The three-dimension finite element analysis on stress of different materia post-core of posterior tooth with or without PFM / 重庆医科大学学报

Objective:To compare influence the residual dentin stress of posterior teeth post-core different materials with or without porcelain fused metal crown (PFM), in order to instruct clinically rational choice of materials. Method:Models were created by abrasive methnd which piclures were acqiured with digital camera. Three-dimensional models of maxillary first molar short in medial palatal cusp were constructed and restored with of different materials post-core on condition of having or not having PFM. Then the magnitude and distribution of model residual dentin stress were analyzed by the three-dimension finite element analysis. Result:1 When maxillaU first molar which is short in medial palatal cusp was restored with post-core and porcelain fused mental crown, its peak value of stress was evidently less than that with post-core but without porcelain fused mental crown, meanwhile, they had different stress distribution. 2 When maxillary first molar which is short in medial palatal cusp was restored with post-core and porcelain fused mental crown, post-core of different materials had little influence on peak value of stress of residual dentin, but post-core of high elasticity modulus change normal dentin stress distribution, while post-core of low elasticity modulus did not. Conclusion:On the condition of normal occlusal force, PFM is extremely important to protect no-vital tooth, which is crucial for successful post-core crown. Meanwhile, post-core of different materials show little difference in fracturing rate of tooth restored with post-core and porcelain fused menial crown, and the fracture namely happen.

Three dimensional finite element stress analysis of five different taper design implant systems / 대한치과보철학회지

STATEMENT OF PROBLEM: Dental implant which has been developed gradually through many experiments and clinical applications is presently used to various dental prosthetic treatments. To conduct a successful function of implant prosthesis in oral cavity for a long time, it is important that not only structure materials must have the biocompatibility, but also the prosthesis must be designed for the stress, which is occurred in occlusion, to scatter adequately of load support. Therefore, it is essential to give the consideration about the stress analysis of supporting tissues for higher successful rates. PURPOSE: Recently, many implant manufacturing company produce various taper design of root form implant, the fixture is often selected. However, the stress analysis of taper form fixture still requires more studies. MATERIAL AND METHOD: This study we make the element models that five implant fixture; Branemark system(Nobel Biocare, Gothenberg, Sweden), Camlog system(Altatec, Germany), Astra system(Astra Tech, Sweden), 3i system(Implant Innovations Inc, USA), Avana system(Osstem, Korea)were placed in the area of mandibular first premolar and prosthesis fabricated, which we compared with stress distribution using the three-dimension finite element analysis under two loading condition. RESULTS: This study compares the aspect of stress distribution of each system with the standard of Von mises stress, among many resulted from finite element analysis so that this research gets the following results. 1. In all implant system, oblique loading of maximum Von mises stress of implant, alveolar bone and crown is higher than vertical loading of those. 2. Regardless of loading conditions and type of system, cortical bone which contacts with implant fixture top area has high stress, and cancellous bone has a little stress. under the vertical loading, maximum Von mises stress is more higher in order of Branemark, Camlog, Astra, 3i, Avana. under the horizontal loading, maximum Von mises is more higher in order of Camlog, Branemark, Astra, 3i, Avana.

The three-dimension finite element analysis on stress of different length post of posterior tooth on post-core crown / 重庆医科大学学报

Objective: To compare influence of residual dentin stress on condition of different post length of posterior teeth post-core,to discover reasonable post length of posterior teeth post-core,in order to instruct clinic rational design.Methods:Models were created by abrasive method and way which pictures were acqiured with digital camera.To generate three-dimensional models of maxillary firster molar which is short in medial palatal cusp restored with post-core crown.Then analyse magnitude and distribution of model residual dentin stress by the three-dimension finite element analysis.Result:When maxillary firster molar which is short in medial palatal cusp restored with middle fusion metal post-core and porcelain fused mental crown,on condition of 1/2 post length and2/3 post lengths,it has the same magnitude of Von mises stress? most main stress ? least main stress and the same stress distribution on residual dentin.Conclusion:When maxillary firster molar which is short in medial palatal cusp restored with middle fusion metal post-core and porcelain fused mental crown,on condition of 1/2 post length and2/3 post lengths,it has no infulence in magnitude and distribution of stress of residual dentin.

Establishment of three-dimension finite element mode of residual root restored with post-core crown / 重庆医科大学学报

Objiect:To generate three-dimension finite element mode of the first maxillary molar residual root restored with post-core crown,to analyse the stress of post-core crown of posterion tooth.Methods:Models were generate by CT scan,Mimics software and Abaqus software. Result:The three-dimensional models of the first maxillary molar residual root restored with post-core crown were generated. Conclusion:The generated three-dimensional models of the first maxillary molar residual root restored with post-core crown.were highly similar in geometry and mechanics to the real instance,which could be used to study stress of posterion tooth residual root restored with post-core crown