两种远移方法在新型患者特异性有限元分析中的比较。

Two distalization methods compared in a novel patient-specific finite element analysis.

机构信息

Division of Orthodontics and Dentofacial Orthopedics, American University of Beirut Medical Center, Beirut, Lebanon.

Department of Mechanical Engineering, Maroun Semaan Faculty of Engineering and Architecture, American University of Beirut, Beirut, Lebanon.

出版信息

Am J Orthod Dentofacial Orthop. 2019 Sep;156(3):326-336. doi: 10.1016/j.ajodo.2018.09.017.

DOI:10.1016/j.ajodo.2018.09.017

PMID:31474262

Abstract

INTRODUCTION

Orthodontic mini-implants aid in the correction of distocclusions via direct anchorage (pull from mini-implant to teeth) and indirect anchorage (teeth pulled against other teeth anchored by the mini-implant). The aim of this study was to compare stress levels on the periodontal ligament (PDL) of maxillary buccal teeth in direct and indirect distalization against orthodontic mini-implants and accounting for individual variation in maxillary anatomy and biomechanical characteristics of the compact bone.

METHODS

A 3D model of the maxilla containing the different components (teeth, PDL, trabecular and cortical bones) was generated from a computed tomographic scan. Cortical bone was divided into several areas according to previously defined zones. Bone stiffness and thickness data, obtained from 11 and 12 cadavers, respectively, were incorporated into the initial model to simulate the individual cortical bone variation at the different locations. Subsequently, a finite element analysis was used to simulate the distalization modalities.

RESULTS

Stresses at the buccal, palatal, mesial, and distal surfaces were significantly different between adjacent teeth under stiffness but not thickness variation. In both distalization modalities, low or no significant correlations were found between stress values and corresponding cortical bone thicknesses. High significant and inverted correlations were observed at the first molar between stress amounts and cortical bone stiffness (direct modality: -0.68 < r < -0.72; indirect modality: -0.80 < r < -0.82; P <0.05).

CONCLUSIONS

With the use of a novel finite element approach that integrated human data on variations in bone properties, findings suggested that cortical bone stiffness may influence tooth movement more than bone thickness. Significant clinical implications could be related to these findings.

摘要

引言

正畸微型种植体通过直接锚固（从微型种植体到牙齿的拉力）和间接锚固（牙齿对抗由微型种植体锚固的其他牙齿的拉力）帮助矫正错位。本研究旨在比较直接和间接远移对抗正畸微型种植体时上颌颊侧牙齿牙周膜（PDL）的应力水平，并考虑上颌解剖结构和密质骨的生物力学特征的个体差异。

方法

从计算机断层扫描生成包含不同组件（牙齿、PDL、小梁和皮质骨）的上颌 3D 模型。皮质骨根据先前定义的区域分为几个区域。从 11 个和 12 个尸体中分别获得骨刚度和厚度数据，并将其纳入初始模型，以模拟不同位置的个体皮质骨变化。随后，使用有限元分析来模拟远移模式。

结果

在刚度而不是厚度变化的情况下，相邻牙齿的颊侧、腭侧、近中和远中表面的应力差异显著。在两种远移模式下，应力值与相应皮质骨厚度之间均未发现显著相关性。在第一磨牙之间，观察到应力量与皮质骨刚度之间存在高度显著的反向相关（直接模式：-0.68<r<-0.72；间接模式：-0.80<r<-0.82；P<0.05）。