背景:不同角度的牵引力对具有变化的倒转角度(IA)的撞击中切牙(ICI)的影响可能不同。这项研究的目的是分析不同力方向(FD)对多角度变化的发育性倒置ICI的生物力学影响,并为倒置ICI的治疗提供见解和指导。
方法:采用三维有限元方法模拟倒置ICI牵引的临床情景。因此,0.2N的力(方向:90°的前上角度,100°,110°,120°,并且相对于倒置ICI冠部的长轴为130°)以40°的反向角度(IA)应用于倒置ICI,30°,20°,10°和0°。比较了ICI根尖倒置和VonMises对牙周膜(PDL)和牙槽骨的应力。
结果:IA和FD对PDL中的应力分布影响最小,由于较高的应力集中在顶端区域。牙槽骨中的较高应力集中在牙齿的颈部和顶端区域。特别是,IA对牙槽骨中应力分布的影响比FD更显著。IA对倒置ICI根尖位移的影响年夜于FD。
结论:为了促进牙根和牙周组织的健康,当处理大的IA(>20°)发育倒置的ICI时,建议相对于ICI牙冠的长轴使用100°-110°的角度。相反,可以使用110°-120°的角度。
BACKGROUND: The effects of traction forces at different angles on impacted central incisors(ICI)with varying inverted angles (IA) may be different. The objective of this study was to analyze the biomechanical effects of different force directions (FD) on developmentally inverted ICI with multi-angle variations and to offer insights and guidance for the treatment of inverted ICI.
METHODS: Three-dimensional finite element method was employed to simulate clinical scenarios of inverted ICI traction. As such, 0.2 N of force (direction: antero-superior angles of 90°, 100°, 110°, 120°, and 130° relative to the long axis of the inverted ICI crown) was applied to the inverted ICI with inverse angles (IA) of 40°, 30°, 20°, 10° and 0°. Inverted ICI apical displacement and Von Mises stress on periodontal ligament (PDL) and alveolar bone were compared.
RESULTS: IA and FD showed minimal influence on the stress distribution in the PDL, as higher stresses were concentrated in the apical region. The higher stresses in the alveolar bone are focused on the cervical and apical regions of the tooth. In particular, IA exerts a more significant impact on stress distribution in the alveolar bone than FD. The influence of IA on the apical displacement of inverted ICI is larger than that of FD.
CONCLUSIONS: To promote the health of the root and periodontal tissues, it is recommended to use an angle of 100°-110° relative to the long axis of the ICI crown when dealing with a large IA (> 20°) developmentally inverted ICI. Conversely, an angle of 110°-120° can be used.