Measurement of Viscosity, pH, and Titratable Acidity of Sport Drinks

Acidic soft drinks, including sports drinks, have been implicated in dental erosion with only limited supporting data. The potential for dental erosion increases with drinks that have a low pH (below 5.5) and high titratable acidity (greater buffer capacity) and a longer oral exposure due to substantivity (viscosity) or frequency of consumption. Purpose: The purpose of this study is to measure the viscosity and titration pH to 7, and pH of common sports drinks on the market today. Methods: 65 common sports drinks were selected based on their availability in Iowa City and Coralville, Iowa. Powdered drinks are mixed with sterile water prior to measurment. The pH is measured using an Orion Model 420A pH meter. The machine is calibrated with Fisher buffer solution (pH 2.00 and 7.00). The titratable pH is measured using a Brinkman pH meter E512 with 0.1 M NaOH base for titrating. Data is reported as mls of base needed to reach pH 7.0. The viscosity is measured at 37.1 C using a Brookfield Model DV viscometer. Results: The data provided evidence of a relationship between level of viscosity and level of pH, based on Spearman’s correlation test of 0.54 with p-value < 0.0001. This data showed that drinks with higher viscosity also had higher pH. However, levels of titratable acidity varied for all the pH ranges tested. Conclusion: It was noted that the majority of sport drinks have pH below the critical value of 5.5 for enamel dissolution; however, high viscosity drinks have a higher pH that indicates that erosion is less likely. Supported by the UI College of Dentistry Dental Research Award.