使用改型腭杆辅助压低过长上后牙的临床研究

目的评价使用改型腭杆辅助压低过长上后牙的临床效果。方法5名成年患者，因无法使用种植体支抗而使用改型腭杆辅助压低5颗过长的上后牙。在矫治前、后采取研究模型，进行三维测量，明确过长后牙的压低量和支抗后牙的移动量。通过曲断体层片观察上后牙压低后其牙根吸收情况。结果5名患者均完成上后牙压低，平均疗程为6个月。模型测量表明：过长后牙的压低量为（2．29±0．44）mm。采用配对样本t检验表明过长牙的压低量有显著的统计学意义（P〈0．001）；支抗后牙有的伸长，有的被压低，移动量范围是-0．24mm～0．71mm（负值为伸长量，正值为压低量），支抗牙的移动量没有显著的统计学意义（P〉0．05）。X片显示被压低的上后牙和支抗牙没有出现明显的牙根吸收。结论对于不适合植入支抗钉压低过长后牙的患者使用改型腭杆辅助压低是一种有效的正畸矫治方法。

Intrusion of overerupted upper posterior teeth with modified transpalatal arch

Objective To evaluate the clinical effect on intrusion of overerupted upper posterior teeth with modified transpalatal arch. Methods Five adult patients with 5 overerupted upper posterior teeth were treated with modified transpalatal arch. Study models were taken before and after orthodontic treatment. The effect on intrusion of overerupted posterior teeth and movement of anchorage teeth were evaluated three dimensionally. The root resorption was assessed on panoramic radiograph. Results All overerupted upper posterior teeth were intruded by （2. 29±0. 44）mm The average treatment time was 6 months. Comparison of the intrusion amount in this group using the t-test for paired samples showed a statistically significant difference （P〈0. 001）. Some of anchorage teeth were extruded and the others were intruded. The movement ranged from --0. 24 mm to 0. 71 mm （negative value presented extrusion, positive value presented intrusion）. No statistically significant difference was found in the movement amour the anchorage teeth （P〉0.05）. There was no significant root resorption in the intruded posterior teeth and the anchorage teeth. Conclusions The modified transpalatal arch was an effective method to intrude the overerupted upper molars which were not suitable for intrusion with implant anchorage.