Cavities (Dental)

Medically Reviewed on 5/23/2023

What are cavities and microcavities?

Dental Cavities
Not all dental cavities cause toothache or pain.

Dental cavities are holes in teeth caused by tooth decay. Cavities are also referred to as caries. They occur when the bacteria in your mouth produce acid that attacks the outer layer of your teeth, known as the enamel. Over time, this can create a small hole, or cavity, in the tooth.

If you have a cavity, your dentist may recommend a filling, crown, or other treatment to restore the tooth and prevent further damage. In severe cases, a root canal or tooth extraction may be necessary.

What are microcavities?

Microcavities, also known as incipient caries or initial enamel caries, are the earliest stage of tooth decay. Teeth are in an environment of a constant acid attack that strips the teeth of important minerals and breaks them down. While this attack is constantly occurring, minerals are also constantly replenished through mineral-rich saliva and fluoridated water, and toothpaste. In addition to fluoride, calcium, and phosphate also help to remineralize enamel. When the demineralization starts and is confined to the outermost layer of enamel, it is called a microcavity, or incipient cavity. These types of cavities rarely need anything more than very conservative treatment. Only when the cavity breaks through the enamel layer and into the dentin does it threaten the tooth. So when these microcavities are detected, it is best to try a remineralization protocol to see if they can be reversed instead of jumping to a filling right away. A dentist will help in determining the most effective conservative treatment for these early cavities.

The dentist's goal is to achieve a healthy balance between prevention and restoration. It is a balance between being proactive and reactive. The dentist doesn't want to be so proactive that he is recommending things that don't need to be done -- preventing problems that never would have occurred. But he doesn't want to be so reactive that he simply watches small problems become big problems. One mistake people often make is waiting for the pain to dictate the timing of treatment. Once a tooth starts hurting, it is often too late for remineralization or a small filling. The pain usually indicates a need for root canal treatment, a crown, or tooth extraction. There is some variability in how dentists will treat microcavities and when they determine a filling is necessary. Some people are more prone to caries than others. Analyzing one's history of cavities, current diet, and oral hygiene may lead the dentist to be more aggressive or more conservative with his recommendations. This is why each person must find a dentist that echoes his or her philosophy regarding aggressive versus conservative dental treatment.

Treating microcavities early on is important to prevent further decay and potential tooth loss. In many cases, the decay can be reversed through a process called remineralization, which involves applying fluoride treatments or using dental products that contain fluoride.

Regardless of the dentist, regular returns to the dentist are key to being conservative so the cavity can be monitored and treated before it grows too much. Small cavities can become root canals within a year under the right circumstances. As a cavity grows, more tooth structure is lost. Lost tooth structure leads to a greater likelihood of fractured teeth, recurrent decay, and tooth loss. When possible, one is always better off getting a small filling than ending up with a large filling, a root canal, or a crown.

What causes dental cavities?

Two main factors contribute to tooth decay -- bacteria in the mouth and a diet high in sugar and starch.

  • There are over 500 different types of bacteria that are normally present in the mouth. These bacteria combine with food and saliva to form a sticky substance called plaque that attaches to teeth.
  • Foods rich in starches add to the stickiness of the plaque, which begins to get hard if it remains on the teeth after a couple of days and turns into tartar or calculus.
  • Bacteria in the plaque convert sugar into acid that dissolves the tooth structure, causing holes or cavities. Because of these two contributing factors, dental caries has been described as a "diet bacterial" disease.

The parts of teeth that are most vulnerable to tooth decay are areas where plaque can accumulate most easily. Plaque tends to settle into the pits and fissures in the tops of teeth, into the areas in between the teeth, and next to the gum line. Where there is plaque, there are bacteria and acid, and eventually destruction of the tooth surface. The cavity starts in the outer layer of the tooth (enamel) and as it gets deeper, penetrates the softer inner layer of the tooth (dentin). Typically, it isn't until the decay reaches the dentin that a person will start to notice signs and symptoms of the cavity.

What risk factors contribute to tooth decay?

