Tooth decay begins when bacteria in your mouth make acids that attack the tooth’s surface (enamel). This can lead to a small hole in a tooth, called a cavity. If tooth decay is not treated, it can cause pain, infection, and even tooth loss.

People of all ages can get tooth decay once they have teeth—from childhood through the senior years.

Young children are at risk for “early childhood caries,” sometimes called baby bottle tooth decay. This severe tooth decay starts in the baby’s front teeth and extends to the back teeth.

Because many older adults experience receding gums, which allows decay-causing bacteria in the mouth to come into contact with the tooth’s root, they can get decay on the exposed root surfaces of their teeth.

You probably know that a dental cavity is a hole in a tooth. But did you know that a cavity is the result of the tooth decay process that happens over time? Did you know that you can interrupt and even reverse this process to avoid a cavity?

What's inside our mouths?

Our mouths are full of bacteria. Hundreds of different types live on our teeth, gums, tongue and other places in our mouths. Some bacteria are helpful. But some can be harmful such as those that play a role in the tooth decay process.

Tooth decay is the result of an infection with certain types of bacteria that use sugars in food to make acids. Over time, these acids can make a cavity in the tooth.

What goes on inside our mouths all day?

Throughout the day, a tug of war takes place inside our mouths.

On one team are dental plaque–sticky, colorless film of bacteria–plus foods and drinks that contain sugar or starch (such as milk, bread, cookies, candy, soda, juice, and many others). Whenever we eat or drink something that contains sugar or starch, the bacteria use them to produce acids. These acids begin to eat away at the tooth's hard outer surface, or enamel.

On the other team are the minerals in our saliva (such as calcium and phosphate) plus fluoride from toothpaste, water, and other sources. This team helps enamel repair itself by replacing minerals lost during an "acid attack."

Our teeth go through this natural process of losing minerals and regaining minerals all day long.

How does a cavity develop?

When a tooth is exposed to acid frequently -- for example, if you eat or drink often, especially foods or drinks containing sugar and starches -- the repeated cycles of acid attacks cause the enamel to continue to lose minerals. A white spot may appear where minerals have been lost. This is a sign of early decay.

Tooth decay can be stopped or reversed at this point. Enamel can repair itself by using minerals from saliva, and fluoride from toothpaste or other sources.

But if the tooth decay process continues, more minerals are lost. Over time, the enamel is weakened and destroyed, forming a cavity. A cavity is permanent damage that a dentist has to repair with a filling.

How can we help teeth win the tug of war and avoid a cavity?

Use fluoride

Fluoride is a mineral that can prevent tooth decay from progressing. It can even reverse, or stop, early tooth decay.

Fluoride works to protect teeth. It . . .

• prevents mineral loss in tooth enamel and replaces lost minerals
• reduces the ability of bacteria to make acid

You can get fluoride by:

• Drinking fluoridated water from a community water supply; about 73 percent of Americans served by a community water supply system receive fluoridated water.
• Brushing with a fluoride toothpaste

If the dentist thinks your child needs more fluoride, he or she may - 

• Apply a fluoride gel or varnish to tooth surfaces
• Prescribe fluoride tablets
• Recommend using a fluoride mouth rinse

About Bottled Water

Most bottled water does not contain enough fluoride to prevent tooth decay. If your child drinks only bottled water, talk with a dentist or doctor about whether your child needs additional fluoride in the form of a tablet, varnish, or gel.

Keep an eye on how often your child eats, as well as what she eats.

Your child's diet is important in preventing a cavity. Remember . . . every time we eat or drink something that contains sugar or starches, bacteria in our mouth use the sugar and starch to produce acids. These acids begin to eat away at the tooth's enamel.

Our saliva can help fight off this acid attack. But if we eat frequently throughout the day -- especially foods and drinks containing sugar and starches -- the repeated acid attacks will win the tug of war, causing the tooth to lose minerals and eventually develop a cavity.

That's why it's important to keep an eye on how often your children eat as well as what they eat.

