Comparative Study of Fluoride Ion Release from Direct Restorative Materials

Introduction: Glass-ionomer cements (GICs) have been used as restorative materials for over 30 years and have been extensively studied, especially the release of fluoride. Glass Carbomers are a recent addition to the glass-ionomer family and little is known about the release of fluoride from them. Objectives: The aim of this study was to investigate the fluoride ion release from commercial GICs, resin-modifed GICs (RMGICs) and a Glass Carbomer. Methods: Cement Discs (12 mm × 3 mm, n=4) of each material, Ketac Molar, Vitremer, Ketac N100 (3M ESPE Germany), Fuji IX, (GC Europe, Belgium) and Glass Carbomer (First Scientific Dental, Germany), were placed in 15 ml of either distilled water or simulated saliva and were stored in a humid environment at 37°C. Controls were also set up. Samples were taken at 1, 7, 28, 84 and 154 day(s) and fluoride release was determined using an ion selective electrode (Orion Research Inc. USA) with and without the addition of TISAB III. Results: All materials were found to release fluoride and the addition of TISAB III increased the amount of fluoride detected and therefore these data presented here includes the use of TISAB III. All materials followed a normal ion release profile, with a burst of fluoride release for the first 7 days reaching a plateau between 28 and 84 days. Higher fluoride ion release rates were noted into distilled water than simulated saliva, this is thought to be due to the differences in concentration gradients in the two solutions. Ketac N100 released the most fluoride into distilled water, but Vitremer released the most into simulated saliva. The other three materials followed the same trend into both solutions: Glass Carbomer > Fuji IX > Ketac Molar. Conclusion: Glass Carbomer released more fluoride than conventional GICs but less than RMGICs.