title: Maturation affects fluoride uptake by glass-ionomer dental cements.
abstract: OBJECTIVE
  Four commercial glass-ionomer cements have been studied for their ability to take up fluoride from aqueous solution following variable maturation times in the dry at 37°C.
  
  
  METHODS
  Sets of five specimens of four different materials were cured for times of 10 min, 24 h and 1 month, then transferred to a neutral solution of NaF at approximately 1000 ppm in fluoride. Fluoride concentration was then measured at regular time intervals up to 1 month using a fluoride ion selective electrode.
  
  
  RESULTS
  Specimens cured for 1 month showed little or no uptake over 24 h, specimens cured for 24 h showed fluctuating uptake over time, and specimens cured for 10 min showed the greatest fluoride uptake. For the latter specimens, simple kinetic models were found to apply in two cases (pseudo-first order and pseudo-second order for Chemflex and Ketac Molar Quick respectively).
  
  
  CONCLUSIONS
  The ability to take up fluoride has been shown to decline with age of cement which suggests that in clinical use glass-ionomers may become less effective at undergoing fluoride recharge than has been previously assumed.
authors.affiliation: Department of Pharmaceutical, Chemical and Environmental Sciences, School of Science, University of Greenwich, Medway Campus, Chatham, Kent ME4 4TB, UK. J.W.Nicholson@gre.ac.uk
authors.forename: John W
authors.initials: JW
authors.lastname: Nicholson
authors.forename: Beata
authors.initials: B
authors.lastname: Czarnecka
mesh_terms: D002327:Cariostatic Agents / Q000737:chemistry*; D055598:Chemical Phenomena; D005459:Fluorides / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D017736:Ion-Selective Electrodes; D007700:Kinetics; D008422:Materials Testing; D012969:Sodium Fluoride / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D002327:Cariostatic Agents; C410563:ChemFlex; C439808:Fuji IX GP Fast; D005899:Glass Ionomer Cements; C454800:Ketac-Molar Quick; C110713:fuji IX; D012969:Sodium Fluoride; D005459:Fluorides