Taking care of your teeth at home

When it comes to tooth loss, the primary culprits are decay and periodontal disease. Tooth decay, the gradual breakdown of the tooth's enamel and interior tissue, can cause cavities and, eventually, the death of the tooth (see "Tooth decay and cavities"). Periodontal disease, on the other hand, attacks the gum tissue, ligaments, and bone that support the teeth (see "Gum disease"). Both of these conditions result from the uncontrolled growth of bacteria in the mouth.

At any time, the number of microbes living in your mouth exceeds the human population of earth. Although most of these microbes are harmless, some bacterial species — Streptococcus mutans in particular — are responsible for tooth decay. The decay-causing bacteria mix with saliva to form a sticky film, called plaque, that adheres to the surface of your teeth. The bacteria consume sugar from food residue in the mouth and excrete lactic acid, which becomes part of the plaque layer. If plaque isn't removed, the acid dissolves the tooth's enamel and inflames the gum tissue.

The plaque that forms on easily accessible surfaces can be dislodged with natural chewing and tongue movements. However, hard-to-reach places — such as between the teeth, in the furrows of the molars, and at the edges of the gums around the teeth — are likely spots for plaque to build up and disease to develop.

Most people can keep bacteria in check with a relatively simple regimen of home care. Some individuals, however, have less natural resistance to oral bacteria. For these people, decay or gum disease may appear or advance despite their best efforts at hygiene. If your dentist suspects this is your problem, he or she may test your susceptibility to bacteria and tailor your oral care accordingly.

Brushing

The cornerstone of any good oral hygiene program is regular brushing. To prevent the chain of events that occurs when bacteria accumulate, you must remove plaque from the surfaces of your teeth at least once every 24 hours. It's best, though, to brush at least twice daily — once after you eat breakfast in the morning and then again in the evening before you go to sleep. To keep your brushing regimen effective, replace your toothbrush when the bristles splay out of line, generally about once every three months.

Brushing up on toothbrush styles

The concept of mechanically cleaning the teeth has been around since ancient peoples chewed the frayed ends of aromatic twigs. The precursor to the plastic and nylon device we know in 2007 came on the scene in the 1930s. With hundreds of models to choose from, you may want to ask your dentist which style of toothbrush is right for you. Table 2 may also help you make your selection.

Table 2: Choosing a toothbrush
Parts	Choices	Considerations
Bristle surface	Flat, concave, convex, or multilevel	Concave is more effective for cleaning the outer surface, while convex does a better job on inner surfaces. Flat and multilevel are the best over all.
Bristle shape	Blunt or rounded	Opt for rounded. Blunt-cut bristles are more likely than rounded ones to damage delicate gum tissue.
Bristle firmness	Extra soft to extra hard	Excessively hard brushes used with abrasive toothpaste can damage the gums and wear away enamel. In general, most dentists recommend soft brushes, especially for people with sensitive teeth.
Head shape and size	Rectangle, diamond, or polygon shapes; regular or compact size	Compact angled heads are better for people with smaller mouths. Otherwise, choose the size and shape that is the most comfortable.
Handle design	Straight or angled	All handle shapes seem to work equally well. Choose the design that feels the most comfortable to you. The more comfortable you are using your toothbrush, the more likely you are to brush often.

Manual vs. electric: Which is the better brush?

Electric toothbrushes have been widely touted, and indeed they can be effective when used consistently. However, you can achieve similar results with proper use of a manual toothbrush.

Electric brushes resemble the professional cleaning tools that your dentist uses. They use a variety of motions: back and forth, up and down, or rotation. One of the most widely used brushes, the Braun Oral-B 3D Excel, features a three-dimensional rotation pattern and a pressure sensor that stops the toothbrush from pulsating if you are brushing too forcefully. Sonicare, another popular brand of power toothbrush, relies on high-speed vibration (about 31,000 strokes per minute) of the individual bristles rather than movement of the toothbrush head. A variety of studies have been done comparing different power toothbrushes, and results have varied, with each toothbrush maker offering up studies showing that its product is more effective at removing plaque.

