Effects of periodic fluoride treatment on fluoride ion release from fresh orthodontic adhesives

Abstract

ObjectivePeriodic fluoride treatment may contribute to the ability of fresh orthodontic adhesives to provide long-term F− release. The effects of periodic fluoride treatment on the amount of F− release from fresh orthodontic adhesives was investigated. MethodsF− release was measured from a nonfluoride-releasing composite, a fluoride-releasing composite, a polyacid-modified composite (compomer), and two resin-modified glass-ionomer cements (RMGICs) at 1, 2, and 5 days after one of the following treatments: 225ppm F− solution, 900ppm F− solution, acidulated phosphate fluoride gel (APF), fluoridated dentifrice, and deionised water (control). F− release was measured in a 5-day cycle, which was repeated 9 consecutive times. The amount of F− release for each group was analysed using the repeated measures analysis of variance. Statistical significance was set at a level of α=0.05. ResultsPeriodic fluoride treatment temporarily increased F− release in fresh fluoride-releasing orthodontic adhesives, but not in fresh nonfluoride-releasing composite. The order of effective fluoride-release was RMGICs>compomer>fluoride-releasing composite>nonfluoride-releasing composite. The application of APF or 900ppm F− solution was the most effective way to maintain F− release from fresh orthodontic adhesives. However, the amount of F− release gradually decreased with increasing specimen age. ConclusionGiven the difficulty of routine use of APF at home, the results of this study show that a combination of RMGICs and high-dose fluoride mouth rinse is the most effective protocol to maintain F− release from fresh orthodontic adhesives. Clinical significanceMost studies have investigated fluoride-uptake abilities using aged materials in which fluoride had been lost for at least 1 month. This study has found that periodic fluoride treatment altered the conventional F− release pattern of fresh fluoride-releasing materials and type of fluoride-containing medium plays a more critical role in fluoride recharging of the materials than fluoride concentration. This study will help clinicians to find the most effective fluoride treatment protocol of fresh materials.