Tooth Decay

Tooth Decay

Also called: Dental Caries

Summary

Tooth decay is the destruction of tooth enamel by dental plaque that causes holes known as cavities. It strikes people of all ages, but is particularly prevalent in children ages 5 to 17 years, according to the U.S. Centers for Disease Control and Prevention.

A sticky film called dental plaque is the source of tooth decay. Plaque is made up of a combination of bacteria, acid, food particles and saliva. When a person consumes food, especially drinks high in sugars or carbohydrates, dental plaque builds up on the teeth and gradually erodes their structure.

Damage can occur in any part of the tooth that is exposed to plaque, from the crown at the top down to the softer body of the tooth (dentin) and the inner core of the pulp, which contains nerve fibers and blood vessels.

Patients with tooth decay do not usually experience any symptoms initially. However, if a cavity is not detected and begins to progress, it will often cause pain, particularly when eating sweet foods or when the tooth is exposed to hot or cold substances. Tooth pain may be the first physical symptom of tooth decay.

A dentist usually diagnoses tooth decay during a dental examination. Visual inspection and probing of the teeth with a special instrument can help indicate potential signs of damage. X-rays may be taken to confirm a diagnosis or to reveal hidden cavities.

Treatment for tooth decay varies depending on the nature and extent of the damage a patient experiences. In most cases, a dentist treats cavities by using a dental drill to remove the decayed material before filling the remaining space with dental amalgam or composite resin. More significant damage may require an artificial crown or root canal.

The single most important method of preventing tooth decay is to reduce the amount of plaque and bacteria in the mouth. Regular tooth brushing at least twice daily and flossing at least once daily is essential in decay prevention. In addition, patients should have their teeth professionally cleaned in a dentist’s office at least twice a year. People with certain conditions (e.g., diabetes) may require more frequent cleanings.

Patients who avoid sugary and starchy foods, candies and beverages (such as sodas) can keep large amounts of plaque and bacteria from forming in the first place. Fluoridation and dental sealants can also help prevent decay.

About tooth decay

Tooth decay is progressive destruction of a tooth from exposure to dental plaque, a sticky film composed of a combination of bacteria, acid, food particles and saliva. Dental plaque coats teeth after meals and gradually erodes the structure of the teeth, leaving holes known as cavities.

A tooth is made up of several layers. Enamel composes the hard outer layer. Dentin is the next, softer layer. Pulp is the inner layer that contains the nerves and blood vessels. This is the living part of the tooth.

Tooth decay – also known as dental caries – occurs when one or more of these layers begin to gradually dissolve as a result of acid created when bacteria, particularly Streptococcus mutans, feed on food particles, especially bits of sugary and starchy foods. As layer upon layer of plaque accumulates, the substance hardens into tartar. This buildup of plaque and tartar irritates the gums and causes gingivitis and periodontitis.

Tooth decay strikes people of all ages, but is particularly prevalent in children. It is the single most common condition in children ages 5 to 17 years and affects 59 percent of children in this age bracket, according to the U.S. Centers for Disease Control and Prevention (CDC).

Adults also experience tooth decay. About 27 percent of adults ages 35 to 44 and 30 percent of adults age 65 and older have untreated cavities. Much of this decay is found in the edges of fillings often placed during childhood that have weakened, fractured and leaked around the edges due to years of wear and tear. As bacteria seeps into these crevices, decay results.

In addition, recession of the gums often occurs during the aging process and leaves the roots of teeth vulnerable to decay. A soft tissue (cementum) covers tooth roots and is more susceptible to decay. The majority of people over the age of 50 have this form of tooth-root decay, according to the American Dental Association (ADA).

Once a patient experiences tooth decay, additional cavities are more likely to follow. Bacteria tend to adhere better to fillings and other restorations than they do to smooth, natural teeth, so these areas become magnets for the acid that causes cavities. Cracks or gaps in fillings also allow bacteria and food to enter the tooth.

Advanced dental care techniques have resulted in a decline in tooth decay among young children. However, it remains a problem for patients of all ages. About 25 percent of all adults over the age of 60 have lost all their teeth, primarily due to tooth decay and advanced gum disease, according to the CDC.

Potential causes of tooth decay

Tooth decay typically results when dental plaque accumulates on a person’s teeth. Plaque is a sticky film composed of a combination of bacteria, acid, food particles and saliva. The bacteria that accumulate on the teeth in dental plaque feed on all food particles found there – especially those from sugary or starchy foods – creating an acid that begins to destroy the enamel of teeth. The bacteria Streptococcus mutans are well known for their role in causing tooth decay.

Sugary and starchy foods and beverages, such as raisins, cakes, candy, soda, juice and milk, are the greatest contributors to the plaque that causes tooth decay. The acids contained in soda (e.g., phosphoric and citric acids) along with the sugar makes soda consumption a specific contributor to the development of tooth decay.

Plaque is most prevalent in the following regions:

  • Around dental fillings and bridges
  • Between teeth
  • In cracks, pits and fissures of back teeth
  • Near the gum line

Plaque begins to accumulate on teeth within 20 minutes of eating. Over time, plaque begins to dissolve minerals on the surface of the teeth. This process is known as demineralization, and it creates tiny pits and erosions that gradually become larger. When holes form in the teeth, they are known as cavities.

Damage can occur in any part of the tooth that is exposed to plaque, from the crown down to any portion of the root that is exposed due to recession of the gums. A cavity can also work its way deeper into the tooth and reach the softer body of the tooth (dentin). If left untreated, the decay eventually reaches the pulp of the tooth and the nerve fibers and blood vessels within the pulp. If the pulp becomes infected, a swelling (abscess) or opening to the surface of the gum (fistula) can form in the soft tissues.

