© 2025 American Dental Association l 19
Fluoridation Facts
communities, some with optimally fluoridated water and some without. This mobility makes it increasingly
difficult to study large numbers of people who have spent their entire lives in one (fluoridated or non-
fluoridated) community.103 It also means that many individuals benefit from fluoridation for at least some
part of their lives. For children who have resided in fluoridated communities their entire lives, studies have
demonstrated they had less tooth decay than children who never lived in fluoridated communities.106
Brazilian Systematic Review
To assess the impact of water fluoridation on dental caries during the era of widespread use of fluoride
toothpaste, a 2022 systematic review30 of 16 fluoridation studies conducted in Brazil limited its scope
to studies published after 1995. This review compared the tooth decay experience of children younger
than 13 years living in fluoridated communities with that of those in non-fluoridated communities.
It found that children in fluoridated communities had about 46% lower odds of experiencing decay.
Among children aged 5–8 years, those in fluoridated communities had a mean of 2.28 fewer teeth
affected by decay than did those in non-fluoridated communities.30
Despite fluoride from a number of other sources, the “halo effect,” and the mobility of today’s society,
studies show that community water fluoridation prevents about 25% of tooth decay in children and
adults throughout the lifespan.62,63
Additional information on this topic can be found in this Section, Question 11.
9. What happens if water fluoridation is discontinued?
Answer
Tooth decay can be expected to increase if water fluoridation in a community is discontinued, even
if topical products such as fluoride toothpaste and fluoride mouthrinses are used widely.
Fact
In 2013, using an updated systematic review, the CPSTF continued to recommend community water
fluoridation to reduce tooth decay, noting that cavities decreased when fluoridation was implemented
and that cavities increased when fluoridation was stopped, as compared to communities that continued
fluoridation.42 This confirmed the CPSTF’s earlier systematic review published in 2002,62 which also noted
an increase in tooth decay when fluoridation was halted (a median 17.9% increase in tooth decay during
6–10 years of follow-up).
Historical Studies Noting an Increase in Tooth Decay after Discontinuation of Fluoridation:
United States: Antigo, Wisconsin (Lemke et al., 1970)
Antigo, Wisconsin, began water fluoridation in June 1949 and ceased adding fluoride to its water in
November 1960. After 5.5 years without optimal levels of fluoride, children in second grade had a
200% increase in tooth decay experience, fourth graders a 70% increase, and sixth graders a 91%
increase in decay experience compared with the levels of those children of the same ages in 1960.
Residents of Antigo re-instituted water fluoridation in October 1965 on the basis of the severe
deterioration of their children’s oral health.107
Fluoridation Facts
communities, some with optimally fluoridated water and some without. This mobility makes it increasingly
difficult to study large numbers of people who have spent their entire lives in one (fluoridated or non-
fluoridated) community.103 It also means that many individuals benefit from fluoridation for at least some
part of their lives. For children who have resided in fluoridated communities their entire lives, studies have
demonstrated they had less tooth decay than children who never lived in fluoridated communities.106
Brazilian Systematic Review
To assess the impact of water fluoridation on dental caries during the era of widespread use of fluoride
toothpaste, a 2022 systematic review30 of 16 fluoridation studies conducted in Brazil limited its scope
to studies published after 1995. This review compared the tooth decay experience of children younger
than 13 years living in fluoridated communities with that of those in non-fluoridated communities.
It found that children in fluoridated communities had about 46% lower odds of experiencing decay.
Among children aged 5–8 years, those in fluoridated communities had a mean of 2.28 fewer teeth
affected by decay than did those in non-fluoridated communities.30
Despite fluoride from a number of other sources, the “halo effect,” and the mobility of today’s society,
studies show that community water fluoridation prevents about 25% of tooth decay in children and
adults throughout the lifespan.62,63
Additional information on this topic can be found in this Section, Question 11.
9. What happens if water fluoridation is discontinued?
Answer
Tooth decay can be expected to increase if water fluoridation in a community is discontinued, even
if topical products such as fluoride toothpaste and fluoride mouthrinses are used widely.
Fact
In 2013, using an updated systematic review, the CPSTF continued to recommend community water
fluoridation to reduce tooth decay, noting that cavities decreased when fluoridation was implemented
and that cavities increased when fluoridation was stopped, as compared to communities that continued
fluoridation.42 This confirmed the CPSTF’s earlier systematic review published in 2002,62 which also noted
an increase in tooth decay when fluoridation was halted (a median 17.9% increase in tooth decay during
6–10 years of follow-up).
Historical Studies Noting an Increase in Tooth Decay after Discontinuation of Fluoridation:
United States: Antigo, Wisconsin (Lemke et al., 1970)
Antigo, Wisconsin, began water fluoridation in June 1949 and ceased adding fluoride to its water in
November 1960. After 5.5 years without optimal levels of fluoride, children in second grade had a
200% increase in tooth decay experience, fourth graders a 70% increase, and sixth graders a 91%
increase in decay experience compared with the levels of those children of the same ages in 1960.
Residents of Antigo re-instituted water fluoridation in October 1965 on the basis of the severe
deterioration of their children’s oral health.107
