种植钉植入高度对隐形矫治远移下磨牙时应力分布的影响

Effect of miniscrew placement height on the distribution of biological forces produced by clear aligner for mandibular molar distalization

摘要

目的 探究种植钉不同植入高度对隐形矫治配合颌内牵引远移下磨牙时所产生的生物力分布的影响，寻找有利于保护下前牙支抗的种植钉植入位置，为临床治疗方案的设计提供参考。方法 应用Mimics、Geomagic Studio 2017、SolidWorks2016、Ansys workbench建立有限元分析模型并对六种工况进行力学分析。工况一：无种植钉（对照组）;工况二至工况五：种植钉植入于下颌第一磨牙和第二磨牙之间的颊侧骨皮质，距离牙槽嵴顶分别为10 mm、7 mm、4 mm、1 mm;工况六：种植钉植入于下颌升支前缘颊舌向居中，高于𬌗平面5 mm的位置。结果 矢状向，种植支抗使所有牙齿均产生远中向位移;相较于对照组，种植钉组前磨牙远中位移量超过第二磨牙。垂直向，对照组（无种植钉）为类似后倾弯对下颌牙列产生的作用;种植钉组侧切牙、尖牙压低，中切牙、第一前磨牙伸长。冠状向，对照组（无种植钉）第二前磨牙、第一磨牙为舌向位移，种植钉组仅前磨牙及第一磨牙出现了舌向位移;所有牙齿中，尖牙的位移量受种植钉植入高度变化影响最大。结论 种植钉植入位置越高，保护前牙支抗的效果越强。方案设计时应根据种植钉植入高度，适当使下颌牙弓缩窄，中切牙、第一前磨牙压低及侧切牙、尖牙伸长。

Abstract

Objective To explore the effect of different miniscrew placement heights on the distribution of biological forces produced by clear aligner combined with intramaxillary traction for mandibular molar distalization, to identify the miniscrew location that is conducive to the protection of lower anterior tooth anchorage and to provide a reference that can be used when designing clinical treatments. Methods Mimics, GeomagicStudio 2017, SolidWorks 2016, and Ansys workbench were used to establish finite element analysis models and perform mechanical analysis under the following six working conditions: working condition 1 was the control group without miniscrews; working conditions 2 to 5 had miniscrew in the buccal bone cortex between the first and second molars of the lower jaw 10 mm, 7 mm, 4 mm, and 1 mm from the top of the alveolar crest, respectively; working condition 6 had the miniscrew in the center of the buccal tongue at the anterior edge of the ascending branch of the lower jaw 5 mm above the occlusal plane. Results On the sagittal axis, miniscrew anchorage caused distal displacement of all teeth. Compared to the control group, in the miniscrew group, the displacement of the anterior molars exceeded that of the second molars. On the vertical axis, the result in the control group was similar to backward bending; the results in the miniscrew groups resembled the effect of a lever, lowering the lateral incisors and canines and raising the central incisors and first premolars. On the coronal axis, the second premolars and the first molars showed lingual displacement in the control group, and only the premolars and first molars showed lingual displacementin the miniscrew groups. The canines were the teeth that were most strongly affected by the change in miniscrew placement height. Conclusion The higher the miniscrew position is, the stronger the protective effect on the anterior anchorage. According to the miniscrew placement height, the mandibular arch should be properly narrowed, the central incisors and first premolars should be lowered, and the lateral incisors and canines should be raised when designing clinical treatments.

关键词

下颌骨 / 错??畸形 / 正畸 / 无托槽隐形矫治器 / 支抗 / 微螺钉种植体 / 牙齿应力分析 / 有限元分析

Key words

mandible / malocclusion / orthodontics / clear aligner / anchorage / miniscrew implant / dental stress analysis / finite element analysis

Author summay

王宋庆，住院医师，研究生在读，Email：[e-mail]