University of Twente, Department of Tissue Regeneration, Enschede, The Netherlands.
Acta Biomater. 2010 Jun;6(6):2219-26. doi: 10.1016/j.actbio.2009.11.028. Epub 2009 Nov 26.
Carbonated apatite ceramics, with a composition similar to that of bone mineral, are potentially interesting synthetic bone graft substitutes. In the present study, two porous carbonated apatite ceramics were developed, characterized and tested for their bone repair capacity and osteoinductive potential in a goat model. Although the two ceramics were prepared from a similar starting powder, their physico-chemical and structural characteristics differed as a consequence of different preparation methods. Both ceramics had an open and interconnected porous structure with a porosity of about 80%. The morphology of the surface of CA-A and CA-B at the submicron level differed significantly: CA-A consisted of irregular grains with a size of 5-20microm, with 1-10microm large micropores among the grains, whereas CA-B surface consisted of much smaller and regular shaped grains (0.05-0.5microm), with most micropores smaller than 1microm. The specific surface area of CA-B was about 10 times larger than that of CA-A due to its significantly smaller grain size. CA-A and CA-B ceramics contained 3 and 5 wt.% of B-type carbonated apatite, respectively. Although neither ceramic succeeded in completely bridging the 17mm iliac wing defect with new bone after 12weeks of implantation, CA-A showed significantly more bone formation in the pores of the implant than CA-B. The total area percentage of new bone in the total defect area was 12.7+/-1.81 and 5.51+/-1.37 (mean+/-SEM) for CA-A and CA-B, respectively. Intramuscular implantation of the ceramics led to ectopic bone formation by CA-A in all three implanted specimens, in contrast to CA-B, where no new bone was observed in any of the 11 animals. CA-A showed a more pronounced degradation than CA-B both in vitro and in vivo at both implantation sites, which was unexpected based on the physico-chemical and structural properties of the two ceramics. Both physico-chemical and structural properties of the ceramics could, dependently or independently, have affected their in vivo behaviour, emphasizing the importance to control individual parameters for successful bone repair.
碳酸化磷灰石陶瓷，其组成与骨矿物质相似，是一种有潜力的合成骨移植替代物。本研究制备了两种多孔碳酸化磷灰石陶瓷，对其进行了表征，并在山羊模型中对其骨修复能力和成骨诱导潜力进行了测试。尽管这两种陶瓷是由相似的起始粉末制备的，但由于不同的制备方法，它们的物理化学和结构特性有所不同。两种陶瓷均具有开放且相互连通的多孔结构，孔隙率约为 80%。CA-A 和 CA-B 的亚微米级表面形貌差异显著：CA-A 由大小为 5-20μm 的不规则晶粒组成，晶粒之间有 1-10μm 的大微孔，而 CA-B 表面由更小且规则形状的晶粒（0.05-0.5μm）组成，其中大部分微孔小于 1μm。由于晶粒尺寸显著较小，CA-B 的比表面积约为 CA-A 的 10 倍。CA-A 和 CA-B 陶瓷分别含有 3wt.%和 5wt.%的 B 型碳酸化磷灰石。尽管两种陶瓷在植入 12 周后都未能完全用新骨桥接 17mm 髂骨翼缺损，但 CA-A 在植入物的孔隙中形成的骨量明显多于 CA-B。CA-A 和 CA-B 的新骨在总缺损面积中的总面积百分比分别为 12.7+/-1.81 和 5.51+/-1.37（平均值+/-SEM）。陶瓷的肌肉内植入导致 CA-A 在所有 3 个植入标本中均形成异位骨形成，而 CA-B 在 11 只动物中均未观察到新骨。CA-A 的体外和体内降解速度均明显快于 CA-B，这与两种陶瓷的物理化学和结构特性不符。陶瓷的物理化学和结构特性可能独立或共同影响其体内行为，强调了为成功修复骨骼而控制单个参数的重要性。
