BACKGROUND:The elastic modulus of traditional solid titanium alloy implants is higher than that of human bone,and the resulting"stress shielding"phenomenon may affect the osseointegration of implants.Simultaneously,the wettability of 3D printed titanium alloy surface needs to be improved.OBJECTIVE:To prepare hydrophilic Gyroid implants with excellent biomechanical properties.METHODS:The 3D models of Gyroid implant,solid implant,mandibular bone and crown were established,and the mechanical properties of different implants were analyzed by finite element analysis.The Gyroid structure implant model was imported into the 3D printer to make the Gyroid structure implant materialized,and then the hydrophilic Gyroid structure implant with excellent mechanical properties and surface activity was prepared by sandblasting acid etching and ultraviolet functionalization.The morphology and hydrophilicity of 3D printed Ti6Al4V specimens before and after surface modification were analyzed by scanning electron microscopy and contact angle test.RESULTS AND CONCLUSION:(1)The finite element analysis results showed that under the vertical average bite force,the Gyroid structure could uniformly disperse the load acting on the implant into the entire structure.The load on the solid structure implant could only be dispersed on its outer surface and concentrated in the neck.The maximum equivalent stress of the Gyroid structure implant was 200.67 MPa,which did not exceed 50%of the yield strength of Ti6Al4V material.The maximum equivalent stress of the Gyroid structure implant on the surrounding bone tissue was 24.27 MPa,which was slightly higher than the maximum equivalent stress of the solid structure implant 17.32 MPa,and in the range of 20-60 MPa.The stimulation effect of the Gyroid structure implant on new bone formation was better than that of the solid structure implant.(2)The 3D printing technology could materialize the Gyroid structure implant model.Scanning electron microscopy showed that there were many unmelted spherical metal particles on the surface of the 3D printed Ti6Al4V specimens.After sandblasting and acid etching,a micron-scale mesh pore structure was formed on the surface,and no protruding metal particles were seen.The surface morphology of the superimposed UV functional treatment group was basically consistent with that after sandblasting and acid etching.The contact angle test results showed that the surface hydrophilicity of the specimens treated with ultraviolet functionalization plus sandblasting and acid etching was better than that of the sandblasting and acid etching and non-surface treatment groups.(3)The sandblasting and acid etching technology can remove the weakly connected metal particles on the 3D printed specimen and improve the similarity between the solid model and the design model.On this basis,the ultraviolet functionalization treatment can significantly improve the hydrophilicity of the 3D printed Gyroid structure implant surface without affecting its structure.

BACKGROUND:The elastic modulus of traditional solid titanium alloy implants is higher than that of human bone,and the resulting"stress shielding"phenomenon may affect the osseointegration of implants.Simultaneously,the wettability of 3D printed titanium alloy surface needs to be improved.OBJECTIVE:To prepare hydrophilic Gyroid implants with excellent biomechanical properties.METHODS:The 3D models of Gyroid implant,solid implant,mandibular bone and crown were established,and the mechanical properties of different implants were analyzed by finite element analysis.The Gyroid structure implant model was imported into the 3D printer to make the Gyroid structure implant materialized,and then the hydrophilic Gyroid structure implant with excellent mechanical properties and surface activity was prepared by sandblasting acid etching and ultraviolet functionalization.The morphology and hydrophilicity of 3D printed Ti6Al4V specimens before and after surface modification were analyzed by scanning electron microscopy and contact angle test.RESULTS AND CONCLUSION:(1)The finite element analysis results showed that under the vertical average bite force,the Gyroid structure could uniformly disperse the load acting on the implant into the entire structure.The load on the solid structure implant could only be dispersed on its outer surface and concentrated in the neck.The maximum equivalent stress of the Gyroid structure implant was 200.67 MPa,which did not exceed 50%of the yield strength of Ti6Al4V material.The maximum equivalent stress of the Gyroid structure implant on the surrounding bone tissue was 24.27 MPa,which was slightly higher than the maximum equivalent stress of the solid structure implant 17.32 MPa,and in the range of 20-60 MPa.The stimulation effect of the Gyroid structure implant on new bone formation was better than that of the solid structure implant.(2)The 3D printing technology could materialize the Gyroid structure implant model.Scanning electron microscopy showed that there were many unmelted spherical metal particles on the surface of the 3D printed Ti6Al4V specimens.After sandblasting and acid etching,a micron-scale mesh pore structure was formed on the surface,and no protruding metal particles were seen.The surface morphology of the superimposed UV functional treatment group was basically consistent with that after sandblasting and acid etching.The contact angle test results showed that the surface hydrophilicity of the specimens treated with ultraviolet functionalization plus sandblasting and acid etching was better than that of the sandblasting and acid etching and non-surface treatment groups.(3)The sandblasting and acid etching technology can remove the weakly connected metal particles on the 3D printed specimen and improve the similarity between the solid model and the design model.On this basis,the ultraviolet functionalization treatment can significantly improve the hydrophilicity of the 3D printed Gyroid structure implant surface without affecting its structure.