萌出诱导矫治器治疗儿童个别前牙反的三维数字化分析

Three-dimensional analysis of the early correction of anterior crossbite using eruption guidance appliance

目的:探讨萌出诱导矫治器治疗混合牙列期儿童个别前牙反的临床效果。方法:选择10例存在个别前牙反的混合牙列期患儿,共计12颗前牙,用藻酸盐采取上、下颌印模并灌制硬石膏模型,送做萌出诱导矫治器,应用该矫治器进行治疗。通过Smart Optics Activity 880牙颌模型扫描仪,获取患儿治疗前、后的三维牙颌数字模型,应用逆向工程软件Geomagic Studio 2012构建三维重叠模型,利用Imageware 13.2软件测量反的上、下切牙在三维方向上的移动变化,对矫治前、后的覆、覆盖进行测量。应用铜丝测量法直接测量上、下颌牙弓弧长,相应的牙冠宽度(未萌出的恒牙按照X线片法预测牙冠宽度)减去牙弓弧长计算上、下颌牙弓的拥挤程度。使用SPSS17.0软件对同一患儿的术前、术后测量值进行统计学分析,首先对测量指标的术后改变量进行正态性检验,发现符合正态分布,然后采用配对样本t检验,双侧检验,显著性水平为0.05。结果:疗程为(5.6±2.7)个月,矫治过程中,上、下切牙在三维位移上均主要表现为唇倾(P<0.001、P=0.025)。经过萌出诱导矫治器的治疗,覆减少了(1.01±0.9)mm(t=-3.531,P=0.006),差异具有统计学意义,而术前、术后覆盖的差异不具有统计学意义(t=0.771,P=0.460)。上颌拥挤度减少了(1.9±0.99)mm(t=-6.042,P<0.001),下颌拥挤度减少了(1.9±0.74)mm(t=-8.143,P<0.001),差异均具有统计学意义。结论:萌出诱导矫治器可以治疗混合牙列期个别前牙反,同时有建立正常覆、覆盖,排齐牙齿的作用。

Objective： To investigate the clinical effect of eruption guidance appliance in the treatment of anterior cross bite in mixed-dentition children. Methods： In the study,10 mixed-dentition children with anterior cross bite,totally 12 incisors,were selected. Alginate was used to take upper and lower dentition impression and make a hard plaster model,which served as the eruption guidance appliance for treatment. The pre-and post-operative dental casts were digitized with Smart Optics Activity 880 scanner,and the three-dimensional overlapping models were obtained by reverse engineering software,Geomagic Studio 2012,then the three-dimensional movements of the upper and lower incisors were analyzed using Imageware 13. 2 software. The overbite and overjet were analyzed using the same methods. Measurement with copper wire was used to analyze the upper and lower arch length. Space analysis was the result by the sum of crown width minus the arch length. The crown width of unerupted permanent teeth was according to X-ray method to predict. The SPSS 17. 0 software was used to analyze the pre-and post-operative measurements of the same child. The normality test of the measured data showed that it conformed to the normal distribution. Therefore,the t test and double side test were used,and the significance level was0. 05. Results： The course of treatment was（ 5. 6 ± 2. 7） months. During orthodontic treatment,the upper incisors moved mainly labially（ P〈0. 001） in three-dimensional displacement,and the lower incisors moved mainly the same direction（ P = 0. 025）. During the treatment of eruption guidance appliance,the average overbite decreased（ 1. 01 ± 0. 9） mm（ t =-3. 531,P = 0. 006）,and the difference was statistically significant. There was no statistically significant difference between the pre-and post-operative average overjet（ t = 0. 771,P = 0. 460）. The severity of crowding in upper arch decreased（ 1. 9 ± 0. 99） mm（ t =-6. 042,P〈0. 001）,and that in lower arch decreased（ 1. 9 ± 0. 74） mm（ t =-8. 143,P〈0. 001）,both of the differences were statistically significant. Conclusion： The anterior cross bite in mixed dentition could be corrected by eruption guidance appliance,and at the same time,the normal overjet and overbite were established,and the teeth were aligned.