Similarly, studies comparing power brushes with manual ones have turned up conflicting evidence. According to an article published in the International Journal of Dental Hygiene, there is general agreement that power brushes are as safe as manual ones, but studies disagree on which type of brush removes plaque more effectively. This is due in large part to differences in the ways the studies were designed.

However, an analysis sifted through the existing information and found that one type of toothbrush was better at eliminating plaque than the rest. The Cochrane Collaboration, an independent nonprofit organization, evaluated randomized studies of toothbrushes done from 1966 to 2004. The researchers compared brushes' effectiveness at removing plaque, maintaining gum health, and removing stains, as well as their dependability and adverse effects. The power brushes were divided into seven groups based on how they worked.

What they found is that most of the power toothbrushes were no more effective than manual toothbrushes. Just one type of brush — the rotation oscillation design (where the brush heads rotate in one direction and then the other) — was consistently better at removing plaque and reducing gingivitis (gum inflammation) than a manual toothbrush. Examples of rotation oscillation brushes include the Braun Oral-B 3D and the Philips Jordan HP 735.

An electric toothbrush can be particularly helpful for people who have trouble reaching all corners of their mouth. For example, power brushes are useful for people with braces, parents brushing their young children's teeth, and individuals with mental or physical disabilities that impair dexterity. The thicker handle on power models is also a plus for some older patients and people with arthritis who have difficulty grasping the thinner shaft of a manual brush.

Your dentist may have good advice on which toothbrush is best for you. Consider bringing your toothbrush to your next dental visit so your dentist can examine it. While you're at it, demonstrate your brushing technique, so your dentist or hygienist can make sure you are brushing correctly.

Toothpaste: More than just mint

When it comes to plaque removal, it's your toothbrush that does most of the heavy lifting, but toothpaste contributes by removing stains and leaving your mouth fresher. Typically, commercial toothpastes are a concoction of abrasives, foaming agents, water, and binders, with flavor, color, and sweeteners added. They may also contain therapeutic agents such as fluoride or ingredients designed to combat tooth sensitivity. The main difference between gels and pastes is that gels contain more thickeners.

An important consideration when choosing toothpaste is its level of abrasiveness. Materials such as chalk, bicarbonate, and silicon or aluminum oxides remove external tooth stains. Polishers are included to restore the luster that abrasive materials dull. Although you want a toothpaste with enough abrasiveness to remove stains, high abrasive content and an incorrect brushing technique can lead to permanent tooth damage, particularly around the gum line. Abrasion can also wear away the fragile gum tissue, causing the gums to recede faster. If you don't smoke and have few stains, low-abrasive toothpaste is best for you. A standard test is used to determine the abrasiveness of toothpaste, and the result is a Relative Dentin Abrasivity (RDA) value. Unfortunately, the RDA values of different brands of toothpastes aren't readily available. Since the ADA only issues its seal of approval to toothpastes that are mild to moderately abrasive (250 RDA or less), choosing a toothpaste that carries the ADA seal is a simple way to ensure that your toothpaste isn't too harsh.

Also, choose toothpaste with fluoride. This additive is instrumental in warding off tooth decay. Most brands on the market in 2007 contain fluoride. Another ingredient, triclosan, has long been used in European dental products to combat gingivitis, a form of periodontal disease. Colgate Total was the first FDA-approved brand of toothpaste in the United States to contain this antimicrobial agent.

Some toothpastes are designed to reduce hypersensitivity. The ADA has granted approval to several products formulated for this purpose. Some antisensitivity toothpastes contain fluoride as well.

Toothpaste companies have bombarded the marketplace with toothpastes that claim to whiten teeth. Most major brands have at least one such toothpaste. All toothpastes contain mild abrasives that help remove surface stains. However, "whitening" toothpastes that contain the ADA Seal of Acceptance also have chemical or polishing agents that provide added stain removal power. For more information on whitening products, see "Teeth whitening."

