MBT矫治前后牙弓宽度变化的模型分析研究

目的 分析牙列拥挤患者不拔牙与拔牙的MBT矫治对牙弓宽度变化的影响。方法 选择我院正畸科2008—2011年MBT矫治器治疗的牙列拥挤患者40例。其中轻中度牙列拥挤患者20例，使用MBT矫治器进行不拔牙正畸；中重度牙列拥挤患者20例，使用MBT矫治器进行拔除4颗第一前磨牙的拔牙正畸。测量术前术后石膏模型的牙弓宽度，对矫治前后不拔牙组和拔牙组的测量数据分别进行组内、组间统计学分析。结果 矫治前后不拔牙组:上颌尖牙间宽度增大，上下颌第一前磨牙、第一磨牙间宽度增大，有统计学意义；拔牙组:上颌尖牙间宽度增大，上下颌第二前磨牙、第一磨牙间宽度变小，有统计学意义。矫治前2组上下颌尖牙、第一磨牙间牙弓宽度相近，无统计学差异；矫治后不拔牙组上下颌第一磨牙间牙弓宽度大于拔牙组，有统计学意义，2组上下颌尖牙间牙弓宽度相近，差异无统计学意义。结论 不拔牙矫治牙弓宽度变化与拥挤部位、拥挤程度有关，拔牙矫治牙弓宽度变化主要与牙齿移动方向有关。拔牙矫治后尖牙间宽度不会减小。

Model analysis of changes in dental arch width before and after orthodontic treatment with MBT appliance

Objective To investigate the changes of dental arch width after extraction and nonextraction treatment with MBT appli- ance. Methods 40 patients with crowded denture who received treatment with MBT appliance from 2008 to 2011 in our hospital were randomly selected. 20 patients with mild dental crowding who received nonextraction treatment were in the nonextraction group, while 20 patients with severe dental crowding whose 4 first premolars were extracted in the treatment with MBT appliance were in the extrac- tion group. SPSS 11.0 software package was used for paired-samples t Test and independent-samples t Test. Results The upper in- ter-canine widths, the upper and lower inter-first bicuspid widths, the upper and lower inter-first molar widths of nonextraction cases in- creased significantly after the treatment. The upper inter-canine widths of extraction cases increased significantly after the treatment. The upper and lower inter-second bicuspid widths, the upper and lower inter-first molar widths of extraction cases decreased significant- ly after the treatment. Conclusions Dental arch widths of nonextraction cases increased significantly after the treatment and the change related to how and where the crowding existed. Dental arch widths of extraction cases increased significantly after the treatment and the change related to the direction of the tooth movement. Extraction treatment did not result in narrower dental arches than nonex- traction treatment.