Effect of prior acid etch on rate of Sn3F3PO4 formation subsequent to topical application of SnF2

The effect of prior acid etch on the rate of Sn3F3PO4 formation subsequent to in vitro SnF2 interaction with human dental mineral has been investigated using light microscopy, surface replicas, and internal reflection spectroscopy. Results showed that Sn3F3PO4 forms more rapidly on etched surfaces as compared with nonetched controls. The observed accelerated rate was attributed to increased reaction surface provided by prior acid etch plus a rougher surface conducive to crystal nidus formation.