Sugar Content, Acidity and Effect on Plaque pH of Fruit Juices, Fruit Drinks, Carbonated Beverages and Sport Drinks

The concentration of fructose, glucose and sucrose, the pH and the titratable amount of acid were analyzed in the following groups of soft drinks (8–11 samples per group): (1) fruit juices, (2) fruit drinks, (3) carbonated beverages and (4) sport drinks. Moreover, the effect of representative products on pH changes of dental plaque was studied in two groups of teenagers with 16 or 19 subjects per group. The fruit juices, fruit drinks and carbonated beverages contained, on average, a total amount of sugars (fructose + glucose + sucrose) of 9.3–9.8%. The corresponding value for sport drinks was 4.4%. The sucrose content was high in 1-week-old fruit drinks and carbonated beverages, but decreased, by spontaneous hydrolysis, to relatively low values when stored at room temperature for 5 months. The mean pH values in the various soft drinks varied between 3.1 and 3.6. Fruit juices had the highest titratable amount of acid, approximately 2–3 times higher than the three other groups of products. Mouth rinses with orange juice, orange drink and Coca-Cola® resulted in low and about the same plaque pH. The sport drinks (Gatorade® and Pripps Pluss®) induced also low plaque pH values but somewhat less than the other products (p < 0.01). When Coca-Cola was consumed either from a glass or with a straw, the pH decrease was significantly smaller compared to a mouth rinse with the same product (p < 0.001). To conclude, the results from the present investigation indicate that commonly used soft drinks, i.e. fruit juices, fruit drinks, carbonated beverages and sport drinks, have about the same ‘cariogenicity’ as far as the total amount of sugars, acidity and the effect on plaque pH are concerned.