定滑轮原理应用于微型种植体增强磨牙支抗

Fixed pulley principle applied in micro-implant for maximum anchorage cases

目的评价定滑轮原理应用于微型种植体增强磨牙支抗的有效性。方法30例安氏Ⅱ类上颌前突患者,矫治设计均为拔除上颌两侧第一前磨牙,内收前牙阶段的治疗应用微型种植体。实验组应用定滑轮原理,将微型种植体植入于上颌第一恒磨牙与第二恒磨牙颊侧根尖部之间的牙槽间隔内,对照1组微型种植体植入部位同实验组;对照2组微型种植体植入于上颌第二前磨牙和第一磨牙颊侧根尖部之间的牙槽间隔内,两对照组牵引钩均直接与微型种植体相连。三组均以每侧120 g力滑动法内收上前牙。比较内收前后头颅X线侧位片,测量前牙内收情况和磨牙支抗的变化。结果所有患者拔牙间隙均关闭。实验组上颌切牙切缘内收量大于对照1、2组(P<0.01),对照1组和对照2组上颌切牙切缘内收量差异无统计学意义。实验组第一磨牙前移量小于对照1、2组(P<0.01),对照1组和对照2组第一磨牙前移量差异无统计学意义。实验组内收量/前移量比值大于对照1、2组(P<0.01),对照1组和对照2组内收量/前移量比值差异无统计学意义。结论定滑轮原理应用于微型种植体可增强磨牙支抗。

Objective To evaluate the efficiency of fixed pulley principle applied in microimplants for maximum anchorage cases. Methods 30 cases presented with Class Ⅱ skeletal pattern, maxillary protrusion. Maximum molar anchorage and maxillary first premolar extraction were required. In the stage of anterior teeth retraction, micro-implants were applied. In experimental group micro-implants were inserted into the buccal alveolar bone between maxillary first molar and second molar, and fixed pulley principle was applied. The area where micro-implants were inserted in control 1 group was the same as the experimental group. In control 2 group micro-implants were inserted into the buccal alveolar bone between maxillary first molar and second premolar. Traction hooks were directly connected with micro-implants in two control groups. Sliding mechanics with 120 g force was used to retract anterior teeth. The cephalometric films before and after retraction were measured. Results The extraction space of all patients was closed. In experimental group the distance of maxillary incisors edge moved distally was more than those of control 1 group and control 2 group （P 〈0.01）, but there was no significant difference between control 1 group and control 2 group. In experimental group the distance of anchorage molar moved anteriorly was less than those of control 1 group and control 2 group（P 〈0.01）, but there was no significant difference between control 1 group and control 2 group. In experimental group the ratio of incisors edge and anchorage molar moved was more than those of control 1 group and control 2 group（P 〈0.01）, but there was no significant difference between control 1 group and control 2 group. Conclusion Fixed pulley principle applied in micro-implants can be used as a more efficient method for anchorage control and a very important choice for maximum molar anchorage.