title: Chitosan effect on dental enamel de-remineralization: an in vitro evaluation.
abstract: OBJECTIVE
  The aim of this work was to evaluate the in vitro effect of chitosan (concentration and time of action) treatment on enamel de-remineralization behavior upon a pH cycling assay.
  
  
  METHODS
  Different group of human tooth samples were exposed to de-remineralizing solutions of controlled pH using a random experimental design. Microhardness and phosphorus chemical analysis were employed to evaluate the loss of phosphorus from the samples. Optical coherence tomography (OCT) images were obtained for selected specimens in order to evaluate the degree of penetration of chitosan into enamel.
  
  
  RESULTS
  Vickers microhardness results were higher for samples treated with chitosan for concentration between 2.5mg/mL and 5.0mg/mL and time of action between 60s and 90 s. A maximum inhibition of mineral loss of 81% was obtained. Chemical analysis indicated lower net pohosphorus loss (net P loss) for samples treated with chitosan. Best results were obtained in the same conditions found out with microhardness measurements. Chitosan had little effect on the remineralization process. OCT results indicated a correlation of chitosan penetration with chitosan concentration. For chitosan concentrations of 2.5 g/mL and 5.0 g/mL the penetration was up to the dentin-enamel junction.
  
  
  CONCLUSIONS
  Chitosan interferes with the process of demineralization of the tooth enamel inhibiting the release of phosphorus in this laboratory study. Demineralization is influenced by the concentration and exposure time of the biopolymer to the enamel. Microhardness measurements may be used as an indication of mineral loss from tooth enamel. Additionally, OCT images support the idea that chitosan may act as a barrier against acid penetration, contributing to its demineralization inhibition.
authors.affiliation: Graduate Program on Materials Science, UFPE, Cidade Universitária, 50670-901 Recife, PE, Brazil.
authors.forename: Thatiana M Stamford
authors.initials: TM
authors.lastname: Arnaud
authors.forename: Benício
authors.initials: B
authors.lastname: de Barros Neto
authors.forename: Flamarion B
authors.initials: FB
authors.lastname: Diniz
mesh_terms: D001672:Biocompatible Materials / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D002327:Cariostatic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D048271:Chitosan / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D003743:Dental Enamel / Q000187:drug effects* / Q000378:metabolism; D003804:Dentin / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006244:Hardness; D006801:Humans; D006851:Hydrochloric Acid / Q000009:adverse effects; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D010758:Phosphorus / Q000032:analysis; D011189:Potassium Chloride / Q000627:therapeutic use; D013053:Spectrophotometry; D013997:Time Factors; D041623:Tomography, Optical Coherence; D017001:Tooth Demineralization / Q000517:prevention & control*; D014089:Tooth Remineralization
chemical_list: D001672:Biocompatible Materials; D002327:Cariostatic Agents; D010758:Phosphorus; D011189:Potassium Chloride; D048271:Chitosan; D006851:Hydrochloric Acid