What is a cavity?

Also known as dental caries, cavities are holes in teeth caused by tooth decay. They are common at all ages — in fact, around 90% of adults have had at least one cavity by age 20!1

The good news is that cavities are nearly 100% preventable. You can protect yourself from cavities with a good oral hygiene routine, regular dental exams, and a healthy diet that is low in sugar and other refined carbohydrates.

How do cavities form?

Cavities develop when harmful bacteria form plaque around your teeth which then digest the food we eat and forms acids that damage the tooth surface. Plaque does the most damage when it has frequent access to sugary foods, drinks, and other carbohydrates.

It is important to remove plaque from your teeth regularly to prevent acids from breaking down your tooth structure, creating cavities.

Types of cavities

The type of cavity you have will depend on where it forms on your tooth, which can influence methods of prevention and treatment. Types of cavities include:

  • Smooth surface cavities form on the smooth, flat surfaces on the sides of your teeth. They usually develop slowly, which gives you time to prevent or even reverse the decay process before it creates a cavity. Fluoride from tap water, toothpaste, rinses, and varnishes or gels from your dentist will help prevent or reverse early smooth surface decay.
  • Pit and fissure cavities are most common in children and form in the pits and grooves on your back teeth. These cavities typically progress faster than smooth surface cavities. Dental sealants help prevent them from forming.
  • Root cavities are on the roots of your teeth and develop when gum recession leaves your teeth roots exposed, making those root surfaces more vulnerable to acid released by dental plaque and are most common among older adults, who are more likely to have receding gums. Once formed, root cavities can be difficult to treat.
  • Recurrent cavities form at the margins of existing fillings or crowns, often from bacteria that leaks through a gap between the tooth and the filling.

What do cavities look and feel like?

Cavities often have no visible symptoms in the early stages of development, but you may see a white spot on your tooth surface. As development progresses, you may notice small holes or pits in your teeth, tooth pain, or tooth sensitivity in response to various stimuli such as cold or hot.

Cavities are not all the same and some are more noticeable than others. Without a regular oral health routine, they can occur anywhere on your teeth — on the biting surfaces, between teeth, and at or below the gum line.

Your dentist will most likely notice early decay and cavities before you do, especially if the problem is located between your teeth, which may only be visible on an X-ray. This is one reason why regular checkups are so important. Small cavities are easier to treat, and in the early stages of decay, the process may even be reversed with early intervention.

What are the stages of a cavity?

Cavities develop over time and progress through five main stages:

  1. Demineralization: The acid in plaque breaks down minerals in your tooth enamel. Remineralization may be possible at this stage.
  2. Enamel decay: The acid has removed enough tooth structure to form a hole in the enamel, your tooth’s outermost layer. Once a hole has formed, you will need to work with your dentist to repair.
  3. Dentin decay: The decay process may accelerate as acids begin to affect the softer layer of dentin under your enamel.
  4. Pulp damage: Once enough dentin is destroyed, the bacteria may infect the pulp. Treatment for pulp damage requires a root canal.
  5. Abscessed tooth: If the infected pulp is left untreated, then it can cause an abscess at the end of the root and into the bone. To treat this, your dentist may drain the abscess, perform a root canal, or possibly even remove the infected tooth.


Cavities develop slowly, and you can proactively prevent them by attending your regularly scheduled dentist appointments and maintaining a daily brushing and flossing routine.

If you are concerned that you have a cavity, then visit your dentist as soon as possible so they can diagnose the problem and discuss treatment options. Addressing the problem early will help you avoid advanced tooth decay, tooth abscesses, and tooth loss.

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