An in vitro comparison of nickel and chromium release from brackets

• Published in: Brazilian oral research 2009-12, Vol.23 (4), p.399-406
• Main Authors: Haddad, Ana Cristina Soares Santos, Tortamano, Andre, Souza, Alexandre Luís de, Oliveira, Pedro Vitoriano de
• Format: Article
• Language: English
• Subjects: artificial; Chromium; Chromium - chemistry; Chromium Alloys - chemistry; Corrosion; Dentistry; DENTISTRY, ORAL SURGERY & MEDICINE; Materials Testing; Mouth - chemistry; Nickel; Nickel - chemistry; Orthodontic Brackets; Saliva; Saliva, Artificial - chemistry; Spectrum Analysis; Stainless Steel - chemistry; Statistics, Nonparametric; Time Factors
• ISSN: 1806-8324; 1807-3107; 1807-3107; 1806-8324
• DOI: 10.1590/s1806-83242009000400009

This study aimed at comparing amounts of nickel (Ni) and chromium (Cr) released from brackets from different manufacturers in simulated oral environments. 280 brackets were equally divided into 7 groups according to manufacturer. 6 groups of brackets were stainless steel, and 1 group of brackets was made of a cobalt-chromium alloy with low Ni content (0.5%). International standard ISO 10271/2001 was applied to provide test methods. Each bracket was immersed in 0.5 ml of synthetic saliva (SS) or artificial plaque fluid (PF) over a period of 28 days at 37 degrees Celsius. Solutions were replaced every 7 days, and were analyzed by spectrometry. The Kruskal-Wallis test was applied. Amounts of Ni release in SS (microg L(-1) per week) varied between groups from 'bellow detection limits' to 694, and from 49 to 5,948.5 in PF. The group of brackets made of cobalt-chromium alloy, with the least nickel content, did not release the least amounts of Ni. Amounts of Cr detected in SS and in PF (microg L(-1) per week) were from 1 to 10.4 and from 50.5 to 8,225, respectively. It was therefore concluded that brackets from different manufacturers present different corrosion behavior. Further studies are necessary to determine clinical implications of the findings.