正畸力内收前牙对牙槽骨吸收程度不同后牙的影响

目的 通过有限元法模拟不同程度的后牙牙槽骨吸收状态,分析骨吸收情况下的牙周应力分布和总位移趋势,以便为临床施加合适的矫治力提供指导。方法 在建立正常牙槽骨高度（1号模型）的基础上,通过删减单元格获得后牙牙槽骨高度水平均衡降低2、4、6 mm的2、3、4号模型;在各模型上进行模拟加载,加载力1.47 N,分析在施加矫治力的情况下,各模型后牙组牙的牙周膜初应力及牙齿初始总位移的分布情况。结果 随着牙槽骨高度的降低,后牙组牙总位移增加,牙周膜Von Mises应力逐渐增大,当牙槽骨吸收达4 mm时,应力值和牙齿初始总位移值明显增加。结论 对于伴有牙槽骨丧失的患者,应当避免受力或显著减小受力,避免造成牙周组织不可逆的损伤和牙根、牙槽骨的持续吸收。

Finite element analysis of maxillary anterior teeth retraction of posterior teeth with different alveolar bone absorption heights under orthodontic force

Objective This study applied the direct orthodontic force system to explore the applicability of the finite element method in the simulation of alveolar bone absorption and analyze periodontal stress distribution and the overall displacement trend. Methods The horizontal balanced alveolar bones of model 2, 3 and 4 were reduced by 2, 4, and 6 mm by deleting elements in reference to the established height of the normal alveolar bone model 1. Then, stress distribution on the posterior set of teeth and initial total tooth displacement under the simulated load of 1.47 N of orthodontic force were investigated. Results The total displacement of posterior teeth increased and parodontium Von Mises stress gradually increased as the alveolar bone height decreased. The total displacement trend and parodontium stress drastically increased when alveolar bone absorption reached the height of 4 mm. Conclusion When treating patients with alveolar bone loss, stress should be avoided or drastically reduced to prevent irreversible damage to periodontal tissue and to improve the quality of medical treatment.