title: Invitro Evaluation of Fluoride Release from Hydroxyapatite Reinforced Glass Ionomer with or without Protective Coating.
abstract: BACKGROUND
  Glass Ionomer Cement (GIC) is well known for its fluoride releasing property but has its own drawbacks of poor mechanical properties, sensitivity to initial desiccation and moisture contamination. To overcome these, search led to the reinforcement of hydroxyapatite and application of surface coating agent but their effect on fluoride release is still not clear.
  
  
  OBJECTIVE
  To evaluate and compare the release of fluoride from Hydroxyapatite Reinforced Glass Ionomer (HA-GIC) with and without protective coating.
  
  
  METHODS
  Specimens were prepared as follows- Eight percent by weight conventional glass ionomer was replaced by hydroxyapatite powder (HA) and an indigenous product was prepared (HA-GIC). This powder was mixed with liquid of conventional GIC and allowed to set, then G coat plus coating agent was applied in surface coated group and light cured. Fluoride release of the sample was measured every 24 hrs for seven days and weekly from 7(th) to 21(st) day using combination ion selective electrode.
  
  
  RESULTS
  Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both the groups. Results of repeated measure ANOVA revealed statistically significant difference between two groups (p <0.001).
  
  
  CONCLUSIONS
  Coating the hydroxyapatite reinforced glass ionomer will allow for slow and steady release of fluoride for a long period of time into oral environment.
authors.affiliation: Assistant Professor, Department of Paediatric and Preventive Dentistry, Peoples College of Dental Sciences , Bhopal, India .
authors.forename: Shilpi
authors.initials: S
authors.lastname: Tiwari
authors.affiliation: Professor and Head, Department of Paediatric and Preventive Dentistry, JSS Dental College and Hospital , Mysore, India .
authors.forename: Bhojraj
authors.initials: B
authors.lastname: Nandlal
keywords: Conventional glass ionomer; Indigenous product; Restorative material