title: Effect of iron on enamel demineralization and remineralization in vitro.
abstract: OBJECTIVE
  To evaluate the effect of ferrous sulphate on enamel demineralization and remineralization, using pH-cycling models.
  
  
  METHODS
  Fifty blocks were selected by their initial surface hardness and subjected to a pH-cycling demineralization process. Artificially demineralized lesions were produced in 60 blocks; out of these blocks, the surface hardness of 50 blocks and the cross-sectional hardness of 10 blocks were determined. The 50 blocks were then subjected to a remineralization pH-cycling process. Treatments were carried out using ferrous sulphate solutions of different concentrations (0.333, 0.840, 18.0, and 70.0 μg Fe/mL) and a control group (deionized water). The final surface hardness (SH(2)) was determined, and the integrated subsurface hardness (ΔKHN) was calculated. The enamel blocks were analysed for fluoride, calcium, phosphorus, and iron. The obtained data were distributed heterogeneously and were analysed using the Kruskal-Wallis test (p<0.05).
  
  
  RESULTS
  In demineralization pH cycling, the group treated with the 18.0 μg Fe/mL solution had higher secondary surface hardness and lower integrated subsurface hardness (ΔKHN) than the other groups. In remineralization pH cycling, the control group showed the lowest value of ΔKHN. A decline in Ca and P concentration was observed when the Fe concentration increased (p<0.05). There was no significant difference in the F concentration (p>0.05) and an increase in Fe concentration (p<0.05) in the enamel was observed when the Fe concentration increased in both the demineralization and remineralization experiments.
  
  
  CONCLUSIONS
  The results suggest that iron reduces demineralization but does not allow remineralization to occur.
authors.affiliation: Faculdade de Odontologia, UNESP - Univ. Estadual Paulista, Departamento de Odontologia Infantil e Social, R. José Bonifácio 1193, CEP 16015-050 Araçatuba, SP, Brazil.
authors.forename: Karina Mirela Ribeiro Pinto
authors.initials: KM
authors.lastname: Alves
authors.forename: Karina Simões
authors.initials: KS
authors.lastname: Franco
authors.forename: Kikue Takebayashi
authors.initials: KT
authors.lastname: Sassaki
authors.forename: Marília Afonso Rabelo
authors.initials: MA
authors.lastname: Buzalaf
authors.forename: Alberto Carlos Botazzo
authors.initials: AC
authors.lastname: Delbem
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D002327:Cariostatic Agents / Q000494:pharmacology*; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects*; D005296:Ferrous Compounds / Q000494:pharmacology*; D005459:Fluorides / Q000032:analysis; D006244:Hardness / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D017001:Tooth Demineralization / Q000517:prevention & control*; D014089:Tooth Remineralization
chemical_list: D002327:Cariostatic Agents; D005296:Ferrous Compounds; D010758:Phosphorus; C020748:ferrous sulfate; D007501:Iron; D005459:Fluorides; D002118:Calcium