Chumbo no esmalte dentario como indicador biologico de exposição ambiental e sua relação com defeitos do esmalte e carie em dentes deciduos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Nowadays, environmentallead pollution has been considered a major public-health and dental enamel could be a biomarker of past exposure to lead, as lead incorporation in this tissue is permanent. An in vivo enamel biopsy technique has enabled the lead levei in the enamel surface to be determined without harming its integrity. Lead content in the enamel structure seems to be related to an increase in enamel defects and dental caries prevalence, respectively. Thus, the objectives of this study, based on 3 papers, were (1) to test whether enamel biopsies in vivo were an appropriate method for screening the population of young children from different areas (industrial and non- industrial) for environmental exposure to lead, (2) to relate the lead content, enamel defects and dental caries among these children and (3) to relate enamel defects and dental caries in the pre-school population. In the first paper, the sample was composed of 329 children from municipal pre-schools in art industrial area (n=132) and another non-industrial area (n=197) in Piracicaba city. A solution of 1.6 mol I -1 HCI in 70% glycerol (v/v) were used for the enamel biopsy procedure and the lead content of these biopsy samples was assessed by graphite furnace atomic absorption spectrometer. The second paper worked with the same children involved in the first paper and clinical examinations to record enamel defects (DOE Index) and dental caries (dmft index) were carried out using FOI and WHO diagnostic criteria, respectively. In the third paper, developmental defects (presence of hypoplasia and demarcated opacity) and dental caries (dmft index) were carried out using WHO diagnostic criteria among the population of pre-school children (n=2,846). In the first paper, lead concentration in enamel biopsies of children from industrial area (median:169 ppm Pb) was significantly higher than that of children living far from industries (median:118.1 ppm Pb) (P<0.0001). Data analysis showed that more reliable results for comparisons between groups was found among biopsies deeper than 3.9 µm. In the second paper, according to lead level, enamel defects and dental caries, a higher proportion of children with caries was found among those with higher lead levels in enamel from non-industrial area (P=0.02); however, the same was not observed among children from industrial area (P=0.89). There was high relative risk (RR) of dental caries among children from non- industrial area. Relationship between hypoplasia and dental caries (P<0.0001), was observed in the population of preschool children (third paper), however no relationship was observed between demarcated opacities and dental caries (P<0.4110). Among children with hypoplasia there was 27.0% more chance of having caries in relation to the children with normal enamel, and there was no increased risk of having caries among the children with demarcated opacities. Thus, enamel biopsy was feasible for population screening for lead content; and there was no evidence of a relation between enamel lead level and enamel defects in both groups, however, there was relationship between enamel lead level and dental caries in the non industrial area. The presence of hypoplasia in deciduous teeth could be a dental caries risk factor, suggesting that this indicator should be used in epidemiological surveys

ASSUNTO(S)

pre-escolares metais pesados meio ambiente epidemiologia odontologia

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