Acidogenic bacteria in the dental plaque produce acids while metabolizing carbohydrates. As these acids diffuse through the plaque into the enamel, hydrogen ions are released. During this process, the acidogenic oral pH favors the dissolution of the minerals on the enamel surface. The diffusion of calcium and phosphate ions out of enamel produces a chalky white spot lesion. During orthodontic treatment, the formation of white spot lesions around the brackets due to poor oral hygiene has long been a recognized problem. Approximately, 50% of orthodontic patients will develop these lesions during treatment of approximately 2 years. These incipient caries can appear in as little as 2-3 weeks after plaque accumulation in gingival areas of teeth.

In this study, a novel approach will be used to develop a fluoride-delivery system to provide fluoride ion release in a controlled and continuous manner in an effort to eliminate the formation of white spot lesions. Our attention is focused on orthodontic ligature ties (o-rings), which are renewed during the routine adjustment appointments of an orthodontic patient during treatment. In this study, we present our initial results on the performance of a delivery matrix that is capable of releasing fluoride in a pre-designed manner at a constant rate during the 30 to 45 day period between these appointments. This method of fluoride delivery presents the potential to eliminate any need for patient compliance and would ensure delivery of fluoride at each orthodontic visit by simply replacing the elastomeric rings.