Release of fluoride from fluoride-containing chewing gum.

The release of fluoride from fluoride-containing chewing gum and the fluoride concentration in whole saliva was measured at different intervals after the start of the chewing procedures. The residual fluoride contents were 78, 32, and 6% of the initial 0.25 mg in the gum after chewing for 2, 5, and 10 min, respectively. When chewing for 10 min, the salivary fluoride increased from 0.05 to 11.7 and 15.3 parts/10(6) after 2 and 5 min, respectively, followed by a fall to 3.9 parts/10(6) after 10 min. Concentrations exceeding the preintake level were still recorded 60 min after the start of the chewing.