Interproximal in situ Plaque pH after a Sugar Challenge in Relation to Caries in Adults before and after Short-Term Use of 1.5% Arginine Toothpaste

Background: The evidence of the anti-caries effect of arginine toothpaste has been questioned and randomised trials independent of commercial interests have been required. Aim: To examine, in relation to caries, the pH response in interproximal plaque in situ to an acidic challenge and the pH and buffer capacity of stimulated saliva following a six-week period of using a toothpaste containing 1.5% arginine/1450 ppm fluoride or no arginine/1450 ppm fluoride. Methods: Thirty-three healthy adults with no visible caries lesions or ≥ 1 current manifest lesion participated in the study. Acid plaque responses were examined by interproximal pH-measurements using pH-indicator strips. Two weeks after professional cleaning, pH-measurements were performed before and up to 15-min after a 1-min rinse with 10 ml of a 10% sucrose solution. This procedure was repeated after a 6-week test period of using randomly selected toothpaste with arginine and fluoride or with fluoride alone. The stimulated salivary-pH and buffer capacity were also measured. Results: In the caries group, the use of toothpaste with arginine and fluoride resulted in increased pH-values in the four sites tested. No statistically significant increased plaque pH-values were found in the no-caries group. In addition, saliva buffer capacity and pH was increased in the caries group. Conclusion: Using fluoride toothpaste with 1.5% arginine affects the oral environment positively in adults with caries, in the form of increased supragingival plaque pH and increased salivary pH and buffer capacity