and well-being of children and youth
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The introduction of fluoride to drinking water in 1958 resulted in a dramatic reduction of dental caries . Subsequently, fluoride supplements were advocated for children whose water was not fluoridated, and now almost all toothpaste contains fluoride. The result is that multiple sources of fluoride, such as fluoridated toothpastes, fluoride supplements (drops and lozenges) and naturally occurring fluoride, have contributed to an increase in the incidence of fluorosis. The challenge is to provide the right amount of fluoride in a reliable and safe manner. Fluoride has been found to be effective in preventing caries but there have been no controlled studies to evaluate the optimal dose.
The recommendations on fluoride use in a 1995 statement by the Canadian Paediatric Society (CPS)  differed substantially from those of the Canadian Dental Association (CDA). The position of the CDA  was that, apart from fluoride in water, the main source of fluoride should be fluoridated toothpaste, and that supplements should not be used in children younger than three years of age. The CPS position was that proper tooth brushing, especially in high risk populations, may be difficult to implement; that delaying supplementation until three years of age would result in higher caries rates; and that supplements should be started at six months of age . More recent studies of the actions of fluoride resulted in the modification of these two positions. The position outlined in the present statement follows the principles agreed on at the 1997 Canadian Consensus Conference on fluoride use .
Dental fluorosis, a condition associated with abnormal enamel development, was first noted in communities with high levels of naturally occurring fluoride in the drinking water, but has since appeared in individuals ingesting fluoride from other sources.
This condition, occurring mainly in children younger than seven years of age, is associated with impaired biosynthesis of dental matrix. Manifestations can vary from minimal changes (Toxic Effect [TF] of 1), comprising 80% to 90% of the cases, and noted only by close dental examination; to rarer, florid, unsightly mottling and pitting of the teeth, enamel striations, and in severe cases, ‘snow-capped cusps’ and chalky-white teeth (TF of 2 or more), which may be unsightly and require cosmetic treatment. Secondary teeth are at the greatest risk for fluorosis at 15 to 24 months of age .
The prevalence of fluorosis has increased since 1945 , paralleling the increase in possible sources of fluoride, including water, toothpaste, foods and drinks made with fluoridated water, and fluoride supplements such as drops, mouthwashes and lozenges. Fluorosis prevalence varies inversely with caries control. In a large study of 18,755 children by Heller et al , the sharpest decline in decayed, missing, filled surfaces occurred with increasing drinking water concentrations of fluoride from 0 to 0.7 ppm, with little additional benefit above this concentration. The prevalence of fluorosis increased with increasing water fluoride concentration, from 13.5% in children exposed to water containing less than 0.3 ppm of fluoride to 41.4% when they were exposed to greater than 1.2 ppm. The use of supplements added to the effect and was associated with a further lowering of caries at the cost of increased fluorosis. A suitable trade-off between caries and fluorosis occurred at around 0.7 ppm of fluoride . Other studies - have also found fluorosis prevalence of greater than 40% with increasing fluoride exposure, although only a small proportion of dental changes due to fluorosis are noticeable enough for treatment to be considered. A recent study of fluorosis among 2435 children aged seven to 13 years in Toronto, Ontario  found dental fluorosis of moderate degree (Tooth Surface Index of 2 – fluorosis of moderate severity) in 14% of seven-year-olds, 12.3% of 13-year-olds and 13.2% of the two groups combined, a prevalence similar to most of the recent studies performed in Toronto.
Fluoride prevents caries mainly by its topical effect . Dental caries result when plaque, a sticky film of bacteria on the surface of the tooth, feeds on sugar and food residue to produce acid, which dissolves the surface of the tooth (demineralization). Bathing the surface of the tooth with as little as 1 ppm of fluoride causes a dramatic decrease in enamel solubility. Ingested fluoride, on the other hand, has little effect on caries, but contributes significantly to the development of fluorosis.
Enamel development is characterized by three stages.
Fluoride delivered systemically to the tooth affects both the transition and maturation stages. Enamel development is most sensitive to systemic fluoride during the transition stage. The matrix becomes porous as fluoride and other ions accumulate. In the maturation stage, altered mineral deposition occurs. This effect of fluoride results in interference with crystal deposition, altered cell modulation and delayed maturation of bone.
Topical fluoride acts in three main ways to prevent dental caries .
Toothpaste is available with or without fluoride. Toothpaste tubes containing fluoride are now labeled and contain approximately 0.5 mg fluoride per gram of toothpaste. Some tubes suggest covering the bristles with toothpaste. A ‘pea-sized’ portion weighs approximately 0.75 g and contains about 0.4 mg of fluoride; a ‘full cover’ portion weighs approximately 2.25 g and contains about 1.0 mg of fluoride. Thus, brushing twice a day would deliver 0.8 to 2.0 mg of fluoride, depending on which regimen is used. If swallowed, the amount of fluoride could be excessive and could contribute to the development of fluorosis.
There is no doubt that the use of fluoride decreases dental caries. On the other hand, it is clear that the ingestion of too much fluoride can result in varying degrees of fluorosis. Thus, in practice, the administration of fluoride should strike a balance between the two situations.
Recommended supplemental fluoride concentrations for children
|Age of child||<0.3 ppm||>0.3 ppm|
|0 to 6 months||None||None|
|> 6 months to 3 years||0.25 mg/day||None|
|> 3 to 6 years||0.5 mg/day||None|
|> 6 years||1.00 mg/day||None|
Members: Margaret Boland MD (chair); Robert Issenman MD (director responsible); Alexander Leung MD; Valérie Marchand MD; Anthony Otley MD
Consultants: Claude Roy MD; Reginald Sauve MD; Stanley Zlotkin MD
Liaisons: Anne Kennedy, National Institute of Nutrition; Marilyn Sanders, Breastfeeding Committee for ; Donna Secker; Rosemary Sloan, Population and Public Health Branch, Health Canada; Christina Zehaluk, Health Products and Food Branch, Health Canada
Principal author: John Godel MD
Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.