远移上颌磨牙对、颌面垂直关系改变的初步研究

Effect of maxillary molar distalization on occlusal and maxillofacial vertical dimension :an preliminary study

目的:探讨远移上颌磨牙是否对患者牙合、颌面垂直关系产生变化及其相关因素。方法:回顾性研究远移上颌磨牙的牙性Ⅱ类错牙合病例88例(女48例,男40例),比较其矫治前后的X线头颅定位侧位片中反应牙合、颌面垂直关系的5项观察指标。结果:88例矫治后前牙覆牙合明显减小(2.86±2.69 mm),腭平面角改变无统计学意义(0.21°±3.54°),牙合平面角、下颌平面角及患者的下前面高均有少量增加(0.91°±3.37°,1.29°±4.66°,1.05±3.82 mm)。高中低角患者的这5项观察值不存在统计学差别;上颌第二磨牙萌出与否、以及支抗的种类对远移磨牙产生的垂直关系改变有一定影响,但作用较小。结论:远移上颌磨牙会一定程度的减小患者前牙覆牙合,但就整个颌面垂直关系而言变化较小。提示远移上颌磨牙产生垂直向变化可能存在其它原因。

Objective.. To examine whether distalization of upper molar can change vertical dimension of occlusion and jaw and study the relative factors preliminarily. Method：A retrospective study was conducted to compare the pretreatment and posttreatmem cephalograms of 88 patients （48 female, 40male） with Class Ⅱ malocclusions treated with distalization of maxillary molar. Result：The overbite of the 88 patients showed statistically significant decreases of 2.86 ± 2,69 mm with nonsignificant changes in the SN-PP angle of 0.21 ± 3.54°and a few increases in SN-OP ,SN-MP angle and lower anterior facial height of 0.91 ± 3. 370,1.29 ± 4.66°, 1.05 ± 3.82 mm, respectively. No statistically significant differences in the 5 vertical indexes were observed among patients with high, neutral, or low mandibular plane angles. Whether patients had second molars or hadn＇t and the kinds of anchorage used for moving upper molar made letter influnce on the vertical di- mension changes caused by moving maxillary molar, Conclusion： Distalization of maxillary molar can cause decrease of overbite to some extent. However, as for whole vertical skeletal relationships, the influnce caused by moving maxillary molar is negligible. This study suggests that there must be some other factors of vertical dimension changes caused by maxillary molar distalization.