■要比较施加在牙列上的应力分布和总应变,牙周韧带(PDL)和皮质骨和骨小梁三个II类校正使用有限元分析。
■用三种II类校正器对牙列的应力和总应变进行三维分析。
■计算研究。
■II类弹性的三维有限元模型,Forsus抗疲劳装置(FRD)和Carriere运动装置(CMA)是根据正畸II类患者的锥形束计算机断层扫描(CBTC)图像构建的。上颌牙列应力(vonMises和主应力)和总应变(mm)的分布,PDL,皮质骨和骨小梁进行了分析。
■三个模型中最高的vonMises屈服和最大主应力都是在牙齿上发现的,接着是皮质骨,骨小梁和PDL。在II类弹性和CMA模型中,最大应力和总变形位于上犬齿和下磨牙,在ForsusFRD和CMA的上第一磨牙中,在ForsusFRD的较低的第一前磨牙中。此外,应力分布在牙齿的前部和后部区域,并且在上弓的远端方向和下弓的内侧方向上发现了总变形。
■三个模型中的应力集中位置靠近每个器具的有源元件,产生特定的应力分布和位移模式,在计划用于II类错牙合矫正的矫治器类型时应考虑这些模式。
To compare the stress distribution and total strain applied to the dentition, periodontal ligament (PDL) and cortical and trabecular bones by three Class II correctors using finite element analysis.
Three-dimensional analysis of stresses and total strain of the dentition with three Class II correctors.
Computational study.
Three-dimensional finite element models of Class II elastics, the Forsus Fatigue Resistant Device (FRD) and the Carriere Motion
Appliance (CMA) were constructed from a cone-beam computed tomography (CBTC) image of an orthodontic Class II patient. The distribution of stress (von Mises and principal stress) and the total strain (mm) in maxillo-mandibular dentition, PDL, cortical and trabecular bone were analysed.
The highest von Mises yield and the maximum principal stress in the three models were found at the teeth, followed by the cortical bone, trabecular bone and PDL. The maximum stress and total deformation were located at the upper canines and lower molars in the Class II elastics and CMA models, in the upper first molars in the Forsus FRD and CMA, and in the lower first premolars in the Forsus FRD. In addition, stress was distributed in the anterior and posterior regions of the teeth, and the total deformation was found in the distal direction in the upper arch and in the mesial direction in the lower arch.
The stress concentrations in the three models were located close to the active components of each
appliance, producing specific patterns of stress distribution and displacement that should be taken into account when planning the type of
appliance to be used for the correction of the Class II malocclusion.