SZAREK Arkadiusz Czestochowa University of Technology

Hydroxyapatite is a material which is widely used in medicine. As an osteoconductive material, hydroxyapatite is a source of substances which stimulate bone growth, thus inducing bone reconstruction and providing direct connection of fibrocartilage callus with HAp layer. Implants coated with HAp layer quickly acquire stability in bone tissue. However, HAp is demineralised in the course of time and it loses its original strength parameters, which causes that hydroxyapatite is detached from prosthesis core. Hydroxyapatite is recognized by the bone as a material store for bone system, which results in creation of demineralised areas. In such cases, the risk of prosthesis loosening as a result of losing primary stability of implants in bone is dramatically increased. This paper attempts to determine the parameters of porosity and decohesion force in HAp coating on implant surface before implantation and after a particular time of presence in human body. Commercial implants will be used as research material, with HAp layer used for connecting them with the bone. Prostheses (from hip joint or shoulder joint) included in the study, characterized by specific lifetime, were removed due to asceptic loosening from human body. The investigations were carried out using Nikon Eclipse MA200 microscope and Scratch Tester (Revetest Express Instruments).