Fluoridation

How does fluoride work to prevent cavities?



The answer to that question depends on how the fluoride ion is presented, either systemically or topically. Topical fluorides strengthen teeth already present in the mouth by making them more cavity-resistant. Topical fluorides come in many forms: toothpaste, mouth rinses, fluoride gels and professionally applied varnishes and foams. While systemic fluorides are those ingested into the body and become incorporated into developing tooth structures. They can be found in naturally or added into drinking water or in supplemental forms such as vitamins or drops. The systemic form can also give topical protection because fluoride will spill over into the saliva which bathes the teeth present in the mouth.

Tooth decay occurs when the rate of demineralization exceeds the rate of remineralization. Demineralization happens when cavity-causing bacteria are able to metabolize enough sugar to produce acidic plaque. This acidic plaque causes the enamel matrix to lose calcium and phosphate ions. At a microscopic level the enamel matrix breaks apart, and when the unchained links are large enough they will cause cavitations (a cavity). These small openings in the enamel allow more acid-producing bacteria to shelter themselves inside the tooth gaining access to the softer dentin layer. However, once the plaque acid has been neutralized minerals can return to the enamel surface by a process known as remineralization. Fluoride therapy is most dentist’s favorite way to remineralize teeth because remineralization with fluoride produces enamel made with fluoroapatite, a stronger more acid-resistant molecule, than the original hydroxyapatite that formed the tooth layers.