THE EFFECT OF BICARBONATE FLUORIDE DENTIFRICES ON HUMAN PLAQUE PH/

The acidogenic response in dental plaque after rinsing with sodium bic arbonate/fluoride dentifrice slurries was studied using three intra-or al models. In the first model, resting plaque pH was monitored in mesi obuccal plaque on upper molars and premolars in six healthy subjects a fter abstinence from normal oral hygiene for three days. These measure ments were followed by a three-minute rinse with 10% sucrose and, foll owing a two-minute interval, a three-minute rinse with a test dentifri ce slurry. After the test denrifrice rinse, pH was monitored at regula r intervals up to 60 minutes. Flow rate, pH and buffer capacity of sti mulated saliva were also determined. Changes in resting pH. plaque pH minima, and maximum pH drop were calculated. A clear elevation in the resting pH was observed after bicarbonate/fluoride denrifrice rinses, and a significant increase was obtained in the pH minima. The smallest pH drop also was found after treatment with the bicarbonate/fluoride dentifrice rinse treatment (p < 0.02). A second model using telemetric partial dentures with interproximally placed micro-antimony pH electr odes was used to study the effects of rinsing with increasing concentr ations of sodium bicarbonate and calcium carbonate solutions, and with a fluoride dentifrice containing sodium bicarbonate. The response to these treatments was found to be rapid, dose-dependent, and was the gr eatest from the sodium bicarbonate. A third model used 24 subjects to assess the effects of sodium bicarbonate/fluoride dentifrice on plaque pH before and after a glucose challenge. The use of the bicarbonate/f luoride dentifrice resulted in significantly less measurable plaque ac id than the fluoride dentifrice treatment. Collectively, these results indicate bicarbonate in dentifrice to be an effective buffering agent for stabilizing the pH and neutralizing plaque acids in dental plaque .