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Dental Cavity

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Last updated August 27, 2020

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A dental cavity is a common dental problem that signifies an infection of the tooth and loss of tooth mass. Symptoms include a toothache, pain in your mouth, and a tooth cracking or changing color. The best way to prevent a cavity is to practice good oral hygiene.

Dental cavity quiz

Take a quiz to find out if you have dental cavity.

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What is a dental cavity?

A dental cavity (caries) is an infection of the tooth, which is the result of long-term acid production by bacteria that sit on your teeth. This can result in pain and the spread of infection into the tooth pulp, and, if untreated, into your jaw bone or bloodstream. The development of a cavity is highly dependent on your lifestyle and is largely a preventable disease. Poor dental hygiene, a diet high in sugar, and the presence of aggressive bacteria in your mouth increase the risk of development of cavities. Once you have a cavity, it is important to see a dentist and have the cavity filled and improve oral hygiene at the recommendation of a dentist. Filing a cavity can protect against the spread of infection and improve your symptoms. Failure to fill a cavity may result in removal of the tooth (extraction) or cleaning/drilling into your jaw (root canal).

You should go see your dentist as soon as possible. If a cavity worsens, it can cause a tooth to die.

Dental cavity symptoms

Main symptoms

As a tooth begins to become infected, there may be no symptoms at all. Typically, once a cavity forms, you may experience the following:

  • Toothache
  • Pain in the mouth
  • Breaking (fracture) of a tooth
  • Changes in the color of your teeth

Signs of advanced disease

The following symptoms may indicate that the infection has spread into the pulp (inside) of your tooth or into your jaw. They signify the need for immediate attention.

  • Severe toothache: This is an ache that can be worsened by hot and cold drinks or food.
  • Severe jaw pain: This may signify that the infection has spread to the jaw bone.
  • Inability to open your mouth (trismus): This may signify infection of the muscles that open your mouth.
  • Cheek swelling

Complications of cavities

Dental cavities don’t just cause pain. They also have the potential to result in life-threatening complications, such as:

  • Removal of teeth
  • Bloodstream infection
  • Infection of the heart (endocarditis)
  • Infection of the deep neck tissues
  • Infection of the jaw bones
  • Infection of the muscles in your head and neck

Dental cavity quiz

Take a quiz to find out if you have dental cavity.

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What causes a dental cavity?

There are many causes and risk factors for the development of dental cavities. If you have many of the risk factors combined, you have a higher chance of developing a cavity. A cavity forms because bacteria that sit on the surface of your teeth produce acid. This acid wears away at the outer tooth, leading to degradation of the tooth and an increase in the amount of bacteria present. Eventually, the enamel of the tooth wears away and the bacteria can then infect the pulp (inside) of the tooth. Once this happens, the bacteria can continue to spread and infect the jaw bone, muscles of your head and neck, and even your blood and heart.

Why does a cavity form?

A cavity forms when there is too much acid produced by the bacteria on your teeth. Factors that increase the number of bacteria, include:

  • Eating sugar: You can think of sugar is a fuel source for bacteria. Eating more sugar means more bacteria can grow, which can produce increased amounts of acid.
  • Poor oral hygiene: Not brushing your teeth long enough or in the right ways leaves bacteria on your teeth.
  • Having a dry mouth

Conditions that increase chances of a cavity

The following conditions can increase the likelihood of development of a cavity:

  • Diabetes
  • Drug/alcohol use
  • A history of cavities
  • Eating disorders: Such as bulimia nervosa or anorexia
  • Disabilities
  • Being on steroid medication
  • A history of radiation therapy or exposure
  • Using bisphosphonate medication
  • Being colonized with especially aggressive bacteria

Risk factors for cavities in children

Children have unique risk factors for cavity development, in addition to those above:

  • A parent that has cavities
  • Eating sugary snacks
  • Drinking juices
  • Developmental disability
  • Defects in the tooth enamel

Treatment options and prevention for a dental cavity


Treatment of a cavity is best administered by a dentist. The primary treatment is to “fill” the cavity with a substance called “dental amalgam.” Before filling, a dentist must diagnose that you have a cavity. To do this, a dentist will inspect your mouth with a mirror-like instrument and use a probe on your teeth to “feel” your teeth.

It is important to understand that just because a dentist does not “see” or “feel” a cavity, does not mean that you do not have a cavity in the early stages. Below are the main treatments a dentist can offer, in order of commonality:

  • “Filling” of the cavity
  • Extracting (pulling out) the infected tooth
  • Root canal

However, filling alone will not prevent a cavity from getting worse in the same tooth or more cavities from forming in other teeth. A filling must be combined with improvements in dental hygiene in order to be effective. Read on for strategies to prevent cavities.

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The following are methods to improve your oral hygiene. They are recommended even if you do not have cavities.

  • Use a toothpaste with fluoride in it (most important)
  • Brush your teeth after each meal
  • Floss between your teeth
  • Use a mouthwash: Note, this is not a replacement for brushing teeth.
  • Supervise children when they brush their teeth
  • Proper brushing technique: Use an electric toothbrush or make sure to make a circling motion with the toothbrush.
  • Stop smoking
  • Chewing gum with xylitol sweetener: If you like chewing gum or having breath mints, do not choose those that are sweetened with sugar.

Another strategy to prevent cavities is for your dentist to provide you with a “sealant” over your teeth. You can think of this as a protective layer that surrounds your teeth that resists the acid produced by bacteria. Note, however, that this is only routinely offered to children.

Other methods to prevent cavities include:

  • Decrease (ideally eliminate) sugar consumption
  • Do not chew hard candy
  • Treat diabetes or dry mouth if you have these conditions
  • Have regular dental examinations
  • Have your dentist apply fluoride to your teeth

When to seek further consultation for dental cavity

You should always obtain regular dental care from a dentist. Regular care can prevent the development of cavities because the dentist can catch cavities before they need filling, provide you with protective fluoride, and educate you on the best oral hygiene practices.

If you begin to experience a tooth or jaw ache that does not go away, it is a good idea to see a dentist. If this progresses to jaw or cheek pain, this is a dental emergency and you should seek immediate care. The earlier you catch a cavity, the higher the chance that you can keep your tooth. You also have a lower chance of getting a bad infection of your jaw or muscles if you seek treatment early.

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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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