crowding or lower molar mesially moving.