Proper brushing technique

Numerous toothbrushing techniques have been recommended over the years. All have similar goals — removing food, stimulating gums, and preventing plaque buildup. Some people may get better results with one method than another, depending on their particular dental conditions and oral anatomy. Your dentist can help you decide which method is best for you. In the meantime, here's a basic brushing plan that works for many people.

Start on the outside surface of your top teeth, beginning with the furthermost molars on one side and working forward.

Holding your brush horizontally, place the bristles against the gum line at a slight angle (about 45 degrees). Using a short, rolling stroke, gently brush down toward the chewing surfaces of the teeth.

Repeat this motion at least five times before moving along the gum line, overlapping brushing sites slightly.

Repeat the same procedure over the inner surfaces of the teeth.

For the bottom teeth, repeat the steps above, brushing up from the gum line toward the chewing surfaces.

To get behind the top and bottom front teeth, hold the brush vertically with the bristles pressing against the interior surface of the teeth. Move the tip of the brush up and down over the teeth and gums.

To clean the chewing surfaces of the teeth, use short vibrating strokes pushing down slightly so that the bristles penetrate the grooves of the teeth.

Brushing your tongue when you cleanse your teeth will cut down on the hordes of bacteria that congregate on the tongue's surface. It can also help banish bad breath. To brush your tongue, place your toothbrush as far back toward the throat as you can without gagging. Sweep the brush forward six to eight times. Or, if you prefer, you can use a flexible strip of plastic or stainless steel called a tongue scraper. Center the arch of the scraper on your tongue as far back as you can without gagging and pull it forward, pressing lightly.

Finish up by brushing the roof of your mouth.

All gummed up

In an ideal world, you would brush after every meal. But if you're like most people, you don't carry a toothbrush around in your pocket or purse. A study in the July 2000 Journal of the American Dental Association found that chewing gum with xylitol (a sweetener derived from the bark of birch trees) may be the next best thing.

A group of 151 people at the University of Minnesota Oral Health Research Clinic chewed a commercial gum sweetened with xylitol for five minutes after each meal. A similar-sized group chewed a standard sorbitol-sweetened gum at the same intervals. A third group didn't chew gum at all. To bring decay-causing bacteria to the lowest level possible, all 151 subjects used a powerful antiseptic mouth rinse for two weeks before beginning the chewing regimen. After three months, the number of bacteria in the saliva of the xylitol group remained lower than in the other two groups.

Another study, done in Sweden, suggests that when mothers of young children chew xylitol gum, they are less likely to transmit the bacteria in their saliva to their infants through everyday contact such as kissing or tasting food.

How does xylitol work? The sugar or starch in foods and beverages supply the bacteria in your mouth with energy, allowing them to multiply and produce acids that attack tooth enamel. But because bacteria in the mouth aren't able to digest xylitol, this sweetener inhibits the growth of these microorganisms and reduces the production of destructive acids. In addition, xylitol may interfere with the ability of Streptococcus mutans to produce the sticky substance that helps these bacteria adhere to the teeth.

Although sugarless gum without xylitol doesn't seem to suppress bacteria, it can help increase the flow of saliva, which protects teeth (see "Salivary glands"). Still, because gum with xylitol offers this benefit as well as protection against bacteria, it's an even better choice.

A 2006 study published in the Journal of Dental Research looked at how much xylitol was necessary to reduce bacteria. The study divided 132 participants randomly into four groups: those given 3, 6, or 10 grams a day and those receiving a placebo. The 3-gram dose didn't seem to have an effect, but the higher doses significantly reduced Streptococcus mutans in the mouth. Thus, the researchers recommend getting between 6 and 10 grams of xylitol a day from chewing gum. For the best results, break the dose up, so you chew xylitol-containing gum three or four times a day. One of the researchers also notes that in order to get the full amount of xylitol, you must chew the gum for at least five minutes.

