Department of Oral Science, Alma Mater Studiorum University of Bologna, Bologna, Italy.
J Biomater Appl. 2013 Aug;28(2):207-18. doi: 10.1177/0885328212443296. Epub 2012 Apr 5.
In this study, rapid CAD-CAM prototyping of pure hydroxyapatite to replace temporomandibular joint condyles was tested in sheep. Three adult animals were implanted with CAD-CAM-designed porous hydroxyapatite scaffolds as condyle substitutes. The desired scaffold shape was achieved by subtractive automated milling machining (block reduction). Custom-made surgical guides were created by direct metal laser sintering and were used to export the virtual planning of the bone cut lines into the surgical environment. Using the same technique, fixation plates were created and applied to the scaffold pre-operatively to firmly secure the condyles to the bone and to assure primary stability of the hydroxyapatite scaffolds during masticatory function. Four months post-surgery, the sheep were sacrificed. The hydroxyapatite scaffolds were explanted, and histological specimens were prepared. Different histological tissues penetrating the scaffold macropores, the sequence of bone remodeling, new apposition of bone and/or cartilage as a consequence of the different functional anatomic role, and osseointegration at the interface between the scaffold and bone were documented. This animal model was found to be appropriate for testing CAD-CAM customization and the biomechanical properties of porous, pure hydroxyapatite scaffolds used as joint prostheses.
本研究在绵羊中测试了快速 CAD-CAM 原型设计的纯羟基磷灰石来替代颞下颌关节髁突。将三个成年动物植入 CAD-CAM 设计的多孔羟基磷灰石支架作为髁突替代品。通过减法自动化铣削加工（块体减少）实现所需的支架形状。通过直接金属激光烧结创建定制手术导板，并将其用于将虚拟的骨切割线规划导出到手术环境中。使用相同的技术，创建固定板并在术前应用于支架，以将髁突牢固地固定到骨上，并确保在咀嚼功能期间羟基磷灰石支架的初始稳定性。术后 4 个月，处死绵羊。取出羟基磷灰石支架，并准备组织学标本。记录穿透支架大孔的不同组织、骨重塑的顺序、由于不同功能解剖作用而产生的新骨和/或软骨的附加、以及支架与骨之间界面的骨整合。发现该动物模型适用于测试 CAD-CAM 定制和用作关节假体的多孔纯羟基磷灰石支架的生物力学特性。
