Craniofacial Orthodontist, Division of Orthodontics, Teeth "N" Jaws Center, Lake Area, Chennai- 600034, Tamil Nadu, India.
Assistant Professor, Department of Mechanical Engineering, College of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu, 603203, Tamil Nadu, India.
Comput Methods Programs Biomed. 2021 Mar;200:105835. doi: 10.1016/j.cmpb.2020.105835. Epub 2020 Nov 10.
Four tie wings brackets are widely used in orthodontics, while the Six Tie Wings Brackets (STWB) are recently emerging in fixed orthodontic appliances due to their claim for less friction and thus faster teeth movement. The aim of this work was to evaluate the stress distribution and deformation during simulated mesio-distal tipping forces in Stainless Steel (SS) six tie wings orthodontic bracket using Finite Element Analysis (FEA).
A six tie wings bracket (Synergy®, RMO, USA) dimensions were measured using the Vision system and a 3D model of the bracket was constructed. A Finite Element (FE) model was developed and mesio-distal tipping forces of 1.22 N to 1.96 N (125 to 200 gm) in increments were applied on the gingival and incisal slot walls. The stress distribution and deformation were recorded at specific points in the bracket and analyzed.
The maximum deformation and stress distribution for the mesial and distal tipping forces of 1.96 N were recorded as 0.137 µm and 10.60 MPa respectively. The stress concentration was more at the junction of the slot wall and the slot base. For mesial tipping,the deformation was more on the disto-incisal and mesio-gingival tie wings. Similarly, for distal tipping the deformation was more on the mesio-incisal and disto-gingival tie wings. The mid-tie wings showed minimal deformation during both distal and mesial tipping.
Our study visualized both the mesial and distal tipping forces induced stress distribution in the bracket tie wing-slot junctions. The deformation was present maximum in the mesio-incisal and disto-incisal tie wings and minimal in the mid-tie wings. Clinicians should be aware of this behavior of STWB in making decisions to alter the tipping forces in the archwire to compensate for the tie wing deformation in refining the teeth position.
四翼托槽在正畸中广泛应用，而六翼托槽（STWB）由于其声称摩擦力更小，从而可以更快地移动牙齿，最近在固定正畸器械中出现。本研究旨在通过有限元分析（FEA）评估不锈钢六翼托槽在模拟近远中倾斜力作用下的应力分布和变形。
使用 Vision 系统测量六翼托槽（Synergy®，RMO，美国）的尺寸，并构建托槽的三维模型。开发了一个有限元（FE）模型，并在龈槽和切槽壁上施加 1.22 N 至 1.96 N（125 至 200 克）的近远中倾斜力。记录托槽特定点的应力分布和变形，并进行分析。
记录到 1.96 N 近远中倾斜力的最大变形和最大应力分布分别为 0.137 µm 和 10.60 MPa。在槽壁和槽底交界处的应力集中更为明显。对于近中倾斜，变形主要在远中切和近中龈翼上。同样，对于远中倾斜，变形主要在近中切和远中龈翼上。中翼在近远中倾斜时显示出最小的变形。
本研究可视化了托槽翼槽交界处的近中倾斜和远中倾斜引起的应力分布。变形主要出现在近中切和远中切翼上，而在中翼上最小。临床医生在决定改变弓丝中的倾斜力以补偿托槽变形从而精细调整牙齿位置时，应了解 STWB 的这种行为。
