title: Longitudinal evaluation of fluoride levels in nails of 18-30-month-old children that were using toothpastes with 500 and 1100 μg F/g.
abstract: OBJECTIVE
  This study aimed to evaluate the fluoride concentration in the fingernails and toenails of children aged 18-30 months during use of fluoride-containing toothpastes supplemented with calcium glycerophosphate (CaGP) or sodium trimetaphosphate (TMP).
  
  
  METHODS
  According to the toothpaste used, children (n = 56) were randomly assigned into three groups: 500 μg F/g with 1% TMP, 500 μg F/g with 0.25% CaGP, and 1100 μg F/g. Fingernails and toenails were collected monthly over a period of 330 days, from the beginning of toothpaste use. Fluoride concentration in the water consumed by the volunteers and fluoride intake from diet and toothpaste were also determined. Fluoride analyses were performed with the electrode after hexamethyldisiloxane-facilitated diffusion or by the direct method, according to the samples. Data passed normality and homoscedasticity tests and were analyzed by 2-way analysis of variance (anova) and 1-way anova followed by Student-Newman-Keuls test (P < 0.05).
  
  
  RESULTS
  Fluoride levels in the fingernails and toenails as well as fluoride intake from toothpaste were similar for the groups treated with 500 μg F/g with 1% TMP and 500 μg F/g with 0.25% CaGP toothpastes, but significantly lower than the 1100 μg F/g group (P < 0.05). No significant differences were noted among the groups regarding fluoride intake from diet and that by water consumed by the volunteers (P > 0.05).
  
  
  CONCLUSIONS
  The results of the longitudinal study suggest that the level of fluoride present in nails was lower with the use of toothpastes with a low fluoride concentration.
authors.affiliation: Department of Pediatric Dentistry and Public Health, Araçatuba Dental School, UNESP - University of Estadual Paulista, Araçatuba, Brazil.
authors.forename: Jackeline G
authors.initials: JG
authors.lastname: Amaral
authors.forename: Isabelle R
authors.initials: IR
authors.lastname: Freire
authors.forename: Eduardo F R
authors.initials: EF
authors.lastname: Valle-Neto
authors.forename: Robson F
authors.initials: RF
authors.lastname: Cunha
authors.forename: Cleide C R
authors.initials: CC
authors.lastname: Martinhon
authors.forename: Alberto C B
authors.initials: AC
authors.lastname: Delbem
mesh_terms: D002327:Cariostatic Agents / Q000737:chemistry*; D002675:Child, Preschool; D005260:Female; D005459:Fluorides / Q000032:analysis*; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D009262:Nails / Q000737:chemistry*; D014100:Toothpastes / Q000737:chemistry*
chemical_list: D002327:Cariostatic Agents; D014100:Toothpastes; D005459:Fluorides
keywords: fluoride; nails; toothpaste