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

Abstract

Objective: Periodic 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. Methods: F(-) 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: 225 ppm F(-) solution, 900 ppm 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 alpha = 0.05. Results: Periodic 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 900 ppm 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. Conclusion: Given 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 significance: Most 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. (C) 2011 Elsevier Ltd. All rights reserved.