Dental Fluorosis: Much Ado about Nothing

Stephen Barrett, M.D.
January 13, 2019

Fluoridation opponents would like you to believe that water fluoridation is dangerous because it leads to a high incidence of dental fluorosis. This article explains why they are wrong.

Dental fluorosis is an alteration of dental enamel caused by ingestion of more than the optimal amount of fluoride during tooth development. The degree of fluorosis is usually classified this way:

Fluoridation opponents like to cite CDC statistics showing that the incidence among adolescents aged 12-15 rose from 22.6% in 1986-87 to 40.7% in 1999-2004 [1]. Taken by itself, that statement is factual but misleading. Questionable, very mild, and mild fluorosis and most cases of moderate fluorosis are barely visible and pose no problem whatsoever. In addition, it’s been shown that teeth with fluorosis are more resistant to decay than teeth without fluorosis [2]. The teeth may appear whiter than otherwise, but they are neither unattractive nor structurally damaged. Moreover, many people think that extra whiteness makes the teeth more attractive. Severe fluorosis that adversely affects both appearance and function is close to zero among people who drink water that is optimally fluoridated. A comprehensive review of published studies found that very mild to mild fluorosis had no negative effects on the subjects’ quality of life, with some evidence suggesting enhanced quality of life with mild fluorosis [3]. A study in which children noted to have mild or very mild fluorosis in 2003 and 2004 were re-evaluated 7 to 9 years later found that these conditions had a tendency to diminish with time and had no negative effect on the participants’ perception of their oral health [4].

The incidence of fluorosis depends on the fluoride intake from all sources during the years when teeth are formed—usually up to the age of 12. In addition to fluoridated water, the sources can include fluoridated toothpaste, other therapeutic fluoride products, and foods and beverages. Fluoride given to adolescents and adults does not and cannot cause them to develop fluorosis.

For more than 40 years, the recommended level of fluoridated water in the United States and Canada averaged 1 part of fluoride per million parts of water. When studies showed that the intake of fluoride from other sources had increased, the relevant government agencies lowered their recommendation to 0.7 parts per million [5,6].

In 2018, Public Health Ontario reaffirmed the safety of the 0.7 fluoridation level. Its report noted that (a) mild fluorosis might occur if infant formulas prepared with fluoridated water are used as a child’s main food source and (b) if prevention of mild fluorosis is desired, the formula should sometimes be prepared with low-fluoridated bottled water and early exposure to other forms of fluoride should be monitored [7].

  1. Beltran-Aguilar E and others. Prevalence and severity of dental fluorosis in the United States, 1999-2004. NCHS Data Brief No. 53, Nov 2010.
  2. Iida H, Kumar, J. The association between enamel fluorosis and dental caries in U.S. schoolchildren. Journal of the American Dental Association 140:855-862, 2009.
  3. Chankanka O and others. A literature review of aesthetic perceptions of dental fluorosis and relationships with psychosocial aspects/oral health-related quality of life. Community Dentistry and Oral Epidemiology 38:97-109, 2010.
  4. Do LG and others. Natural history and long-term impact of dental fluorosis: a prospective cohort study. Medical Journal of Australia 204:25.e1, 2016.
  5. EPA and HHS announce new scientific assessments and actions on fluoride / Agencies working together to maintain benefits of preventing tooth decay while preventing excessive exposure. EPA news release, Jan 7, 2011.
  6. Findings and recommendations of the fluoride expert panel. January 2008, Health Canada.
  7. Public Health Ontario. Evidence review for adverse health effects of drinking optimally fluoridated water (2010-2017). October 2018

This article was revised on January 13, 2019.