Maine Oral Health Program

Questions and Answers about Fluoride and Community Water Fluoridation in Maine


What is fluoride?

Fluoride is a naturally occurring substance. It comes from the element fluorine, which is abundant in rocks and soil. As water passes through the earth it absorbs fluoride. As a result, there are small amounts of fluoride in all water sources.

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What is water fluoridation?

Water fluoridation means that a public water system monitors the amount of fluoride in a public water supply to assure optimal fluoride levels to safely support oral health. In some areas this means that they water system managers add some fluoride to the water supply. Fluoride levels of .7 to 1.2 parts per million are considered safe and effective levels of fluoride in public water and will help prevent tooth decay.

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What is the right amount of fluoride?

The best level for fluoride in drinking water is between 0.7 to 1.2 parts per million. This amount can help prevent tooth decay. One part per million means one “part” of fluoride is mixed in one million parts of water. This can be compared to 1 inch in 16 miles, or 1 cent in $10,000.

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How do I know how much fluoride my water has?

See if your town or city has fluoridated public water (PDF)

Your public water district can also provide information on levels, or contact the Maine Drinking Water Program, at 287-2070.

If you have well water, you need to have your water tested to find out how much fluoride you have. Contact the Maine Health & Environmental Testing Lab or call 287-2727 about testing wells for fluoride. There are also private labs that will test well water.

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How does fluoride help prevent decay?

Fluoride protects teeth in two ways:

Systemic fluoride. This is the fluoride in drinking water, fluoride vitamins or supplements. This fluoride is swallowed. Systemic fluoride in saliva strengthens the tooth structure and helps prevent decay. It reaches teeth still forming, even before you can see them in the mouth.

Topical fluoride. This is the fluoride in toothpaste, gels and rinses. It strengthens teeth already in the mouth. When drinking water is fluoridated, there is also a slight topical effect from the water. Both topical and systemic fluoride help prevent decay by strengthening teeth. Fluoride can help reverse early decay.

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Is tooth decay a serious problem?

Yes. Tooth decay is a disease caused by bacteria. It is the most common and costly oral health problem for people of all ages. It is also the most common chronic disease of childhood. It is 5 times more common than asthma. By the time they are 18 years old, 80% of all children have had tooth decay. Children and adults need good oral health as part of good overall health.

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Does water fluoridation help prevent tooth decay?

Yes. Many studies have shown that water fluoridation helps reduces tooth decay for children and adults. Studies show reductions between 18% to 40% in children. For adults the estimates are around 35

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Do adults benefit from water fluoridation?

Yes. People of all ages benefit from water fluoridation. Fluoride in saliva strengthens the tooth surface and helps prevent decay.

Older people have receding gums. This leads means small areas of teeth are exposed that can be very sensitive to hot or cold. Fluoride help strengthen the teeth so temperature changes are less painful.

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Is fluoride in the water supply safe for human health?

Yes. The safety of fluoridated water has been studied many times, for over 60 years. These studies show that fluoridation of community water supplies is both safe and effective. The Maine CDC agrees with this scientific evidence.

Maine’s water companies make sure that the amount of fluoride in drinking water is the right amount, between 0.7 and 1.2 parts per million.

Many healthful substances can be harmful you get too much. This is true of salt, iron, vitamins A and D, and even water itself. Fluoride can also be harmful in excessive quantities. Water companies carefully control the amount of fluoride allowed in the water. Fluoride is safe at the levels recommended in Maine.

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How much fluoride should I have each day to reduce tooth decay?

When drinking water has fluoride added to help prevent tooth decay, your normal drinking should provide the right amount of fluoride. For infants, there are new guidelines. Link here to question below “What about fluoridated water and infants?”

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What is dental fluorosis?

Dental fluorosis (“floor-oh-sis”) is not a disease but it can change how teeth look. It is from too much fluoride while teeth are forming under the gums. It is a change in the outward appearance of teeth.

