TiN 및 WC 코팅된 치과용 어버트먼트 나사의 안정성

Abstract

Dental implant system is composed of abutment, abutment screw and implant fixture connected with screw. The problems of loosening/ tightening and stability of abutment screw depend on surface characteristics, like a surface roughness, coating materials and friction resistance and so on. For this reason, surface treatment of abutment screw has been remained research problem in pro- sthodontics. The purpose of this study was to investigate the stability of TiN and WC coated dental abutment screw, abutment screw(External, Deasrh, Dentis. Co) was used, respectively, for experiment. For improving the surface characteristics, TiN and WC film coating was carried out on the abutment screw using EB-PVD and sputtering, respectively. In order to observe the coating surface of abutment screw, surfaces of specimens were observed by field emission scanning electron microscope(FE-SEM) and energy dispersive x-ray spectroscopy(EDS) at the screw top, flank and valley of abutment screw. The stability of TiN and WC coated abutment screw was tested by using potentiodynamic, and cyclic potentiodynamic polarization method in 0.9% NaCl solution at 36.5 ± 1℃. The results were as follows: 1. Potentidynamic test results The corrosion potential of TiN coated specimen was higher than those of WC coated and non-coated abutment screw. Whereas, corrosion current density of TiN coated screw was lower than those of WC coated and non-coated abutment screw. The stability of screw decreased in the order of TiN coating, WC coating and non-coated screw. 2. Cyclic potentidynamic polarization test results The pitting potential of TiN and WC coated specimen were higher than that of non-coated abutment screw, but repassivation potential of WC coated specimen were lowerr than those of TiN coated and non-coated abutment screw due breakdown of coated film. The degree of local ion dissolution on the surface increased in the order of TiN coated, non-coated and WC coated screw. It is considered that the stability of abutment screw depended on coating materials, and confirmed that stability of screw can be increased the implant life by dense TiN film coating.