A Dynamic Finite Element Analysis Of Stress Distribution In The Supporting Bone Of Tooth-implant Fixed Bridge

ObjectiveThe finite element method (FEM) was used to analyze the stresses induced in the supportedbone tissue surrounding tooth-implant fixed bridge abutments under dynamic loads, so as toprovide theoretical references of biomechanics for clinical application of tooth-implantsupported fixed bridge.MethodsA three-dimensional finite element model simulated a3-unit left mandibular posteriortooth-implant supported fixed bridge and corresponding periodontal substance with computedtomography (CT) scan images combined with3-D computer-aided (CAD) software, Soliworkssoftware and Ansys software. In the model, natural tooth was marked as35, bridge marked as36,and the dental implant marked as37. Finite element analysis was performed on the model undercontinuous dynamic loads to explore the stress and stress-distribution induced in the supportedbone tissue surrounding abutments before-and-after the fixed bridge restoration in onemasticating cycle and three masticating cycles respectively.Results1. The combined application of CT scan images, AutoCAD software, Soliworks software andAnsys software could accurately construct a three-dimensional finite element model of thefixed bridge and corresponding supported bone tissue.2．Before-and-after restoration, the stress and stress-distribution of the supported bone tissue wasinfluenced by different loading directions and time, The peak stress was in leaning loading.Besides, the implant possessed was more than natural tooth. Specifically, the maximum Vonmises of the supported bone tissue of implant was141.773Mpa, while natural tooth was63.179Mpa, and the maximum average deviation of the two abutments was70Mpa.3．Before-and-after the fixed bridge restoration, the stress concentration were in the twoabutments cervical cortical bone, while the below cervical turned out to be small andbalanced. The positions that the stress concentrated was mainly influenced by the loadingdirections, in particular, the implants mostly suffered stress in the mesial and the buccolingual of the cervical, while the natural tooth mainly was the buccolingual of thecervical.4．At the final period of unloading, the bone tissue exists residual stress, while the natural toothsuffered was0.048～5.698Mpa, the dental implant was0.055～8.894Mpa.Conclusion1．The cortical bone of the cervical of the two abutments appeared high concentration of stress,while the area below the cervical showed low concentration of stress with balanceddistribution; the stress and stress-distribution of the supported bone tissue surrounding fixedbridge abutments was influenced by the loading condition.2．Though the stress of the supported bone tissue of the implant was lager than that of the naturaltooth, the implant showed faster stress release; besides, the residual stress intensity of the twoabutments at the final period of unloading was similar.3．The results evidenced that the design of the tooth-implant supported fixed bridge is feasibleand practicable.