Taddei Paola, Pavoni Eleonora, Affatato Saverio
Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna, Italy.
Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Via di Barbiano, 1/10, 40136 Bologna, Italy.
Materials (Basel). 2017 Jul 3;10(7):744. doi: 10.3390/ma10070744.
Biolox delta has been widely used in joint replacements thanks to its high strength and wear resistance. In this study, eleven Biolox delta femoral head retrievals affected by metal transfer (MT) were analysed by Raman spectroscopy to estimate the tetragonal to monoclinic zirconia phase transformation, whose occurrence may compromise ceramic chemical stability and mechanical strength. The residual stress state was evaluated by both Raman and photoemission spectroscopy. V monoclinic zirconia contents were higher near the centre of the articulating surface and in the MT area than in the border control area of the retrievals. In only one retrieval, stress related to MT appeared a more severe condition, able to induce zirconia phase transformation; for all the others, stresses related to loading in the central region and related to MT, were conducive to a zirconia phase transformation of nearly the same extent. V depth profiling analyses showed that the transformation involved different thicknesses in different samples. Raman data allowed for the investigation of the mechanism of zirconia phase transformation and confirmed that the growth stage was absent and the nucleation stage was not occurring as freely as it would in unconstrained zirconia.
由于其高强度和耐磨性，Biolox delta已广泛应用于关节置换。在本研究中，通过拉曼光谱分析了11个受金属转移（MT）影响的Biolox delta股骨头翻修件，以评估四方氧化锆向单斜氧化锆的相变，这种相变的发生可能会损害陶瓷的化学稳定性和机械强度。通过拉曼光谱和光发射光谱评估残余应力状态。与翻修件边缘对照区域相比，单斜氧化锆含量在关节表面中心附近和MT区域更高。仅在一个翻修件中，与MT相关的应力似乎更为严重，能够诱导氧化锆相变；对于所有其他翻修件，中心区域与MT相关的加载应力导致氧化锆相变的程度几乎相同。深度剖析分析表明，不同样品中的相变涉及不同的厚度。拉曼数据有助于研究氧化锆相变的机制，并证实不存在生长阶段，且成核阶段不像在无约束氧化锆中那样自由发生。
