Purpose: The aim of this study was to evaluate the solubility and the fluoride release of different materials used for orthodontic band cementation in different solutions and at different times.
Materials and methods: Three materials were selected: Ultra Band-Lok (UBL); RelyX (RLX) and Ketac-Cem (KTC). Sixteen standard samples from each material were prepared, according to the manufacturers' instructions. The samples were stored in two different solutions (n = 8): 0.9% saline solution (pH 7.0) and 0.1 mol/l lactic acid (pH 4.0). The storage solutions were changed after 24 h and after 7, 15 and 30 days. The fluoride release was determined with an ion-specific electrode (Analion). For the solubility evaluation, the formula Wsl = (m1-m2)/V was used to determine the loss of mass. Data were submitted for statistical analysis using the non-parametric Kruskal-Wallis test.
Results: With respect to the solubility, immersion in lactic acid increased the solubility when compared with saline solution (P < 0.01). In both the solutions, there were differences among materials (P < 0.01) with the following rankings: UBL < RLX < KTC for lactic acid and UBL < RLX < KTC for saline solution. The ranking of fluoride release was UBL < KTC < RLX. In the two tested solutions, RLX exhibited the highest fluoride release (P < 0.01), whereas KTC showed more fluoride release than that of UBL (P < 0.05). Fluoride release decreased over time and the storage solution influenced the fluoride-releasing capacity of some materials.
Conclusions: It was found that fluoride release was influenced by storage solution, materials and immersion time. Materials and storage solution were the significant factors for solubility.