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Your Guide to Fluoride

Fluoride is used to prevent cavities. It was originally thought that fluoride worked to decrease cavities solely by making the enamel stronger. However, new studies have determined that fluoride also helps in re-mineralization (a process of rebuilding the tooth after damage) and fighting bacteria. The use of fluoride has substantially declined the rate of cavities.

When children receive an adequate level of fluoride the enamel of the teeth is found to have a formation of fluorapatite crystals that are smaller and stronger and more resistant to breakdown. Fluoride can also act in a process called bacterial inhibition to stop the production of cavities by interfering with cavity-forming bacteria found in plaque.

Fluoride can be found in many sources. Fluoride is intentionally added to toothpaste, some mouth rinses, fluoridated water, and fluoride supplements. It is found naturally in some well water, in some brewed tea, in some bottled water, and some fish. (Products made from or that come from naturally fluoridated water.)

Fluoride was first introduced into the water supply intentionally to help prevent cavities in the 1940s. Communities in Arizona that have chosen to adjust the fluoride level in their drinking water include but are not limited to: Bisbee, Chandler, Gilbert, Phoenix, Tempe, Glendale, El Mirage, Mesa, and Yuma.

Fluoride levels can fluctuate, but are strictly controlled by the local water treatment plant. “The best source of information on fluoride levels in your water system is your local water utility. All water utilities must provide their consumers with a Consumer Confidence Report that provides information on a system’s water quality, including its fluoridation level. The state drinking water administrator or state oral health program also should be able to help you identify the fluoride level of your drinking water. Optimal fluoride levels recommended by the U.S. Public Health Service and CDC for drinking water range from 0.7 parts per million (ppm) for warmer climates to 1.2 ppm for cooler climates to account for the tendency for people to drink more water in warmer climates.”(2)

For example, The City of Chandler strives to maintain fluoride levels at the Sewage Waste Treatment Plant between 0.7 & 1.0 PPM, which is the level recommended by the National Public Service, EPA and the American Dental Association. Ground water does not receive additional fluoride, however, the natural occurring fluoride averages 0.9 PPM. (2) Furthermore, the city of Scottsdale does not add fluoride to the drinking water. However, Scottsdale water sources contain low levels of naturally-occurring fluoride ranging from 0.3 to 1.0pp.(3)

Data obtained from 1992 to 2004 shows the naturally occurring level of fluoride in Maricopa county. It is broken down in this chart based on the water system. As you can see the levels naturally occurring are higher than the recommended levels by the ADA and the EPA. In cases such as this, as a public health measure, the excess fluoride would be removed during processing.


The Environmental Protection Agency has set a maximum level of 4 mg/L fluoride for human consumption. Levels above this can cause fluorosis. The symptoms of mild fluorosis include white mottled areas of enamel due to hypomineralization which can cause a cosmetic concern. More severe fluorosis can result in pitted and malformed areas of enamel and brittle enamel. Fluorosis does not occur in adults because it must occur during pre-eruptive enamel maturation (development of the adult tooth before it erupts from the gum tissue); ingestion of excess fluoride after this developmental phase cannot result in fluorosis. Generally most children have developed all their adult teeth by the age of 8 and therefore, it is very unlikely to see fluorosis in someone older than this age.

In contrast, Reverse osmosis typically removes at least 80% of most constituents, including fluoride. However, you may want to contact the manufacturer of the reverse osmosis device to determine the removal rate for your system. It is possible that if you have fluoridated water and use a reverse osmosis system in your home, then you are not getting adequate levels of fluoride.

If the water supply does not provide adequate fluoride, then supplementation can help to decrease the risk of developing cavities. For children under 16 years of age, chewing or sucking fluoride tablets and lozenges prior to swallowing will maximize the effect of these supplements by providing an additional topical effect before being absorbed systemically. Current recommendations from the American Academy of Pediatric Dentistry, ADA, and American Academy of Pediatrics are to start fluoride supplements, if required, at 6 months of age because prior to that most infants do not have teeth.
The selection, use, and frequency of various types of fluoride treatments for an individual patient are based on his or her risk level, ADA recommendations, patient age, product efficacy, clinical support, safety, ease of use, and patient preference. Your dentist can provide an in-office fluoride treatment in the form of a varnish, gel, foam or rinse. The concentration of in-office fluoride treatments is significantly higher than at-home treatments. The use of at-home fluoride treatments include toothpastes/ gels, and rinses. At home dentifrice (for example: a toothpaste such as colgate or crest) twice daily provides a regular supply of fluoride that results in the presence of low levels of fluoride intra-orally on the teeth and soft tissues. (5) Dr. McCargar, a dentist in Scottsdale, Arizona states that at-home fluoride treatments are most effective if the patient does not swish with water after using. “Many people after brushing rinse their mouth with water, this washes away the fluoride treatment. An extensive number of clinical trials have demonstrated a significant reduction in cavities if people use the fluoride treatments as directed.”

(1) http://apps.nccd.cdc.gov/MWF/Index.asp
(2) http://www.chandleraz.gov/default.aspx?pageid=458
(5) Twetman S. Caries prevention with fluoride toothpaste in children: an update. Eur Arch Paediatr Dent. 2009 Sep; 10(3):162-67