Root proximity is a major factor for screw failure in orthodontic anchorage
Root proximity is a major factor for screw failure in orthodontic anchorage
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DOI：
10.1016/j.ajodo.2006.06.017
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发表时间：
2007-04-01
影响因子：
3
通讯作者：
Takano-Yamamoto, Teruko
中科院分区：
文献类型：
--
作者：
Kuroda, Shingo;Yamada, Kazuyo;Takano-Yamamoto, Teruko
简介：本研究的目的是评估牙根接近作为一个风险因素失败的微螺钉作为正畸支抗。方法：我们使用牙科X线片和三维计算机断层扫描图像检查110例患者的216枚钛螺钉。每个螺钉根据其与相邻牙根的接近程度进行分类。I类，螺钉与根部完全分离; II类，螺钉尖端似乎接触硬脑膜; III类，螺钉主体覆盖在硬脑膜上。如果正畸力可以施加到螺钉上1年（或直到完成正畸治疗），我们记录螺钉支抗成功。结果：螺钉的成功率很高-超过80%。上颌骨螺钉的成功率明显高于下颌骨螺钉。成功率与牙根接近度之间存在显著相关性。I类和II类、I类和III类以及II类和III类之间的成功率存在显著差异。尽管上颌骨中所有3种类型的螺钉以及下颌骨中I类和II类螺钉的成功率均高于75%，但下颌骨中III类螺钉的成功率较低，为35%。结论：微螺钉与牙根的距离是螺钉支抗失败的主要危险因素。这种倾向在下颌骨中更为明显。
Introduction: The purpose of this study was to evaluate root proximity as a risk factor for the failure of miniscrews used as orthodontic anchorage. Methods: We used dental radiographs and 3-dimensional computed tomography images to examine 216 titanium screws in 110 patients. Each screw was classified according to its proximity to the adjacent root. Category I, the screw was absolutely separate from the root; category II, the apex of the screw appeared to touch the lamina dura; and category III, the body of the screw was overlaid on the lamina dura. If the orthodontic force could be applied to the screw for 1 year ( or until completion of orthodontic treatment), we recorded the screw anchorage as a success. Results: The screws had a high success rate - above 80%. Screws placed in the maxilla had a significantly higher success rate than those in the mandible. There was a significant correlation between success rate and root proximity. There were significant differences in the success rates between categories I and II, I and III, and II and III. Although screws in all 3 categories in the maxilla and categories I and II in the mandible showed high success rates above 75%, screws in category III in the mandible had a low success rate of 35%. Conclusions: The proximity of a miniscrew to the root is a major risk factor for the failure of screw anchorage. This tendency is more obvious in the mandible.