Tooth Enamel - Oral Hygiene and Fluoride

Oral Hygiene and Fluoride

Considering the vulnerability of enamel to demineralization and the daily menace of sugar ingestion, prevention of tooth decay is the best way to maintain the health of teeth. Most countries have wide use of toothbrushes, which can reduce the number of bacteria and food particles on enamel. Some isolated societies do not have access to toothbrushes, but it is common for those people to use other objects, such as sticks, to clean their teeth. In between two adjacent teeth, floss is used to wipe the enamel surfaces free of plaque and food particles to discourage bacterial growth. Although neither floss nor toothbrushes can penetrate the deep grooves and pits of enamel, good general oral health habits can usually prevent enough bacterial growth to keep tooth decay from starting.

These methods of oral hygiene have been helped greatly by the use of fluoride. Fluoride can be found in many locations naturally, such as the ocean and other water sources. Naturally occurring calcium fluoride is not the same as sodium fluoride, a byproduct of the fertilizer industry and the fluoride that is added to drinking water. The recommended dosage of fluoride in drinking water depends on air temperature; in the U.S. it ranges from 0.7 to 1.2 mg/L. Fluoride catalyzes the diffusion of calcium and phosphate into the tooth surface, which in turn remineralizes the crystalline structures in a dental cavity. The remineralized tooth surfaces contain fluoridated hydroxyapatite and fluorapatite, which resist acid attack much better than the original tooth did. Fluoride therapy is used to help prevent dental decay.

Many groups of people have spoken out against fluoridated drinking water, for reasons such as the neurotoxicity of fluoride or the damage fluoride can do as fluorosis. Fluorosis is a condition resulting from the overexposure to fluoride, especially between the ages of 6 months to 5 years, and appears as mottled enamel. Consequently the teeth look unsightly, although the incidence of dental decay in those teeth is very small. It is important, however, to note that all substances, even beneficial ones, are detrimental when taken in extreme doses. Where fluoride is found naturally in high concentrations, filters are often used to decrease the amount of fluoride in water. For this reason, codes have been developed by dental professionals to limit the amount of fluoride a person should take. These codes are supported by the American Dental Association and the American Academy of Pediatric Dentistry. The acute toxic dose of fluoride is ~5 mg/kg of body weight. Furthermore, whereas topical fluoride, found in toothpaste and mouthwashes, does not cause fluorosis, its effects are also less pervasive and not as long-lasting as those of systemic fluoride, such as when drinking fluorinated water. It is also claimed, all of a tooth's enamel gains the benefits of fluoride when it is ingested systemically, through fluoridated water or salt fluoridation (a common alternative in Europe) and that only some of the outer surfaces of enamel can be reached by topical fluoride. However, since there is no connection between the bloodstream and the enamel, ingested (systemic) fluoride works topical as well: With raised fluoride blood levels, fluoride levels in saliva increase also. Here fluoride mediates the remineralization with fluorapatite. The cavity-prevention mechanism of systemic fluoride is the same as that of fluoride from tooth paste, albeit the former usually results in prolonged fluoride presence in saliva which in turn may result in a deeper fluorapatite remineralisation. Despite fluoridation's detractors, most dental health care professionals and organizations agree that the inclusion of fluoride in public water has been one of the most effective methods of decreasing the prevalence of tooth decay. Four out of five dentists agree with fluoride treatment.