© 2025 American Dental Association l 25
Fluoridation Facts
demineralization and enhance remineralization.74,77,131 In other words, drinking fluoridated water provides
the right amount of fluoride at the right place at the right time. Fluoride in water and water-based
beverages is consumed many times during the day, providing frequent contact with tooth structures and
making fluoride available to fluoride reservoirs in the mouth. This helps explain why fluoride at the low
levels found in fluoridated water helps prevent tooth decay in teeth after they have erupted.74
Additional information on this topic can be found in this Section, Question 2.
Benefit of Community Water Fluoridation for Adults
All adults receive the benefit of decay protection while teeth are already present in the mouth when
exposure to water fluoridation begins. However, studies have indicated that adults who have consumed
fluoridated water continuously from birth receive the maximum protection against tooth decay.77–81
Journal of Dental Research Meta-Analysis
A meta-analysis published in 2007 in the Journal of Dental Research showed that fluoridation
prevents approximately 27% of tooth decay in adults. The studies for this meta-analysis were limited
to participants who were lifelong residents of communities with fluoridated water and control
groups of lifelong residents of communities without fluoridated water.63
Additional studies summarized in this section provide evidence for the benefit of community
water fluoridation on adults.
Study of Adults in Washington State
A study published in 1992132 in the Journal of the American Dental Association examined adults aged
20–34 years in the state of Washington and found that those who had a continuous lifetime exposure
to optimally fluoridated water had 31% less tooth decay experience compared to similar aged adults
with no exposure to fluoridated water. It also concluded that exposure to fluoridation only during
childhood has lifetime benefits because adults exposed to fluoridated water only during childhood
had decay experiences similar to those adults exposed to fluoridated water only after age 14.132
Decay among Australian Defense Force Personnel
A noteworthy Australian study133 published in 2008 examined decay experience among Australian
Defense Force personnel and showed that a longer period of exposure to water fluoridation was
associated with lower decay rates in adults between the ages of 17–44. Adults who lived at least
90% of their lifetime in communities with fluoridated water had 24% less decay than adults who
lived in fluoridated areas for less than 10% of their lifetimes.133
Data from the Australian National Survey of Adult Oral Health
A 2013 study using data from the Australian National Survey of Adult Oral Health showed that adults
with greater lifetime exposure to fluoridated water had lower caries experience.134
Another study emphasized that benefits from lifetime access to fluoridated water could be observed
clearly up to age 45 but seemed to flatten out in older age groups. The authors suggested that a
cumulative measure such as the number of tooth surfaces classified as decayed, missing, or filled could
become “saturated” in a chronic disease such as dental caries, making it hard to show differences by
exposure level.135
Fluoridation Facts
demineralization and enhance remineralization.74,77,131 In other words, drinking fluoridated water provides
the right amount of fluoride at the right place at the right time. Fluoride in water and water-based
beverages is consumed many times during the day, providing frequent contact with tooth structures and
making fluoride available to fluoride reservoirs in the mouth. This helps explain why fluoride at the low
levels found in fluoridated water helps prevent tooth decay in teeth after they have erupted.74
Additional information on this topic can be found in this Section, Question 2.
Benefit of Community Water Fluoridation for Adults
All adults receive the benefit of decay protection while teeth are already present in the mouth when
exposure to water fluoridation begins. However, studies have indicated that adults who have consumed
fluoridated water continuously from birth receive the maximum protection against tooth decay.77–81
Journal of Dental Research Meta-Analysis
A meta-analysis published in 2007 in the Journal of Dental Research showed that fluoridation
prevents approximately 27% of tooth decay in adults. The studies for this meta-analysis were limited
to participants who were lifelong residents of communities with fluoridated water and control
groups of lifelong residents of communities without fluoridated water.63
Additional studies summarized in this section provide evidence for the benefit of community
water fluoridation on adults.
Study of Adults in Washington State
A study published in 1992132 in the Journal of the American Dental Association examined adults aged
20–34 years in the state of Washington and found that those who had a continuous lifetime exposure
to optimally fluoridated water had 31% less tooth decay experience compared to similar aged adults
with no exposure to fluoridated water. It also concluded that exposure to fluoridation only during
childhood has lifetime benefits because adults exposed to fluoridated water only during childhood
had decay experiences similar to those adults exposed to fluoridated water only after age 14.132
Decay among Australian Defense Force Personnel
A noteworthy Australian study133 published in 2008 examined decay experience among Australian
Defense Force personnel and showed that a longer period of exposure to water fluoridation was
associated with lower decay rates in adults between the ages of 17–44. Adults who lived at least
90% of their lifetime in communities with fluoridated water had 24% less decay than adults who
lived in fluoridated areas for less than 10% of their lifetimes.133
Data from the Australian National Survey of Adult Oral Health
A 2013 study using data from the Australian National Survey of Adult Oral Health showed that adults
with greater lifetime exposure to fluoridated water had lower caries experience.134
Another study emphasized that benefits from lifetime access to fluoridated water could be observed
clearly up to age 45 but seemed to flatten out in older age groups. The authors suggested that a
cumulative measure such as the number of tooth surfaces classified as decayed, missing, or filled could
become “saturated” in a chronic disease such as dental caries, making it hard to show differences by
exposure level.135
