增材制造Ti⁃6Al⁃4V钛合金种植体骨结合的动物实验研究

Animal experimental study on the osteointegration of additive manufacturing Ti⁃6Al⁃4V titanium alloy implants

目的探讨增材制造Ti⁃6Al⁃4V(TC4)钛合金种植体动物体内的骨结合和成骨效果,为进一步临床应用提供实验依据。方法选择健康雄性新西兰兔42只,以兔双侧后腿股骨髁部为种植体植入区,将实验兔先分为2周(A组)、8周(B组)2个大组,每组21只;每大组中再分为3个亚组,分别为A1组、A2组、A3组和B1组、B2组、B3组,每小组7只。A1组和B1组实验兔双侧后腿股骨髁部分别植入原始表面和表面改性TC4钛合金种植体各1枚;A2组和B2组实验兔植入原始表面TC4钛合金种植体和钛骨种植体各1枚;A3组和B3组实验兔植入表面改性TC4钛合金种植体和钛骨种植体各1枚;使2周、8周均含有3种种植体各14枚。术后2、8周观察并比较分析3种种植体的植入成功率和骨结合情况,观察指标为:骨体积分数(BV/TV)、骨小梁面积密度(BS/BV)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)和骨小梁间隔(Tb.Sp)。对各组不同时段种植体骨界面骨密度指标,使用SPSS 21.0软件包对数据进行双因素方差分析,验证不同表面、不同时间对种植体骨结合水平的影响,并采用Tukey′s多重比较检验分析组间统计学差异。结果3种种植体不脱钙组织切片、骨块微CT扫描及光学显微镜观察显示,随着植入后的时间进展,3种种植体表面骨组织的量逐渐增多,分布逐渐变密。2周时,表面改性TC4钛合金种植体组的BV/TV、Tb.N显著高于原始表面和钛骨组,差异有统计学意义(P<0.05);Tb.Th显著高于钛骨组(P<0.05);BS/BV、Tb.Sp显著低于钛骨组,差异有统计学意义(P<0.05)。8周时,3种种植体的BV/TV、BS/BV、Tb.Th、Tb.N和Tb.Sp差异均无统计学意义(P>0.05)。结论表面改性TC4钛合金种植体2周时即能形成更多的骨组织,骨小梁的分布更密集,骨结合能力更强,有望成为口腔种植体的优选材料。

Objective To explore the osteointegration and osteogenic efficacy of additive manufacturing Ti⁃6Al⁃4V(TC4)titanium alloy implants,so as to provide experimental evidence for further clinical application.Methods A total of 42 healthy male New Zealand rabbits were selected.Implants were divided into three groups,i.e.,the original surface,surface⁃modified TC4 titanium alloy implants and titanium bone implants.The femoral condylar of rabbit bilateral hind leg was used as the implantation area.The experimental rabbits were divided into two large groups,2 weeks(Group A)and 8 weeks(Group B),with 21 rabbits in each group.Each large group was divided into three subgroups,namely,group A1,A2,A3,B1,B2 and B3,with 7 rabbits in each group.One TC4 titanium alloy implant with original surface and one TC4 titanium alloy implant with surface modification were implanted in group A1 and B1,respectively.In group A2 and B2,rabbits were implanted with TC4 titanium alloy implant and titanium bone implant with the original surface.In group A3 and B3,rabbits were implanted with surface modified TC4 titanium alloy implant and titanium bone implant,respectively.There were 14 implants for each of the three kinds of implants at 2 and 8 weeks.At 2 and 8 weeks after operation,the implant success rate and osseointegration of the three groups were observed and compared for the following indexes:bone volume fraction(BV/TV),bone trabecular area density(BS/BV),bone trabecular thickness(Tb.Th),bone trabecular number(Tb.N),and bone trabecular septum(Tb.SP).Using SPSS 21.0 software package,the data of bone mineral density at implant bone interface of three groups at different times were analyzed by two factor ANOVA to verify the influence of different surfaces and times on osteointegration.Tukey′s Multiple Comparisons Test was used to analyze the statistical differences between the groups.Results With the progress of osteointegration,both the amount and density of bone tissue on the surface of implants in the three groups gradually increased.At 2 weeks,the BV/TV and Tb.N of the surface modified TC4 titanium alloy implant group were significantly higher than those of the original surface and the titanium bone group(P<0.05),while its Tb.Th was significantly higher than that of the titanium bone group(P<0.05),whereas its BS/BV and Tb.Sp were significantly lower than that of the titanium bone group(P<0.05).At 8 weeks,the differences in BV/TV,BS/BV,Tb.Th,Tb.N and Tb.Sp among the three groups of implants were not statistically significant(P>0.05).Conclusions More bone tissues can be formed on the surface modified TC4 titanium alloy implants than the other kinds of implants at 2 weeks.The surface⁃modified TC4 titanium alloy implant could be a promising dental implant due to its strong capacity in osteointegration represented by much dense bone trabecular on the surface.