Chen Pin-Yu, Huang Heng-Li, Yu Jian-Hong, Hsu Jui-Ting
School of Dentistry, China Medical University, Taichung, Taiwan.
Department of Biomedical Engineering, China Medical University, Taichung, Taiwan.
J Dent Sci. 2024 Oct;19(4):2007-2017. doi: 10.1016/j.jds.2024.07.005. Epub 2024 Jul 12.
BACKGROUND/PURPOSE: Clear aligners are popular orthodontic tools because of their relatively aesthetic appearance and convenience of use. Nevertheless, bodily tooth movements still present challenges. This study evaluated various configurations of attachments placed on the mandibular canine in terms of the efficiency of canine bodily movement and correction of tipping.
A finite element model of the mandible was constructed to investigate the effects of various attachment configurations on the overall bodily movement and undesirable tipping of a mandibular canine. Canine movements were categorized into four types, namely tipping and bodily movements in the mesial and distal directions. The size and shape of the attachments were fixed, but their placement and orientation were varied. Five and seven attachment configurations were evaluated for their influence on tipping and bodily movements, respectively.
Attachment configuration significantly influenced mandibular canine tipping. The mesial occlusal-distal cervical and mesial occlusal-mesial cervical configurations had notable effects on mesial tipping, and the mesial occlusal-mesial cervical configuration excelled in distal tipping by increasing strain by 33.1%. The mesial occlusal-mesial cervical attachment configuration consistently had superior efficiency in facilitating both mesial and distal bodily movements of the canine.
The mesial occlusal-mesial cervical attachment configuration excelled in all four types of canine movement. Irrespective of the attachment configuration, canines tend to move overall with slight tipping due to skeletal resistance and their center of rotation. The attachment configuration is crucial to the success of clear aligner treatment and must be carefully considered in clinical practice.
背景/目的：透明矫治器因其相对美观的外观和使用便利性，成为流行的正畸工具。然而，牙齿整体移动仍存在挑战。本研究评估了放置在下颌尖牙上的不同附件构型对尖牙整体移动效率和扭转矫正的影响。
构建下颌骨的有限元模型，以研究不同附件构型对下颌尖牙整体移动和不必要扭转的影响。尖牙移动分为四种类型，即近中向和远中向的扭转及整体移动。附件的尺寸和形状固定，但其放置位置和方向有所变化。分别评估了五种和七种附件构型对扭转和整体移动的影响。
附件构型对下颌尖牙扭转有显著影响。近中咬合-远中颈缘和近中咬合-近中颈缘构型对近中扭转有显著影响，近中咬合-近中颈缘构型在远中扭转方面表现出色，使应变增加了33.1%。近中咬合-近中颈缘附件构型在促进尖牙近中向和远中向整体移动方面始终具有更高的效率。
近中咬合-近中颈缘附件构型在尖牙的所有四种移动类型中均表现出色。无论附件构型如何，由于骨骼阻力及其旋转中心，尖牙整体移动时往往会伴有轻微扭转。附件构型对透明矫治器治疗的成功至关重要，在临床实践中必须仔细考虑。
