Extra Teeth and Adult Teeth That Have Not Come In: What Can Be Done

How many teeth should there be?

An adult usually has 32 permanent teeth, including four wisdom teeth. The American Dental Association notes that all 32 have usually come in by the age of 21¹. Not everyone has all 32, and not everyone has only 32.

Some people have fewer. Leaving wisdom teeth aside, a review of many studies found at least one adult tooth that never formed in about 6 in 100 people². This is called hypodontia.

Extra teeth are the opposite: a tooth that forms in addition to the usual set. A meta-analysis of 14 prevalence studies found figures between 0 and 3 in 100 people³. In people of European origin the average was about 1.6 in 100. Males were affected more often than females. The figure depends on how people were examined: studies that also used X-rays found more than those that relied on looking in the mouth.

A review of the research reported that extra teeth are more common in the upper jaw than the lower⁴. They can be shaped like a normal tooth or be small and cone-shaped. Some are found by chance on an X-ray taken for another reason.

What problems can extra teeth cause?

Many extra teeth cause no problem at all. When they do, the same review found that the most common one is an adult tooth next to it coming in late⁴. Other problems it lists are:

• an adult tooth that stays in the bone (an impacted tooth)
• a tooth that comes in out of place, or is pushed sideways or twisted
• crowding, or a gap between the front teeth
• a fluid-filled sac (cyst) forming around the extra tooth

The upper front teeth usually come in during the early years of mixed baby and adult teeth⁵. A British guideline on upper front teeth that have not come in says the cause is often local, in the mouth itself. An extra tooth is one such cause.

Cleidocranial dysplasia: extra teeth in a wider condition

Extra teeth are sometimes part of a wider condition. Cleidocranial dysplasia is one of them. It is a rare genetic condition that affects how the bones and teeth develop. It occurs in about 1 in a million people worldwide⁶ and is usually caused by a change in a gene called RUNX2. A parent with the condition can pass it to a child.

Typical signs in the mouth are baby teeth that stay for a long time, adult teeth that come in late, and many extra teeth. Other signs include short or missing collarbones and a soft spot on the skull that closes late⁶.

In 2026, 13 experts published consensus recommendations⁷ for the condition. They note that in cleidocranial dysplasia the baby teeth rarely fall out and the adult teeth rarely come in without help. Assessment and planning should therefore start early rather than waiting for the teeth to come in. The operations themselves are timed to how far the teeth have developed. The main points for the teeth are:

• an assessment by an orthodontist experienced in the condition by the age of 6
• close monitoring of tooth development with X-rays
• treatment timed by dental age, meaning how far the teeth have developed rather than the child's age in years; in this condition dental age typically runs about three years behind
• a phased approach: extra teeth and baby teeth are removed and adult teeth uncovered in stages, then braces guide them into place

The panel also says that implants, bridges or dentures can be considered for someone who cannot have, or does not want, this orthodontic treatment. These are expert opinions, not the results of trials. The panel notes that 'standard' orthodontic treatment for the condition is not well established.

A public example

The actor Gaten Matarazzo has said publicly that he has cleidocranial dysplasia. In January 2020 he wrote on Instagram about an operation that lasted four hours. According to his own post, the team removed 14 extra teeth and uncovered six of his adult teeth⁸. The post was also reported by NBC News⁹.

We mention him only because he made these details public himself. Naming him does not suggest any link between him and this clinic. His post does not show what treatment another person would need: that depends on an examination and X-rays.

How an adult tooth that has not come in is brought into place

The plan depends on the cause, the position of the tooth, how far its root has formed and the person's age. For upper front teeth in children, the British guideline sets out the general principles. They are to make enough space in the arch and remove whatever is blocking the tooth⁵. If needed, the tooth can then be uncovered surgically, with or without braces to pull it into place. The guideline recommends that a team of dental specialists work on the case together.

1. Examination and X-rays. The dentist checks which teeth are present and which are still in the bone. X-rays show where the extra tooth and the adult tooth lie. A 3D scan is sometimes needed.
2. Removing what is in the way. An extra tooth is usually removed. A review found no agreement on the best time to do this⁴. An extra tooth that causes no problem may instead be monitored. A baby tooth that has stayed too long may also be removed.
3. Making space. If the gap has closed, a brace may be used to open it.
4. Waiting, or uncovering the tooth. Sometimes the adult tooth comes in by itself once the way is clear. If it does not, the tissue covering it is opened under anaesthetic. In some plans, such as those for cleidocranial dysplasia, teeth are uncovered in the same operation that removes the extra teeth. The tooth may be left uncovered (open technique). Or a small attachment with a fine chain is bonded to it and the gum stitched back over it (closed technique).
5. Guiding the tooth with braces. Gentle force from the braces, applied through the attachment, is used to guide the tooth into line over months.

Most of the research on uncovering teeth concerns upper canines that lie in the roof of the mouth. A Cochrane review of three small trials found that the open and closed techniques may be equally successful¹⁰ at exposing these teeth. The evidence was of low quality. The same review describes fixed braces for two to three years after the canine is uncovered.

What to be aware of

• It is surgery. Uncovering a tooth is an operation under anaesthetic, with the usual after-effects of oral surgery such as swelling and discomfort. In one trial in the Cochrane review, one person needed antibiotics for an infection and another had pain when the chain came through the gum.
• The attachment can come off. If it does, a further procedure may be needed.
• It takes time. Guiding a tooth into place takes many months. In the canine trials, braces were worn for two to three years after the tooth was uncovered. In cleidocranial dysplasia there are several operations over years.
• Not every tooth can be brought in. A tooth may be in a position or at a stage that makes guiding it unrealistic. Other options are then discussed, such as removing the tooth and filling the gap later.
• No figures for your case. We have found no pooled success rate for bringing teeth into place in cleidocranial dysplasia, so we do not give one.

When to see a dentist

Ask a dentist to check if you notice any of these, in a child or an adult:

• an adult tooth has come in on one side but not the matching tooth on the other side
• a baby tooth stays in place long after the others around it have fallen out
• an extra tooth is visible, or a tooth comes in behind or out of line with the others
• a new gap between the front teeth, or front teeth that are twisted or pushed aside
• a swelling in the gum or jaw over a tooth that has not come in

A child may have several of these, or other signs such as a soft spot on the head that stays open. If so, tell the dentist and the family doctor. An assessment by a doctor or geneticist may be advised.

Emergencies. Difficulty breathing or swallowing, rapidly spreading swelling of the face or neck, high fever or swelling around the eye are serious signs. Do not wait for a clinic's reply: go to the nearest emergency department or call 112.

Frequently asked questions