Tooth-friendly tips:

• Limit between-meal snacks. This reduces the number of acid attacks on teeth and gives teeth a chance to repair themselves.
• Save candy, cookies, soda, and other sugary drinks for special occasions.
• Limit fruit juice. Follow the Daily Juice Recommendations from the American Academy of Pediatrics.
• Make sure your child doesn't eat or drink anything with sugar in it after bedtime tooth brushing. Saliva flow decreases during sleep. Without enough saliva, teeth are less able to repair themselves after an acid attack.

Make sure your child brushes

Brushing with fluoride toothpaste two times each day is important for preventing cavities.

Be sure to supervise young children when they brush. Here’s what you should know:

• For children aged 3 to 6, you put the toothpaste on the brush. Use only a pea-sized amount of fluoride toothpaste. (In children under age 2, dental experts recommend that you do not use fluoride toothpaste unless a doctor or dentist tells you to.)
• Encourage your child to spit out the toothpaste rather than swallow it. Children under 6 tend to swallow much of the toothpaste on their brush. If children regularly consume higher-than-recommended amounts of fluoride during the teeth-forming years, their permanent teeth may develop white lines or flecks called dental fluorosis. Fluorosis is usually mild; in many cases, only a dental professional would notice it.
• If your child is younger than 6, you will need to help your child brush. Young children cannot get their teeth clean by themselves. Try brushing your child’s teeth first, then let them finish.

Talk to a dentist about sealants

Dental sealants are another good way to help avoid a cavity. Sealants are thin, plastic coatings painted onto the chewing surfaces of the back teeth, or molars. Here's why sealants are helpful: The chewing surfaces of back teeth are rough and uneven because they have small pits and grooves. Food and bacteria can get stuck in the pits and grooves and stay there a long time because toothbrush bristles can't easily brush them away. Sealants cover these surfaces and form a barrier that protects teeth and prevents food and bacteria from getting trapped there.

Since most cavities in children and adolescents develop in the molars (the back teeth), it's best to get these teeth sealed as soon as they come in:

• The first permanent molars called - "6 year molars" - come in between the ages of 5 and 7.
• The second permanent molars - "12 year molars" - come in when a child is between 11 and 14 years old.

Take your child to the dentist for regular check-ups

Visit a dentist regularly for cleanings and an examination. During the visit the dentist or hygienist will:

• Remove dental plaque
• Check for any areas of early tooth decay
• Show you and your child how to thoroughly clean the teeth
• Apply a fluoride gel or varnish, if necessary
• Schedule your next regular check-up

Cavities of the teeth, known clinically as dental caries, are microbial lesions that cause damage to the teeth. Over time, the lesion can grow through the outer enamel layer to infect the underlying dentin or even the innermost pulp. If dental caries are not treated, the infection can become an abscess that spreads to the deeper tissues of the teeth, near the roots, or to the bloodstream.

Tooth decay results from the metabolic activity of microbes that live on the teeth. A layer of proteins and carbohydrates forms when clean teeth come into contact with saliva. Microbes are attracted to this food source and form a biofilm called plaque. The most important cariogenic species in these biofilms is Streptococcus mutans. When sucrose, a disaccharide sugar from food, is broken down by bacteria in the mouth, glucose and fructose are produced. The glucose is used to make dextran, which is part of the extracellular matrix of the biofilm. Fructose is fermented, producing organic acids such as lactic acid. These acids dissolve the minerals of the tooth, including enamel, even though it is the hardest material in the body. The acids work even more quickly on exposed dentin. Over time, the plaque biofilm can become thick and eventually calcify. When a heavy plaque deposit becomes hardened in this way, it is called tartar or dental calculus. These substantial plaque biofilms can include a variety of bacterial species, including Streptococcus and Actinomyces species.

Some tooth decay is visible from the outside, but it is not always possible to see all decay or the extent of the decay. X-ray imaging is used to produce radiographs that can be studied to look for deeper decay and damage to the root or bone (Figure 24.8). If not detected, the decay can reach the pulp or even spread to the bloodstream. Painful abscesses can develop.

