Trantolo Debra J, Sonis Stephen T, Thompson Benjamin M J, Wise Donald L, Lewandrowski Kai-Uwe, Hile David D
Cambridge Scientific, Cambridge, Massachusetts 02138-1112, USA.
Int J Oral Maxillofac Implants. 2003 Mar-Apr;18(2):182-8.
Bioresorbable bone graft substitutes could eliminate disadvantages associated with the use of autografts, allografts, and other synthetic materials. The authors investigated the osteoinductive capacity of a bioresorbable bone graft substitute made from the unsaturated polyester poly(propylene glycol-co-fumaric acid) (PPF) for mandibular reconstruction in a rat model. The eventual intention is to use this material either as a stand-alone bone graft substitute or as an extender to autograft harvested from mandibular reconstruction sites.
The PPF bone graft was crosslinked in the presence of a hydroxyapatite filler and effervescent foaming agents to develop porosity in situ by generating carbon dioxide during the effervescent reaction of citric acid and sodium bicarbonate. The latter reagents are responsible for foam formation and expansion, resulting in a polymeric scaffold with pore sizes in the range of 100 to 500 microm. Twenty adult Sprague-Dawley rats had 3-mm-diameter cortical defects decorticated on the outer aspect of their left mandibular ramus using a Hall drill. Animals were divided into 2 groups of 10 animals each. Animals in group A were treated with implantation of the PPF-based bone graft substitute. Implants were applied buccally to defects on the left side. In group B animals with similar defects, the drill holes were left to heal unaided. The amount of new bone formation and the presence of an inflammatory infiltrate were evaluated at 7 weeks postoperatively.
Histologic analysis of the healing process revealed enhanced in vivo new bone formation with the PPF bone graft substitute. These findings were corroborated by the histomorphometric analysis of new bone formation.
Results of this study demonstrated biocompatibility of the porous PPF-based scaffold in a mandibular defect.
These findings may have applicability to the further development of bone graft substitutes for oral/maxillofacial applications.
生物可吸收骨移植替代物可消除与使用自体骨、异体骨和其他合成材料相关的缺点。作者在大鼠模型中研究了由不饱和聚酯聚（丙二醇-共-富马酸）（PPF）制成的生物可吸收骨移植替代物用于下颌骨重建的骨诱导能力。最终目的是将这种材料用作独立的骨移植替代物或用作从下颌骨重建部位采集的自体骨的扩展材料。
PPF骨移植材料在羟基磷灰石填充物和泡腾发泡剂存在的情况下交联，通过柠檬酸和碳酸氢钠的泡腾反应产生二氧化碳，从而原位形成孔隙。后两种试剂负责泡沫的形成和膨胀，形成孔径在100至500微米范围内的聚合物支架。20只成年Sprague-Dawley大鼠，使用霍尔钻在其左下颌支外侧制备直径3毫米的皮质骨缺损。动物分为两组，每组10只。A组动物接受基于PPF的骨移植替代物植入治疗。植入物经颊侧应用于左侧缺损处。B组有类似缺损的动物，钻孔不做处理任其自行愈合。术后7周评估新骨形成量和炎性浸润情况。
愈合过程的组织学分析显示，PPF骨移植替代物可增强体内新骨形成。新骨形成的组织形态计量学分析证实了这些发现。
本研究结果表明，多孔PPF基支架在下颌骨缺损中具有生物相容性。
这些发现可能适用于口腔/颌面应用的骨移植替代物的进一步开发。