Many gum manufacturers now offer brands containing xylitol. Often, however, these brands also contain other sweeteners, such as sorbitol. Currently, most food stores only stock gum that combines xylitol with other sweeteners. Although gum with sweeteners in addition to xylitol may provide some benefits, gum with xylitol as its only sweetener is thought to be more effective. You can buy such gum — as well as xylitol candy, which also shows promise for reducing bacteria — from several Web sites (such as www.xylipro.com, www.xylitol.org, and www.epicdental.com), or directly from some dentists' offices.

Flossing

No matter how thoroughly you brush your teeth, it's impossible to reach the plaque and food debris that lodge between teeth and under the gum line. Using dental floss every time you brush not only makes your teeth cleaner, it also stimulates gums, polishes tooth surfaces, prevents buildup of plaque, and reduces gum bleeding. And flossing can help you prevent gum disease.

How many people heed the message that flossing is important for good dental health? According to a 2005 survey sponsored by the American Dental Association, nearly 52% of adults said they flossed at least once a day, while 32% floss less than daily and 16% never floss.

Flossing is simple, and synthetic fibers make it easier to floss between closely spaced teeth. Flavored flosses make the experience tastier, too. In addition, a variety of other products are available to help clean between teeth and under the gum line. For a look at some of these options, see Table 3. Your dentist or hygienist can advise you on which one is right for you.

Table 3: Types of dental floss and cleaning devices
Product	Description	Considerations
Unwaxed floss	Thin nylon yarn composed of 35 strands twisted together for strength.	Can be inserted between closely spaced teeth, but more likely to break or fray than the waxed variety.
Waxed floss	Basic dental floss coated with a light layer of wax.	More resistant to breaking than unwaxed floss. Wax may make it harder to use in tight spaces.
Polytetrafluoro-ethylene floss	Floss made from the same synthetic fiber used for high-tech rain gear (Gore-Tex). One brand is Glide.	Strong fibers resist breaking and fraying. Slippery surface slides easily between closely spaced teeth.
Dental tape (waxed or unwaxed)	Broader and flatter than traditional floss.	More effective than traditional floss for cleaning between teeth that are not tightly spaced.
Super Floss	Yarnlike fabric with stiffer portions on either end.	Stiff ends can be guided through dental work such as implants, braces, or bridges. Individual threads include unwaxed portions for normal flossing.
Floss threader	Needle-type device through which floss is threaded.	"Needle" allows floss to be pushed through spaces in dental work. Similar to Super Floss.
Floss holder	Y-shaped plastic tool that holds a length of floss between two prongs.	Can make flossing easier for people who have trouble manipulating the floss or fitting their fingers into their mouth.
Toothpick	Common pointed cleaning tool made from wood, ivory, or metal.	Useful for cleaning around gums and between teeth. Use toothpicks made out of a material, such as wood, that is softer than the tooth. Moisten before using. Take care not to press too hard on gums.
Toothpick holder	Device to hold a toothpick at the correct angle for cleaning.	Useful for cleaning gum line, gingival pockets, concave tooth surfaces, exposed roots, and areas around fixed bridges. Can be used to apply medications to gum areas.
Tip stimulator	Cone-shaped rubber nub found at the end of many toothbrushes or mounted on a handle of its own.	Useful for massaging gums, freeing trapped food, and dislodging plaque.
Wedge stimulator	Triangular plastic or wooden tool.	Especially useful for removing plaque and reducing inflammation in areas where the gum tissue between the teeth is missing. Moisten wooden stimulators before use and discard when the wood starts to splinter.
Interproximal brushes and swabs	Small spiral brushes or swabs that are pushed in and out of gaps between widely separated teeth or around braces or prosthetic devices.	Brush should be slightly larger than the space being cleaned. Brushes with special plastic-coated stems are available to avoid scratching implant abutments (see "Dental implants").
End-tufted brushes	Plastic handle with toothbrush-type bristles on either end.	Useful for cleaning hard-to-reach areas on the gum line such as the margins of crowns and the insides of the lower back teeth. Used with a paintbrush-style motion.
Irrigation devices	Motorized units that send a steady or pulsating stream of water or mouth rinse through a detachable nozzle to a targeted area of the mouth.	Good for flushing out accumulated debris from braces, bridges and other restorations, and deep gum pockets. However, irrigation does not completely remove plaque.

