At the beginning of the 20th century, dental caries were widespread and lead to serious tooth loss. In fact, having sound teeth was so important and such a rarity in the general population that the U.S. military made having a minimum of six opposing teeth a requirement during recruitment for WW I and II.
The first glimmer of an association between fluoride and oral health was observed by Dr. Frederick S. McKay in 1901. Noticing a brown stain on the teeth of his patients, Dr. McKay found that those who had these stains seemed to have fewer caries. In 1909, Dr. F.L. Robertson noticed mottling on the enamel (the hard outer surface) of children's teeth after the digging of a new well—source of the local drinking water. It wasn't until 1930 that the well water was analyzed, and high concentrations of fluoride were found. Fluoride, a naturally occurring fluorine ion, is found in soil, foods, and water.
The brown staining and mottling were characteristic of fluorosis, an abnormal condition caused by excessive exposure to fluoride while a child's teeth are forming under the gums. It affects the formation of tooth enamel and can vary from very mild to severe. Very mild fluorosis is manifested as tiny, white spots on 25% of a tooth's surface. Mild fluorosis covers 26% to 50%, and moderate fluorosis compromises all of a tooth's surface. It is most often characterized by brown discoloration of the tooth. Severe fluorosis involves pitting of the enamel and more serious brown staining. Approximately 94% of dental fluorosis today ranges from very mild to mild.
Extensive studies of national water supplies have been conducted. It has been found that dental caries were fewer in cities with more fluoride in the community water supply. A 1945 field study was conducted in four pairs of cities to determine whether a low level of fluoride (between 1.0 ppm and 1.2 ppm) could prevent dental caries. The result was a 50% to 70% reduction in the number of dental caries in communities with fluoridated water; only 10% of the people had mild fluorosis.
In 1962, another study found an optimal fluoride level of 0.7 parts per million (ppm) to 1.2 ppm (warm climates, where water consumption is higher, vs. cooler climates, respectively). This fluoride level range was determined to combat dental caries and pose only a slight risk of mild fluorosis.
Water fluoridation was rapidly adopted in major U.S. cities. About 46% of all public water supplies, however, remain non-fluoridated. Still, there has been a drastic reduction in the incidence of dental caries among children. In 2000, about half of all American children aged five to 17 years had never had a cavity in their permanent teeth. Adults also have experienced a 20% to 40% reduction in dental caries on enamel surfaces, as well as on exposed root caries—a condition peculiar to persons with gingival recession. Some of the earlier studies from the 1980s showed little difference in the reduction rates of dental caries between fluoridated communities and non-fluoridated communities. This may be due to improved dental hygiene, and the use of other fluoride products like fluoridated toothpaste and mouth rinses.
Adding fluoride to drinking water has always been controversial. Though fluoride appears naturally in many water supplies, its purposeful introduction into community water supplies has brought claims of causing cancer, heart disease, Down Syndrome, osteoporosis, acquired immunodeficiency syndrome (AIDS ), low intelligence, Alzheimer's disease, nephritis, cirrhosis, intracranial lesions, allergic reactions, and hip fractures. There has been no credible evidence to link fluoride to these diseases.
Early geographic studies in the 1980s reported a correlation between water fluoridation and bone fractures. However, an October 2000 study of women in four U.S. communities who had a continuous 20-year exposure to fluoride in drinking water found that fluoride was not a factor in increased spinal and hip fractures. In fact, these women exhibited greater bone density in the large bones like the femur, the hip, and the lumbar spine, with a slight decrease in hip and spine fractures. There was, however, a slight increase in the incidence of wrist fractures.
Though claims of increased medical risk when drinking fluoridated water still exist, opponents are finding other issues with platforms from which to fight fluoridation (for example, the fact the individuals do not get to decide whether to fluoridate their own personal drinking water) and whether dental caries are a serious public health problem anymore. These opponents cite studies from the mid-1980s that showed only an 18% difference in dental caries among children living in communities with and without fluoridated water. They claim, and rightly so, that this difference is due to widespread use of fluoridated toothpaste. However, increased use of bottled water, and processed foods that may contain fluoridated water, may also be contributing factors.
