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目的:利用有限元法分析不同数目桩、不同材料桩核及不同载荷对磨牙桩核冠修复后剩余牙体组织的应力大小及其分布的影响。方法:采用CT扫描上颌第一磨牙,有限元法建立不同数目桩及不同材料桩核修复上颌第一磨牙后的模型,载荷1以480 N总载荷垂直加载模拟正中咬合,载荷2以200 N总载荷与牙长轴成45°斜向加载模拟咀嚼,采用MSC.Marc软件分析剩余牙体组织的Von Mises应力大小及其分布。结果:随桩核材料弹性模量的增加,牙颈部Von Mises应力峰值减小,牙根内表面的应力值增加;铸造桩组腭根和远中颊根桩修复时,桩周牙本质的应力峰值小于腭根桩修复及腭根和近远中颊根桩修复;载荷2条件下,牙颈部的应力峰值较载荷1条件下的应力峰值小,而牙根内表面的应力峰值较大。结论:桩的数目、桩核材料及载荷大小与方向均对磨牙桩核冠修复后剩余牙本质的应力大小和分布有影响。
OBJECTIVE: To analyze the effect of different numbers of posts, different materials of post and core and different loads on the stress distribution and the residual stress distribution of the residual tooth tissue after the restoration of the mandibular molar crown. Methods: The maxillary first molars were scanned with CT and the finite element method was used to establish the model with different numbers of piles and different materials of post-core to repair the maxillary first molars. The load 1 was loaded vertically at 480 N total load and the load was centered at 200 N The load was loaded obliquely at 45 ° to the long axis of the tooth to simulate chewing. The residual Von Mises stress distribution and its distribution were analyzed using MSC.Marc software. Results: With the increase of the elastic modulus of the core material, the peak value of Von Mises stress in the dental neck decreased and the stress on the inner surface of the root increased. The dentinal stress The peak value was less than the repair of the palatal root and the repair of the palatal root and the mesiodistal root canal. Under the condition of load 2, the stress peak value of the cervical part was smaller than that under the load 1 condition, while the stress peak value of the inner surface of the root was larger. CONCLUSIONS: The number of posts, the size and direction of post-core material and load, all have an effect on the stress distribution and size distribution of residual dentine after the restoration of molar post and core crown.