Flossing technique

Here's one method for flossing your teeth:

Using a piece of floss about 18 inches long, wrap one end securely around the middle finger of one hand. Do the same with the other end and the other hand, leaving a length of several inches in between.

Hold the floss taut with the thumb and forefinger of either hand, leaving about an inch exposed between the fingers.

Gently slide the floss between two teeth using a seesaw motion, which flattens the floss. Avoid snapping the floss into the space between the teeth, as this could damage your gums.

Curve the floss around the side of one tooth, forming a "C" shape, and rub the floss up and down to clean the tooth. Then curve the floss in the opposite direction and repeat the scraping action on the adjacent tooth.

Remove the floss and repeat the procedure between the next pair of teeth. Unwrap more clean floss from around your fingers as needed.

Using mouth rinses

If you walk down the dental care aisle of your local supermarket or pharmacy, you'll find a dizzying array of mouthwashes, plaque-removing rinses, fluoride treatments, and similar products. Do you need one?

Most rinses can effectively freshen your mouth and curb bad breath for up to three hours. However, their success in preventing tooth decay, gum inflammation, and periodontal disease is limited. Rinses can't substitute for regular dental examinations and proper home care. Most dentists believe that a regimen of brushing with a fluoride toothpaste, flossing, and getting routine cleanings and exams is sufficient for fighting tooth decay and gum disease. In some cases, though, a rinse may be helpful, and your dentist might recommend using one.

If you would like to try a rinse, how do you choose one? First, it helps to know that mouth rinses fall into two basic categories: cosmetic and therapeutic.

Cosmetic rinses

These solutions, commonly called mouthwashes, have a pleasant taste and leave your mouth feeling fresher for a time, but they don't possess any lasting ability to fight tooth decay or gum disease. They are best used as a temporary antidote to bad breath in the same way that showering with deodorant soap can control body odor for a period of time.

Mouthwashes contain flavorings, an astringent to make the mouth tingle, and an active ingredient that temporarily kills off bacteria. Some products also contain zinc, which neutralizes odor-causing compounds produced by oral bacteria. Because many brands contain a high percentage of alcohol (as much as 18%–26%), they are potentially poisonous to young children.

Therapeutic rinses

These preparations contain medicinal ingredients. The most popular kinds contain fluoride for cavity prevention. Among these, the Oral-B Anti-Cavity Rinse and ACT for Kids have earned the ADA Seal of Acceptance. Dentists sometimes recommend fluoride rinses for people who are prone to cavities.

Other types of over-the-counter therapeutic rinses advertise plaque-fighting benefits. However, only a few, such as Listerine and various store-brand equivalents (often marketed with the words "antiseptic mouth rinse"), carry the ADA Seal of Acceptance for this purpose. Listerine has been used as an oral antiseptic for more than a century. Listerine's claims are supported by long-term studies demonstrating that rinsing twice a day with the product (or a generic equivalent) can reduce plaque buildup and gum inflammation by 34%.

By far, the most powerful chemical for controlling oral bacteria is a substance called chlorhexidine, which is available only with a prescription from your dentist. It's sold under the brand names of Peridex or PerioGard. Chlorhexidine is most often used before or after oral surgery and for treating periodontal disease. It's also helpful for people who cannot brush effectively — for instance, because of a hand injury. Long-term use of this substance may temporarily stain teeth, but the problem can be corrected with professional cleaning.