To prevent tooth decay, prophylactic treatment and good hygiene are important. Regular tooth brushing and flossing physically removes microbes and combats microbial growth and biofilm formation. Toothpaste contains fluoride, which becomes incorporated into the hydroxyapatite of tooth enamel, protecting it against acidity caused by fermentation of mouth microbiota. Fluoride is also bacteriostatic, thus slowing enamel degradation. Antiseptic mouthwashes commonly contain plant-derived phenolics like thymol and eucalyptol and/or heavy metals like zinc chloride. Phenolics tend to be stable and persistent on surfaces, and they act through denaturing proteins and disrupting membranes.

Regular dental cleanings allow for the detection of decay at early stages and the removal of tartar. They may also help to draw attention to other concerns, such as damage to the enamel from acidic drinks. Reducing sugar consumption may help prevent damage that results from the microbial fermentation of sugars. Additionally, sugarless candies or gum with sugar alcohols (such as xylitol) can reduce the production of acids because these are fermented to nonacidic compounds (although excess consumption may lead to gastrointestinal distress). Fluoride treatment or ingesting fluoridated water strengthens the minerals in teeth and reduces the incidence of dental caries.

If caries develop, prompt treatment prevents worsening. Smaller areas of decay can be drilled to remove affected tissue and then filled. If the pulp is affected, then a root canal may be needed to completely remove the infected tissues to avoid continued spread of the infection, which could lead to painful abscesses.

When decay-causing bacteria come into contact with sugars and starches from foods and drinks, they form an acid. This acid can attack the tooth’s enamel, causing it to lose minerals.

When a tooth is repeatedly exposed to acid, such as when you frequently consume food or drink high in sugar and starches, the enamel continues to lose minerals. A white spot may appear where minerals have been lost. This is a sign of early decay.

Tooth decay can be stopped or reversed at this point. Enamel can repair itself by using minerals from saliva and fluoride from toothpaste or through the application of fluoride by a dentist or dental hygienist. If more minerals are lost than can be restored, the enamel weakens and eventually breaks down, forming a cavity.

In early tooth decay, there are not usually any symptoms.

As tooth decay advances, it can cause a toothache (tooth pain) or tooth sensitivity to sweets, hot, or cold. If the tooth becomes infected, an abscess, or pocket of pus, may form, causing pain, facial swelling, and fever.

Tooth decay can be found during a regular dental check-up. Tooth decay signs include white, brown, or black staining on the tooth. If the decay is more advanced, it may form a hole, or cavity. The dentist can also check the teeth for soft or sticky areas or take an x-ray, which can show decay.

If tooth decay is still in its early stages, before a hole (cavity) forms, the dentist can apply fluoride to reverse the decay.

Dentists commonly treat cavities by filling them. A dentist will remove the decayed tooth tissue and then restore the tooth by filling it with a filling material.

Protect your child’s teeth with fluoride.

Fluoride is a mineral that helps protect teeth from decay.

Use fluoride toothpaste.

When you shop for toothpaste, read the label to be sure it has fluoride.

Ask your child’s doctor about fluoride varnish.

After your child’s first tooth comes in, ask the doctor to give your child fluoride varnish (a thin coating of fluoride put on the teeth). Fluoride varnish helps prevent tooth decay.

Find out if there’s fluoride in your water.

Fluoride is added to the drinking water in many towns and cities. Check with your child’s doctor or your local water company to find out if your tap water has fluoride in it.

Give your child tap water to drink.

If your water has fluoride added, be sure to give your child tap water (not bottled water) to drink. Most bottled water doesn’t have enough fluoride in it to protect your child’s teeth from decay.

Ask for supplements if your water doesn't have added fluoride.

If your tap water doesn’t have fluoride added, ask your child’s doctor or dentist for fluoride supplements (drops or tablets). Children age 6 months and older can take fluoride supplements.

What about the cost of fluoride supplements?

