Abstract Zirconia is the most common ceramic used in dental implants. Even if it possesses both mechanical strength and esthetics, its intrinsic bio-inertness often results in a lack of biological integration. On the other hand, Si3N4 has been proved to be bio-active and to be able to easily osteointegrate. In this work, a Si3N4 powder-based laser-cladding process has been developed in order to improve the biological response to biomedical zirconia. The process resulted in the formation of a composite coating with Si3N4 particles dispersed in nano-crystalline/amorphous silicon. Microscopic observation showed that the layer is adherent to the substrate. The application of the laser cladding treatment resulted in an increase of the roughness, further enhancing the probability of interaction with biological tissues and consequently the bioactivity. Testing with human osteosarcoma cell lines resulted in the formation of bone tissue with high collagen maturity, high carbonate to phosphate ratios and good tissue mineralization, but lower cell proliferation when compared to stoichiometric Si3N4. The bone tissue quality parameters, as measured by Raman spectroscopy, resulted to be comparable to healthy human bone tissue and suggest that laser-cladded Si3N4 treatments might be able to improve the stability of zirconia implants.

中文翻译：

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氮化硅激光熔覆：一种提高氧化锆生物响应的可行技术

摘要 氧化锆是种植牙中最常用的陶瓷。即使它兼具机械强度和美感，其内在的生物惰性往往会导致缺乏生物整合。另一方面，Si3N4 已被证明具有生物活性并且能够轻松地进行骨整合。在这项工作中，开发了一种基于 Si3N4 粉末的激光熔覆工艺，以改善对生物医用氧化锆的生物反应。该过程导致形成了具有分散在纳米晶/非晶硅中的 Si3N4 颗粒的复合涂层。显微观察表明该层粘附在基材上。激光熔覆处理的应用导致粗糙度的增加，进一步提高了与生物组织相互作用的可能性，从而提高了生物活性。用人骨肉瘤细胞系进行的测试导致骨组织的形成具有高胶原成熟度、高碳酸盐与磷酸盐比率和良好的组织矿化，但与化学计量的 Si3N4 相比，细胞增殖较低。通过拉曼光谱测量的骨组织质量参数与健康的人体骨组织相当，表明激光包覆的 Si3N4 处理可能能够提高氧化锆植入物的稳定性。