Look for the seal

Choosing from among the hundreds of brushes, pastes, flosses, rinses, and cleaning devices can be overwhelming for even the savviest consumer. One way to navigate this sea of products is to look for the American Dental Association (ADA) Seal of Acceptance. This imprimatur indicates that based on the clinical data the manufacturer voluntarily submits, the ADA deems that the product fulfills its claims of safety and effectiveness. The absence of a seal can mean that either the manufacturer never submitted an application or the product did not meet ADA criteria.

Beating bad breath

At best, bad breath's an embarrassment. At worst, it can be a sign of serious disease. In extreme cases, bad breath (also called halitosis) can cause a person to live in isolation. Many factors can cause bad breath; here are some of the most common offenders.

Oral hygiene problems. About 90% of bad breath originates with oral bacteria. Food debris that collects in the mouth can rot if it's not removed promptly. In addition to brushing and flossing your teeth daily, brush your tongue every day to keep breath smelling fresh. The area at the far back of the tongue is particularly important, because this is where as much as 80% of odor-causing bacteria congregate. Food particles that collect on poorly fitting or unclean dentures can also cause odor.

Dental problems. There's strong evidence that the same bacteria that cause halitosis also produce gum disease. When plaque collects under the gums, the bacteria in it release foul-smelling sulfur compounds that irritate and eventually destroy the gum tissue and supporting structures. Flossing daily to remove plaque from the gum pockets around the teeth can combat this problem.

Diet. Certain foods have long been linked to breath odor. For example, cabbage produces foul-smelling gases during digestion that are released when you belch. Although garlic is another well-known source of bad breath, it was not until 1999 that scientists explained why its scent is so persistent. A study at the Minneapolis Veterans Affairs Medical Center discovered that when you digest garlic, it releases a specific sulfur compound. This compound progresses unaltered into your bloodstream, and you may exhale it from your lungs up to three hours later. Similarly, alcohol travels unchanged through the digestive system and exits through the respiratory system. Ironically, a lack of food can also affect your breath. Extreme dieting causes changes in the body's metabolism that result in a fruity scent on the breath.

Infection and chronic disease. Kidney failure, liver disease, diabetes, and respiratory tract infections (such as sinusitis and tonsillitis) can cause breath odor. In addition, research in 2007 points to a link between halitosis and Helicobacter pylori, a stomach-dwelling bacterium that causes ulcers and other stomach problems. A 1998 Italian study of 58 people who complained of both stomach problems and halitosis showed that bad breath disappeared when H. pylori was successfully treated. In cases where the stomach bacteria persisted, mouth odor remained, even when the individuals used an antiseptic mouth rinse.

Dry mouth (xerostomia). Too little moisture in the mouth allows dead cells and bacteria to accumulate on your tongue and teeth. This is also the cause of "morning breath."

Tobacco. Smoking and chewing tobacco lend an unpleasant scent to your breath. Tobacco use also contributes to other odor-causing maladies, such as dry mouth and gum disease.

Eliminating bad breath

Fortunately, there's much you can do to battle bad breath. Here are some steps you can take:

Brush and floss daily.

Brush your tongue and use a tongue scraper if necessary.

Rinse with plain water after meals if brushing isn't an option.

Get regular professional checkups to catch and treat periodontal disease.

Seek medical care for underlying health problems.

Snack on sugar-free foods (such as carrots and celery) or chew gum sweetened with xylitol to clear away debris and keep saliva flowing.

Use an over-the-counter mouthwash containing zinc. Your dentist may also prescribe a rinse with chlorhexidine. Be aware, though, that long-term use of this ingredient can stain teeth.

All about fluoride

Fluoride is a powerful ally in your fight against tooth decay. The link between fluoride and the prevention of tooth decay was clear by 1945, when Grand Rapids, Mich., became the first American city to add fluoride to its drinking water. The results were dramatic. Studies that measured the health of children's teeth after 13–15 years showed a 50%–70% drop in the level of tooth decay. In the next five decades, more than 10,000 American communities followed suit. In 2007, over 170 million people in the United States receive fluoridated water — an achievement the CDC lauds as one of the 10 great public health accomplishments of the 20th century.

