Orthodontic patients exposes to fluoride from several source i.e. toothpaste, mouthwash, and professionally topical fluoride treatment. It has been reported that fluoride-containing products interacts with bacterial products, forming the acid condition. This formed acid could lead to the corrosion of orthodontic brackets.
Study from Assist Prof Pintu-on Chantarawaratit and Dr. Tipanan Yanisatapan published in the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO) demonstrated that orthodontic bracket and archwire immersed in solution containing fluoride from toothpaste or acidurated phosphate fluoride exhibited the release of metal ions and the increase of surface roughness. In addition, the release products were toxic to primary gingival fibroblasts in vitro. Acidurated phosphate fluoride caused markedly more corrosion. Hence, acidurated phosphate fluoride application should not be recommended during fixed metal orthodontic treatment.
Importantly, the used brackets were more susceptible to corrosion when immersed in fluoride-containing solution compared with as-received brackets.
Reference
Exposure to the oral environment enhances the corrosion of metal orthodontic appliances caused by fluoride-containing products: Cytotoxicity, metal ion release, and surface roughness. Am J Orthod Dentofacial Orthop. 2021 May 6:S0889-5406(21)00212-2. doi: 10.1016/j.ajodo.2020.03.035.
https://www.sciencedirect.com/science/article/pii/S0889540621002122?via%3Dihub