title: Influence of pH and oxygen-inhibited layer on fluoride release properties of fluoride sealant.
abstract: OBJECTIVE
  This study tested the hypothesis that the oxygen-inhibited layer on a light-cured methacrylate based resin and the pH of the storage medium would increase significantly the initial fluoride release and long-term release rate from fluoride dental sealant.
  
  
  METHODS
  Forty-eight discs (16-mm diameter x 1-mm thick) were made from FluroShield (<5 wt% NaF) and Helioseal F (<30 wt% fluorosilicate glass) sealants. For each sealant, 24 discs were cured through a Mylar strip that covered the surface and the remaining 24 discs were cured in air allowing formation of the oxygen-inhibited surface. Each specimen in the 24-disc groups was stored individually in 25-mL vials, and divided into four six-vial groups to receive 10 mL of pH4-pH7 (designation of pH 4-7) lactate buffer solutions. The buffer solutions were replaced periodically up to 121 days. The cumulative fluoride release over time was used to determine the coefficients for short-term and long-term release.
  
  
  RESULTS
  Two-way ANOVA showed that the mean coefficient values for either sealant were significantly influenced by the curing condition (p<0.0001) and pH (p<0.0001), except for short-term release from NaF sealant. The duration of short-term release was much longer for the fluorosilicate glass sealant.
  
  
  CONCLUSIONS
  Both pH and the source of fluoride source incorporated in the sealant play significant roles in fluoride release.
authors.affiliation: Department of Dental Biomaterials, College of Dentistry, University of Florida, Gainesville, FL 32610, USA. cshen@dental.ufl.edu
authors.forename: C
authors.initials: C
authors.lastname: Shen
authors.forename: T E
authors.initials: TE
authors.lastname: Shokry
authors.forename: K J
authors.initials: KJ
authors.lastname: Anusavice
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002327:Cariostatic Agents / Q000032:analysis*; D003188:Composite Resins / Q000737:chemistry; D005459:Fluorides / Q000032:analysis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000737:chemistry; D044367:Phase Transition; D010895:Pit and Fissure Sealants / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry; D012824:Silicic Acid / Q000737:chemistry; D012969:Sodium Fluoride / Q000737:chemistry; D013499:Surface Properties
chemical_list: D002327:Cariostatic Agents; D003188:Composite Resins; D010895:Pit and Fissure Sealants; D011140:Polyurethanes; C059908:Helioseal; C086661:Fluoroshield; D012824:Silicic Acid; C004832:hexafluorosilicate; D017438:Bisphenol A-Glycidyl Methacrylate; D012969:Sodium Fluoride; D005459:Fluorides; D010100:Oxygen