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

尽管传统的磷酸钙骨水泥（c-CPC）被认为是可用于骨缺损重建的理想生物材料之一，但其长的固化时间（30 - 60 min）是其在外科手术中应用的严重缺点。我们提出了快速凝固CPC（FSCPC），它可以在大约5分钟内凝固，因此从初始阶段就显示出更高的机械强度。本研究旨在评价FSCPC的组织反应，使用c-CPC作为对照。将FSCPC和c-CPC植入实验动物的骨缺损和皮下。FSCPC和c-CPC在组织对硬组织的反应和骨传导性方面没有观察到差异。两种CPC均表现出优异的硬组织反应和良好的骨传导性。然而，它们对软组织的组织反应存在显著差异。当糊剂植入实验动物皮下时，发现c-CPC破碎并引起严重的炎症反应。相比之下，FSCPC在植入时保持形状，并显示出优异的组织反应。据推测，软组织的炎症反应是由于较低的机械强度和c-CPC的破碎特性引起的。尽管FSCPC显示出良好的组织反应，无论本研究中使用的植入条件如何，如果FSCPC破碎，可能会引起炎症反应。FSCPC在凝固反应前遇到大量体液时可能会崩溃。FSCPC在各种情况下的进一步评价有待根据本研究中获得的结果。

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.