Fluoride release rate from an orthodontic sealant and its clinical implications

The objectives were to measure the rate and amount of fluoride ions released from the sealant over a period of 17 weeks and to determine whether the fluoride-releasing sealant has a recharging ability when fluoride ions are reintroduced into the environment. Disc-shaped specimens were prepared from two types of sealants: (1) 10 discs were made using a fluoride-releasing sealant and (2) 10 discs were made of a nonfluoride adhesive primer (control). An ion analyzer was used to measure the fluoride release using a fluoride ion-specific combination electrode. The results of the repeated measure analysis (F = 7.76) indicated that the fluoride-containing sealant released fluoride ions into the solution in sustained but significantly (P = .014) decreasing rates from a high of 0.074 +/- 0.04 ppm/week/mm2 in the first week to a low of 0.015 +/- 0.017 ppm/week/mm2 at the end of the 17th week. Furthermore, the Pro Seal discs had the ability to be recharged with fluoride ions introduced from a foaming solution of acidulated phosphate fluoride. The mean fluoride release rate one week after recharging was 0.354 +/- 0.095 ppm/week/mm2 and decreased to 0.014 +/- 0.009 ppm/week/mm2 after eight weeks. The control sealant showed no significant fluoride release and was unable to absorb the fluoride ions available in the solution. The fluoride-containing sealant Pro Seal released fluoride ions in sustained but significantly decreasing amounts. The Pro Seal discs had the ability to be recharged with fluoride ions.