In vivo determination of genotoxicity induced by metals from orthodontic appliances using micronucleus and comet assays

Abstract

ABSTRACT. Orthodontic appliances are usually made of stainless steel, which contains metals such as nickel, chromium and iron that have been associated with DNA damage. The aim of the present study was to determine the genetic toxicity associated with orthodontic fixed appliances in twenty healthy patients (16 ± 2.5 years) undergoing orthodontic treatment (fixed appliances -basic composition: stainless steel alloy), using the micronucleus (MN) and comet (CA) assays in buccal cells. Primary DNA damage level, as assessed by the CA, was low either before the beginning (1.5 ± 1.05 damage index -DI) or 10 days after the placement of the orthodontic appliance (2.5 ± 3.08 DI) and did not change significantly between these time points (P = 0.0913). Conversely, there was a significant increase in MN frequency 30 days after the beginning of the treatment (P = 0.0236). In this study, the MN assay was shown to be more sensitive than the CA. Other investigations are necessary in order to assess the genotoxic potential of orthodontic fixed appliances associated with long-term studies concerning these effects in orthodontic patients.

DNA microarray analysis of genomic responses of yeast Saccharomyces cerevisiae to nickel chloride

“…Therefore, we speculated that cellular iron is increased by the transcriptional response to nickel stress as well as cobalt stress. Furthermore, nickel is known to be a potential carcinogenic and mutagenic agent (Chen et al, 2003;Hu et al, 2004;Westphalen et al, 2008). Consistent with those data, the increased expression of DNA repair-related genes was also observed in our experiment (Table 3).…”

In vitro oxidative stress induced by conventional and self-ligating brackets

“…Compared with the negative control, a higher oxidative stress level was recorded with the full metal brackets Speed and MiniSprint and with polyurethane Quantum brackets. In accordance with other studies, we were expecting to record the highest level of DNA damage with metal brackets, 5,7,22,23 but the highest oxidative stress was induced by polyurethane brackets. Polyurethanes are segmented polymers formed by the reaction of polyether polyol segments with isocyanates and could be, while they are hydrolytically stable, subject to oxidative degradation.…”

“…[1][2][3][4][5][6][15][16][17][18][19][20][21] Few studies have explored the genotoxicity of orthodontic appliances, usually involving stainless steel brackets. [22][23][24] It is known that iron, copper, chromium, and vanadium undergo a redox cycle and thus directly generate free radicals, while cadmium, mercury, nickel, and lead create them indirectly. 7 It seems that polymers, ceramics, and synthetic sapphire, used for esthetic components of brackets, are not inert materials.…”

Genotoxicity in oral epithelial cells in children caused by nickel in metal crowns

“…In odontology, nickel (Ni) is used for fashion brackets, fillings, space maintainers, and crowns (Bass et al, 1993;Westphalen et al, 2008). The oral cavity is particularly suited for the biodegradation of metals due to its ionic, thermal, microbiological, and enzymatic properties (Vijaya Bhaskar and Subba-Reddy, 1997;Faccioni et al, 2003;Shin and Hwang, 2003;Liu et al, 2007;Amini et al, 2008).…”