Simultaneous pH and fluoride telemetry from the oral cavity.

A new telemetric system was used to determine, simultaneously, plaque pH and salivary fluoride when sucrose-containing fluoride tablets of 0.25 mg and 1.0 mg NaF were dissolved in the oral cavity. Dissolution of 1.0 mg fluoride tablets on the dorsum of the tongue produced transient interproximal plaque acidification not lower than pH 5.2 combined with an increased salivary F-level between 0.19 and 19 ppm for up to 1 hr at the entrance of the interproximal space. Interference of plaque glycolysis by F was evident when rinsings with 250 ppm F as NaF combined with 10% sucrose resulted in pH levels 1/2-1 unit higher than with 10 percent sucrose alone. The use of sucrose as a vehicle in fluoride tablets is discussed.