Cavities are one of the most common forms of tooth decay among children in the United States. They affect roughly 20 percent of children between the ages of 5 and 11.

Multiple factors can influence how quickly tooth decay progresses, including oral hygiene, diet, and more. However, most cavities take several months or years to form.

In this article, we’ll discuss how cavities form, how long it takes a cavity to progress, and how to maintain good oral hygiene to prevent cavities.

A cavity is damage to the tooth that occurs as the result of unaddressed tooth decay. Cavities develop over time because of factors that contribute to poor oral health, such as not brushing the teeth or eating a diet high in sugar.

Below, you will find the various stages of tooth decay that lead to the progression of a cavity.


Demineralization of the enamel is the first stage of tooth decay. It happens when the tooth is repeatedly exposed to acids from foods.

At this stage of tooth decay, proper oral hygiene and exposure to fluoride can usually reverse the damage.

Enamel decay

Continued demineralization of the enamel leads to further tooth decay over time. This decay can eventually cause holes in the teeth called dental caries, or cavities.

Once a cavity is fully formed, it can’t be reversed and requires treatment.

Dentin decay

If a cavity continues to progress without intervention, the decay will reach the dentin of the tooth. Dentin is the soft tissue beneath the enamel that is extremely sensitive.

Once decay reaches the dentin, you may notice that a cavity becomes sensitive or painful. At this point, you may need a larger filling, inlay, or even a dental crown.

Pulp decay

Beneath the dentin lies the pulp of the tooth, which contains nerves and blood vessels. When a cavity reaches the pulp, the tooth begins to decay faster, leading to inflammation, swelling, and pain.

In most cases, tooth decay that has reached the pulp of the tooth requires treatment with a root canal.


Dental abscesses happen when the bacteria that causes cavities continues to spread beneath the pulp of the tooth. These bacteria cause an infection and a pocket of pus beneath the tooth.

Some abscesses go unnoticed until the pain and swelling become unbearable. Dental abscesses require immediate treatment and, in some cases, result in removal of the tooth.

Unfortunately, there’s no exact timeline for how long it takes a cavity to form, as everyone’s oral hygiene is different. Some of the factors that influence how quickly tooth decay happens include:

  • levels of acidity in the mouth
  • how frequently the teeth are exposed to acid
  • tooth enamel health and thickness
  • location of the cavity

In most cases, cavities develop over years. Depending on oral hygiene, sometimes even months.

Symptoms of a cavity may vary from person to person and generally depend on the severity of the tooth decay.

Initially, you may notice a white spot on the tooth that doesn’t go away with brushing. Over time, this white spot may become a hole in the tooth. A hole in the tooth is a sign that a cavity has formed.

Other symptoms of a cavity may include:

  • sensitivity to hot and cold
  • sensitivity to sweets
  • tooth pain, especially pain that lingers or becomes more severe

Luckily, it’s possible to reverse tooth decay when it’s in the early stages of demineralization.

During the early stages of decay, it’s important to maintain good oral hygiene to help rebuild the minerals in the tooth. Below, you will find some tips for how to slow or reverse the progression of a cavity in the early stages.

  • Watch your sugar intake. Limit overly sugary or starchy foods.
  • Brush often. Brush your teeth twice per day, preferably with a toothpaste that contains fluoride.
  • Floss daily. Floss at least once per day to clean between teeth.
  • Use mouthwash. Consider adding a fluoride mouthwash to your nightly brushing routine.
  • Visit the dentist. Maintain regular visits to the dentists — a cleaning at least every 6 months is recommended.

Unfortunately, once a cavity has formed a hole in the tooth, it is no longer possible to reverse the damage and treatment will be necessary.

A cavity reaches the nerve once the decay has reached the pulp of the tooth. Exposed blood vessels and nerves within the pulp cause the signature tooth pain that’s associated with severe tooth decay.

Unfortunately, there’s no timeline for how long it takes for a cavity to reach the pulp. However, the deeper the decay buries into the tooth, the quicker the cavity will progress.

A cavity can destroy a tooth once it’s reached the pulp stage of tooth decay or becomes an abscess. At this stage, the damage to the tooth may be so severe that it cannot be saved with treatments such as a crown or root canal.

There’s no specific timeline for how quickly a cavity can destroy a tooth. In most cases, severe damage to the tooth occurs because of years of unaddressed tooth decay.

Fortunately, proper dental hygiene and regular dental checkups can save a tooth before it ever gets this bad.

Sometimes, prevention isn’t enough to fully stop a cavity from forming. When this happens, the treatment options for the cavity depend on the extent of the damage to the tooth.

  • Filling. For small, minor cavities, a resin or composite filling can be used to fill the hole and stop the progression of decay into the tooth.
  • Crown. For larger cavities that require the removal of larger portions of tooth, a crown may be needed. Metal or porcelain crowns must be custom made to fit over the surface of the tooth.
  • Root canal. Decay that reaches the pulp can cause permanent damage to the nerve endings inside the tooth, requiring a root canal. In a root canal, decay is removed, the pulp chamber and roots are cleaned, the canals are filled, and your dentist will add a filling on top.
  • Removal. When the damage to a tooth is too much to repair, extraction of the damaged tooth becomes the only option.

As you can see, prevention through healthy oral hygiene is always the best method if you want to avoid extensive treatment options.

Cavities are one of the most common types of tooth decay among children and adults.

While most cavities develop over a period of months or years, a lack of oral hygiene can speed up the progression of tooth decay dramatically.

Once a cavity forms it will require treatment, so maintaining good oral health and keeping up with professional cleanings can help to stop tooth decay in its tracks.