A Guide to Cavities and How to Prevent or Get Rid of Them

Medically Reviewed By Jennifer Archibald, DDS
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A cavity is a small hole in the tooth. It forms when a sticky kind of bacteria called plaque adheres to a tooth and causes tooth decay. Cavities are common in both children and adults. Most people, at some point, will have a cavity. Good dental hygiene and regular dental visits can help prevent cavities and promote good dental health.

This article talks about what cavities are, how they form, and steps you can take to prevent them.

What are cavities?

A woman brushing her teeth
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Cavities are tooth decay that happens when the tooth enamel breaks down. Enamel is the hard outer layer of your teeth.

Cavities occur when plaque, a sticky film of bacteria, forms and adheres to teeth. The bacteria in plaque turn the starch and sugar from foods and beverages into acids. These acids are strong enough to eat away the minerals in tooth enamel.

Over time, plaque can harden and turn into tartar. Tartar not only damages teeth but can also irritate gums and cause gum disease.

An early sign of a cavity is a white spot on a tooth, where minerals have been lost. Eventually, the spot turns into a small hole. Dentists treat cavities by putting a filling into the hole.

Cavities occur in children, teens, and adults. About 90% of adults aged 20 or older have had at least one cavity. Cavities are more common in children and young infants who are given juice or bottles at bedtime. This exposes their teeth to sugar for long periods of time.

Regular dental visits can help prevent cavities and promote good dental health. Your dentist may recommend dental visits every six months. However, you may go more frequently if you are at a greater risk for cavities or gum disease.

Your dentist may also recommend a fluoride rinse, which can reverse or stop early tooth decay. If you have young children, limit their intake of fruit juices and sugary foods. Also, help them brush their teeth daily.

What are the symptoms of cavities?

People with early tooth decay often show no symptoms. However, as tooth decay worsens and forms a cavity, symptoms may include:

  • tooth pain
  • sensitivity to hot, cold, or sweets
  • white or brown stains on the surface of a tooth
  • pain when you bite down

Your dentist will look for stains on your teeth. If they find one, they will watch it closely for early signs of tooth decay and cavity.

What causes cavities?

Cavities form when sticky bacteria, called plaque, cover and adhere to the teeth. Our mouths are normally filled with bacteria. Some are healthy bacteria, and others, such as those that make up plaque, can damage teeth.

The plaque bacteria turn the sugar and starches from foods and drinks into acids. These acids start to eat away at the tooth enamel, causing cavities to form.

The minerals in saliva, such as calcium and phosphate, help replace some of the minerals lost with tooth decay. Fluoride from toothpaste, water, and other sources can help reverse or stop tooth decay caused by plaque buildup.

A white spot on a tooth is an early sign of tooth decay. However, you can help prevent a cavity from forming. Brush your teeth regularly with fluoride toothpaste and limit your intake of sugary and starchy foods.

How do you prevent cavities?

There are steps you can take to prevent cavities. A few examples are:

Use fluoride

Fluoride helps protect tooth enamel by preventing or replacing mineral loss. It also hampers bacteria from making acid and forming plaque. Fluoride is found in many kinds of toothpaste and community water supply. About 74% of Americans served by a community water supply receive fluoridated water. Bottled water usually does not contain enough fluoride to prevent tooth decay. Fluoride can also be found in the form of gels or varnishes, tablets, or mouth rinses.

Make smart food choices

Your diet is an important form of cavity prevention. Try to limit snacking between meals to reduce your teeth’s exposure to acid. Save sugary foods for special occasions.

For children, make sure they do not eat or drink anything sugary after nighttime brushing. Limit their intake of fruit juice. The American Academy of Pediatrics recommends against letting a child carry a cup or box of juice around with them throughout the day.

Form good brushing habits

Good dental hygiene includes brushing teeth twice a day with fluoride toothpaste and flossing regularly. Children under 7 or 8 years old will need help brushing their teeth. Supervise them while they brush their teeth and encourage them to spit out their toothpaste rather than swallow it.

Talk to your dentist about sealants

Dental sealants can be helpful in children, who are more prone to cavities than adults. A sealant is a thin, plastic coating painted onto the chewing surfaces of the back teeth, or molars.

Most cavities in children and adolescents develop in the molars. Sealants help form a barrier that prevents food and bacteria from getting trapped in the pits and grooves of the back teeth.

Visit a dentist regularly

Dentists recommend a professional cleaning twice a year. If you are prone to cavities or start developing tooth pain or gum disease, your dentist may recommend more frequent visits. During a professional cleaning, a dental hygienist removes plaque and looks for early signs of tooth decay. These could be white spots on the teeth. If necessary, the dental hygienist will have you rinse your mouth with fluoride at the end of the visit.

How do you treat cavities?

Dentists treat cavities by removing the decayed tooth tissue and then filling the hole. This is typically done using a local anesthetic in the mouth. This procedure is done in the dentist’s office and typically takes less than an hour.

A dentist uses a small drill to remove the decayed tooth enamel. They will then fill the hole, most likely with a white composite material. Your dentist will seal the hole and ask you to bite down a few times. This is done to make sure the filling is sealed to your comfort level.

Over-the-counter pain relievers such as ibuprofen (Motrin) or acetaminophen (Tylenol) can help with pain from a cavity before your dental appointment. Tooth pain resolves after the cavity is filled.

Dentists may recommend a fluoride treatment or rinse to prevent a decayed area from forming a cavity.

When to see a dentist for a cavity

You should see a dentist for a cavity if you are having tooth pain or sensitivity to hot, cold, or sweets. If your dentist notices a cavity at your dental visit, they will want to fill it as soon as possible.

If you have early signs of tooth decay, such as white spots, your dentist may ask to see you more regularly to monitor for signs of a cavity.

To help stop the progression of tooth decay, dentists may recommend:

  • an in-office fluoride treatment
  • at-home fluoride rinse
  • a fluoride toothpaste, brushing at least twice daily

Here are six reasons to see a dentist.

What are the potential complications of cavities?

Potential complications of cavities include:

  • tooth pain
  • tooth abscess
  • irritation to the nerve
  • infection of the bone
  • bone loss
  • fractured tooth
  • inability to bite down on the tooth

If the cavity is deep enough that it extends to the pulp of the tooth, treatment involves a root canal. For a root canal, a dental professional will clean the inside of the tooth and root. You will get a temporary filling and return later to get a permanent filling.

Sometimes a cavity that is severe enough to damage the pulp cannot be fixed with a root canal and filling. Instead, treatment may involve tooth extraction and dental implant. This is only done in the most severe cases.


Cavities are a common form of tooth decay. They occur when plaque builds up and breaks down the tooth enamel, forming a small hole in the tooth. Cavities are most common in children, but they also occur in adults.

You can prevent cavities by brushing your teeth twice daily, limiting sugary foods and drinks, and visiting your dentist regularly. Treatment for cavities involves removing the dead tissue and filling the hole with a filling material. In severe cases, cavities can cause a tooth abscess or irritation to the tooth’s nerve.

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Medical Reviewer: Jennifer Archibald, DDS
Last Review Date: 2022 Aug 29
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