Abstract
Previously, nano‐sized calcium fluoride (CaF~2~) particles were prepared using a spray drying method by simultaneously feeding Ca(OH)~2~ and NH~4~F solutions to a two‐liquid nozzle. The aim of the present study was to prepare better‐dispersed nano‐CaF~2~ particles by co‐forming a soluble salt, sodium chloride (NaCl). NaCl of various concentrations were added to the NH~4~F solution, leading to formation of (CaF~2~+NaCl) composites with CaF~2~/NaCl molar ratios of 4/1, 4/4, and 4/16. Pure nano‐CaF~2~ was also prepared as the control. Powder X‐ray diffraction analysis showed that the products contained crystalline CaF~2~ and NaCl. Scanning electron microscopy examinations showed that both the CaF~2~/NaCl composite and pure CaF~2~ particles were about (50–800) nm in size and consisted of primary CaF~2~ particles of < 50 nm in size. BET surface area measurements showed similar primary particle sizes for all samples. Dynamic light scattering measurements showed that the washed (CaF~2~+NaCl) particles were much smaller than the pure CaF~2~ as the dissolution of NaCl “freed” most of the primary CaF~2~ particles, leading to a greater degree of particle dispersion. The well‐dispersed nano‐CaF~2~ may be expected to be a more effective anticaries agent than NaF by providing longer lasting elevations of fluoride concentrations in oral fluids. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.