title: Effect of fluoride gels on micromorphology of resin-modified glass-ionomer cements and polyacid-modified resin composites.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the surface micromorphology of resin-modified glass-ionomer cements and polyacid-modified resin composites subjected to a neutral sodium fluoride (NNaF) and an acidulated phosphate fluoride (APF) gel application.
  
  
  METHODS
  Thirty standardized cylindric specimens were randomly obtained from each of two resin-modified glass-ionomer cements-Fuji II LC Improved and Photac-Fil Aplicap-and two polyacid-modified resin composites--Dyract and F2000-amounting to 120 samples. After 1 week, the specimens were finished and polished with aluminum oxide disks. Surface treatments with fluoride gels, or distilled water as a control, were performed four times, interspersed with eight pH cycles, simulating high cariogenic challenges. Five calibrated evaluators assessed the surface micromorphology through photomicrographs.
  
  
  RESULTS
  The Kruskal-Wallis test showed no significant difference between the control and experimental groups for Fuji II LC Improved and Dyract. Photac-Fil Aplicap showed less micromorphologic change as a result of distilled water application, unlike the NNaF and APF treatments, which revealed no significant difference from each other. For F2000, there was no significant difference between the surfaces treated by NNaF and distilled water; the highest degradation occurred with the APF.
  
  
  CONCLUSIONS
  Both the resin-modified glass-ionomer cements and the polyacid-modified resin composites showed erratic behaviors concerning their micromorphology when subjected to fluoride gel application.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry of Piracicaba, State University of Campinas, Sao Paulo, Brazil. mcserra@terra.com.br
authors.forename: C P
authors.initials: CP
authors.lastname: Turssi
authors.forename: C S
authors.initials: CS
authors.lastname: de Magalhães
authors.forename: M C
authors.initials: MC
authors.lastname: Serra
mesh_terms: D000149:Acidulated Phosphate Fluoride / Q000737:chemistry*; D020770:Compomers / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011897:Random Allocation; D012117:Resins, Synthetic / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D012969:Sodium Fluoride / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013499:Surface Properties
chemical_list: D020770:Compomers; C088486:Dyract; C118368:F2000 cement; C431351:Fuji II LC cement improved; D005782:Gels; D005899:Glass Ionomer Cements; D008689:Methacrylates; C081144:Photac-Fil; D012117:Resins, Synthetic; D017640:Silicates; D000149:Acidulated Phosphate Fluoride; D012969:Sodium Fluoride