8 l © 2025 American Dental Association
Introduction
Water Fluoridation’s Role in Reducing Tooth Decay
Water fluoridation has played a significant role in improving oral health. Numerous studies and reviews on
fluoridation have been published, making it one of the most widely studied public health measures in history.
Studies show that community water fluoridation prevents about 25% of tooth decay in children62 and adults,63
even in an era with widespread availability of fluoride from other sources, such as fluoride toothpaste.
Tooth decay is caused by sugars in food and beverages being converted into acid by the bacteria in dental
plaque, a thin, sticky, colorless deposit on teeth. The acid attacks the tooth enamel (the hard surface of the
tooth) or root surface. After repeated attacks, the enamel or root surface loses minerals (a process called
demineralization), and the acids and bacteria penetrate the dentin (an inner softer layer of tooth). Without
intervention, the decay process can reach the innermost part of the tooth called pulp. The soft tissue of
the pulp contains nerves and blood vessels. Once the decay enters the pulp, the pulp becomes infected,
and without treatment, the infection progresses and travels into the surrounding tissues. It can enter the
bloodstream and potentially spread the infection to other parts of the body like the brain or the throat
closing off the airway, which can be life-threatening.64
Additional information about this topic can be found in the Benefits Section, Question 2.
There are a number of factors that increase an individual’s risk for tooth decay:65–69
• Recent history of tooth decay
• Elevated oral bacteria count
• Inadequate exposure to fluoride
• Exposed roots
• Frequent intake of sugar or sugary foods and sugar-sweetened beverages
• Poor or inadequate oral hygiene
• Decreased flow of saliva
• Deep pits and fissures on the chewing surfaces of teeth
Exposure to fluoride is a key component in any recommended decay prevention strategy however, the use
of fluoride alone will not prevent all tooth decay. In formulating a decay prevention program, in addition
to consuming fluoridated tap water, a number of intervention strategies should be considered. These can
include improved daily home care, including brushing with fluoride toothpaste, reducing sugar in the diet,
placement of dental sealants, home use of prescription-strength fluoride toothpaste, and professionally
applied topical treatments.
Ongoing Need for Water Fluoridation
Because of the risk factors for tooth decay noted previously, many indi0viduals and communities still
experience high levels of tooth decay. Although water fluoridation demonstrates an impressive record
of effectiveness and safety, only 72.3% of the US population on public water supplies in 2022 received
fluoridated water containing protective levels of fluoride57 Unfortunately, some people continue to be
confused or misinformed about this effective public health measure. If the number of individuals drinking
fluoridated water is to increase, the public must be accurately informed about its benefits and safety.
Introduction
Water Fluoridation’s Role in Reducing Tooth Decay
Water fluoridation has played a significant role in improving oral health. Numerous studies and reviews on
fluoridation have been published, making it one of the most widely studied public health measures in history.
Studies show that community water fluoridation prevents about 25% of tooth decay in children62 and adults,63
even in an era with widespread availability of fluoride from other sources, such as fluoride toothpaste.
Tooth decay is caused by sugars in food and beverages being converted into acid by the bacteria in dental
plaque, a thin, sticky, colorless deposit on teeth. The acid attacks the tooth enamel (the hard surface of the
tooth) or root surface. After repeated attacks, the enamel or root surface loses minerals (a process called
demineralization), and the acids and bacteria penetrate the dentin (an inner softer layer of tooth). Without
intervention, the decay process can reach the innermost part of the tooth called pulp. The soft tissue of
the pulp contains nerves and blood vessels. Once the decay enters the pulp, the pulp becomes infected,
and without treatment, the infection progresses and travels into the surrounding tissues. It can enter the
bloodstream and potentially spread the infection to other parts of the body like the brain or the throat
closing off the airway, which can be life-threatening.64
Additional information about this topic can be found in the Benefits Section, Question 2.
There are a number of factors that increase an individual’s risk for tooth decay:65–69
• Recent history of tooth decay
• Elevated oral bacteria count
• Inadequate exposure to fluoride
• Exposed roots
• Frequent intake of sugar or sugary foods and sugar-sweetened beverages
• Poor or inadequate oral hygiene
• Decreased flow of saliva
• Deep pits and fissures on the chewing surfaces of teeth
Exposure to fluoride is a key component in any recommended decay prevention strategy however, the use
of fluoride alone will not prevent all tooth decay. In formulating a decay prevention program, in addition
to consuming fluoridated tap water, a number of intervention strategies should be considered. These can
include improved daily home care, including brushing with fluoride toothpaste, reducing sugar in the diet,
placement of dental sealants, home use of prescription-strength fluoride toothpaste, and professionally
applied topical treatments.
Ongoing Need for Water Fluoridation
Because of the risk factors for tooth decay noted previously, many indi0viduals and communities still
experience high levels of tooth decay. Although water fluoridation demonstrates an impressive record
of effectiveness and safety, only 72.3% of the US population on public water supplies in 2022 received
fluoridated water containing protective levels of fluoride57 Unfortunately, some people continue to be
confused or misinformed about this effective public health measure. If the number of individuals drinking
fluoridated water is to increase, the public must be accurately informed about its benefits and safety.
