Why Do Some Adults Still Have Milk Teeth?

A milk tooth falls out because the permanent tooth growing underneath presses on its root and dissolves it. When nothing presses, the root stays and the tooth stays. This happens in two main ways.

The first is that the permanent tooth was never formed. This is called hypodontia, and it is not caused by anything the person or parent did. It runs in families. The second is that the permanent tooth exists but is impacted, meaning it is stuck in the bone or tilted and cannot come through, so it does not push the milk tooth out.

Sometimes a milk tooth is also kept because it fused to the bone after an injury or infection. You can usually only tell which by looking at an X-ray.

The back lower milk molars, which should be replaced by the second premolars, are the milk teeth most often kept into adult life, because the second premolars are the permanent teeth most often missing, apart from wisdom teeth. The small upper side incisors are among the other teeth that are often missing.

Upper canines are the teeth most often impacted. A milk canine that has not fallen out by about twelve or thirteen, with no permanent canine visible, is worth an X-ray. The usual ages for normal shedding are in when milk teeth fall out.

A milk tooth that looks smaller, rounder and more yellow than its neighbours, with a tidy gap around it, is often the clue. In many adults it is noticed by chance at a routine check-up.

There is no fixed time. Some retained milk teeth last into the thirties, forties or later with no trouble. Others loosen, break down, or sink slightly below the level of the surrounding teeth as the jaw continues to grow around them, in the thirties or earlier.

A milk tooth has a shorter root and thinner enamel than an adult tooth, and the root slowly dissolves even when no permanent tooth is pushing. It is also as prone to decay as any milk tooth. Our page on cavities in milk teeth explains why the enamel wears through faster, and that applies to adults as well.

So the honest answer is that it may last a long time and it may not, and the dentist can judge from the X-ray how much root is left.

A panoramic X-ray shows the whole jaw, including teeth that have not come through. It tells the dentist whether a permanent tooth exists under the milk tooth, where it lies, how much bone is there, and how much of the milk tooth root is left.

That decides everything else. A missing permanent tooth means the milk tooth is the only tooth in that spot. An impacted tooth means there is something to rescue. Guessing without an X-ray risks removing a tooth that was holding the space for good.

The same check is worth doing in a child whose milk teeth are very late to fall, or whose parents or siblings had missing teeth, because the plan is simpler when it starts early. Our kids dentistry page explains how that review works.

If the milk tooth is healthy, firm, and the bite is comfortable, the usual advice is to keep it and look after it with careful cleaning and regular check-ups. It holds the space and the bone. A filling or a crown can protect it if it starts to decay or wear.

If it fails later, the gap can be replaced with a dental implant or a bridge. Implants need enough bone, which the retained tooth has helped to preserve. Our dental implant cost page has Lucknow ranges, and the dental bridge cost page shows the alternative.

If the permanent tooth is impacted, especially a canine, orthodontic treatment can often expose it and bring it into line, which is a different plan from replacement. Sometimes gaps are closed by braces instead of being replaced. Which is right depends on the X-ray, the bite and your wishes.

Call the clinic to ask what any of these would involve and what it would cost.