Most parents expect permanent teeth to follow a fairly predictable pattern: a baby tooth gets loose, falls out, and before long a permanent tooth takes its place.
But occasionally, a permanent tooth doesn’t follow the plan.
It may be developing in the wrong direction. It may be blocked by another tooth. There may not be enough room for it to erupt. Or it may simply stop moving toward its normal position in the mouth.
When a permanent tooth becomes stuck and cannot erupt normally, we call it an impacted tooth.
What many parents don’t realize is that we can often see signs of trouble well before that happens.
An impacted tooth usually doesn’t become impacted overnight
When I evaluate a child, I’m not only looking at the teeth that are already visible. I’m also looking at the permanent teeth that are still developing underneath the gums and asking an important question:
Are they headed where they are supposed to go?
Sometimes a permanent tooth is still developing and has not technically become impacted, but its position or direction makes me concerned that it may not erupt normally.
I often describe this to parents as a tooth that is “pre-impacting.”
In other words, it isn’t necessarily stuck yet—but it is heading in a direction that may eventually cause it to become impacted.
That distinction is important because this can be one of those situations where finding a problem early gives us more options.
Canines are especially important to watch
The permanent upper canine teeth—the pointed teeth near the corners of your smile—have one of the longest eruption paths of any teeth in the mouth.
They begin developing relatively high in the upper jaw and gradually travel downward into their final position.
That long journey gives them more opportunity to get off course.
Sometimes we see one canine developing normally while the canine on the other side is angled differently, positioned too far toward the palate, or beginning to overlap the roots of the nearby teeth.
From the outside, everything may look completely normal.
A baby canine may still be sitting in the mouth and causing no discomfort at all.
But underneath it, the permanent tooth may be going in the wrong direction.
Impacted teeth can sometimes run in families
There can also be a genetic component to impacted teeth.
This is especially true with certain eruption problems involving the upper permanent canines. If a parent, sibling, or other close relative had an impacted canine or a permanent tooth that needed help erupting, that family history can be another reason for me to watch a child’s developing teeth a little more closely.
Genetics is not the only reason a tooth becomes impacted. Crowding, lack of space, extra teeth, an abnormal eruption path, and previous injury to a baby tooth can all contribute.
But sometimes a child may simply have a greater inherited tendency for certain teeth to develop or erupt abnormally.
That does not mean the tooth will necessarily become impacted. It means we have another clue telling us that early observation may be especially valuable.
This is one more reason I like to evaluate the developing permanent teeth before there is an obvious problem. A child may have no pain and everything may look normal in the mouth, while an X-ray is already showing us that a permanent tooth is moving in an unusual direction.
Other permanent teeth can become impacted too
Although canines are one of the teeth orthodontists watch particularly closely, they are not the only permanent teeth that can become impacted.
We occasionally see impacted front teeth, including the upper central incisors.
When one front tooth comes in and the matching tooth on the other side does not, that deserves investigation rather than simply assuming the tooth is a “late bloomer.”
An upper front tooth may be prevented from erupting by an extra tooth, a lack of space, an unusual position, or sometimes an injury to a baby tooth that occurred years earlier.
Other permanent teeth can also become impacted depending on their position and how the jaws and teeth are developing.
The important part is recognizing when a tooth is no longer following a normal eruption pattern.
How late is too late?
Parents often ask me when a particular permanent tooth is supposed to come in.
There is actually a fairly wide range of normal. Children do not all lose their baby teeth or get their permanent teeth at exactly the same age.
As a general guide, the first permanent molars and lower front teeth usually begin appearing around age 6 or 7. The upper front teeth generally follow around ages 7 to 9. Premolars and lower canines typically appear between about ages 9 and 12, while the upper permanent canines often arrive later—usually around ages 11 to 12. The second permanent molars generally erupt around ages 12 to 14.
Those ages are useful guidelines, but I am often more interested in the pattern of eruption than the exact age.
If a tooth is several months later than average but everything is developing symmetrically, that may be perfectly normal.
What gets my attention is when the two sides are behaving differently.
If the permanent canine has erupted on one side but the baby canine on the other side is still firmly in place, I want to know where that permanent tooth is.
If one upper front tooth appears and the matching tooth does not, I want to know why.
Those differences do not automatically mean something is wrong. But they are clues that it may be worth taking a closer look.
Why not just wait and see if it comes in?
There are certainly times when watching a developing tooth is exactly the right thing to do.
But once we see that a permanent tooth is significantly off course, simply waiting can make the problem more difficult.
A tooth that is moving in the wrong direction can come into contact with the roots of neighboring permanent teeth. In some cases, that pressure can actually cause portions of those roots to resorb—or essentially be worn away.