Saliva helps prevent plaque from attaching to teeth and helps wash away and digest food particles. A low salivary flow or dry mouth leaves the teeth more vulnerable to tooth decay. This is particularly common in patients with diseases that feature dryness of the mouth, such as Sjögren's syndrome and other diseases of the salivary glands.

Genetic factors that affect tooth decay are the following:

  • Tooth size and shape: Small teeth with numerous deep pits and grooves will be more vulnerable to cavity formation than large teeth with fewer and shallower grooves. The grooves and pits provide areas for plaque to build up and are difficult to brush thoroughly.
  • The thickness of enamel: Enamel is the tooth's main defense against cavities, so the more of it a person has, the longer it will take for a cavity to break through to the inside of the tooth.
  • Tooth position and bite: Crooked, overlapped teeth provide more areas for plaque to accumulate and are harder to keep clean. Many problems can occur if the bite is poorly aligned. Poor alignment of the bite can cause the enamel on certain teeth to wear down rapidly, leaving soft dentin exposed. Orthodontics is a great cavity-prevention measure because straight teeth that are in a proper bite position tend to stay cleaner and more cavity-free throughout a person's lifetime.
  • Tooth eruption time and sequence: People who get their permanent teeth earlier in life are at greater risk for cavities because oral hygiene practices may not be developed yet.


What causes tooth decay? See Answer

What are the symptoms of cavities?

When a cavity advances deep into the tooth, it may produce increased sensitivity to foods that are cold, hot, or sweet. But not all cavities will cause a toothache. If they are small or progressing slowly, they may only be detected by a dentist before they cause pain. Cavities on front teeth are easiest for a person to see, and they will be visible as a light or dark brown spot. The brown spot is a tooth structure that has become soft due to the acid attack from bacteria. Generally, light brown represents a fast-growing cavity and dark brown represents a slower-growing cavity. If the cavity gets large enough, part of the affected tooth may break off and leave a hole.

The signs and symptoms of cavities can vary depending on the severity and location of the decay. Some common signs and symptoms include:

  • Toothache or sensitivity to hot, cold, or sweet foods and drinks.
  • Visible holes or pits in the teeth.
  • Dark spots or staining on the tooth surface.
  • Pain or discomfort when biting down or chewing.
  • Bad breath or an unpleasant taste in the mouth.
  • Swelling or pus around the affected tooth (in advanced cases).

It's important to note that not all cavities cause pain or noticeable symptoms in their early stages, which is why regular dental checkups and cleanings are essential for detecting and treating cavities early on.

How are cavities diagnosed?

A dentist can detect a cavity by using a sharp instrument to feel tooth structure that has been softened by tooth decay. If a cavity forms in between the teeth, it may only be visible on an X-ray.

Other diagnostic tools that are used to detect cavities include:

  • Ultrasound
  • Fluorescence
  • Fiberoptic transillumination

Regular dental exams are recommended so cavities can be diagnosed when they are small cavities (incipient caries or microcavities) instead of waiting until they grow large enough to produce pain and require more extensive treatment.

What is the best treatment for cavities?

There are three things to consider in the treatment of dental cavities: prevention, remineralization, and restoration.


A greater emphasis on preventive dentistry has helped reduce the incidence of premature tooth loss. Since we can't eliminate the bacteria that are in the mouth, limiting the amount and frequency of sugars and starches in our diet is the easiest way to prevent dental caries.

  • Maintaining a healthy diet to prevent tooth decay is very important in children and toddlers both for baby teeth and as they start to get their adult teeth.
  • Sugary soft drinks and juices are especially harmful to the teeth. When possible, sweeteners such as sucralose should be substituted for sucrose because they can't be digested by bacteria. Xylitol is another sugar substitute that kills bacteria, so chewing xylitol gum after meals will greatly reduce the incidence of cavities.

Plaque can be removed from the outside of teeth by brushing and from in between the teeth with dental floss. The use of mouthwash also helps by limiting the number of harmful bacteria in the mouth. A dentist will often suggest placing plastic sealants in the pits and grooves of teeth in children to protect them from decay. Visiting the dentist regularly will help prevent cavities from forming or catch them when they're small.


