Tooth decay, also known as caries, will occur when the dental enamel dissolves. This will happen at a pH value below 5.5

Nearly all common soft drinks, as well as most fruit drinks have a pH (far) below 5.5. Cola drinks are the most acid drinks, with a pH of 2.7, making them more acid than vinegar. As the pH scale is a logarithmic scale, a pH of 3 is ten times more acid than pH 4, or hundred times more than pH 5. Only natural uncarbonated spring water has a pH above 5.5.

Besides the pH, two other factors increase the risk of tooth decay. Sugars are easily fermented by the oral bacteria, which results in acid production. This acid enhances the tooth decay. Phosphoric acid, used for example in cola drinks, also increases the risk, as it readily removes calcium from the enamel.

After drinking soft drinks the pH should be neutralised as soon as possible. The best way to achieve this is to eat sugar-free chewing gum, as it improves saliva production, which acts as a buffer and actively neutralises the acids.

Brushing your teeth has a detrimental effect, as the enamel becomes softer due to the acid. Brushing can remove the soft enamel more easily, thereby increasing dental decay.