Salivary pH and glucose after consuming various beverages, including sugar-containing drinks.

Abstract

Dental erosion is often seen on the lingual tooth surfaces. For this reason tongue pH after consuming orange juice, Coca-Cola (old and new formula), Coca-Cola Light, Jaffa orange beverage, Hart-Sport sport drink, coffee (with and without sugar), beer, sour milk, and strawberry yoghurt was studied in a test panel. The lowest pH values which also remained low for the longest time were observed after consuming Hart-Sport (pH down to 3.80), orange juice, yoghurt, Coca-Cola, and Jaffa, in comparison with coffee (pH down to 5.26), Coca-Cola Light, and beer (p < 0.001). The total glucose concentration in the products and in saliva after consuming them was measured in order to assess the clearance of the products from the mouth. Hart-Sport yielded the highest salivary glucose concentrations (14,000 ppm total glucose) immediately after consuming while yoghurt (4,520 ppm) and coffee with sugar (6,480 ppm) caused the least elevation (p < 0.05). All study products, however, were quickly cleared from the mouth and practically no glucose was left in saliva 30 min after ingestion. Since all the studied products caused lowering of tongue pH below pH 5.5, they have the potential to cause adverse effects on the teeth in patients with impaired salivary function. In the healthy subjects in this study, however, the buffering capacity in the mouth was so strong that not even tongue mucosa could be shown to keep low pH levels a couple of minutes after consumption.