In vitro study of fluoride release of calcium fluoride–porcine bone–derived hydroxyapatite composite

Fluoride-releasing materials are helpful in the remineralization of enamel in teeth that erodes due to caries. These materials range from glass ionomers, composites, and amalgams that are usually incorporated with filler materials. In this study, a composite that has the potential to be a fluoride-releasing component in dental materials was synthesized using two biocompatible components: calcium fluoride (CaF 2 ) and porcine bone–derived hydroxyapatite (HA). The synthesized material was characterized based on its fluoride release in water. The HA were obtained from porcine bones via calcination and were mixed with CaF 2 through manual grinding. The resulting powder mixture was pelletized and sintered at 900 °C to form a disc-shaped green compact. FTIR analysis of the resulting pellet showed that the HA and CaF 2 formed fluorapatite (FA), given the absence of OH peaks. The XRD pattern confirmed that a proportion of HA transformed into FA and that there are three phases (HA, FA, and CaF 2 ) present in the pellet. Results of immersion experiments showed that the line of the best-fit model to describe the amount of fluoride released over time is a linear relationship. It was also found that there is an initial high release of fluoride caused by surface wash-off. Furthermore, the synthesized pellets were found to be hydrolytically stable due to the very small mass loss observed even after 16 days of immersion. With the capability to release fluoride and its stability, the synthesized material has the potential to be a cheap alternative material in dental applications.