Oral rehydration therapy products - a plaque pH study under normal and dry mouth conditions

The aim of this study was to investigate oral rehydration therapy (ORT) products and their effect on plaque pH under normal and dry mouth conditions.

Three commercial oral rehydration therapy products, prepared according to the manufacturers' instruction, plus a 10% glucose solution, which served as control, were tested in 10 healthy subjects (mean age 25 years): (1) Electral (Arrow Pharmaceuticals), (2) Resorb Junior (Nestlé) and (3) Vätskeersättning (Semper). pH was measured in the maxillary premolar region in situ with the so-called microtouch method. The area under the pH curve was calculated. Their carbohydrate content was also analysed.

The oral rehydration therapy products gave the same low pH values in plaque as the glucose solution. Dry mouth condition, obtained by injection of methylscopolamine nitrate in the labial sulcus, resulted in an overall more pronounced fall in pH and in a delay in the pH recovery compared with normal salivary conditions. The chemical analyses showed that all three test-products contained glucose and starch as the main carbohydrates.

Rinsing with oral rehydration therapy products leads to a greater pH decrease in dental plaque during low compared with normal salivary conditions. As diarrhoea may result in dehydration and thereby in dry mouth, we believe that ORT products have a high cariogenic potential.