Cranial implants are used to repair bone defects following neurosurgery or trauma. At present, there is a lack of data on their mechanical response, particularly in impact loading. The aim of the present study was to assess the mechanical response of a recently developed composite calcium phosphate–titanium (CaP–Ti) implant at quasi-static and impact loading rates.

Two different designs were tested, referred to as Design 1 (D1) and Design 2 (D2). The titanium structures in the implant specimens were additively manufactured by a powder-bed fusion process and subsequently embedded in a self-setting CaP material. D1 was conceptually representative of the clinically used implants. In D2, the titanium structure was simplified in terms of geometry in order to facilitate the manufacturing. The mechanical response of the implants was evaluated in quasi-static compression, and in impact using a drop-tower.

Similar peak loads were obtained for the two designs, at the two loading rates: 808 ± 29 N and 852 ± 34 for D1, and 840 ± 40 N and 814 ± 13 for D2. A strain rate dependency was demonstrated for both designs, with a higher stiffness in the impact test. Furthermore, the titanium in the implant fractured in the quasi-static test (to failure) but not in the impact test (to 5.75 J) for D1. For D2, the displacement at peak load was significantly lower in the impact test than in the quasi-static test. The main difference between the designs was seen in the quasi-static test results where the deformation zones, i.e. notches in the titanium structure between the CaP tiles, in D1 likely resulted in a localization of the deformation, compared to in D2 (which did not have deformation zones). In the impact test, the only significant difference between the designs was a higher maximum displacement of D2 than of D1. In comparison with other reported mechanical tests on osteoconductive ceramic-based cranial implants, the CaP–Ti implant demonstrates the highest reported strength in quasi-static compression. In conclusion, the titanium structure seems to make the CaP–Ti implant capable of cerebral protection in impact situations like the one tested in this study.

颅骨植入物用于修复神经外科手术或创伤后的骨缺损。目前，关于它们的机械响应，特别是在冲击载荷方面，缺乏数据。本研究的目的是评估在准静态和冲击负荷率下最近开发的复合磷酸钙钛复合材料（CaP-Ti）植入物的机械响应。

测试了两个不同的设计，称为设计1（D1）和设计2（D2）。植入物样本中的钛结构通过粉末床融合工艺相加制造，然后嵌入自固化的CaP材料中。D1在概念上代表了临床上使用的植入物。在D2中，简化了钛结构的几何形状以便于制造。植入物的机械响应通过准静态压缩和使用落塔的冲击评估。

两种设计在两种加载速率下获得了相似的峰值负载：D1为808±29 N和852±34，D2为840±40 N和814±13。两种设计都证明了应变率依赖性，在冲击试验中具有较高的刚度。此外，对于D1，植入物中的钛在准静态测试（至失效）中断裂，但在冲击测试中（至5.75 J）未断裂。对于D2，冲击试验中的峰值负载位移明显低于准静态试验中的位移。设计之间的主要区别在于准静态测试结果，与D2相比，D1中的变形区域（即CaP瓷砖之间的钛结构中的凹口）可能导致变形局部化（没有D2）。有变形区）。在冲击测试中 设计之间的唯一显着差异是D2的最大位移高于D1。与其他已报道的对基于骨传导性陶瓷的颅骨植入物的机械测试相比，CaP-Ti植入物在准静态压缩方面显示出最高的强度。总之，钛结构似乎使CaP-Ti植入物能够在撞击情况下提供大脑保护，如本研究中所测试的那样。