Fluoride deposited by topical applications with stannous fluoride in human enamel

The aim of this study was to quantify the fluoridating effect of a 4% aqueous solution of SnF2 applied for 5 min. and 30 min. resp., and to measure the amounts of KOH soluble fluoride and acquired fluoride separately (APF gel data being included for comparison). Blocks of intact enamel were treated with the topical agents and subsequently exposed to 1 M KOH solutions for 24 h. No significant amount of fluoride was dissolved from control specimens by this treatment. Subsequently, the acquired F in the enamel was determined by the acid etch technique. The amount of fluoride in the KOH solutions after 5 and 30 min. SnF2 application are comparable : 6.2 and 7.4 micrograms . cm(-2) resp. A single topical treatment of SnF2 of 5 and 30 min. did not produce a significant enrichment of fluoride in the enamel. The considerable accumulation of fluoride reaction products on the outer enamel surface was only 1/3 of the amount deposited by APF gels.