Water fluoridation provides inexpensive prevention for at-risk populations in every community. Despite Medicaid benefits that cover dental treatment, poor children often have less access than higher income families to dentists and fluoridated dental hygiene products. Children in non-fluoridated communities seek dental treatment in hospital emergency rooms more often than children in fluoridated communities; this increases costs for their dental treatment. The consumption of fluoridated water can reduce these expenses.
Adding fluoride to drinking water is the most cost-effective method for preventing dental caries. The average costs of fluoridation is around $0.50 per person annually, with some communities paying out only $0.12 per person. Smaller areas with fewer than 10,000 people, however, have costs that can run between $3 and $5 a year per person. Still, the cost of fluoridation for a single person over his or her lifetime can be less than the cost of one filling.
Fluoridation has been found to be effective for all citizens within a community regardless of socioeconomic status, and it has been proven safe for every person to use. Fluoridated water has a topical benefit. It provides ambient fluoride, which promotes remineralization of teeth to all ages and populations who consume the treated water. The latest concern, however, centers on over-fluoridation. There are many more ways to ingest fluoride than just in drinking water. Fluoride is added to prepared foods and bottled drinks. Carbonated drinks, juices, and some bottled waters have fluoride in varying amounts. Often, the fluoride in these products is not revealed on the label. Foods high in fluoride are fish with bones, tea, poultry products, cereals, or infant formula, which is made with fluoridated water. Dental products such as mouth rinses, toothpaste, and fluoride supplements all have added fluoride. Some pediatricians prescribe fluoride supplements without determining the fluoride content of the water a child drinks or assessing the amount of fluoride exposure the child has in his or her environment. Parents need to take a proactive role in learning the contents of their children's prescriptions.
It is of most concern when children ingest large amounts of fluoride, not because of known health risks related to fluoride, but because of the added potential of having fluorosis in children's permanent teeth. Young children under six years of age often use too much fluoride toothpaste and consistently swallow it. This alone has been the biggest cause of excess fluoride ingestion. For that reason, fluoride products should be kept out of the reach of children. Parents should supervise children who are under six years of age as they brush their teeth, ensuring that only a peasized drop of toothpaste is used, and directing them not to swallow toothpaste. Children under six should not use fluoridated mouth rinses.
Water fluoridation has been recognized by more than 90 professional health organizations in the world as the most effective dental caries preventive in the 20th century. Dentists, dental hygienists, pediatricians, nurses, dietitians, and professionals from the United States Centers for Disease Control have endorsed the benefits of fluoridated water. Unfortunately, about half of the population of the United States lives in areas that do not have fluoridated water. Health care professionals need to be aggressive in their efforts to bring fluoride to these areas. Careful monitoring of fluoride present in all environments, and an assessment of the client's fluoride history, need to be carried out by local pediatricians and dentists before fluoride supplements are prescribed. Nurses and other professionals need to take a role in educating parents about fluoride dental products and foods containing fluoride, as well as proper fluoride consumption by children under the age of six.
Dental caries— Tooth decay.
Enamel— The hard, calcified outer surface of a tooth; the hardest known substance in the human body.
Fluoride— A fluorine ion used to treat water or apply directly to tooth surfaces to prevent dental caries.
Fluorosis— Fluorosis is an abnormal condition caused by excessive exposure to fluoride while a child's teeth are forming under the gums. It affects the formation of tooth enamel and can be very mild (a few white spots on a tooth) to severe (etching, pitting, and brown discoloration).
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American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. (847) 434-4000. 〈http://www.aap.org〉.
American Dental Association. 211 East Chicago Ave., Chicago, IL 60611. (800)947-4746, (312)440-2500. 〈http://www.ada.org〉.
National Association of Pediatric Nurse Associates & Practitioners. 1101 Kings Highway, N., Suite 206, Cherry Hill, NJ 08034-1912. 〈http://www.napnap.org〉.
"American Dental Association: Oral Health Topics: Fluoridation Facts: Safety Question 18." April 20, 2001. 〈http://www.ada.org〉.
"American Dental Association: Statement on Water Fluoridation Efficacy and Safety." April 20, 2001. 〈http://www.ada.org〉.