Three-dimensional Finite Element Analysis Of Molar With Different Prosthodontic Design After Hemisection Therapy

AIM: To establish a 3-D finite-element model of the mandibular second premolar the mandibular first molar and the mandibular second molar and their periodontal tissues of human being. Observe the stress distribution of the reserved healthy root of the mandibular first molar with different prosthodontic design after hemisection therapy. Discuss the feasibility of fixed prosthodontic after hemisection and optimize the clinical project to provide biomechanics foundation for clinic.Methods: (1)Established a 3-D finite element model of the mandibular second premolar,the mandibular first molar and the mandibular second molar and their periodontal tissues by-means of SCT scanning technology and software of image processing and finite element analyzing program.(2)On the base of having established the 3-D finite-element model of the mandibular second premolar,the mandibular first molar and the mandibular second molar, we obtained models of different prosthodontic design through modifying the parameters of materials and bowdlerizing the model:Model combined crown prosthodontics; Model 4: combined crown prosthodontics; Model 5: combined crown prosthodontics; Model 6: single crown prosthodontics.The stress distribution of the reserved root with different prosthodontic design after hemisection therapy under the vertical loading and obliquely loading was observed.(3) On the base of the model of combined crown prosthodontic, three models of different level of alveolar bone loss(l/4, 2/4, 3/4) were generated.The stress distribution of the reserved root of the mandibular first molar were analyzed .Results : (1) Established a 3-D finite element model of themandibular second premolar,the mandibular first molar and the mandibular second molar and their periodontal tissues including enamel,dentin,cementum,cortical bone,sponge bone,pulp and mucosa. The model has favorable comparability. (2)Single crown isn't good to the health of the reserved root because the stresses increase obviously than the normal . The stress of periodontical tissues is nearly two times than normal with free end brige. So choose it cautiously when the periodontal tissue is not healthy.The design of rigid fixed bridge is superior to free-end fixed bridge and be propitious to the the health of the reserved root by dispersing the stress of reserved root more effectively.(3) The loss of alveolar bone can increase the stress of the butments' periodontal tissues.Conclusions: (1)It is feasible and scatheless to establish the teeth and alveolar bone by means of SCT scanning technology and software of image processing and finite element analyzing program.(2)Rigid fixed bridge is the first selection as a prosthodontic design of the mandible first molar with hemisection therapy. (3)It is important to pay attention to the health of the periodontal tissues before making prosthodontic design after hemisection therapy.