Comparison of enamel fluoride uptake between three different glass ionomers used in orthodontic banding: an in vitro study

Decalcification of the teeth remains a problem during orthodontic treatment with fixed appliances. It has been suggested that fluoride-releasing glass ionomer cements could decrease the risk of enamel decalcification under orthodontic bands. The objective of this study was to compare enamel fluoride uptake from three different glass ionomer cements (AquaCem, Resilience and Bandite) used for band cementation in permanent teeth in vitro. Methods & Materials: In an experimental in vitro randomized trial, 33 sound premolars that were extracted for orthodontic purposes were randomly divided into three groups. In each group one of the glass ionomer cements was tested. A 6 mm diameter adhesive tape was placed over the center of buccal enamel surface of each tooth and then the entire surfaces of them were painted with two layers of an acid protective nail polish. After removing adhesive tapes, brackets were cemented with one of the cements over the window. Then all the specimens were immersed in 5ml de-ionized water for one month. Brackets were debonded and remnants of cements were removed. The windows were etched with 1ml perchloric acid 0.5 M for 60 seconds and then 4 ml of 0.5 M Total Ionic Strength Adjustment Buffer (TISAB) was added to perchloric acid. Fluoride and calcium concentration of the solutions were determined by Potentiometer and Inductively Coupled Plasma, respectively. The depth of etch and fluoride concentration in the enamel were calculated, and the results were analyzed with one way ANOVA and Kruskal-Wallis test. In Resilience the mean fluoride concentrations group were higher and depths of etch were lower than in the other two groups. But there was no statistically significant difference between them. It seemed that an increase in fluoride uptake may be capable of rendering a tooth more resistant to dental decalcification.