title: A three layer structure model of fluoridated enamel containing CaF2, Ca(OH)2 and FAp.
abstract: OBJECTIVE
  The aim of this study was to develop a molecular-based structural model of human teeth after fluoridation with a commonly used amine fluoride, which is highly significant for understanding the effectiveness of topical fluoridation.
  
  
  METHODS
  This multi method study used XPS, MAS-NMR and Raman-spectroscopy measurements in order to analyze powdered synthetic hydroxylapatite (HAp), powdered human enamel samples and human enamel pieces treated with amine fluoride (Elmex) fluid) in vitro.
  
  
  RESULTS
  The results lead to a complete structural characterization of the fluoridation products. A three layer composition of calcium hydroxide, calcium fluoride and an apatite species was identified.
  
  
  CONCLUSIONS
  The top surface CaF(2) layer acts as a fluoride reservoir and covers a layer of antimicrobial effective Ca(OH)(2). Ca(OH)(2) is a well-known therapeutic agent. However, up to now Ca(OH)(2) has not been described as a reaction product after topical fluoridation. Below the Ca(OH)(2) layer an acid resistant apatite species (FAp) was detected which reached directly into the bulk enamel HAp species. The three layer composition identified helps to understand the influence of fluoride application in the pathogenic mechanisms of tooth decay. Each component in this newly suggested structure model has a specific function, which explains how topical fluoridation of enamel reduces dental caries and influences its pathogenic mechanisms.
authors.affiliation: Institute of Physical Chemistry, University of Münster, Germany.
authors.forename: Hans U V
authors.initials: HU
authors.lastname: Gerth
authors.forename: Till
authors.initials: T
authors.lastname: Dammaschke
authors.forename: Edgar
authors.initials: E
authors.lastname: Schäfer
authors.forename: Harald
authors.initials: H
authors.lastname: Züchner
mesh_terms: D000588:Amines / Q000493:pharmacokinetics*; D001031:Apatites; D002124:Calcium Fluoride; D002126:Calcium Hydroxide; D002327:Cariostatic Agents / Q000493:pharmacokinetics*; D003743:Dental Enamel / Q000737:chemistry / Q000378:metabolism*; D003959:Diamines; D017886:Durapatite; D004577:Electron Probe Microanalysis; D005459:Fluorides / Q000493:pharmacokinetics*; D005460:Fluorides, Topical / Q000493:pharmacokinetics*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D013059:Spectrum Analysis, Raman; D017001:Tooth Demineralization / Q000378:metabolism
chemical_list: D000588:Amines; D001031:Apatites; D002327:Cariostatic Agents; D003959:Diamines; D005460:Fluorides, Topical; C495399:Olaflur; D017886:Durapatite; C025105:fluorapatite; D002124:Calcium Fluoride; D002126:Calcium Hydroxide; D005459:Fluorides