Water is necessary for all bodily functions. In addition, water treated with fluoride has become an essential part of maintaining good oral health. Fluoride is a mineral that helps strengthen teeth and protects them from decay. Most U.S. communities now add fluoride to their water systems.

Fluoridation of community water supplies enables fluoride to routinely enter the mouth. Dental plaque absorbs some of this fluoride. Fluoride from water also rests loosely on dental enamel and remains in saliva for a period of time. Fluoridation of the water supply is estimated to reduce tooth decay by between 20 percent and 40 percent, according to the American Dental Association (ADA).

People obtain their daily water supply from different sources. For many years, tap water has been the primary source of water for most people. However, in recent years increasing numbers of Americans have begun to get their daily water from sources other than the tap. Such sources include bottled water, water machines, and water that is filter treated at home. In many cases, these alternative sources of water do not offer the same fluoridation benefits as tap water.

Few brands of bottled water add fluoride to their water, and the majority fail to contain optimal levels (0.7 to 1.2 parts per million) of fluoride necessary to protect teeth, according to the ADA. In addition, some home water treatment systems actually reduce the amount of fluoride in tap water, although others do not.

In recent decades, water consumption has become more important in maintaining good oral health. This is because most U.S. communities now add a mineral called fluoride to their water systems. Fluoride helps strengthen teeth and protects them from decay. In addition, water moistens body tissues, including those of the mouth.

Water is the most abundant and essential nutrient in the human body. It comprises approximately 60 percent of the total body weight of a normal adult and provides the medium by which nutrients reach all body cells and waste products are excreted. It also serves as the medium in which many metabolic reactions can occur.

A person cannot survive for long without drinking water. Low levels of water can lead to dehydration, a condition in which water loss is greater than water intake, resulting in a negative water balance. Although people can survive for several weeks without consuming any food, they cannot live more than a few days without water. Since the human body cannot store water, it must be constantly replenished. Most experts recommended that people drink at least eight 8 ounce glasses of water daily.

In the 1930s, scientists first noticed that people who drank fluoridated water had less tooth decay. Fluoride is a mineral that helps harden developing tooth enamel (remineralization) and protects teeth from tooth decay. Beginning in 1945, some communities began adding fluoridation to drinking water and for more than 50 years, the American Dental Association (ADA) has recommended that others follow suit.

When communities decide to fluoridate the water supply, the amount of fluoride that is naturally found in water is artificially boosted to a level that can protect teeth from decay. Usually, this requires adding just a tiny amount of extra fluoride.

Fluoridation of community water supplies is the most important public health tool for preventing tooth decay, according to the ADA. Regular consumption of fluoridated water helps to prevent the complications of tooth decay such as abscessed teeth, which may require tooth extraction. Dental plaque absorbs some of the fluoride. Fluoride from water also rests loosely on dental enamel and remains in saliva for a period of time (about one to two hours). Certain beverages (e.g., fruit juices) and foods (e.g., spaghetti sauce) may also contain some fluoride if they are processed in areas where the water supply contains the mineral.

Fluoridation of the water supply is estimated to reduce tooth decay by between 20 percent and 40 percent. More than two-thirds of Americans live in communities where the water is fluoridated, according to the ADA. People can find out whether or not their water supply is fluoridated by contacting a local dentist, the local or state department of health, or the local water supplier.

People obtain their daily water supply from different sources. For many years, tap water has been the primary source of water for most people in the United States. For more than 50 years, water has been fluoridated in ever-growing numbers of communities.

Fluoridated water contains levels of fluoride added to the water within the limitations set by federal regulations. Before fluoridation of water, tooth decay was much more prevalent. Adding fluoride to drinking water, toothpaste, and mouth rinses has helped to prevent cavities in many people. In children under five, too much fluoride can cause a disruption in enamel formation (fluorosis), so careful monitoring of ingested fluoride products should be performed.

Although most community water supplies now contain fluoride, in recent years increasing numbers of Americans have begun to get their daily water from sources other than the tap. Such sources include bottled water, water machines at work and water that is filter treated at home. In many cases, these alternative sources of water do not offer the same fluoridation benefits as tap water.

People can choose from a wide array of available bottled water. The water source differs from brand to brand and is listed on the water’s packaging. The word “natural” is only allowed for bottled water that is derived from springs or wells without altering the original composition of the water through a treatment process. The following are some examples of different bottled water sources:

• Artesian well water. Comes from a well that taps a confined aquifer (a water-bearing underground layer of rock or sand). It is usually collected without mechanical pumping.
  
