Studies on the tissue response to fast-setting calcium phosphate cement

虽然传统的磷酸钙骨水泥（c-CPC）被认为是一种理想的用于骨缺损重建的生物材料，但其固定时间较长（30 - 60min）是其在外科手术中的应用的一个严重缺点。我们提出了快速凝固的CPC (FSCPC)，它可以在大约5分钟内凝固，因此比初始阶段具有更高的机械强度。本研究旨在以c-CPC为对照，评估FSCPC的组织反应。实验动物将FSCPC和c-CPC分别植入骨缺损和皮下。FSCPC和c-CPC在组织对硬组织的反应和骨导电性方面没有差异。两种CPCs均表现出优异的硬组织反应和良好的骨导电性。然而，他们的组织对软组织的反应有显著差异。实验动物皮下植入后，c-CPC出现碎裂，引起严重的炎症反应。相比之下，FSCPC在植入时保持了形状，并表现出良好的组织反应。假设软组织的炎症反应是由于c-CPC较低的机械强度和由此产生的破碎特性引起的。尽管无论本研究中使用的植入条件如何，FSCPC都表现出良好的组织反应，但如果FSCPC碎裂，可能会引起炎症反应。当FSCPC在凝固反应之前面对大量的体液时，它可能会被粉碎。基于本研究获得的结果，FSCPC对各种病例的进一步评估有待于进一步研究。

Although conventional calcium phosphate cement (c-CPC) is thought as one of the ideal biomaterials that can be used for the reconstruction of bony defects, its long setting time, 30 - 60 min, was a serious shortcoming for its application in the surgical procedure. We have proposed fast-setting CPC (FSCPC) which can set within approximately 5 min and thus shows higher mechanical strength from the initial period. This study aimed to evaluate the tissue response of FSCPC using c-CPC as a control. FSCPC and c-CPC were implanted in the bony defect and subcutaneously in experimental animals. No difference was observed between FSCPC and c-CPC with respect to their tissue response to hard tissue and their osteoconductivity. Both CPCs showed excellent hard tissue response and good osteoconductivity. However, there was a significant difference in their tissue response to soft tissue. When, the pastes were implanted subcutaneously in experimental animals, c-CPC was found crumbled and caused severe inflammatory response. In contrast, FSCPC set keeping the shape at implantation and showed excellent tissue response. It was assumed that the inflammatory response to soft tissue was caused due to the lower mechanical strength and the resulting crumbing properties of the c-CPC.Although FSCPC showed excellent tissue response regardless of the implantation condition used in this study, there could be a case that FSCPC cause inflammatory response if it crumbled. FSCPC could be crumbled when it faces plenty of body fluid before its setting reaction. Further evaluation of FSCPC for various case is awaited based on the findings obtained in this study.