TiN 코팅된 지대주 나사의 마모에 관한 연구

Abstract

The purpose of this study was to evaluate surface changes and abrasion of the implant fixture and TiN coated abutment screw after repeated delivery and removal under SEM and universal measuring microscope. Implant systems used for this study were Osstem and 3i. Seven pairs of implant fixture, abutment and abutment screws for each system were selected and all fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. Titanium abutment screws of Osstem and 3i were assigned to Group 1 and Group 2 respectively. TiN coated Abutment screws of Osstem and 3i were classified to Group 3 and Group 4. After 20 times of repeated closing and opening test, the evaluation for the change of inner surface of implant and TiN-coated abutment screw, and measurement of weight loss were performed. Mann-Whitney test with SPSS statistical software for Window was applied to analysis the measurement of weight loss. The results were as follows ; 1. Mean weight loss of abutment screws for four groups was 0.181± 0.145mg in Group 1, 0.069±0.023mg in Group 2, 0.056± 0.026mg in Group 3 and 0.043±0.016mg in Group 4. 2. In the comparison of weight loss of Group 1 and Group 3, there was a statistically significant difference between Group 1 and Group 3 (P<0.05, Mann-Whitney test). 3. In the comparison of weight loss of Group 2 and Group 4, Group 2 revealed a statistically higher mean value than Group 4(P<0.05, Mann-Whitney test). 4. Abrasion and defect of mating thread surface of abutment screw were considerable in both Group 1 and Group 2, while only slight abrasion and defect were founded in Group 3 and Group 4. 5. In the SEM view of internal mating surface of implant, Group 1 and Group 2 showed a heap of titanium particles formed by galling and seizing tendency of titanium on the mating surface while Group 3 and Group 4 revealed slight abrasion or scratches on the mating surface. Conclusively, TiN coating of abutment screw showed better resistance to abrasion than titanium abutment screw. It was concluded that TiN coating of abutment screw would reduce the loss of preload with good abrasion resistance and low coefficient of friction, and help to maintain screw joint stability.