FLOURIDE RELEASE AND RECHARGE ABILITY OF GLASS-IONOMER AND FLUORIDE RELEASING RESIN-BASED TOOTH SEALANT
FLOURIDE RELEASE AND RECHARGE ABILITY OF GLASS-IONOMER
Keywords:fluoride release, fluoride recharge, glass ionomer, resin-based sealant
Fluoride has been added to tooth sealant to increase its efficacy. In this study we aimed to determine the ability of fluoride-releasing resin-based and glass ionomer cements to release fluoride over time and if this fluoride releasing ability can be recharged by exposure to fluoride gel in order to inform sealant decisions of dental providers. We conducted an in vitro study of 3 sealants: Concise white sealant™ (a non-fluoride-releasing resin-based sealant) used as the control, Clinpro™ (a fluoride-releasing resin-based sealant) and Fuji VII® (a glass ionomer, fluoride-releasing sealant). We prepared 45 discs, 15 discs made from each of the 3 studied sealants; each disc was 11 mm diameter and 1 mm thick. We placed each disc in a plastic container containing 10 ml deionized water and replaced this water daily throughout the study. We measured the fluoride concentration in the water in each container using a fluoride ion analyzer on Days 1, 2, 3, 4, 5, 6, 7, 14 and 21. On Day 21 each sample was submerged in 5 ml 1.23% acidulated phosphate fluoride (APF) gel for 4 minutes and then the sample was placed back in fresh deionized water and replaced daily. The fluoride concentration of the water was checked daily for 5 days after gel exposure. We used the one-way ANOVA and least significant difference tests to determine significant differences in fluoride concentration. Significance was set at p?0.05. The highest mean fluoride concentrations were on Day 1: 6.62±2.07 ppm for the glass ionomer cement and 0.41±0.06 ppm for the fluoride-releasing resin-based sealant. The lowest mean fluoride concentrations were on Day 21: 0.55±0.31 ppm for the glass ionomer cement and 0.02±0.00 ppm for fluoride- releasing resin-based sealant. Mean fluoride concentration for the control was 0.00±0.00 ppm throughout the 21-day initial study period. The glass ionomer cement released significantly (p<0.05) more fluoride during the initial 21-day study period than the control and the fluoride-releasing resin-based sealant. The fluoride-releasing resin-based sealant released significantly (p<0.05) more fluoride during the initial 21-day study period than the control. After exposure to 1.23% APF gel, the highest mean fluoride concentrations were on Day 22 (Day 1 after fluoride gel exposure): 15.42± 2.48 ppm for the glass ionomer cement, 0.16±0.02 ppm for the fluoride-releasing resin-based sealant and 0.10±0.03 ppm for the control. The lowest mean fluoride concentration was on Day 26 (Day 5 after fluoride gel exposure): 1.24±0.31 ppm for the glass ionomer cement 0.02±0.00 ppm, for the fluoride-releasing resin-based sealant and 0.01±0.00 ppm for the control. There was a significant (p<0.05) increase in fluoride release from all groups during the 5-day post fluoride gel exposure study period, with the glass ionomer cement releasing significantly (p<0.05) more fluoride than both the resin-based sealants, which released fluoride in levels not significantly different (p>0.05) from each other. In our study, the glass ionomer cement released more fluoride than the other tested sealants and was recharged with 1.23% APF gel and released more fluoride after recharge than the other sealants. Therefore, we conclude for patients requiring a sealant releasing fluoride, the glass-ionomer sealant is the better option. Further studies are needed to determine how often glass-ionomer sealant should be recharged with 1.23% APF gel and whether it can play a role in caries inhibition.