Fluoride metabolism and fluorosis

J Dent. 2005 Mar;33(3):177-86. doi: 10.1016/j.jdent.2004.10.003. Epub 2004 Dec 9.


Objectives: This paper is primarily concerned with the only proven risk associated with water fluoridation: enamel fluorosis. Its purpose is to review current methods of measuring enamel fluorosis, its aetiology and metabolism. A further objective is to identify risk factors to reduce the prevalence of enamel fluorosis and employ methods to manage such risk factors.

Data: The prevalence of enamel fluorosis is increasing in Ireland and internationally. A critical period has been identified at which teeth are most at risk of developing enamel fluorosis: 15-24 months of age for males and 21-30 months of age for females. The data included took these two factors into account.

Source: A thorough narrative review of published literature was conducted to identify studies concerning the aetiology and metabolism of enamel fluorosis. Risk factors for fluorosis were identified from these studies.

Study selection: As it is the pre-eruptive phase of enamel development which represents the greatest risk to developing enamel fluorosis, studies examining sources of fluoride ingestion for young children were selected. These included studies on ingestion of fluoride toothpaste by young children, fluoride supplementation and infant formula reconstituted with fluoridated water.

Conclusions: There is evidence that the age at which tooth brushing with fluoride toothpastes is commenced and the amount of fluoride placed on the brush are important risk factors in the incidence of dental fluorosis. It is recommended that brushing should not commence until the age of 2 and that a pea-sized amount (0.25 g) of toothpaste should be placed on the brush.

Publication types

  • Review

MeSH terms

  • Adolescent
  • Cariostatic Agents / administration & dosage
  • Cariostatic Agents / adverse effects
  • Cariostatic Agents / pharmacokinetics*
  • Child
  • Child, Preschool
  • Dental Enamel / metabolism
  • Dietary Supplements / adverse effects
  • Female
  • Fluorides / administration & dosage
  • Fluorides / adverse effects
  • Fluorides / pharmacokinetics*
  • Fluorosis, Dental / diagnosis
  • Fluorosis, Dental / epidemiology*
  • Fluorosis, Dental / etiology
  • Fluorosis, Dental / metabolism*
  • Humans
  • Infant
  • Infant Formula / chemistry
  • Ireland / epidemiology
  • Male
  • Prevalence
  • Risk Factors
  • Sex Factors
  • Toothpastes / adverse effects
  • Toothpastes / chemistry


  • Cariostatic Agents
  • Toothpastes
  • Fluorides