Three-dimensional Finite Element Analysis Of The Influence Of Different Buccal-lingual Bone Thickness On Stress Around The Implant

Objective: In recent years,with the rapid development of oral implantation technology,the restoration of missing teeth by implantation technology has been increasingly used in the clinic.Clinical and scientific researchers have conducted a lot of research to obtain a higher success rate and better long-term effects of implant surgery.As the finite element method has entered the field of biomedicine and up to the field of oral implantology,it has provided good technical support for implant-related research.The finite element method uses computer simulation to conduct mechanical analysis and research on implants under different conditions,and has a wide range of applications in the field of oral implants.Among the many factors that affect the success rate of implantation,the bone mass of the patient’s implantation area is one of the most important factors.In this study,the three-dimensional finite element analysis method was used to establish the implant-mandibula models with different buccal-lingual bone thicknesses to explore the stress and strain of the surrounding bone when the implant was stressed,and to choose the clinical implant repair scheme and its subsequent effects Evaluation provides a reference.Methods:1.Apply three-dimensional modeling software to establish three simplified three-dimensional geometric models of mandibular bone mass.2.Application of 3D modeling software to establish a threaded implant model.3.Model assembly and grouping of implant and mandibula.4.Establish a finite element model,impose restrictions,and perform mesh division.5.Apply vertical and inclined static loads to the upper surface of the implant.6.Using ANSYS 16.2,measure and record the Von-Mises Stress of the implant and mandibula,the maximum principal strain of the mandibula under load conditions,and analyze the stress and strain of the implant and bone when the bone thickness is different.Results:1.Using Solid Works 2015,a three-dimensional geometric model of the mandibula with the same length and height(30mm in length and 25 mm in height)and different thickness(8mm,9mm,and 10mm)was established.The thickness of the cortical bone was constant.2.Apply Solid Works 2015 to establish an implant model: the upper part of the implant is simplified into a solid column shape with a diameter of 4mm;the thread is continuous and uninterrupted,with a length of 10mm;0-8mm from the bottom of the implant is a thick thread;the pitch is 1.2mm;8-10 mm from the bottom of the body is a fine thread with a pitch of 0.6mm.3.Establish a geometric model of implant-mandibula using translation and Boolean subtraction operations.Import the model into ANSYS Workbench in SLDPRT format.The whole and various parts of the model can be displayed in ANSYS Workbench.4.Establish a finite element model.All materials in the model adopt continuous,homogeneous and isotropic linear elasticity assumptions to limit the displacement of the mandibula and perform automatic meshing.5.Apply two static uniform loads of vertical 100 N and inclined 30 ° 60 N to the upper surface of the implant.the Von-Mises Stress and the maximum principal strain are indicators in cloud map after the model is solved.6.Analyze the cloud map of each group of models1)The Von-Mises Stress distributions of implants are similar,the Von-Mises Stresses in the middle and lower parts are small,and the maximum stress value appears at the interface with the cortical bone.The buccal-lingual bone thickness increased,and the maximum Von-Mises Stress of the implant increased accordingly.2)The Von-Mises Stress of the mandibula is mainly concentrated in the upper edge region of the cortical bone.When the thickness of the bucco-lingual bone increases,the maximum Von-Mises Stress of the cortical bone increases,but the high strain area decreases;the maximum strain value increases,but the strain attenuation accelerates.3)The Von-Mises Stress of cancellous bone is concentrated near the implant thread,when the thickness of buccal-lingual bone increases,the maximum Von-Mises Stress of cancellous bone increases,but the high strain area decreases;the maximum strain value increases,but the strain attenuation accelerates.Conclusions:1.When the buccal and lingual bone thickness of the implant is more than 2mm,the Von-Mises Stress of the implant is concentrated in the area in contact with the cortical bone.As the bone thickness increases,the maximum Von-Mises Stress increases accordingly.2.When the buccal and lingual bone thickness of the implant is more than 2mm,as the bone thickness increases,the maximum Von-Mises Stress and the maximum principal strain increase.It is suggested that the stress concentration of mandibula after loading is consistent with the trend of implant stress concentration.3.When the thickness of the buccal and lingual bone of the implant is more than 2mm,the area of high stress and strain of the mandibula will be significantly reduced,and the maximum Von-Mises Stress and the maximum value of the principal strain will decay faster,suggesting that the increase of the bone thickness is conducive to stress’ s evacuation of the mandibula.Evacuation can improve the overall stability of the implant-mandibula structure.