外力方向对防护牙托性能影响的有限元分析

Effect of impact direction on the cushion property of mouthguards: a finite element analysis

目的:运用有限元分析评估外力方向对牙托缓冲能力的影响。方法:采集仿真模型锥形束CT (CBCT)影像资料,利用MIMICS软件建立分析模型。运用ABAQUS软件模拟研究在牙托厚度不同的情况下(分别为0、1.5、3、4.5和6 mm),经不同方向外力(撞击方向与牙长轴交角分别为30°、60°、90°和120°)撞击后,牙体表面的应力变化情况,进而评价牙托的缓冲能力。结果:在研究实验条件下,当牙托厚度较薄时(1.5 mm和3 mm),与其他方向相比,牙托缓冲效率在60°交角时最低,在120°交角时最高。而在牙托厚度增加后(4.5 mm和6 mm),牙托缓冲效率在90°交角时最低,在30°交角时最高。外力方向不同时,牙托的应力缓冲效率随着牙托厚度的增加而提高。结论:外力方向对防护牙托的缓冲能力有一定影响,但其易受牙托厚度的影响。

PURPOSE:The aim of this study was to evaluate the cushion property of mouthguards when the impact object came from different directions.METHODS:A 3D finite element model of upper central incisor,periodontal ligament and alveolar bone was developed based on cone-beam CT (CBCT) images of a plastic teeth model.The mouthguards were modeled in 5 different thickness (T:0,1.5,3,4.5 and 6 mm) and a nonlinear dynamic impact analysis,in which the finite element models were collided by a steel ball from different directions (D:angles between the impact direction and the long axis of tooth were 30°,60°,90°,120°,respectively),was performed.The stress cushion efficiency was calculated.RESULTS:The stress cushion efficiency of the mouthguards varied with different thicknesses and impact directions.When T=1.5 mm and 3 mm,the stress cushion efficiency was minimal as D=60° and maximal as D=120°.However,when T=4.5 mm and 6 mm,the stress cushion efficiency was minimal as D=90° and maximal as D=30°.Moreover,the stress cushion efficiency of mouthguards improved with the increasing thickness in each impact direction.CONCLUSIONS:The impact direction affects the stress cushion efficiency of mouthguards,which however is influenced by the thickness of mouthguards.