Fluoride Decay Prevention

How to Brush Your Teeth

How do teeth decay?

Tooth decay begins when the outer surface of the tooth is attacked by acid. The acid is produced by bacteria which live on the surfaces of the teeth as a layer called plaque. When foods or drinks containing sugars enter the mouth, the bacteria within the plaque rapidly convert the sugars into acid. The plaque can hold the acid in contact with the tooth surface for up to 2 hours before it is neutralised by saliva.

During the time that the plaque is acidic, some of the calcium and phosphate minerals, of which enamel is largely composed, are dissolved out of the enamel into the plaque. This process is called demineralisation. However, once the plaque acid has been neutralised the minerals can return to the enamel surface – a process called remineralisation. This whole process is often described as an “ionic see-saw” in which mineral ions constantly move back and forth between the tooth surface and the plaque.

The capacity for remineralisation is, however, limited, and if sugars enter the mouth too frequently a net loss of mineral from the enamel surface results in a cavity through which bacteria can penetrate and infect the inner structure of the tooth. This is tooth decay and, if left untreated, will gradually destroy the tooth causing pain and often the formation of an abscess.

How does fluoride protect our teeth?

The relationship between fluoride and tooth decay is complex and probably not yet fully understood. However, it is known that fluoride interferes with the process of tooth decay in at least four ways:

Work to further develop our knowledge of the mechanism of fluoride continues. However, our knowledge is sufficiently well developed to be able to say that of the four mechanisms the second – the remineralisation effect – is the most important. The emphasis in health promotion terms is now focussed on the goal of maintaining low levels of fluoride in everybody’s mouths for as long as possible – particularly during waking hours when foods and drinks containing sugars are likely to be ingested.

For this reason control of sugars in the diet, water fluoridation, and the regular use of fluoride toothpaste remain the cornerstones of tooth decay prevention.



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