Effects of magnetic fields from electric toothbrushes on fluoride- and oral bacteria-induced corrosion of orthodontic metallic wires

Abstract

Corrosion of metallic materials in the oral cavity could trigger metal allergy in patients. To clarify the risk elevation of magnetic fields (MFs) exposure on metallic corrosion when combined with fluoride-containing dental care products and indigenous oral bacteria, we investigated electric toothbrush-derived MF-induced corrosion of orthodontic stainless steel (SUS) and nickel titanium (Ni-Ti) wires in the presence of fluoride and oral bacteria, i.e. Streptococcus (S) mutans and S. sanguinis. MFs induced an electric current in the wires under both environments. Oral bacteria corroded SUS wires, and fluoride corroded SUS and Ni-Ti wires as previously reported; however, no additive or synergistic effects of MF exposure on fluoride-and microbiologically-induced metallic corrosion were observed. These results suggest that the MFs from electric toothbrushes do not increase the risk of corrosion of metallic appliances, given that the oral environment of patients is exposed to oral bacteria and fluoride-containing products.

Assessing the Potential Association Between Microbes and Corrosion of Intra-Oral Metallic Alloy-Based Dental Appliances Through a Systematic Review of the Literature

“…Of the 25 articles selected 5 were from the USA (Vaidyanathan et al, 1991;Chang et al, 2003;Oshida et al, 2003;Pozhitkov et al, 2015;Sridhar et al, 2016), 3 each were from Japan (Fukushima et al, 2014;Kameda et al, 2014Kameda et al, , 2019, Portugal (Souza et al, 2010;Proença et al, 2015;Figueiredo-Pina et al, 2019), France (Laurent et al, 2001;Mabilleau et al, 2006;Jorand et al, 2015), Poland (Mystkowska, 2016;Cwalina et al, 2017;Mystkowska et al, 2017), 2 each from Brazil (Heggendorn et al, 2015;Zavanelli et al, 2015) and China (Zhang et al, 2013;Lu et al, 2017), 1 each from Croatia (Pavlic et al, 2019), Spain (Díaz et al, 2018), Italy (Lucchetti et al, 2015), and India (Maruthamuthu et al, 2005).…”

“…Titanium (Ti) was assessed in 16 studies (Oshida et al, 2003;Maruthamuthu et al, 2005;Mabilleau et al, 2006;Souza et al, 2010;Fukushima et al, 2014;Kameda et al, 2014;Jorand et al, 2015;Pozhitkov et al, 2015;Mystkowska, 2016;Sridhar et al, 2016;Díaz et al, 2018;Figueiredo-Pina et al, 2019), stainless steel (SUS) in five studies (Chang et al, 2003;Oshida et al, 2003;Maruthamuthu et al, 2005;Kameda et al, 2014;Heggendorn et al, 2015;Mystkowska et al, 2017), nickel (NiCr) and cobalt-chromium (CoCr) alloys in seven studies (Laurent et al, 2001;Chang et al, 2003;Oshida et al, 2003;Lucchetti et al, 2015;Proença et al, 2015;Mystkowska, 2016;Lu et al, 2017), neodymium-iron, zirconia (Figueiredo-Pina et al, 2019, amalgam and copper aluminum alloy (Zavanelli et al, 2015) and precious metal alloys (Vaidyanathan et al, 1991) were each assessed on one study. The bacteria that were studied include probiotic bacteria Lactobacillus reuteri (Pavlic et al, 2019), Streptococcus (S.) mutans (Chang et al, 2003;Oshida et al, 2003;Souza et al, 2010;Fukushima et al, 2014;Kameda et al, 2014Kameda et al, , 2019Zavanelli et al, 2015;…”

“…The S. mutans adhere to both amalgam and copper/aluminum alloy and cause corrosion 2015; Proença et al, 2015;Sridhar et al, 2016;Cwalina et al, 2017;Lu et al, 2017), confocal laser scanning microscopy (CSLM) (Kameda et al, 2014(Kameda et al, , 2019Mystkowska, 2016;Cwalina et al, 2017;Mystkowska et al, 2017), microhardness with atomic force microscopy (AFM) (Mabilleau et al, 2006;Pavlic et al, 2019), atomic absorption spectrophotometry (Zavanelli et al, 2015), mass spectroscopy (Lucchetti et al, 2015;Pozhitkov et al, 2015), corrosion potential measurement (Chang et al, 2003;Oshida et al, 2003;Maruthamuthu et al, 2005;Proença et al, 2015;Figueiredo-Pina et al, 2019), impedance spectroscopy (Maruthamuthu et al, 2005;Zhang et al, 2013), and electrochemical analysis (Souza et al, 2010). Only one study by Vaidhyanadhan et al ( 26) used visual examination by macro photography to assess the corrosion.…”

“…Probiotics-like Lactobacillus Reuteri (Pavlic et al, 2019) increases the surface roughness of Ti mini-implants while less effect is seen on SUS. In a study by Kameda et al (2019), oral bacteria like S.mutans and S.sanguinis were shown to corrode stainless steel orthodontic wires. S.mutans has been shown to increase the corrosion of both SUS and Ti alloys (Chang et al, 2003;Oshida et al, 2003;Souza et al, 2010;Fukushima et al, 2014;Kameda et al, 2014Kameda et al, , 2019Proença et al, 2015;Zavanelli et al, 2015;Sridhar et al, 2016;Díaz et al, 2018).…”

Low temperature polytetrafluoroethylene (PTFE) coating improves the appearance of orthodontic wires without changing their mechanical properties

“…In such cases, β-titanium wires are more suitable because they are bendable and exhibit the mechanical property of high elasticity 6) . Titanium wires (both Ni-Ti and β-titanium wires) are corroded by fluoride [7][8][9][10] . Approximately half the content of Ni-Ti wire is nickel, which tends to cause allergic and toxic reactions, whereas β-titanium wires do not contain nickel.…”