Oxidative genomic damage in pediatric patients exposed to mercury released by dental amalgam

Mercury (Hg) is the major component of dental amalgam which has been utilized for decades because it is durable, inexpensive and easy to manipulate and position, as well as having a relatively low cost. Hg from dental amalgam fillings has been shown to be released into the buccal cavity due to processes such as abrasion and corrosion, and which could represent a continuous source of oxidative damage to mouth tissues. Therefore, this study assessed the impact of Hg-containing dental amalgams exposure on the oxidative genomic damage using a means of the buccal micronucleus cytome assay by counting the nuclear abnormalities (NAs) in buccal mucosa cells and by analyzing in whole saliva the molecules 8-hydroxy-2′-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) in whole saliva. This study was conducted on 120 healthy children divided into two groups-group 1 (or the control group) (n = 60), including participants without dental caries, no history of dental amalgam (Hg-containing) restorations, and no other dental treatments, and group 2 (the intervention group) (n = 60), including participants with dental caries involving enamel or dentin, who received dental amalgam restorations in two posterior teeth. Oral epithelial cell and whole saliva samples were taken at baseline and 30 days later for group 1, while for group 2, samples were obtained at different pre-treatment (baseline) and post-amalgam placement time points at 15 and 30 days. An increased frequency of NAs (p < 0.05) and higher levels of 8-OHdG (p < 0.05) and MDA (p < 0.05) were observed after Hg-dental amalgams exposure. In addition, a positive correlation existed between NAs and oxidative stress induced by Hg from dental amalgam. The presents study shows that individuals exposed to Hg-containing dental amalgam exhibit increased NAs in oral epithelial cells, as well as increased levels of 8-OHdG and MDA in saliva, which are directly related to genotoxicity, oxidative DNA damage and lipid peroxidation, respectively. Exposure to Hg- containing dental amalgams may contribute to oxidative stress and genetic damage, potentially leading to long-term implications for both oral and systemic health.