Fluoride supplements for kids ages 6 months to 5 years who don’t have fluoride in their water are covered under the Affordable Care Act. Depending on your insurance plan, your child may be able to get fluoride supplements at no cost to you.

Direct Fillings

While the uses of dental amalgam has been declining through the years, other materials are widely used to fill tooth cavities caused by dental decay. Like dental amalgam, these direct filling (restorative) materials are used to restore the biting surface of a tooth that has been damaged by decay.

Your dentist can discuss treatment options based on the location of cavities in your mouth and the amount of tooth decay. Other restorative materials used to fill tooth cavities include the following:

• Composite Resin Fillings
• Glass Ionomer Cement Fillings

Every restorative material has advantages and disadvantages.

Composite Resin Fillings

Composite resin fillings are the most common alternative to dental amalgam. They are sometimes called "tooth-colored" or "white" fillings because of their color. Composite resin fillings are made of a type of plastic (an acrylic resin) reinforced with powdered glass filler. The color (shade) of composite resins can be customized to closely match surrounding teeth. Composite resin fillings are often light cured by a "blue-light" in layers to build up the final restoration.

Advantages of composite resin fillings include:

• Available in colors that blend in with surrounding teeth
• High strength
• Allows for minimal removal of healthy tooth structure for placement

Disadvantages of composite resin fillings include:

• May not bond to the tooth as well in the presence of moisture
• May be more difficult to place than dental amalgam in certain clinical situations and can blend in with tooth structure making removal difficult without removing tooth structure
• Potentially lower durability than dental amalgam and therefore may be at greater risk for fracture and the need for replacement
• Higher cost of placement

Glass Ionomer Cement Fillings

Glass ionomer cements contain organic acids, such as eugenol, and bases, such as zinc oxide, and may include acrylic resins. Like some composite resins, glass ionomer cements include a component of glass filler that releases fluoride over time. Also, like composite fillings, glass ionomer cements are tooth-colored. The composition and properties of glass ionomer cements are best suited for very small restorations. Unlike composite resin fillings, glass ionomer cements are self-curing and usually do not need a "blue light" to set (harden).

Advantages of glass ionomer cements include:

• Available in colors to blend in with surrounding teeth
• Minimal removal of healthy tooth structure for placement

Disadvantages of composite resin fillings include:

• Unsuitable for large restorations
• Not as durable as dental amalgam

Indirect Fillings

Other options for replacement of lost tooth structure is through the use of indirect fillings, for example "caps," which are made from ceramics or precious metals such as gold, and the most durable and costly treatment options.

Here are some things you can do to prevent tooth decay:

• Use fluoride, a mineral that can prevent tooth decay from progressing, and even reverse, or stop, early tooth decay. You can get fluoride by:
  • Brushing with a fluoride toothpaste.
  • Drinking tap water that has fluoride.
  • Using fluoride mouth rinse.
• Have a good oral hygiene routine. Brush teeth twice a day with a fluoride toothpaste and regularly clean between teeth with floss or another interdental (between-the-teeth) cleaner.
• Make smart food choices that limit sugary drinks and foods high in sugars and starches. Eat nutritious and balanced meals and limit snacking.
• Do not use tobacco products, including smokeless tobacco. If you currently use tobacco, consider quitting.
• See a dentist for regular check-ups and professional cleanings.

In addition, when your child’s permanent (second) teeth come in, talk to your dentist about sealants. They cover the chewing surfaces of teeth and can help prevent decay.

What is tooth decay?

Tooth decay is damage to a tooth's surface, or enamel. It happens when bacteria in your mouth make acids that attack the enamel. Tooth decay can lead to cavities (dental caries), which are holes in your teeth. If tooth decay is not treated, it can cause pain, infection, and even tooth loss.

What causes tooth decay?

Our mouths are full of bacteria. Some bacteria are helpful. But some can be harmful, including the ones that play a role in tooth decay. These bacteria combine with food to form a soft, sticky film called plaque. The bacteria in plaque use the sugar and starch in what you eat and drink to make acids. The acids begin to eat away at the minerals on your enamel. Over time, the plaque can harden into tartar. Besides damaging your teeth, plaque and tartar can also irritate your gums and cause gum disease.

