种植支抗后牵引猴上颌骨颌面形态变化的实验研究

Dentofacial changes by retractive force with zygomatic implant anchorage to the maxilla of rhesus monkey

目的研究种植支抗后牵引猴上颌骨颌面形态的变化。方法选用生长发育期雄性恒河猴3只,随机分为2组,对照组1只,实验组2只。于双侧颧骨植入钛板,通过镍钛拉簧牵拉上颌骨种植体,向后牵引上颌骨。牵引力值每侧2.94 N,时间3个月。对比研究治疗前后面像、牙模型和X线头影测量数值。结果实验期间,种植体稳定;实验组前牙覆盖及上牙弓长度均显著减小,上牙弓宽度增加;实验组SNA、ANB减小,A点均后移2 mm;实验组和对照组的上颌平面角都增加,上颌骨轻度顺时针旋转。结论口内种植支抗后牵引上颌骨能抑制上颌向前生长,为治疗生长发育期上颌前突错畸形新方法提供实验依据。

Objective To investigate the dentofacial changes caused by retractive force with zygomatic implant anchorage to the maxilla of rhesus monkeys. Methods Three male rhesus monkeys with mixed dentition were randomly assigned to 2 groups： 2 monkeys for experimental group,and 1 for control group. The implants in anterior maxilla were loaded by retractive forces with zygomatic miniplates through Ni Ti coilsprings. A backward force of 2. 94 N was exerted on each side of maxilla for 3 months. Facial characters,model measurements,and X-ray cephalometric results were compared before and after treatments. Results The implants kept stable during the whole experiment. The anterior overjet and the length of upper dental arch significantly decreased in experimental group,while the width of upper dental arch increased; SNA and ANB angles reduced and maxillary A point was moved 2mm backward for both monkeys in the experimental group. The angle of palatal plane was increased in both groups,and maxilla rotated clockwise slightly. Conclusions Retracting maxilla with intraoral implant anchorages can inhibit the forward maxillary growth in growing rhesus monkeys,providing experimental basis for a new method of treating maxillary protrusion in mixed dentition.