The contribution of orthodontic braces to aluminum exposure in humans: an experimental in vitro study.

There is limited information on whether metals such as aluminum (Al) can migrate from orthodontic braces to saliva and subsequently contribute to its exposure in humans. This study aimed to assess this experimentally by incubating elastomeric orthodontic ligatures in artificial saliva for 30 days and other components of orthodontic braces (brackets, arch wires, and retainers) up to 180 days. As demonstrated, significantly higher levels of Al were leached from elastomeric ligatures (mean ± SD 28.2 ± 6.8 μg compared with their stainless steel counterparts (3.6 ± 0.1 μg) during 30 days. The higher the incubation time, the greater levels of Al leaching to artificial saliva were observed with the highest levels found for CNA β arch wire (252 ± 12 μg), Ni-Ti-Al arch wire (224 ± 11 μg), ceramic brackets (199 ± 10 μg), stainless steel arch wire (108 ± 5 μg), and metallic brackets (81.0 ± 4.2 μg) after 180 days of incubation. However, considering the tolerable weekly intake (TWI) established by the European Food Safety Authority, the intraoral use of orthodontic braces considered in this study would in the worst case constitute 0.04% and 0.09% of TWI in 70-kg adults and 30-kg children, respectively. In conclusion, the orthodontic braces considered in this study have no contribution to Al exposure in humans and can be considered safe in this regard.