You get fluoride from toothpaste, water, and other sources. This fluoride, along with your salvia, helps the enamel repair itself by replacing the minerals. Your teeth go through this natural process of losing minerals and regaining minerals all day long. But if you don't take care of your teeth and/or you eat and drink lots of sugary or starchy things, your enamel will keep losing minerals. This leads to tooth decay.

A white spot may appear where minerals have been lost. This is an early sign of tooth decay. You may be able to stop or reverse the decay at this point. Your enamel can still repair itself, if you take better care of your teeth and limit sugary/starchy foods and drinks.

But if the tooth decay process continues, more minerals are lost. Over time, the enamel is weakened and destroyed, forming a cavity. A cavity is a hole in your tooth. It is permanent damage that a dentist has to repair with a filling.

Who is at risk for tooth decay?

The main risk factors for tooth decay are not taking care of your teeth and having too many sugary or starchy foods and drinks.

Some people have a higher risk of tooth decay, including people who:

• Don't have enough saliva, because of medicines, certain diseases, or some cancer treatments
• Don't get enough fluoride
• Are very young. Babies and toddlers who drink from bottles are at risk, especially if they are given juice or get bottles at bedtime. This exposes their teeth to sugars for long periods of time.
• Are older. Many older adults have receding gums and more wear on their teeth. These raise the risk of decay on the exposed root surfaces of their teeth.

What are the symptoms of tooth decay and cavities?

In early tooth decay, you usually don't have symptoms. As tooth decay gets worse, it can cause:

• A toothache (tooth pain)
• Tooth sensitivity to sweets, hot, or cold
• White or brown stains on the surface of a tooth
• A cavity
• An infection, which can lead to an abscess (pocket of pus) forming. The abscess can cause pain, facial swelling, and fever.

How are tooth decay and cavities diagnosed?

Dentists usually find tooth decay and cavities by looking at your teeth and probing them with dental instruments. Your dentist will also ask if you have any symptoms. Sometimes you may need a dental x-ray.

What are the treatments for tooth decay and cavities?

There are several treatments for tooth decay and cavities. Which treatment you get depends on how bad the problem is:

• Fluoride treatments. If you have early tooth decay, a fluoride treatment can help the enamel to repair itself.
• Fillings. If you have a typical cavity, your dentist will remove the decayed tooth tissue and then restore the tooth by filling it with a filling material.
• Root canal. If the damage to the tooth and/or an infection spreads to the pulp (inside of the tooth), you might need a root canal. Your dentist will remove the decayed pulp and clean inside the tooth and root. The next step is to fill the tooth with a temporary filling. Then you will need to come back to get a permanent filling or a crown (a cover on the tooth).
• Extraction (pulling the tooth). In the most severe cases, when the damage to the pulp cannot be fixed, your dentist may pull the tooth. Your dentist will suggest that you get a bridge or implant to replace the missing tooth. Otherwise, the teeth next to the gap may move over and change your bite.

Can tooth decay be prevented?

There are steps that you can take to prevent tooth decay:

• Make sure that you get enough fluoride by
  • Brushing with a fluoride toothpaste
  • Drinking tap water with fluoride. Most bottled water does not contain fluoride.
  • Using fluoride mouth rinse
• Practice good oral health by brushing your teeth twice a day with a fluoride toothpaste and regularly flossing your teeth
• Make smart food choices by limiting foods and drinks that are high in sugars and starches. Eat nutritious, balanced meals and limit snacking.
• Do not use tobacco products, including smokeless tobacco. If you currently use tobacco, consider quitting.
• See a dentist for regular check-ups and professional cleanings
• Make sure that your children get sealants on their teeth. Dental sealants are thin plastic coatings that protect the chewing surfaces of the back teeth. Children should get sealants on their back teeth as soon as they come in, before decay can attack the teeth.