Evaluation of fluoride release and mechanical properties of different glass ionomers

OBJECTIVE: To assess the fluoride release and mechanical properties of four restorative glass ionomer cements (GIC) and to determine the correlation between the mechanical properties and fluoride release. \nMATERIALS AND METHODS: Four restorative glass ionomers were studied: ChemFil ROCK (DENSPLY), Fuji IX (GC), Riva self cure (SDI), and Ketac Nano (3M ESPE). Fluoride release in deionized water from the tested specimens was measured using a fluoride-selective ion electrode for 9 days. The compressive strengths and diametral tensile strengths after storing in distilled water (room temperature, 24) were tested. Glass ionomer surface wear by dental ceramic (Vita Mark II cylinders) was evaluated by a depth micro analyzer. Data were analyzed using ANOVA followed by Tukey’s test or Bonferroni method (p= 0.05). \nRESULTS: The fluoride release exhibited high concentration, following by a significant drop on the second day. Fuji IX had the highest fluoride release followed by “Ketac”,” Riva”, and “ChemFil”. Compressive strength results ranked that ChemFil as the highest value, followed by Fuji IX, Ketac, and Riva. The diametral tensile strength test ranked ChemFil and Ketac as the highest values. Surface ear against dental ceramic (Vita Mark II cylinders) revealed that Fuji IX had the lowest material loss, followed by Ketac, ChemFil, and Riva. Data showed significant differences between all of them. After coating the glass ionomer, the surface wear loss was reduced significantly in Riva and ChemFil. \nCONCLUSIONS: The tested restorative glass ionomers showed differences in fluoride release and the differences decreased over time, with Fuji IX releasing the highest amount of fluoride ion. ChemFil Rock showed the highest mechanical properties but the lowest fluoride release. Riva self cure had the highest material loss value in wear test. There was a weak inverse correlation between fluoride release and compressive strength (r = - 0.32); fluoride release and diametral tensile strength (r = - 0.60), and fluoride release and surface wear against dental ceramic (Vita Mark II cylinders) (r = - 0.55).