Fluoride & Caries

Figure: Severe carious teeth

Over 50 years of extensive research throughout the world has consistentlydemonstrated the safety and efficacy of fluoride in preventing dental decay. Thescientific basis for the use of fluoride and its safety has been accepted by numerousscientific bodies, expert groups and Government agencies. The use of fluoride hasresulted in a substantial decline in the incidence and prevalence of dental decay andhas improved the quality of life for millions of people.

How Fluoride Inhibits Caries

The original investigations into the role of fluoride in the prevention of dental decaylinked its mode of action to its presence and concentration in the water supply. Itwas assumed that the beneficial effect of fluoride related to its systemic effect instrengthening tooth enamel during development.It has now become clear that the constant supply of appropriate levels of fluoride inthe mouth is the most important factor, as the presence of low levels of fluorideinhibits demineralisation and encourages remineralisation of the tooth enamel duringthe dental decay process.These findings are of profound importance with regard to the use of fluoride as apreventive or therapeutic measure. They have confirmed that the topical applicationof fluoride, or indeed any means of maintaining an adequate concentration of fluoridein the mouth, is of central importance in preventing dental decay.

Delivery systems for fluoride

Fluoridation of water supplies

Fluoridation of water supplies, where possible, remains the most effective publichealth measure for the prevention and treatment of dental decay. This is attributableto the fact that water is a dietary component required and used by everyone andtherefore benefits all sectors of the community. The only limitations to its use are areliable and controllable water supply, which almost invariably means a centralisedpiped source of water.The availability of fluoride from other sources needs to be known in order todetermine the most appropriate water fluoride levels for a given population orgeographical area.. Recommendations for the concentration of fluoride in waterdepend primarily on water consumption, which may be effected by climate. Inaddition, local cultural or dietary practices should also be taken into account.

Fluoridated salt

Administration of fluoride via salt intake is an alternative where the local situation isnot suitable for water fluoridation. Studies have produced consistent data indicatingits effectiveness in reducing dental decay. The production of fluoridated salt for aparticular country or geographical area should be centralised with strong technicalsupport to ensure controlled production.Concentration of fluoride in salt must be based on studies of salt intake and theavailability of fluoride from other sources. The fluoride concentration should appearon the salt packaging.

Fluoridated milk

Fluoridated milk has been used as a fluoride source, especially for young childrenthrough school programmes. A number of studies have shown it to be effective.However it has had limited exposure as a public health measure.

Fluoride-Containing Dentifrices

Of all the delivery systems in use at the present time, fluoride dentifrices have beenthe subject of the most comprehensive testing. A wide range of well-controlledstudies has been carried out and almost all of these have demonstratedconsiderable reductions in dental decay resulting in greatly improved oral health.Fluoride dentifrices are therefore a most important public health measure and effortsshould be made to extend their use.Excessive swallowing of toothpaste by young children may result in an increase inthe prevalence of very mild dental fluorosis (enamel opacities). In order to reducethis possibility the ingestion of toothpaste by children should be minimised. In someregions of the world low concentration fluoride-containing dentifrices (550ppmfluoride), especially for children, are available. There is conflicting evidence of theireffectiveness in reducing dental decay.Dentifrices should be used at least twice per day with a minimum amount of waterused to rinse the mouth after brushingDentifrice containers must display the fluoride concentration and a notice thatchildren under 6 years of age should be supervised during brushing, and only use asmall amount (e.g. pea-sized portion) of toothpaste.

Fluoride Supplements

Fluoride tablets may be recommended for at-risk individual patients and can also beconsidered for general use in at-risk groups in the community when other fluoridesources are not available. The effectiveness of fluoride tablets is not as clearlydocumented as other delivery systems. In view of the recognition of the importanceof the topical effect of fluoride it is recommended that supplements should besucked, chewed or dissolved in the mouth before being swallowed. There is also thepossibility of an increased risk of opacities/ fluorosis if supplements are usedinappropriately.Dosage must take into account local fluoride availability particularly in the watersupply. Dosage schedules should, where available, be consulted. There are severalnational dosage schedules available which differ somewhat in theirrecommendations. These must be monitored carefully and updated regularly in thelight of other sources of fluoride.

Fluoride Mouthrinses

In at risk individuals and populations fluoride mouthrinses may be an effectivemeasure. Mouthrinses can be used on a daily basis or at other intervals as dictatedby local needs. Fluoride mouthrinsing is not recommended for children under sixyears of age.Commercially available fluoride mouthrinses intended for individual use have beendemonstrated to be effective and should be used according to the specific needs ofthe individual.

Professionally applied gels

Professionally applied gels are indicated for individuals at-risk of dental decay.Concentrations are usually high. In view of this they must be handled with care.

Fluoride Varnishes

Fluoride varnishes are indicated for individuals at-risk of dental decay or for patient’sat increased risk due to dental or medical treatment.Fluoride exposure from multiple sources

Fluorides are found naturally throughout the world.

They are present to some extentin all foods and waters so that all humans ingest some fluoride. Fluoride has become more available via food and drink, fluoridated water, dentifrices,mouthwashes etc. This can be extremely beneficial in terms of the prevention of dental decay. It can also increase the risk of the milder forms of dentalopacities/fluorosis. Because of this there should be a co-ordinated approach tofluoride delivery. It is imperative that fluoride availability from all sources is takeninto account before embarking on a specific course of fluoride treatment.

Health risk assessment

It is clear from a vast amount of scientific evidence that, if used properly, and at theconcentrations appropriate for the prevention of dental decay, fluoride is safe andeffective. However enamel opacities / fluorosis can be caused by excessive fluorideingestion during the pre-eruptive development of teeth. At the fluoride levels usedto prevent decay opacities/fluorosis only occur in a relatively small proportion of thepopulation and the changes are very mild and are primarily of aesthetic interest.Recent studies have shown that the public generally do not notice or find objectionable these minor changes on teeth.Provided that levels of intake are carefully monitored, fluoride is considered to be amost important public health measure in maintaining oral health.

adapted from FDI Statement Fluoride and Dental Caries June 2000.