title: Effects of artificial saliva and APF gel on the surface roughness of newer glass ionomer cements.
abstract: OBJECTIVE
  To investigate the surface roughness changes of newer esthetic dental restorative materials with aging and acid erosion in a simulated oral environment.
  
  
  METHODS
  The materials included two viscous conventional glass ionomer cements originally marketed for the ART approach, one resin-modified glass ionomer cement and two resin composites. Ten specimens for each material were prepared according to the manufacturers' instructions, then each specimen was immersed in 2 ml of buffered artificial saliva at 37 degrees C for three weeks. For each material, five specimens (Group B) were then coated with 1.23% acidulated phosphate fluoride (APF) gel for four minutes, rinsed and immersed again in artificial saliva for another three weeks. Gel was not applied to the Group A specimens. For each material, the surface roughness of an additional three fresh specimens and those from Groups A and B were evaluated using a profilometer and SEM.
  
  
  RESULTS
  The resin composites showed the least effects of acidic corrosion on their surface texture. The viscous glass ionomer cements showed the greatest changes, with significantly increased surface roughness p<0.001).
  
  
  CONCLUSIONS
  The immersion of two newer viscous GICs in a buffered artificial saliva and the single application of APF gel resulted in significantly rougher surfaces over a relatively short six-week period.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, PR China. hkyip@hkusua.hku.hk
authors.forename: H-Kevin
authors.initials: HK
authors.lastname: Yip
authors.forename: William M
authors.initials: WM
authors.lastname: To
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Smales
mesh_terms: D000149:Acidulated Phosphate Fluoride / Q000737:chemistry*; D002327:Cariostatic Agents / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D003343:Corrosion; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014783:Viscosity
chemical_list: D002327:Cariostatic Agents; D003188:Composite Resins; C444701:Filtek Z250; C439808:Fuji IX GP Fast; D005899:Glass Ionomer Cements; D019279:Resin Cements; D012464:Saliva, Artificial; C407402:Unifil Bond; C084550:Vitremer; C110712:ketac-molar; D000149:Acidulated Phosphate Fluoride