That means an impacted canine, for example, can potentially damage a perfectly healthy lateral incisor next to it.
And unfortunately, the child usually cannot feel that happening.
This is one of the reasons orthodontic X-rays are so useful during the years when permanent teeth are developing. We can see a problem that would otherwise remain completely hidden.
Early treatment does not necessarily mean braces
Finding a tooth that appears to be heading toward impaction does not automatically mean a child needs a full set of braces.
Sometimes the first step is surprisingly simple.
If a baby tooth is interfering with the path of the permanent tooth, removing it at the right time may help. In other situations, we may need to create additional space so the permanent tooth has somewhere to go.
And sometimes the best treatment really is careful observation—but now we are watching the tooth intentionally rather than simply waiting and hoping.
The goal is to give the permanent tooth the best opportunity to erupt naturally whenever that is still possible.
That is very different from discovering years later that the tooth has become deeply impacted.
Once a tooth is impacted, it usually needs some help
If a permanent tooth has become truly impacted, we generally should not assume it will eventually work its way into place on its own.
Fortunately, an impacted tooth does not necessarily have to be removed.
In many cases, we can create the space it needs and work with an oral surgeon to bring the tooth into the mouth.
The surgeon exposes a small portion of the impacted tooth and attaches a tiny orthodontic attachment to it. We can then apply very gentle forces over time to guide the tooth toward its proper position.
It is usually a slow process.
We aren’t simply “pulling the tooth down.” We are carefully moving it through bone while protecting the roots of the surrounding teeth and the gum tissue that will eventually surround it.
Where the impacted tooth is located, which direction it is facing, how close it is to neighboring roots, and the age of the patient all affect how difficult that process may be.
Age matters more than many people realize
This is another reason I prefer to identify these problems while children are still developing.
As an impacted tooth remains buried in bone for many years, there is a greater chance that it can become ankylosed.
An ankylosed tooth has essentially fused to the surrounding bone.
Normal teeth are separated from the bone by a very thin periodontal ligament. That ligament is one of the things that allows us to move teeth orthodontically.
If that normal separation is lost and the tooth becomes fused to bone, orthodontic forces may no longer be able to move it.
That can dramatically change the treatment options.
This does not mean that every impacted tooth in an adult is ankylosed or that impacted teeth cannot be treated successfully in adults. They often can.
But the risk increases with age, and a tooth that has become ankylosed may be much more difficult—or impossible—to bring into the mouth orthodontically.
That is one reason I would much rather identify a potentially impacted tooth in a child than discover the same problem decades later.
Sometimes we can see the problem before there is a problem
To me, this is the most important part of the conversation.
Parents sometimes wonder why orthodontists want to evaluate children while they still have a mixture of baby teeth and permanent teeth.
This is one of the reasons.
We are not necessarily looking for an excuse to put braces on a seven- or eight-year-old.
We are looking at development.
Are the permanent teeth present?
Do they have enough room?
Are they developing in reasonable positions?
Are the right and left sides progressing similarly?
Is a permanent tooth following an eruption path that gives it a realistic chance of reaching the mouth?
Finding something early doesn’t always mean treating it early.
But finding it early means we can make that decision while we still have choices.
The baby tooth that stays too long can be a clue
One of the easiest things for a parent to notice is asymmetry.
If the permanent canine has erupted normally on the right side but the baby canine is still firmly in place on the left, it is worth asking why.
The same is true if one permanent front tooth erupts and its partner doesn’t appear.
There can be completely innocent explanations for differences in eruption timing, so this doesn’t mean something is necessarily wrong.
But it is a reason to look.
An X-ray can often tell us very quickly whether the permanent tooth is simply developing a little later—or whether it is headed somewhere it shouldn’t be.
When it comes to impacted teeth, earlier information is valuable
The best outcome is usually the patient’s own permanent tooth in its proper position, surrounded by healthy bone and gum tissue.
Sometimes achieving that is straightforward.
Sometimes it requires orthodontic treatment and the help of an oral surgeon.
And occasionally the position or condition of a tooth means that another solution makes more sense.
But one thing is consistent:
We have more options when we know what is happening early.
That is why I pay attention not only to the teeth a child has today, but also to the teeth that are still on their way.
If your child has a permanent tooth that hasn’t appeared when you expected it to—or a baby tooth that seems to be hanging around much longer on one side than the other—it doesn’t necessarily mean there is a problem.
But it is worth finding out.
At our Charlottesville orthodontic office, we can evaluate the developing permanent teeth and determine whether everything is progressing normally or whether a tooth needs a little help finding its way.
- Dr. Suzanne Dennis
