An extra safety belt
The role of fluoride in the prevention of dental caries is well-known in the dental profession and the use of fluoridated toothpastes and mouthwashes is widespread in UK households. The benefits of fluoride when it comes into contact with tooth enamel were discovered at the beginning of the 20th century in the USA when residents of an area in Colorado with high levels of fluoride naturally present in the drinking water were found to have a surprisingly high resistance to tooth decay, as well as rather unpleasant brown stains caused by fluorosis on the surface of their teeth.
This accidental discovery led to further research and water fluoridation studies which validated the initial observations and led to widespread water fluoridation programmes across many US states, a timely intervention as the national diet evolved to incorporate more and more sugar over the ensuing decades.
The presence of more sugar in the oral cavity leads to increased levels of organic acids such as lactic acid, which destabilise the natural balance of mineralisation and remineralisation in the hydroxyapatite phase of the tooth. According to studies, the presence of lactic acid at the tooth surface enhances the rate of demineralisation relative to that of remineralisation leading to a loss of hydroxyapatite from the mineral phase and resultant tooth decay.