Water Fluoridation and Industrial Symbiosis

Water fluoridation is the generally well-regarded practice of adding fluoride to water supplies in order to combat tooth decay. Tooth decay, or dental caries, is the gradual degradation of dental material that can result in discoloration and the physical decomposition of teeth. Studies have shown that adding an optimal amount of fluoride to a water supply is a cost-effective way to help combat dental caries. Additionally, fluoridated water has no perceivable taste, odor or color. Obtaining bulk amounts of fluoride to add to water supplies can be problematic, because bulk fluoride production can be expensive and complicated, but fortunately other industries produce fluorides as unneeded byproducts. This exchange can be viewed as an industrially symbiotic relationship.

Dental Caries and Fluoride

Dental caries is a term for a problem involving tooth decay, discoloration and physical degradation of teeth. Dental caries is generally the result of increased plaque, which is an organic mixture of bacteria, food items, cells and saliva. Plaque adheres to dental surfaces and, if left unchecked, grows and begins the gradual process of tooth demineralization. This dissolving is because the bacteria produces acids that colonize tooth enamel and destroy the minerals that comprise it. Low level tooth decay can result in discolorations and lesions, while untreated tooth decay can produce cavities in teeth and the death of dental nerves, causing great pain to the sufferer.

Dental caries is a common problem that affects a large percentage of the population. Roughly 85 percent of adults in the United States have suffered some degree of dental caries. While generally anyone can suffer from dental caries, studies have shown that people of low socioeconomic backgrounds and children are the most susceptible to the disease, as they don’t have the means to adequately limit risks and treat symptoms or are developing and do not have the biological ability to do so.

For over a century, scientists have noticed fluoride’s ability to both slow and prevent dental caries’ development as well as, in some cases, reverse its effects. This effect occurs because fluoride attacks plaque and the bacteria it carries in several ways. Fluoride is carried by saliva and attaches to plaque material as it demineralizes and dissolves enamel. As this process occurs, acids release from the plaque along with fluoride minerals. When this fluoride is ejected, it mixes with dissolved enamel and adheres to stable enamel, creating a new tougher, more durable enamel coating. This increase in strength is because the newly created enamel contains less minerals that attract plaque and is more acid resistant. Because of this creation of new enamel, when dental caries are exposed to a continued assault of low level fluoridation, the process can be reversed and repair old damage already incurred.

Water Fluoridation

Due to these findings, many municipalities have mandated active water supply fluoridation as an inexpensive method of limiting high percentages of tooth caries in populations. According to a report on tooth decay prepared by the Centers for Disease Control and Prevention (CDC), water fluoridation has been found to decrease the amount of dental caries at a lower cost than dental procedures, because the water fluoridation process is inexpensive.

Water fluoridation is achieved by adding fluoride minerals to a water supply in a recommended dose. Water treatment facilities generally add one of three different types of fluoride to a water supply: sodium fluoride, fluorosilicic acid, or sodium fluorosilicate.

The recommended fluoride dose is different for each community, depending on local climate, geography, geology. For instance, in warmer climates, people tend to drink more water, so fluoridation is lower than in colder climates. Water pulled from deep wells generally has a higher fluoridation quantity than water taken from rivers and lakes.

Obtaining Fluoride

Dedicated fluoride production is a very expensive and intensive process, and without the interaction between different industries water fluoridation would be considerably more expensive. However, because fluorides considered appropriate for drinking water are created as byproducts in other manufacturing processes, water treatment facilities have reasonable access to necessary raw materials. Sodium fluoride, for instance, is a byproduct of aluminum production. Sodium fluoride was originally considered a very negative byproduct, because its disposal is quite expensive. Scientists recognized the mutual benefits between these problems and sodium fluoride was identified as the ideal candidate for water fluoridation. As a result, it was processed into salts and slow-release tablets and sold by the aluminum industry to water treatment plants in order to facilitate fluoridation. Fluorosilicic acid and its liquid form of sodium fluorsilicate are byproducts produced by the fertilizer industry. Like sodium fluoride and aluminum, they are generally expensive to dispose of and cannot be produced in dedicated facilities.

The availability of all three of these chemical compounds for fluoridation purposes has made water fluoridation a completely cost effective process. In the United States, the average cost of public fluoridation per person per year is $0.94, compared to the costs of treating just one carious surface, which can cost $8 to $12 more.

Special thanks to B. Lane at ThomasNet.com's Need to Know Guides.