A study on metal release of tin ion-plated stainless steel orthodontic appliances

Kim, Myung Sook; Sung, Jae Hyun; Kwon, Oh Won

Abstract

This study was conducted to examine the metal release of TiN-plated stainless steel orthodontic appliances by constructing the simulated orthodontic appliances equivalent to maxillary half arch, by dividing into TiN-plated and TiN-nonplated groups and by dividing again these groups into welded and nonwelded groups. And then, the total quantity of metal release was obtained by measuring the amounts of both soluble and precipitated nickel and chromium after immersing in artificial saliva for 15 days. And then, the corrosion appearance of surface structure was observed by using SEM. The results of this study were summarized as follows. 1. The total amounts of released nickel and chromium showed that the TiN-plated group after welding (Group I) was 25.46microgram, respectively, and 17.4microgram, while the TiN-nonplated group after welding(Group III) was 54.69microgram, respectively, and 85.27microgram. Then, the TiN-plated group indicated less amounts of metal release(p<0.05). 2. The total amounts of the TiN-plated group without welding (Group II) was 0.05microgram and 0.34microgram, respectively. Then, it was shown that the TiN-plated group without welding(Group II) indicated less metal release than that of the TiN-plated group after welding(Group I)(p<0.01, p<0.05). 3. When observing their surface structure, there were a lot of precipitate and pitting corrosion in the groups with welding(Group I & III), when the TiN-plated group(Group I) showed lower level than the TiN-nonplated group(Group III). On the other hand, the groups without welding(Group II & IV) indicated a little of pitting corrosion. 4. In case of observation with the naked eyes, it was shown that there were significant discoloration and corrosion in the groups with welding(Group I & III), while there was no any remarkable change in the groups without welding(Group II & IV).