Fluoride Release from Glass Ionomer Cements: Effect of Temperature, Time Interval and Storage Condition

Abstract

Objectives: Fluoride plays a pivotal role in oral health promotion and is the corner stone in the prevention of dental caries. The purpose of this study was to evaluate the effects of temperature, time interval and storage conditions on fluoride release by three commercial glass ionomer cements (GIC). Materials and methods: Three commercial glass ionomers: GC Gold Label Universal Restorative (conventional), GC Gold Label Light-Cured Universal Restorative and GC Fuji VII (GC Corporation, Tokyo, Japan) were used to investigate fluoride release. The 6 × 2 mm disk-shaped specimens prepared from each material were immersed in distilled water or artificial saliva at temperatures 4°C, 37°C or 55°C. The amount of fluoride release from these specimens was studied for the period of 1, 7, 14 and 28 days with the help of fluoride selective ion electrode. Results: The amount of fluoride release was significantly (p < 0.001) high in distilled water when compared to artificial saliva in all the three types of GIC studied. The highest level of fluoride release was observed on the first day of the study, followed by days 7 and 14, with least release on days 28. It was also observed that at 55°C, the amount of fluoride release was significantly (p < 0.001) high in all three GIC. However, there was no significant difference among the three GIC studied. Conclusion: The amount of fluoride release depends on temperature, time interval and storage condition. The result from the study concludes that GIC in the oral cavity serve as fluoride reservoir and contribute a low fluoride release in oral fluids. Clinical significance: The clinical use of GIC that release fluoride is relevant mainly in patients at risk of or with caries activity, thereby preventing initiation of secondary caries and failure of restorations. It may also be important in developing regimes for improving the delivery of tropical fluoride products. This study would be helpful to make some considerations about clinical indication and longevity of restorative materials studied.