People with the purging type of the eating disorder bulimia nervosa, in which patients regularly binge eat and then vomit, are at increased risk for tooth and gum decay because the acids in vomit can dissolve the tooth enamel.

Signs and symptoms of tooth decay

Patients with tooth decay do not usually experience any initial symptoms. If a cavity is not detected and treated and instead begins to progress, it often will result in pain, particularly when eating sweet foods or being exposed to hot or cold substances. Experts are not sure what causes this pain, but theories include inflammation caused by bacteria, exposure of the root surface and fluid imbalance in tubules inside the dentin.

Untreated cavities can cause several related problems, including weight loss, bad breath (halitosis), absence from work or school and poor cosmetic appearance. A decline in self-esteem is also sometimes attributed to a history of tooth decay.

Diagnosis methods for tooth decay

A dentist usually diagnoses tooth decay during a dental examination. Visual inspection and probing of the teeth with a special instrument (explorer) can help indicate potential signs of damage. In some cases, pits or holes in the teeth may be visible. In other instances, the surface of the tooth may prove to be soft when probed with an instrument.

X-rays may be taken to confirm a diagnosis or to reveal hidden cavities.

Treatment options for tooth decay

Treatment for tooth decay varies depending on the nature and extent of the damage a patient experiences. If acid has not yet eroded through the enamel (a condition typically indicated to dentists by white spots on the tooth, but no holes), the tooth may repair itself naturally with the use of fluoride treatments provided in a dental office or at home.

However, once a cavity has penetrated the enamel, it cannot be reversed. Instead, the goal is to arrest further progression of the cavity. Left untreated, a cavity typically continues to deepen and worsen, although the length of time a cavity takes to progress varies.

Dentists typically treat cavities by using a dental drill to remove the decayed material and fill the hole with a material such as dental amalgam (made from silver alloyed with copper or other materials), composite resin (made of a tooth-colored substance) or porcelain (also made of a tooth-colored substance). Gold inlay is sometimes used when greater strength is needed.

If the damage from a cavity is extensive, the dentist may have to cover the filling with an artificial crown. This helps minimize the risk of a weakened tooth cracking. Crowns typically are made of gold, porcelain or porcelain fused to metal.

When damage extends into the interior of the tooth, a root canal procedure may be needed to remove the tooth’s pulp (including the nerve and blood vessel tissue) and replace it with a sealing material. A dental professional called an endodontist performs this procedure. Once the root canal is finished, the tooth is covered with an artificial crown.

Before any of these procedures are performed, the patient receives a local anesthetic or nitrous oxide (laughing gas) provided by a mask placed over the patient’s mouth and nose. In some cases, a general anesthetic will be used so that the patient is not conscious during the procedure. Treatment is usually less extensive, less painful and less expensive when the cavity is detected early.

In most cases, the prognosis after treatment is excellent. However, some patients may experience complications such as pain, discomfort or tooth sensitivity. More serious complications include tooth abscess from fracturing of a tooth. All of these complications can be treated.

Prevention methods for tooth decay

The single most important method of preventing tooth decay is to reduce the amount of plaque and bacteria in the mouth. Regular brushing at least twice daily and flossing at least once daily is essential in achieving this goal. In addition, patients should have their teeth professionally cleaned in a dentist’s office at least twice a year. People with certain conditions (e.g., diabetes) may require more frequent cleanings. X-rays may be taken during dental visits every year or two to identify potential trouble spots in the early stages.

Patients who avoid sugary and starchy foods, candies and beverages (such as sodas) can prevent large amounts of plaque and bacteria from forming in the first place. In addition, patients who eat fewer snacks between meals will reduce the amount of plaque and bacteria that forms in the mouth. Sugarless chewing gum that contains the ingredient xylitol can help break down acid that forms on the teeth. Brushing after snacks will also help prevent plaque from forming.

Fluoridation can also help prevent tooth decay. In the past several decades, the number of cavities has declined substantially as a result of fluoridation. Many cities add fluoride to their water system, and children in these communities have 29 percent fewer cavities than children in communities without fluoridation, according to the U.S. Centers for Disease Control and Prevention (CDC). Regular fluoride treatments at a dentist’s office can also help protect teeth, especially in children.

Finally, dental sealants can be applied to a child’s molars and premolars once they fully erupt into the mouth. Sealants can be applied when the first permanent molars come in between ages 5 and 7, and when the second set comes in between ages 10 and 14. These sealants are a plastic, protective coating that can be applied to the chewing surfaces of back teeth. Sealants provide extra protection from cavity formation. In some cases, they can even arrest the formation of a cavity once it has begun. Some states provide dental sealant programs through schools for low income families. Although sealants are usually applied to children’s teeth, some adults may benefit from the procedure.

Researchers are investigating additional methods to prevent tooth decay, including specifically targeting the bacteria that cause decay, inhibiting the growth of these bacteria and promoting good bacteria to compete with cavity-causing bacteria.

Questions for your doctor about tooth decay

Preparing questions in advance can help patients to have more meaningful discussions with their dentists regarding their conditions. Patients may wish to ask their doctor the following questions related to tooth decay:

  1. What are the most important steps for preventing tooth decay?
  2. What type of toothbrush and dental floss should I use?
  3. Would I receive greater benefit from having professional cleanings more often than every six months?
  4. How can I find out if my tap water is fluoridated? If it isn’t, should I take fluoride supplements?
  5. What types of foods should I avoid to lower the risk of tooth decay?
  6. Should I have sealants applied to my teeth, or am I too old for this procedure?
  7. Can the decay on my tooth be reversed? If so, what treatments are available?
  8. What are the risks associated with various treatments for tooth decay?
  9. If I need a root canal, can you suggest a good endodontist?
  10. Should I chew sugarless gum after eating?
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