Objectives

The aim of the present study was the qualitative and quantitative evaluation of osseous graft consolidation using allogeneic bone blocks for vertical bone augmentation in an animal model.

Material and methods

Standardised allogeneic and autologous bone blocks were fixed on the frontal skull of 20 adult female pigs and covered with a resorbable collagen membrane. Animals were sacrificed after 2 and 6 months. Specimens were histologically and histomorphometrically analysed focusing on the amount of vital bone, residual bone substitute material and connective tissue. Furthermore, the amount of expression of bone matrix proteins (collagen type I and osteocalcin) and de novo vessel formation (von Willebrand factor) were quantified by immunohistochemistry.

Results

Significantly more allogeneic bone blocks failed for both evaluation time points (p < 0.05). Allogeneic blocks showed significantly less vital bone with more connective tissue formation compared to autologous bone blocks. Increased vessel formation could be detected for both evaluation time points in the contact area of autologous bone with local bone. The expression of collagen type I and osteocalcin was significantly lower in the allogeneic bone graft.

Conclusions

Allogeneic cancellous bone blocks showed a significantly higher failure rate compared to autologous bone blocks. Allogeneic bone blocks seemed to negatively affect bone formation or negatively influence the host in the long term, and increased connective tissue formation and block loss should be anticipated.

Clinical relevance

In order to maintain patient safety and treatment success clinicians should be persuaded to make a conscious choice of the applied biomaterials with regard to their components and structure.

中文翻译：

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同种异体骨块中的骨向内生长用于垂直骨增强：一项临床前随机对照研究。

目标

本研究的目的是使用同种异体骨块对动物模型中的垂直骨进行定性和定量评估骨移植固结。

材料与方法

将标准化的同种异体骨和自体骨块固定在20只成年雌猪的额颅骨上，并覆盖有可吸收的胶原膜。2和6个月后处死动物。对标本进行组织学和组织形态学分析，重点是活骨，残余骨替代材料和结缔组织的数量。此外，通过免疫组织化学定量骨基质蛋白（I型胶原和骨钙素）的表达量和新生血管形成（von Willebrand因子）。

结果

在两个评估时间点上，明显有更多的同种异体骨块失败（p <0.05）。与自体骨块相比，同种异体块显示出明显更少的重要骨骼，具有更多的结缔组织形成。在自体骨与局部骨的接触区域中的两个评估时间点都可以检测到增加的血管形成。同种异体骨移植物中I型胶原和骨钙素的表达明显降低。

结论

与自体骨块相比，同种异体松质骨块显示出明显更高的失败率。从长远来看，同种异体骨阻滞似乎会对骨形成产生不利影响或对宿主产生负面影响，因此应预期结缔组织形成的增加和阻滞的丧失。

临床相关性

为了维持患者的安全和治疗的成功，应该说服临床医生对所用生物材料的成分和结构进行有意识的选择。