Biomechanical Analysis Of The 3D Printed Porous Titanium Alloy Implant

Purpose:This experiment will apply reverse engineering technology and computer aided design to construct 3D printed CAD model for dental implant with porous structure on the surface and construct CAD model of lower anterior teeth.The method of static stress loading is used to simulate functional load of dental implant and lower anterior teeth.The three-dimensional finite element analysis method is utilized to explore biomechanical characteristics of surface pore structure design of dental implant.Method:(1)Selected a group of normal CBCT data to be imported into Mimics 17.0software to extract data.Then used Geomagics studio 11.0 to establish a model for a complete length of mandible(including cortical bone with 2mm for thickness of outer layer and cancellous bone of inner layer)and model for lower anterior teeth;(2)Used3D scanner to scan 48/18/33/10 Straumann dental implant to get related data and established the implant 3D model(RI),followed by using Geomagics studio 11.0 to construct CAD model of solid dental implant with pore structure(PRI)according to RI: The solid section in the center of dental implant had a diameter of 2mm,and surface pore structural sheet was 0.65 mm thick.The pore structure surrounded central solid section and was vertical to long axle of dental implant,with a diameter of0.7mm;(3)Used PRO/E 5.0 software to assemble lower anterior teeth,RI,PRI and mandible model;(4)Loaded axial force of 100 N to three groups of models,and static force of 120 N which is 45° from long axle of dental implant and is toward the buccolingual direction,with loading point at 1/2 in incisal margin of crown;(5)Used Ansys Workbench software to analyze the three groups of models to get the stress distribution of lower front teeth,RI,PRI and mandible.Result:(1)When the two forces were being loaded,the stress distribution of the three groups of models was similar,and was all uniform.The Von Mises stress of loweranterior teeth,RI and PRI was mainly concentrated at neck.The stress distributed at apical of lower anterior teeth,RI and PRI was the minimal.The stress when vertical force was being loaded was smaller than the stress when oblique force was being loaded.The maximum Von Mises stress of PRI is greater than the maximum Von Mises stress of RI.(2)When the two forces were being loaded,the stress distribution for three groups of mandibles was similar,and was all uniform.The Von Mises stress at the interface of bone tissue is all concentrated in the cortical bone area and cancellous bone area contacting neck of lower anterior teeth and implant.The maximal Von Mises stress is in cortical bone area at neck edge for lingual side of lower anterior teeth and cortical bone area at neck edge for lip and tongue sides of RI and PRI.The maximum Von Mises stress of mandible in PRI group is greater than the maximum Von Mises stress of mandible in RI group.Conclusions:(1)The porous structure design can lower elastic modulus of surface of dental implant;(2)When vertical force and oblique force are being loaded,the cortical bone is more sensitive to morphological change of dental implant surface.Compare with RI,PRI stress is well conducted to the mandible,thereby reducing the effect of "stress shielding".