Análise da presença de metais no esmalte em dentes decíduos de crianças residentes em regiões distintas da cidade de Ribeirão Preto - SP: relações neurotóxicas e abertura de dados junto às comunidades escolares

Abstract

Metals are ubiquitous on the Earth's crust. Many nonessential metals were not present in high lever in our environment prior to technologic use of them (starting 8,000 years ago) as an anthropic use. The bioaccumulation of metals causes problems because of their toxic effects, particularly when they are neurotoxic. To be able to determine metals, many exposure biomarkers can be use. Dental enamel has the following advantages over some other biomarkers: it is stable over time, the sample collection is easy, the method is noninvasive, and the cost is low. This study aimed at evaluating the concentrations of several metals on the enamel surface of primary teeth collected at different areas of Ribeirao Preto, SP, Brazil. Tooth donation and collection was done based on a large campaign called "Doe Seu Dentinho" (Donate your little tooth) that took place between April 2018 and March 2019. Microbiopsies (a superficial etch with HCl in 70% glycerol) were done on the tooth surface on teeth randomly selected from the 4 districts of the city, with 10 boy-and girl teeth selected from each district (n=4 x 20 primary teeth). Only incisors were used in the process of random selection. Samples were then analyzed by ICP-MS for the presence of Manganese, Zinc, Arsenic, Cadmium, Lead and Mercury. Results were expressed as the amount of metals per gram of dental enamel, since calcium had also been determined. Our results are the first for the presence of some of these metals on the superficial enamel determined by ICP-MS. Results suggest that certain children have high levels of metal that we had not expected to be high, such as Arsenic, Cadmium and Mercury. In comparison to earlier studies of our group in our city 10 years ago and using the same methods, lead levels on superficial enamel were lower. There was a high and statistically significant correlation for the concentration of these metals on the superficial enamel. For all methods, boys always showed higher concentrations than girls (p<0,0001). In conclusion, our results suggest that other toxic metals besides lead and cadmium can be determined on superficial enamel by golden standard analytical techniques, and that the concentrations seem to be high for some of them. Thus, more studies are needed to determine what are the concentrations associated with toxicity and what are the possible sources of exposure in our urban environments.