How does it work?

Fluoride is a common mineral found in all of the earth's water sources and many foods. Fluoride in the saliva enhances the body's ability to rebuild the mineral crystals that make up tooth enamel when acid-producing bacteria cause them to decay. The new enamel created during this remineralization process is actually harder and more decay-resistant than the original tooth surface. In addition, fluoride seems to inhibit bacteria's ability to produce the sticky substance that enables plaque to adhere to the tooth surface. It also makes it more difficult for bacteria to turn sugar into acid.

Fluoride has the greatest power to fight decay when it's present on an ongoing basis after the teeth have erupted through the gum. This revelation means that people of all ages — not just young children — can reduce their risk for decay by regularly exposing their teeth to fluoride.

How do you get it?

One of the simplest methods is from drinking water. In 1962, the U.S. Public Health Service determined the optimum standard of fluoride in drinking water to be 0.7–1.2 parts per million (ppm) — the equivalent of 0.7–1.2 milligrams per liter of water. This level has proved successful in fighting decay without posing a risk of overexposure. Another means is to use toothpaste that contains fluoride. For most people, these two sources of fluoride are sufficient to keep decay in check.

If your community doesn't have fluoridated water or if your family uses bottled water, your dentist may suggest getting fluoride from other sources. Most brands of bottled water do not contain the recommended amounts of fluoride, and some brands contain no fluoride at all. Often, water is treated before it is bottled. Some types of water treatment (called reverse osmosis or distillation) actually take the fluoride out of the water. Fluoride is also removed from the water in some home water treatment systems. If you have a water filtering system, check the manual or contact the manufacturer to find out how the filter affects fluoride levels in your water.

People who are at high risk for decay or who don't drink fluoridated water can get additional fluoride via mouth rinses, oral supplements, or treatments such as fluoride gels and varnishes applied by a dental professional. Talk to your dentist about whether you and your family are getting the fluoride you need.

Is it safe?

Despite fluoridated water's solid track record in improving oral health, rumors abound linking fluoride to a broad range of ills, from heart disease to allergies to genetic abnormalities. Numerous studies conducted in the past 60 years refute claims that the current level of fluoride in drinking water causes these diseases.

A host of national and international health organizations have issued statements about the safety and effectiveness of fluoridation. Organizations that support fluoridating water include the CDC, the American Medical Association, the World Health Organization, the National Institute of Dental and Craniofacial Research, the American Dental Association, and the U.S. Public Health Service.

Research on fluoride continues, and a 2006 research paper garnered some attention because it suggested a possible link between fluoride in water and a rare form of bone cancer known as osteosarcoma in young men. However, the author of the paper reported that the study had limitations and that further research was needed to confirm or refute these findings. The paper is based on an analysis of one set of cases from a 15-year study being conducted by the Harvard School of Dental Medicine. The lead researchers of the overall study have reported that their analysis of another set of cases so far does not suggest an association between fluoride and osteosarcoma. Earlier studies on fluoridation and osteosarcoma also do not support such a link.

While the bulk of scientific evidence has found that fluoridation is safe, fluoride can be lethal if you ingest excessive amounts — 2.5–5 grams for an average adult. However, you would have to consume 5,000–10,000 glasses of fluoridated water in one sitting to reach this level. The true poisoning danger is for children who get into improperly stored fluoride tablets or who ingest a large amount of a fluoridated toothpaste or mouth rinse.

A minor drawback to using fluoride is the risk of fluorosis, a condition that discolors tooth enamel. Staining ranges from nearly imperceptible chalklike markings to heavier mottling and brown blemishes. Fluorosis appears in permanent teeth when a child ingests too much fluoride while these teeth are forming in the gum. The risk of fluorosis disappears once the permanent teeth are fully developed — around age eight. Although it's a cosmetic concern, fluorosis doesn't affect the functioning of the teeth.

Review Date: 2007-04-01

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