摇椅形唇弓打开咬合前后上颌牙的三维变化

A study of three dimensional changes in superior teeth with rocking chair archwire

目的:使用激光扫描三维成像技术研究咬合打开前、后上颌牙的三维变化。方法:选取山东大学口腔医学院正畸科收治的15～21岁恒牙期安氏Ⅱ类1分类错并同时伴深覆患者40例,随机分为2组,每组均在用不同的方法打开咬合后留取石膏牙颌模型,用激光扫描三维成像技术建立数字化研究模型,测量上颌牙在打开咬合前、后的三维变化。采用SPSS13.0软件包对数据进行t检验。结果:在矢状向上,切牙表现为唇向倾斜趋势,尖牙及第一恒磨牙表现为远中移动趋势,第二前磨牙变化不明显,摇椅形唇弓有无弓丝末端回弯及尖牙向后"8"字结扎所引起的切牙和第一恒磨牙的变化有显著差异(P<0.05),而尖牙和第二前磨牙的变化无显著差异(P>0.05);在垂直向上,切牙及第一恒磨牙的远中颊尖表现为龈向压低趋势,第二前磨牙表现为向升高趋势,尖牙及第一恒磨牙近中颊尖变化不明显,各组之间无显著差异(P>0.05);在横向上,磨牙区牙弓宽度有增加趋势,尖牙及前磨牙变化不明显,各组之间无显著差异(P>0.05)。结论:标准镍钛摇椅形唇弓打开咬合可引起上颌牙在矢状向、垂直向及横向上的变化,矫治深覆效果显著。

PURPOSE： To observe the three dimensional changes of upper arch using laser scan. METHODS： 40 patients aged from 15 to 21 suffering from Angle＇s Class lI subdivision l malocclusion combined with deep overbite were selected from the Department of Orthodontics, School of Stomatology, Shandong University. The patients were divided into two groups randomly,after the overbites of the two groups were opened using different methods, plaster models were made for each patient. Then, digital research models were available through laser san and three dimensional imaging technique. Finally, the changes in three dimensions of the maxillary teeth were measured. Student＇s t test was performed using SPSS 13.0 software package. RESULTS： In the sagittal dimension, the incisors had a tendency of labial inclination; Canines and the first permanent molars were likely to move distally; No distinct changes were found in the second pemolars; According to whether or not there were tip back of the archwires and ＂8＂ shaped ligation there was significant difference in the change of both incisors and the first molars （P〈0.05）, while there was no significant difference in the change of canines and the second molars. In the vertical dimension, incisors and the distal-buecal cuspids of the first molars had a tendency of intrusion while the second premolars were likely to extrude; there was no significant change in canines and the mesio-buccal cuspids of the first molars and there was no significant difference between the two groups（P〉0.05）. In the transverse dimension, the widths of arches in the molar zone had a tendency to increase, while there was no significant change in canine and premolar zones between the two groups（P〉0.05）. CONCLUSION： Standard Ni-Ti rocking chair arch wire can bring about many changes to the teeth and dental arch in three dimensions and its effect on deep overbite is remarkable.