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目的计算不同硬度隐形矫治器产生的力学效应,为其材料选择和设计提供理论依据。方法建立中切牙近中移动0.3 mm矫治设计量,弹性模量分别为415.6、816.308、2 400 MPa的3个隐形矫治器有限元模型,用三维非线性分析方法计算矫治器、牙齿、牙周组织的应力分布及位移,对不同弹性模量隐形矫治器作用下的上述结果进行比较分析。结果实验条件下,中切牙所受的应力及位移最大,最大位移量为0.17 mm,其冠方的初始位移大于根方,矫治牙始终做倾斜移动;侧切牙次之且位移与中切牙相反,最大位移量为0.10 mm。材料的弹性模量增大,隐形矫治器产生的应力增大,牙周组织所受的应力及矫治牙位移增大。结论隐形矫治器的硬度越大,目标矫治牙的位移量和矫治效能增大,但对于牙齿三维方向上的移动控制能力并未增强,临床上建议添加附件或是配合固定矫治器达到牙齿的整体移动。
Objective To calculate the mechanical effects of stealth appliances with different hardness and to provide a theoretical basis for material selection and design. Methods Three invisible orthodontic appliances with finite element model of 415.6, 816.308 and 2400 MPa were designed and manufactured. The appliance, teeth and periodontal tissues were calculated by three-dimensional non-linear analysis Of the stress distribution and displacement of different elastic modulus stealth appliance under the effect of the above comparative analysis. Results Under the experimental conditions, the stress and displacement of the maxillary incisors were maximal with the maximum displacement of 0.17 mm. The initial displacement of the coronal square was greater than that of the root. The orthodontic teeth always tilted and moved. On the contrary, the maximum displacement is 0.10 mm. The elastic modulus of the material increases, the stress generated by the stealth appliance increases, the stress on the periodontal tissue and the displacement of the orthodontic appliance increase. Conclusion The greater the hardness of the stealth appliance, the greater the displacement of the target teeth and the orthodontic efficacy. However, the ability to control the movement in the three-dimensional direction of the teeth has not been enhanced. It is recommended to add attachments or to fix the appliance to achieve the overall denture mobile.