- The acidity of food/fluids: tooth enamel is composed of minerals, such as calcium and phosphate. Both enamel and dentine are weakened and dissolved by acid (pH less than 5.5). The enamel layer in primary teeth (the first set of teeth in children) is thinner making them particularly vulnerable. In commercially available sports drinks, the pH is 2.4 – 4.5 and hence the concern about damage to teeth.
- The frequency and duration of exposure to acidic products: salivary flow neutralises acids and provides calcium and phosphate to remineralise tooth enamel within a 20-30min “recovery” phase. Frequent sipping of sports drinks/soft drinks increases the length of this recovery phase extending the time in which teeth are ‘vulnerable’ to erosion.
- The sugar content: Cola drinks, sports drinks, gels and energy drinks (and any other type of food which may be “sticky” e.g. honey, glucose syrup, etc) are sources of carbohydrate in the form of sugar for the purpose of easy-digestibility and delivery to working muscles. However, these foods provide sugar in a form that adheres to teeth more than saliva and provide a substrate for additional acid production by oral bacteria.
- Decreased salivary flow: Saliva plays a vital role in protecting teeth. It dilutes and clears liquids at the tooth surface. It neutralises acids in the mouth and provides a mineral source including calcium and phosphate for remineralisation (enamel hardening). Dehydration is a real issue for many athletes, particularly when exercising in the heat, for extended periods and especially for those with a higher-than-average sweat rate. Dehydration causes the mouth to become dry, reducing salivary flow which increases the time of tooth surface damage.