An ex vivo investigation into the release of fluoride from fluoride-containing orthodontic bonding composites

This study was concerned with an evaluation of fluoride release from commercially available orthodontic bonding composite resins, known as Reliance and Mirage Dual Cure, which are claimed to release ionic fluoride. Forty-eight premolar teeth had brackets bonded with four different composite resins--Mirage Dual Cure, Reliance, Right-on and Heliosit. They were then immersed in a demineralizing solution. The amount of fluoride released from the composites into the solution was measured. The results indicated that Mirage Dual Cure released statistically significant amounts of fluoride over the first 2 days. A similar pattern was noted with Reliance albeit releasing a lesser amount. From the third day onwards, fluoride release levelled out to concentrations similar to those of the two control materials, Right-on and Heliosit (i.e. 0.09 ppm). Fluoride-releasing composite resins, therefore, failed to demonstrate any potential long-term fluoride release within the ex vivo model. Even in the short term, the amount of fluoride released was very small.