亲水性Gyroid结构种植体的制备及力学性能分析

Preparation and mechanical property analysis of hydrophilic Gyroid structure implant

背景:传统实心钛合金种植体的弹性模量高于人骨,由此引起的“应力屏蔽”现象可能会影响种植体的骨结合,同时3D打印钛合金表面的亲水性有待提高。目的:制备生物力学性能优良的亲水性Gyroid结构种植体。方法:建立Gyroid结构种植体、实心结构种植体、下颌骨骨块和牙冠的3D模型,对不同结构种植体的力学性能进行有限元分析。将Gyroid结构种植体模型导入3D打印机,使Gyroid结构种植体实体化,然后对种植体表面依次进行喷砂酸蚀和紫外光功能化处理,制备具有优良力学性能和表面活性的亲水性Gyroid结构种植体。通过扫描电镜和接触角测试分析3D打印Ti6Al4V试件表面改性处理前后的形貌与亲水性。结果与结论:①有限元分析结果显示,在垂直向平均咬合力作用下,Gyroid结构可以将作用于种植体上的载荷均匀分散到整个结构中,实心结构种植体上的载荷只能分散在其外表面并集中于颈部;Gyroid结构种植体受到的最大等效应力为200.67 MPa,不超过Ti6Al4V材料屈服强度的50%;Gyroid结构种植体对周围骨组织的最大等效应力为24.27 MPa,略高于实心结构种植体的最大等效应力17.32 MPa,并且在20-60 MPa区间内,Gyroid结构种植体对新骨形成的刺激效果优于实心结构种植体。②3D打印技术可以将Gyroid结构种植体模型实体化,扫描电镜下可见3D打印Ti6Al4V试件表面有许多未熔融的球形金属颗粒,经喷砂酸蚀后表面形成微米级网状孔洞结构,已不见凸出的金属颗粒,紫外光功能化处理+喷砂酸蚀处理的试件表面形貌与喷砂酸蚀组基本一致;接触角测试结果显示,紫外光功能化处理+喷砂酸蚀处理后的试件表面亲水性优于喷砂酸蚀处理组与无表面处理组。③喷砂酸蚀处理可以去除3D打印试件上弱连接的金属颗粒,提高实体模型与设计模型的相似性,在此基础上进行紫外光功能化处理可以显著提高3D打印Gyroid结构种植体的亲水性且不影响其结构。

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.