  
• Mineral water. Contains minerals at a standard level of no less than 250 parts per million (ppm) of total dissolved solids or minerals. These minerals must be naturally present and not added to the water.
  
  
• Spring water. Comes from an underground source and naturally flows to the surface. Spring water must be collected at the spring or through a borehole tapping the underground formation feeding the spring.
  
  
• Well water. Collected from an underground aquifer with a mechanical pump.

The U.S. Food and Drug Administration (FDA) does not consider sparkling water, seltzer water, soda water, tonic water or club soda to be types of bottled water.

In some cases, regular tap water is sold in bottled form after it has been treated. This water is typically referred to as purified water and has been processed or “purified” to remove minerals and other solids or impurities. The water can be purified by a number of different methods, such as:

• Absolute 1 micron filtration. Water flows through filters that remove small particles, such as parasites.
  
  
• Distillation. Water turned into steam and condensed into pure water, removing impurities and reducing levels of all chemicals, including heavy metals such as lead. Due to its purity, distilled water is used in manufacturing of pharmaceuticals and liquid prescriptions. One of the removed chemicals from distilled water is fluoride.
  
  
• Ozonation. Use of an antimicrobial agent called ozone gas to disinfect water. This technique is used instead of chlorination, which can leave a residual taste and odor in the water.
  
  
• Reverse osmosis. The water is forced through membranes to remove minerals.

Few brands of bottled water add fluoride to their water, and the majority fail to contain optimal levels (0.7 to 1.2 parts per million) of fluoride necessary to protect teeth, according to the American Dental Association (ADA). Some brands use treatments that remove all of the fluoride in the water. Therefore, people who only drink bottled water are urged to talk to their dentist about ways to obtain fluoride from other sources. For example, they may need to use fluoridated toothpaste, rinse or a multivitamin with fluoride.

Consumers are urged to check the labels of bottled water to help determine whether or not the water contains adequate levels of fluoride for preventing tooth decay. The FDA requires bottled water with added fluoride to carry labels that say “fluoridated,” “fluoride added” or “with added fluoride.” The fluoride content of bottled water is not required on the label if fluoride is not added during processing. It may be necessary to directly contact the product manufacturer when trying to determine exactly how much fluoride is present in the water.

In 2006, the Food and Drug Administration (FDA) approved a health claim for fluoridated bottled waters. The claim “Drinking fluoridated water may reduce the risk of tooth decay” may be used on bottled water that meets certain standards and contains between 0.6 and 1.0 milligrams per liter of total fluoride. Total fluoride includes both naturally occurring fluoride and added fluoride. However, due to the risk of fluorosis, this claim may not be used on bottle water products marketed specifically for use by infants.

In addition, some home water treatment systems actually reduce the amount of fluoride in tap water, which can reduce the effectiveness of water in fighting cavities. Devices for treating water at home are available in two types. Point of use systems treat the water after it comes through the tap. They include devices that attach to the tap and water pitchers that use filters. Point of entry devices treat all water as it comes into the home.

Home water treatment systems vary in how much fluoride they remove from water. Steam distillation units remove 100 percent of fluoride content and devices that use reverse osmosis remove between 65 percent and 95 percent of fluoride. Meanwhile, the commonly used charcoal filters, carbon filters and water softeners generally do not remove significant amounts of fluoride. Consumers are urged to check with the manufacturer to find out whether or not a home water treatment system removes fluoride from the water.

Preparing questions in advance can help patients to have more meaningful discussions regarding their conditions. Patients may wish to ask their doctor the following questions related to water and oral health:

1. Can you tell me whether or not my water supply is fluoridated?
   
   
2. Am I getting enough fluoride to prevent tooth decay if I drink from the tap once or twice a day?
   
   
3. How much water do I need to drink daily for oral health?
   
   
4. Is there a danger in being exposed to too much fluoride in tap water?
   
   
5. Can drinking a lot of juice provide adequate levels of fluoride?
   
   
6. I drink only bottled water. Should I take fluoride supplements?
   
   
7. Do you know of a brand of bottled water with adequate levels of fluoride?
   
   
8. How can I tell if my home water treatment system removes fluoride?
   
   
9. How much fluoride must be removed from water before it loses its protective effect?
   
   
10. Can drinking more water cure my case of “dry mouth”?