唇舌向正畸中上颌中切牙内收与推出的最佳力系统。
Optimum force system for intrusion and extrusion of maxillary central incisor in labial and lingual orthodontics.
机构信息
Department of Mechanical Engineering, Visvesvaraya National Institute of Technology, Nagpur, Maharashtra, India.
Department of Mechanical Engineering, Visvesvaraya National Institute of Technology, Nagpur, Maharashtra, India.
出版信息
Comput Biol Med. 2016 Feb 1;69:112-9. doi: 10.1016/j.compbiomed.2015.12.014. Epub 2015 Dec 29.
BACKGROUND
The objective of the present study was to specify an optimum force system for intrusion and extrusion of maxillary central incisor and to compare the effects of bracket positioning at different heights from the incisal edge in Labial Orthodontics (LaO) and Lingual Orthodontics (LiO).
METHODS
A mathematical model of maxillary central incisor with normal inclination was developed. Four cases of heights of bracket slot from incisal edge were considered both in LaO and LiO viz. 3mm, 4mm, 5mm and 6mm. Based on a mathematical model, an optimum force system consisting of an intrusive or extrusive force (F) and a moment (M) was devised and moment (M) to force (F) ratio (M:F ratio) was estimated in each case. Then, three-dimensional Computer Aided Design (CAD) models of incisor and surrounding structures were prepared. To validate an optimum force system, finite element analysis was carried out and force system with derived M:F ratio was applied in each case.
RESULTS
In finite element analysis, results were shown in the form of vector graph of nodal displacements along with undeformed and deformed models. The desired intrusion or extrusion of incisor was observed. Thus, force system devised from a mathematical model was validated with finite element analysis in each case.
CONCLUSION
To achieve intrusion or extrusion, M:F ratios required in LaO were same i.e. 8:1 for aforementioned heights of bracket slot from incisal edge but different in LiO i.e. 0:1, 1:1, 2:1 and 3:1 for the heights of 3mm, 4mm, 5mm and 6mm respectively.
背景
本研究的目的是明确上颌中切牙内收和外展的最佳力系统，并比较唇侧正畸（LaO）和舌侧正畸（LiO）中托槽定位在切缘上方不同高度的效果。
方法
建立了具有正常倾斜度的上颌中切牙的数学模型。考虑了 LaO 和 LiO 中托槽槽口距切缘的 4 种不同高度，即 3mm、4mm、5mm 和 6mm。基于数学模型，设计了一个由内收或外展力（F）和力矩（M）组成的最佳力系统，并估计了每种情况下的力矩（M）与力（F）的比值（M:F 比值）。然后，制备了切牙和周围结构的三维计算机辅助设计（CAD）模型。为了验证最佳力系统，进行了有限元分析，并在每种情况下应用了具有推导得出的 M:F 比值的力系统。
结果
在有限元分析中，结果以节点位移的矢量图以及未变形和变形模型的形式呈现。观察到了所需的切牙内收或外展。因此，从数学模型设计的力系统在每种情况下都通过有限元分析得到了验证。
结论
为了实现内收或外展，LaO 所需的 M:F 比值相同，即上述托槽槽口距切缘的高度为 8:1，但 LiO 不同，即 3mm、4mm、5mm 和 6mm 的高度分别为 0:1、1:1、2:1 和 3:1。
Zotero 插件