Fluoride ion release and recharge over time in three restoratives

Methods: Three groups (n=10 each group) were tested: Group 1-ACTIVA BioActive Restorative (Pulpdent); Group 2-Ketac™ Nano Lightcuring Glass Ionomer (RMGI) (3M ESPE); Group 3-GC Fuji Triage® (GI) (GC America).  Sample tabs were created according to manufacturers’ specifications for each group using a Teflon® mold (13mm diameter by 2mm depth). Tabs were placed as filters within a Swinnex® syringe filter holder.  0.5mL of a 5% NaF solution filled the upper chamber and 0.5mL of de-ionized water filled the lower chamber. Upper chamber was recharged and lower chamber was refreshed daily.  Fluoride ion release was measured after each recharge using a fluoride ion electrode after 1, 2, 24, 72 hours and 1, 2, 3 weeks.  

Results:  Values for the median and interquartile range were tabulated.  Kruskal-Wallis test using the Bonferroni correction (p-value approximately 0.007) found statistical significance at 3 time points: 24 hours, 1 week and 3 weeks with p-values 0.001, 0.002, and <0.001 respectively.  Further analysis using the Mann-Whitney U for significant comparison with the Bonferroni correction (p-value 0.017) determined that statistical difference at 24 hours between Groups 1 and 3 (p-value <0.001) and Groups 2 and 3 (p-value 0.015) but not between Groups 1 and 2.  At 1 week, there was statistical difference between Groups 1 and 3 (p-value 0.001) and at 3 weeks between Groups 1 and 3 (p-value 0.001) and Groups 2 and 3 (p-value <0.001).

Median fluoride release:

Conclusions: At the seven time points tested, the new therapeutic bioactive material has statistically greater fluoride release after recharge at 24 hours, 1 week and 3 weeks compared to the other groups tested. This study was supported in part by Pulpdent.