title: Effect of dialyzed saliva on human enamel demineralization.
abstract: BACKGROUND
  Saliva is supersaturated with respect to calcium and phosphate ions. Salivary ions may well play a role in the subsequent adsorption of proteins and consequently in the formation of the acquired enamel pellicle. Among several biological functions, the enamel pellicle forms a selectively permeable barrier that regulates demineralization processes.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the importance of salivary proteins when adsorbed on enamel surface and the resultant protective effect against demineralization without the presence of salivary ions.
  
  
  METHODS
  Enamel surfaces were coated with whole saliva, parotid saliva, dialyzed whole saliva or dialyzed parotid saliva (molecular weight cutoff 1 kDa). Adsorption was allowed to proceed for a period of 2 h. Enamel specimens were then washed with deionized water and immersed into a demineralization solution of pH 4.5 for 12 days. This solution was used to measure the amount of calcium and phosphate released from enamel specimens after the demineralization period.
  
  
  RESULTS
  All coated specimen groups showed a significantly higher protection than those not coated with any type of saliva. In addition, undialyzed saliva (whole saliva and parotid saliva) was more effective in protecting the enamel against demineralization than dialyzed saliva.
  
  
  CONCLUSIONS
  The present investigation indicates that the ionic composition of saliva can amplify the demineralization protection effect by reducing acid-induced enamel demineralization. Moreover, a protective effect of salivary proteins without presence of ions was demonstrated in this study.
authors.affiliation: Department of Biochemistry, Western University, London, Ont., Canada.
authors.forename: C
authors.initials: C
authors.lastname: Martins
authors.forename: G F
authors.initials: GF
authors.lastname: Castro
authors.forename: M F
authors.initials: MF
authors.lastname: Siqueira
authors.forename: Y
authors.initials: Y
authors.lastname: Xiao
authors.forename: P M
authors.initials: PM
authors.lastname: Yamaguti
authors.forename: W L
authors.initials: WL
authors.lastname: Siqueira
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology; D000327:Adsorption; D002118:Calcium / Q000032:analysis; D003720:Densitometry / Q000379:methods; D003743:Dental Enamel / Q000737:chemistry / Q000378:metabolism*; D044622:Dental Pellicle / Q000737:chemistry / Q000502:physiology; D003956:Dialysis; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010306:Parotid Gland / Q000378:metabolism; D010710:Phosphates / Q000032:analysis; D020011:Protective Agents / Q000032:analysis / Q000494:pharmacology; D012463:Saliva / Q000737:chemistry* / Q000502:physiology; D012471:Salivary Proteins and Peptides / Q000032:analysis / Q000493:pharmacokinetics; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013997:Time Factors; D017001:Tooth Demineralization / Q000378:metabolism*
chemical_list: D010710:Phosphates; D020011:Protective Agents; D012471:Salivary Proteins and Peptides; D019342:Acetic Acid; D002118:Calcium