title: Lead deposition in bovine enamel during a pH-cycling regimen simulating the caries process.
abstract: Like fluoride, lead (Pb) accumulates on the enamel surface pre-eruptively, but it is not yet known whether it also deposits on enamel while dental caries is developing. This study evaluates Pb distribution in bovine enamel slabs submitted to a pH-cycling regimen simulating the caries process. The slabs were subjected to 8 cycles of de- and remineralizing conditions, and Pb (as acetate salt) was added to the de- and remineralized solutions at concentrations of 30 μg/l (experimental group, E1) and 300 μg/l (experimental group, E2). The control group (C) consisted of solutions to which Pb was not added. After the pH cycling, 100-μm sections of the slabs were analyzed by polarizing microscopy, to observe the extent of caries-like lesions, and these sections were used for Pb estimation by Synchrotron radiation X-ray microfluorescence. Caries lesions were observed along all superficial enamel surfaces to an extent of 120 μm. A Pb concentration gradient was observed in enamel, which decreased toward dentine. The highest Pb signals were observed for group E2, and the differences were statistically significant at enamel depths of 0 (C vs. E2; p = 0.029) and 50 μm (C vs. E2 and E1 vs. E2; p = 0.029). In conclusion, this study suggests that if Pb is present in the oral environment, it may deposit in enamel during the caries process.
authors.affiliation: Universidade de São Paulo, FORP/USP, São Paulo, Brasil.
authors.forename: G F
authors.initials: GF
authors.lastname: Molina
authors.forename: G R
authors.initials: GR
authors.lastname: Costa de Almeida
authors.forename: C
authors.initials: C
authors.lastname: de Souza Guerra
authors.forename: J A
authors.initials: JA
authors.lastname: Cury
authors.forename: A P
authors.initials: AP
authors.lastname: de Almeida
authors.forename: R C
authors.initials: RC
authors.lastname: Barroso
authors.forename: R F
authors.initials: RF
authors.lastname: Gerlach
mesh_terms: D000818:Animals; D002417:Cattle; D003731:Dental Caries / Q000378:metabolism* / Q000473:pathology; D003743:Dental Enamel / Q000378:metabolism* / Q000473:pathology; D003804:Dentin / Q000378:metabolism / Q000473:pathology; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000493:pharmacokinetics*; D008859:Microscopy, Polarization; D018715:Microscopy, Video; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D011897:Random Allocation; D013052:Spectrometry, X-Ray Emission; D013696:Temperature; D013997:Time Factors; D014089:Tooth Remineralization
chemical_list: D009942:Organometallic Compounds; D007854:Lead; C008261:lead acetate