Research Of Localized Radial Basis Function Collocation Method For Multi-point Stress And Surface Stress Of Three-dimensional Tooth

Oral health is closely related to oral diseases and systemic diseases.Oral diseases include dental caries,pulp diseases,periapical diseases,periodontal diseases and so on,among which dental caries is a common disease in dental clinical work.The World Health Organization had listed it as one of the three key diseases for human prevention and treatment.Therefore,study the force characteristics and stress distribution on the tooth surface when occlusal force is applied is beneficial to understand the mechanism of dental diseases,analyze the causes of dental diseases,and then guide tooth restoration,orthodontics and so on.In this paper,the computational model is established according to the CT images of isolated tooth,and the localized radial basis function collocation method(LRBFCM)is improved,LRBFCM for multi-point stress and surface stress of three-dimensional tooth is studied deeply.The specific studies are summarized as follows:(1)For three-dimensional tooth with complex boundary shapes,the interior nodes of the tooth model are constructed and the boundary nodes are reconstructed.The local domain selection problem of complex boundary is solved by controlling the influence radius to select the local domain.The direct method and fictitious nodes method are combined to solve the first partial derivatives (?)u/(?)n under Neumann boundary conditions to improve the stability and accuracy of the algorithm.(2)A numerical example with an analytical solution of the tooth boundary shape is used to prove the feasibility of the LRBFCM for tooth research.The stress distribution characteristics of normal tooth and dental caries under chewing conditions are compared and analyzed,the effect of chewing on normal tooth and the harm of chewing on dental caries are summarized.(3)A cube example is used to prove the effectiveness of the LRBFCM for computing the two materials in the three-dimensional case.The stress distribution characteristics of tooth filled with different materials in the real chewing situation is studied,and compared with the stress distribution characteristics of normal tooth in the real chewing situation,so as to find suitable materials for filling and restoration,and provide appropriate treatment plans for dental caries.