Fluoride: What Should We Know?

Dental fluorosis is on the rise – a condition that appears as white spots or streaks on a person’s teeth, or as brown markings in more severe cases. Dentists say it’s caused by kids ingesting too much fluoride in the years while their teeth are forming. 


Arnold Weiss, D.D.S., of The Center for Pediatric Dental Care in Brookline, Tufts University School of Dental Medicine clinical professor and a member of the American Academy of Pediatric Dentistry’s Council on Clinical Affairs, defines fluorosis as a “mottling” of tooth enamel “caused by excessive exposure to very high concentrations of fluoride only during the development of the un-erupted teeth.” He says fluorosis sometimes occurs when kids swallow too much fluoride toothpaste or there’s an inappropriate use of fluoride supplements.


The rising incidence of fluorosis is cited by the Fluoride Action Network, a group founded in 2000, as one reason – out of 50 – for why it opposes the fluoridation of U.S. water supplies. The group also speculates that fluoride overexposure poses non-teeth-related health risks, too.


In light of these and other concerns, we asked local dental experts for an overview on fluoride and its safety.


Benefits of Fluoride


“In the early 1930s, dentists noted that people who grew up in areas where water was naturally fluoridated through the soil had up to two-thirds fewer cavities compared to those who lived in areas where the water did not contain fluoride,” says Linda Vidone, DMD, dental director of Delta Dental of Massachusetts. Starting in 1945, U.S. cities (like Grand Rapids, Mich., which was the first) began adjusting fluoride levels in their water supplies for the purpose of lowering tooth decay rates in children. Since then, the Centers for Disease Control and Prevention (CDC) calls water fluoridation one of the top 10 public health achievements of the 20th century.


“Fluoride exists naturally in nearly all water supplies,” explains Htet Htet, DMD, of Kid Care Dental in Stoughton, but “is not always at optimal levels to strengthen the enamel of teeth.” When a public water supply is “fluoridated,” she says, the fluoride amount is adjusted to a level that is most effective to safely prevent tooth decay. “About 74 percent of Americans receive fluoridated water,” she notes.


Dentists say exposing kids to fluoride – particularly between ages 6 months and 16 years when their primary and permanent teeth are forming – is important for developing strong, healthy teeth. According to Weiss, fluoride prevents tooth decay in three ways:


• by strengthening the outside of the tooth, thereby reducing the ability of bacteria and tooth-weakening acids in plaque to destroy tooth structure;   


• by re-mineralizing those tooth areas where acid attack has already begun; and


• by limiting bacterial growth.


The cost of fluoridating drinking water costs less per person over a lifetime than the cost of one filling, notes Vidone.   

Read about optimal amounts of fluoride on the next page.

Optimal Amounts of Fluoride


The American Dental Association and the American Academy of Pediatrics endorse government recommendations regarding frequent childhood (and adult) exposure to small amounts of fluoride each day. Fluoride sources include:


• tap water (if the community’s water supply is fluoridated);


• most toothpastes and mouth rinses;


• certain foods and drinks (especially those processed with fluoridated water);


• fluoride treatments in the forms of varnishes and gels commonly applied during dental checkups; and


• fluoride supplements (sometimes prescribed by dentists for those at high risk for cavities and living in areas without fluoridated tap water).


This past spring, U.S. Surgeon General Regina Benjamin officially endorsed community water fluoridation for promoting good oral health. The CDC reports, “Even today, with other available sources of fluoride, studies show that water fluoridation reduces tooth decay by about 25 percent over a person’s lifetime.”


Just as with other health recommendations, the risks of fluoride continue to be studied with new recommendations made all the time. Experts say fluoride is safe “in optimal amounts,” but consider the following:


• Some kids drink fluoridated tap water all the time while others drink bottled or filtered water, or have a mix of the two. 


• Some infants ingest formula made with fluoridated tap water while others are exclusively breastfed.


Judging just by these two scenarios, if our kids are to receive “optimal amounts” of fluoride, we might need some clarification from dentists and pediatricians about that Goldilocks question: “What is too much? What is too little? And what is just right?”


Cautions to use “training toothpaste,” which doesn’t have fluoride, for brushing a young child’s teeth and only a “tiny smear” of fluoride toothpaste (down from the pea-size amount previously recommended) for children who haven’t mastered spitting also appear to indicate fluoride ingestion shouldn’t be taken lightly. 


The Controversy


The Fluoride Action Network calls fluoride a “corrosive acid captured in the air pollution control devices of the phosphate fertilizer industry.”


Weiss counters this, saying fluoride is a mineral found in varying degrees in soil, plants and water supplies that prevents tooth decay. It’s a “naturally occurring substance, but it can be manufactured,” he says, and it’s “a co-product of fertilizer production rather than a waste product. The results – or byproducts – of various chemical reactions create products we use on a daily basis.”

Read about the controversy of fluoride on the next page.

According to Htet, “any compound that forms fluoride ions in water solution can be used in the fluoridation process.” Sodium fluoride is the most common, and is found in most toothpastes, mouthwashes, dental varnishes and supplements.


“There are many types of fluoride,” says Htet, “not one is more harmful than the others; preference is due to cost and ease of utilization.”


Interestingly, sodium fluoride is also used as an insecticide and pesticide, in making steel and aluminum products, and in the manufacture of chemical and biological weapons.


The Fluoride Action Network makes a point of noting that most developed countries in the world do not fluoridate their water and that the incidence of cavities has been going down globally. The group calls fluoride “the only medicine added to public water” and says “fluoride supplements have never been approved by the FDA (U.S. Food and Drug Administration).”


Vidone responds by saying, “Like a vitamin, fluoride at the right amounts in drinking water improves resistance to tooth decay. It doesn’t cure or medicate. It prevents. The FDA does not look at, recommend or approve preventative methods like fortifying vitamins in foods, adding iodine to salt or fluoride to water. The scientific evidence of the effectiveness of community water fluoridation to prevent tooth decay has been consistent and firm for [nearly] 70 years. Any argument to the contrary is bending the facts.”


Weiss says “in areas of Massachusetts that do not have fluoridated water, decay is much higher” and he says he’s observed in his volunteer work in Europe that “non-fluoridated areas have rampant decay.”


What’s a Parent to Do?


• Be an informed consumer. Talk to your dentist and/or pediatrician to understand the right amount of fluoride for your child’s age, weight and risk of dental decay. 


• Research fluoride’s benefits and risks, such as fluorosis, so you can make informed decisions for your children. Check your dental practice’s website for information.


• When making decisions about whether children should receive fluoride treatments or supplements, make sure to take into account whether you drink bottled or fluoridated tap water.  


• If you’re breastfeeding or bottle-feeding a baby, consider the fluoride issue. Consult pediatricians for guidelines about whether to mix formula with fluoridated tap water, bottled water or a combination of the two.


• Watch out for frequent snacking and avoid prolonged use of bottles or sippy cups, which have been associated with tooth decay. 


• Teach kids to spit out toothpaste! Investigate non-fluoride products if you’re worried (Tom’s of Maine makes a non-fluoridated version of its toothpaste). Carefully supervise the use of prescribed fluoride rinses and supplements.


• Find a “dental home” for your child after the eruption of the first tooth and follow the recommendations of experts you trust.


Mary Alice Cookson is associate editor of Boston Parents Paper.


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11 Feb 2014

By Mary Alice Cookson