微型双皮质双偶支抗种植体夺牙齿移动中的支抗作用

目的观察微型双皮质种植体双侧支抗对狗后牙近中移动的影响,评价微型双皮质双侧支抗种植体作为正畸支抗的可行性.方法取成年beagle犬5只,在一侧下颌第二前磨牙两牙根近抗力中心处植入微型双皮质双侧支抗种植体(实验侧),另一侧相对部位植入相同直径的微型单皮质支抗种植体(对照侧).对第四前磨牙施加100 g近远中方向力.实验侧用2根相同的钛镍螺旋弹簧双侧加载,对照侧用1根钛镍螺旋弹簧单侧加载.测量加载前、加载间隔2周时第一磨牙中央尖到第四前磨牙牙尖距离(M1-P4),尖牙牙尖到第一磨牙中央尖的距离(CA-M1),尖牙牙尖到种植体颊侧端距离(CA-IB).加载3个月后,测量种植体骨结合率(BIC).结果单皮质支抗种植体有1颗初期稳定性较差,在1周内松动脱落,5颗双皮质支抗种植体在整个加载过程中保持稳定.双皮质侧第四前磨牙近中位移为(3.92±0.22)mm,单皮质侧为(2.03±0.15)mm,两者比较有显著性差异(P＜0.05).硬组织切片显示种植体骨界面未见炎性细胞,两组种植体骨结合相似.结论微型双皮质双侧支抗种植体能提供稳定的双侧正畸支抗,在前移后牙时能提供双侧加载力点.

Effect of bicortical orthodontic microimplant on tooth movement in dogs

OBJECTIVE: To evaluate the potential anchorage of bicortical microimplant for tooth movement. METHODS: Five bicortical microimplants were inserted in the interradicular area of the second premolar (P2) in one side of the mandible (test side), 5 monocortical microimplant in the contralateral region (control side) in 5 beagle dogs. A total of 100 g force was generated between the implant and the fourth premolar (P4) in two sides. M1-P4, CA-IB and CA-M1 were measured biweekly. At the end of loading, specimens with P4 segments were cut and grounded to 70 microm to calculate the bone-to-implant contact (BIC). RESULT: All the bicortical microimplants remained stable during the treatment periods, while 1 monocortical microimplant was lost within 1 week. Mesial movement of P4 was ( 3.92+/-0.22) mm in the test side, (2.03+/-0.15) mm in the control side (P<0.05). Analysis showed no difference of the BIC between the bicortical microimplants and the monocortical microimplants. CONCLUSION: The bicortical microimplant may be used as orthodontic anchorage for mesial movement of posterior tooth.