Shallow cavities can be reversed when they are treated with a substance that contains fluoride or calcium. This "rehardening" process is known as tooth remineralization. Fluoride makes the enamel more resistant to cavities and can be applied to teeth through fluoride toothpaste, supplements, dental office fluoride treatments and varnishes, and fluoridated water. The amount of fluoride exposure must be carefully controlled though because high levels can be toxic.


When a cavity is too large to be remineralized, it must be restored.

  • If the cavity is still small, it can be restored with a filling made of composite or silver amalgam.
  • If a large part of the tooth is decayed, it will need to be covered with a crown. Crowns are typically made of gold, porcelain, or zirconium.
  • If the cavity has extended to the center of the tooth and infected the nerve, a root canal will have to be performed.
  • Sometimes, the cavity infects a majority of the tooth surface and the tooth has to be extracted.
  • Areas, where teeth have been extracted, can usually be restored with dental implants or bridges.
  • Baby teeth that get cavities may be restored with a filling, a stainless steel crown, extraction, or pulpotomy. Kids must get their baby teeth treated so that abscesses don't form and oral disease doesn't keep increasing into adulthood.

Treatment of cavities during pregnancy

Hormonal and bacterial quantity changes during pregnancy put pregnant women at greater risk for gingivitis and periodontal disease. Therefore, pregnant women must continue to get regular dental cleanings during pregnancy. Delaying treatment can lead to more serious dental problems and complications.

  • Pregnant women have generally been counseled to avoid elective dental treatment during pregnancy unless they are experiencing an emergency like pain or infection.
  • In this case, the second trimester is the best time for treatment to keep the expectant mother as comfortable as possible. Local anesthetics and other materials used during dental treatment don't increase the risk to the fetus, but untreated oral disease has been shown to lead to adverse pregnancy outcomes.
  • If X-rays are necessary, a protective apron will be placed over the woman's stomach and thyroid.
  • If antibiotics are necessary, tetracycline should be avoided because it will cause staining in the baby's developing teeth.

It's generally safe to undergo dental treatment during pregnancy, although some procedures may need to be postponed until after delivery. Your dentist can work with your healthcare provider to determine the best course of treatment for your individual needs. Some common treatment options for cavities during pregnancy include dental fillings, crowns, and root canal therapy. 

It's also important to maintain a healthy diet during pregnancy and limit your intake of sugary and acidic foods and drinks to help prevent cavities.

What is the prognosis of a cavity?

Dental cavities are a preventable and treatable disease. By making simple changes in diet and hygiene, one can minimize the risk of developing caries.

  • If a person has been diagnosed as being at high risk for dental cavities, the dentist may prescribe a prescription toothpaste or fluoride varnish to protect the restored teeth from getting recurrent caries and prevent new ones from forming.
  • Consistent evaluation and follow-up with a licensed dentist combined with attentive oral hygiene will help a person affected by dental cavities to have a very favorable prognosis.

Can the CAMBRA method help prevent dental cavities?

CAMBRA stands for "Caries Management by Risk Assessment". It is a method for assessing a person's risk for developing dental cavities and making dental treatment decisions and recommendations based on the patient's caries risk. The dentist performing CAMBRA will perform tests for oral bacteria and take X-rays. He will then determine the patient's level of caries risk by analyzing caries history, current caries condition, dietary habits, hygiene habits, prescription medications, salivary flow, and medical conditions.

CAMBRA is based on the idea that dental caries is a preventable disease that can be managed with early detection, risk assessment, and targeted interventions. By identifying and managing risk factors, the goal is to prevent the development of cavities and reduce the need for more invasive and costly dental treatments.

Treatment will then be tailored to the patient based on managing the risk factors through behavioral, chemical, and minimally invasive procedures. No two cavities are the same because no two people are the same. Thus, diagnosis and treatment planning requires risk assessment in addition to caries detection.

CAMBRA is widely recognized as an effective approach to preventing dental caries and is recommended by organizations such as the American Dental Association and the Centers for Disease Control and Prevention. It is often used in both adult and pediatric dentistry to help patients maintain optimal oral health.

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Medically Reviewed on 5/23/2023
Medically reviewed by Kenneth Rotskoff, MD, DDS; Board Certified Dentistry, Oral/Maxillofacial Surgery

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