Porous Titanium Associated with CaP Coating: In Vivo and In Vitro Osteogenic Performance

This in vitro and in vivo study compared different topographies of Ti samples (dense, porosity of 30% and 40%) with or not CaP coating, prepared by powder metallurgy. Osteogenic cells from newborn rat calvaria were plated onto the samples and cell adhesion (24 hours), alkaline phosphatase activity (7 and 10 days) and mineralization nodules (14 days) were assessed. Sixteen rabbits were used for in vivo study. Each animal received three non-treated and three treated implants in the right or left tibia, respectively. Histometric evaluation of bone-implant contact (BIC) were assessed at 1, 2, 4 and 8 weeks. Metallographic analysis revealed porosities of 30% and 40%, with pore size ranging from 250 to 350 µm. Cell adhesion test and ALP revealed similar cell behavior, independently of topography and CaP coating (P > 0.05%). However, CaP coating combined with porosity of 40% influenced positively the mineralized matrix formation (P < 0.05%). CaP-coated implants showed higher BIC than non-CaP implants and BIC was different between the short (1 and 2 weeks) and long (4 and 8 weeks) healing periods (P < 0.05%). The results suggest that CaP coating combined with 40% porosity implants allowed greater osteogenesis in vitro and increased BIC in vivo.

本体外与体内研究对比了通过粉末冶金法制备的不同表面形貌的钛（Titanium, Ti）试样，包括致密试样以及孔隙率30%、40%的试样，部分试样施加或未施加磷酸钙（Calcium Phosphate, CaP）涂层。将新生大鼠颅盖骨来源的成骨细胞接种于上述试样表面，分别检测细胞黏附情况（培养24小时）、碱性磷酸酶（Alkaline Phosphatase, ALP）活性（培养7、10天）以及矿化结节形成情况（培养14天）。本体内实验共使用16只家兔，每只家兔的右侧胫骨与左侧胫骨分别植入3枚未处理试样与3枚经涂层处理的植入体。分别于术后1、2、4、8周，对骨-种植体接触率（Bone-Implant Contact, BIC）进行组织计量学评估。金相分析显示，孔隙率30%与40%的试样孔径范围为250~350微米。细胞黏附实验与碱性磷酸酶活性检测结果显示，细胞行为与试样表面形貌及磷酸钙涂层均无统计学差异（P>0.05%）。然而，孔隙率40%的试样辅以磷酸钙涂层时，可显著促进矿化基质的形成（P<0.05%）。施加磷酸钙涂层的种植体其骨-种植体接触率高于未涂层种植体；且骨-种植体接触率在愈合早期（1、2周）与愈合后期（4、8周）间存在显著差异（P<0.05%）。本研究结果表明，孔隙率40%的钛试样辅以磷酸钙涂层，可在体外促进更强的成骨效应，并在体内提升骨-种植体接触率。