title: Barium and strontium leaching from aged glass particle/resin matrix dental composites.
abstract: OBJECTIVE
  This study characterizes the loss of Ba and Sr from glass particle/resin-matrix dental composites during simulated aging.
  
  
  METHODS
  X-ray wavelength dispersive spectrometry and secondary ion mass spectrometry were used to analyze the Ba and Sr content from the surfaces of three commercial dental composites after aging for 4 and 8 months in humid air, artificial saliva, water, and 50% ethanol.
  
  
  RESULTS
  Aging in artificial saliva caused the greatest leaching of Ba or Sr for all the specimens, compared with either lesser or no leaching for aging in ethanol and water. Differences in leaching were observed between the different composites. Composites aged in artificial saliva also picked up elements in the saliva solution and displayed crystallite formation on the surface. Samples aged in ethanol displayed cracking which was not observed for water or artificial saliva.
  
  
  CONCLUSIONS
  Dental composites display ion leaching from their surfaces over periods of four to eight months. Three mechanisms are proposed to explain differences in leaching for the various composites and aging solutions. Surface mineralization is also proposed to occur as a self-repair mechanism in artificial saliva.
authors.affiliation: Department of Chemistry (M/C 111), University of Illinois at Chicago, 4500 SES, 845 West Taylor Street, Chicago, IL 60607-7061, USA.
authors.forename: Manshui
authors.initials: M
authors.lastname: Zhou
authors.forename: James L
authors.initials: JL
authors.lastname: Drummond
authors.forename: Luke
authors.initials: L
authors.lastname: Hanley
mesh_terms: D000388:Air; D001464:Barium / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D004058:Diffusion; D000431:Ethanol / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D018629:Spectrometry, Mass, Secondary Ion; D013052:Spectrometry, X-Ray Emission; D013324:Strontium / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: C086628:Choice resin cement; D003188:Composite Resins; C481139:MICRONEW; D008689:Methacrylates; C485364:Renew composite; D019279:Resin Cements; D012464:Saliva, Artificial; D012997:Solvents; D014867:Water; D001464:Barium; D000431:Ethanol; D013324:Strontium