Löberg Johanna, Gretzer Christina, Mattisson Ingela, Ahlberg Elisabet
Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96, Gothenburg, Sweden; Dentsply Implants, Box 14, SE-431 21, Mölndal, Sweden.
J Biomed Mater Res B Appl Biomater. 2014 May;102(4):826-39. doi: 10.1002/jbm.b.33065. Epub 2013 Nov 21.
For dental implants, improved osseointegration is obtained by modifying the surface roughness as well as oxide morphology and composition. A combination of different effects contributes to enhanced performance, but with surface roughness as the dominant factor. To single out the effect of oxide conductivity on biological response, oxide films with similar thickness and surface roughness but different electronic properties were formed using galvanostatic anodization. Three different current densities were used, 2.4, 4.8, and 11.9 mA cm(-2) , which resulted in growth rates ranging from 0.2 to 2.5 V s(-1) . The electronic properties were evaluated using cyclic voltammetry and impedance spectroscopy, while the biological response was studied by cell activity and apatite formation. The number of charge carrier in the oxide film close to the oxide/solution interface decreased from 5.8 × 10(-19) to 3.2 × 10(-19) cm(-2) with increasing growth rate, that is, the conductivity decreased correspondingly. Cell response of the different surfaces was tested in vitro using human osteoblast-like cells (MG-63). The results clearly show decreased osteoblast proliferation and adhesion but higher mineralization activity for the oxide with lower conductivity at the oxide/solution interface. The apatite-forming ability was examined by immersion in simulated body fluid. At short times the apatite coverage was ∼26% for the anodized surfaces, significantly larger than for the reference with only 3% coverage. After 1 week of immersion the apatite coverage ranged from 73 to 56% and a slight differentiation between the anodized surfaces was obtained with less apatite formation on the surface with lower conductivity, in line with the cell culture results.
对于牙种植体，可通过改变表面粗糙度以及氧化物形态和成分来实现更好的骨结合。多种不同的效应共同作用提高了性能，但表面粗糙度是主要因素。为了单独研究氧化物导电性对生物反应的影响，采用恒电流阳极氧化法制备了厚度和表面粗糙度相似但电子性能不同的氧化膜。使用了三种不同的电流密度，分别为2.4、4.8和11.9 mA cm(-2)，其生长速率范围为0.2至2.5 V s(-1)。通过循环伏安法和阻抗谱评估电子性能，同时通过细胞活性和磷灰石形成研究生物反应。随着生长速率增加，靠近氧化物/溶液界面的氧化膜中的电荷载流子数量从5.8×10(-19)降至3.2×10(-19) cm(-2)，即导电性相应降低。使用人成骨样细胞（MG-63）在体外测试不同表面的细胞反应。结果清楚地表明，对于氧化物/溶液界面处导电性较低的氧化物，成骨细胞增殖和黏附减少，但矿化活性较高。通过浸泡在模拟体液中来检查磷灰石形成能力。在短时间内，阳极氧化表面的磷灰石覆盖率约为26%，明显高于仅为3%覆盖率的对照表面。浸泡1周后，磷灰石覆盖率在73%至56%之间，阳极氧化表面之间出现轻微差异，导电性较低的表面上磷灰石形成较少，这与细胞培养结果一致。
