The Effect of Acidified Drinking Water on Molar Tooth Enamel in C57BL/6 Mice

The use of hydrochloric acid treatment of drinking water in many academic research rodent colonies and commercial vendors prompted us to investigate its effect on tooth enamel health in mice. Drinks with a low pH such as fruit juices and soft drinks have been demonstrated to cause demineralization of tooth enamel in humans and rodents. This study explored the hypothesis that acidified drinking water at the recommended range of 2.5 to 3.0 pH can lead to enamel erosion and compromised tooth integrity in mice. Specifically, we sought to quantify the effects of pH 2.5 or 3.0 daily drinking water exposure on molar enamel and bone mineral density over 1 and 3 mo. Methylene blue was used to quantify enamel erosion of the molar teeth, while dual-energy X-ray absorptiometry was used to quantify the bone mineral density of the mandible. After 1 mo of drinking water exposure, no statistically significant difference between the groups in enamel erosion or bone mineral density was observed. However, after 3 mo, a significant difference in enamel erosion for the pH 2.5 group compared with the other groups was identified, suggesting a potentially destructive process. There were no differences in bone mineral density between groups at any time point. These findings indicate that acidified drinking water of pH 2.5 may have deleterious effects on the enamel integrity of molar teeth in mice; however, drinking water of pH 3.0 seems safe for tooth enamel in mice during a short-term exposure of 3 mo. As this study only had a 1- to 3-mo exposure period, further study is needed to determine the effects of longer-term use of acidified drinking water at pH 3.0 in mice.