  • Mild fluorosis might be seen as faint white lines or streaks on teeth if it is seen at all.
  • More severe fluorosis can cause small pits and discoloration of teeth.
  • Fluorosis develops in teeth when they are forming under the gums, from birth to around age nine. Once the tooth is formed and in the mouth, fluorosis cannot progress.
  • The first year of life is the most critical time, when teeth can be most affected. This is why monitoring exposure to fluoride for infants is important ( see below).
  • The occasional use of fluoridated water will not harm a baby’s developing teeth.

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What about fluoridated water, fluorosis and infants?

There are new suggestions to help prevent fluorosis. These are from the American Dental Association (ADA). They are for infants up to age three.

This advice is only for babies who get most of their food from infant formula that is mixed with water:

Breast milk is the best food for your baby. The American Academy of Pediatrics recommends breastfeeding only for the first six months. If you use liquid concentrate or powdered infant formula, you can mix it with bottled water that is low fluoride or fluoride free. Low fluoride water is labeled as “purified”, “demineralized”, “deionized”, “distilled” or “reverse osmosis filtered water”. It can be found at the grocery store. If you do use formula, using ready-to-feed formula can help make sure your child doesn’t get enough fluoride to cause fluorosis.

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What does Maine’s Center for Disease Control and Prevention (MCDC) say about community water fluoridation?

Community water fluoridation is safe. Community water fluoridation works. It prevents and reduces tooth decay. Everyone benefits from fluoridated water. People who don’t have insurance, can’t afford or can’t find dental care will especially benefit. Fluoride has been used in public drinking water to help prevent tooth decay for over 60 years. It has been extensively studied and evaluated. Many national and international groups have studied water fluoridation . They have found that it is safe and that it works. These include the federal Centers for Disease Control, the World Health Organization, the Environmental Protection Agency the American Dental Association and many others. The Maine CDC uses these studies to make its recommendations. Read the Maine CDC’s statement on community water fluoridation here.

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Is water fluoridation used in other states and by other countries?

Yes. In the US, most public water is fluoridated water. Nearly two-thirds of those who get public water have fluoridated water. In the rest of the world there are over 405 million people in more than 60 countries that have fluoridated water.

A number of European countries (France, Germany, Spain, Switzerland, Hungary, for example) add fluoride to their salt rather than their water. Salt fluoridation can be as effective as water fluoridation.

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What Maine communities have fluoridated water supplies?

In Maine, 67 water systems provide fluoridated water to 132 communities (PDF) in the state.

The first community in Maine to add fluoride to drinking water was Norway, in 1952. Water is fluoridated by public referendum. People in all the communities served by a water district vote to add fluoride.

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How does water fluoridation compare to other public health measures?

To protect public health we:

  • add folic acid to cereal products to prevent birth defects;
  • add iodide to salt to prevent goiter;
  • add chlorine to water to disinfect it;
  • add vitamin D to milk to build stronger bones.

Fluoridation is similar to other ways we protect public health.

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Does the National Research Council support fluoridation of community drinking water?

The National Research Council, (a private, nonprofit institution that gives science, technology and health policy advice to the federal government) did a study “Fluoride in Drinking Water”, in March 2006. The report was about very high levels of fluoride from naturally-occurring fluoride found in some parts of the country. The levels studied were four times higher than what is put in water supplies.

The report states: “Because fluoride is well known for its use in the prevention of dental caries, it is important to make the distinction here that EPA's drinking-water guidelines are not recommendations about adding fluoride to drinking water to protect the public from dental caries.”

There is nothing in this report that suggests that the recommended levels of fluoride present any danger to consumers.

It is unfortunate that some people have misused the report confuse the public about the safety of fluoride . The report did not question the safety of community water fluoridation.

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Does fluoride help prevent diabetes, heart disease, low birth weight babies and pancreatic cancer?

We are learning more all the time about how important oral health is to the control and prevention of diabetes, heart disease, low birth weight babies and pancreatic cancer. Fluoride helps create good oral health. Indirectly, fluoride helps!

In response to claims that fluoride contributes to cancer, The American Cancer Society states, “Scientific studies show no connection between cancer rates in humans and adding fluoride to drinking water.” (

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