My child's teeth have gaps, or they overlap. Is that normal?

Gaps in the baby teeth: good or bad?

Usually good. Baby teeth are small, and the adult teeth that will replace them at the front are wider. So the gap you see now is the room they will need later.

The opposite tells you something too. If your child's baby teeth sit tight together with no gaps at all, or overlap, the adult teeth are more likely to come in crowded. More likely, not certain. It just means keeping a closer eye on it at the regular check-up.

And at the back?

At the back, a baby molar is a little wider than the tooth that replaces it, and the big adult molar behind uses that extra room to fit properly. Every millimetre counts, and that is why a baby tooth lost early makes a difference.

What is the “mixed stage”?

It is the years when your child has baby teeth and adult teeth in the mouth together. Dentists call it the mixed dentition. It starts at around 6 and ends at around 12. During these years the mouth often looks “untidy”, and that is part of the stage, not a problem in itself.

These ages only give you an idea. Some children are ahead or behind by a few months, up to about a year, and that is usually normal; a bigger delay is worth a check. The order matters more than the date. The full timeline from the very first tooth: When your child's teeth come through: the full timeline.

What is normal at this stage, even if it looks odd?

Plenty of things worry parents and are an ordinary part of the changeover. These are the most common:

• The new teeth look too big for their mouth. An adult tooth is wider and longer than the baby tooth it replaced, so it looks big next to the small baby teeth. Over time, as the teeth beside it change too, it usually evens out.
• They come in a little tilted or overlapping. The adult front teeth often come in slightly tilted or slightly crowded, and sometimes they straighten as the canines come through and the row of teeth widens a little. Sometimes, not always: that is why they are looked at at every check-up, and we never assume they will sort themselves out.
• A gap in the middle, between the two upper front teeth. Many children have this gap once the adult front teeth are in, because the canines still under the gum are moving into place. A small gap often gets smaller as the canines come through. A large gap is less likely to close on its own, so it deserves a look.
• A big molar came through at the back, and nothing fell out. That is the first adult molar, often called the six-year molar, and it comes through at around 6 to 7. There is no baby tooth before it, so nothing falls out when it arrives. Many parents do not notice it has come through, or take it for a baby tooth, so the toothbrush has to reach it: nothing replaces it, and it has to last a lifetime.
• One side got there first. A tooth has come through on the right, and its partner on the left has not yet. A few months between the two sides is normal.

But “normal” here does not mean “wait and forget about it”. It means “keep an eye on it at the regular check-up”, because the difference between normal and something that needs a look sometimes only shows at an examination or on an x-ray. What happens with the baby teeth themselves, and when to worry about them: Baby teeth: when to worry, and when not to.

And when is it worth a check?

When you see any one of these. None of them is an emergency, and none of them means braces for certain. They mean “come in and let us have a look”:

• An adult tooth coming in behind a baby tooth that is still firm. You see two rows. Often the baby tooth loosens and falls out on its own, and the new one moves forward. But if the baby tooth stays firm, or the new tooth is far from the line, it is worth a check. If the new tooth is an upper one coming in behind, come in sooner, because it can end up closing behind the lower teeth.
• A baby tooth lost early, some time ago. To decay, an old knock or an extraction, while the adult tooth underneath is not ready to come through. The baby tooth was holding a space, and when it goes early the teeth beside it can lean into the gap, leaving the adult tooth less room. Sometimes a small appliance holds the space, and sometimes there is no need for one. The examination and the x-ray decide that.
• Clear crowding. Not a slight tilt: a tooth coming in outside the line, a tooth that has found no room to come through, or a canine coming in high and outwards, above the other teeth.
• A bite that does not meet properly. The upper teeth close behind the lower ones, on one side or at the front. Or the jaw slides sideways or forwards as your child closes. Or the front teeth do not meet at all when they bite. Or the upper front teeth stick out well ahead of the lower ones.
• A gap that does not shrink, or a tooth that has not appeared. A large gap in the middle that is still there after the canines have come through, and the examination looks for the cause: a lip tie (the band of tissue under the upper lip) reaching down between the two teeth, a missing tooth, or an extra tooth in the middle. Or a tooth has come through on one side, and its partner on the other side has not appeared after around six months.
• Thumb or dummy sucking that is still going on. When the habit lasts, it can narrow the upper jaw, stop the front teeth meeting, or push the upper ones forward. How to handle it calmly: Thumb or dummy: when does it start to affect your child's teeth?

A knock that has just happened is different: call straight away, and here is what to do in the first hour: Your child knocked out a tooth: the first hour. If the knock was to the head, with dizziness, vomiting or any blackout, even for a moment, go to the nearest hospital emergency department first; the teeth can wait.

At the examination we look at the teeth and the bite, with an x-ray if it is needed, not as routine. The x-ray shows the teeth still under the gum, where they are heading, and whether there is room for them. Then you'll hear one of three things: monitoring only, treatment now, or waiting until more teeth come through. The orthodontic assessment is explained in full on Braces for children and teenagers.

What you can do from today

1. 1

   Photograph their smile every few monthsA phone photo from the front while they smile, and one while they bite together. It helps you see what has really changed, and it is more use at the examination than “I think they've got more crooked”.

2. 2

   A wobbly baby tooth falls out on its ownLet your child move it with their tongue or a clean finger. Do not pull a tooth that is still firm, and do not take it out at home with a thread or by force.

3. 3

   Tell us about any tooth lost earlyTo decay, a knock or an extraction, even long ago. And bring any old dental x-rays you have, from here or from abroad. They help us see how much room there is for the teeth still to come.

4. 4

   Brush every tooth, old and newTwice a day with a fluoride toothpaste, and don't forget the six-year molar at the back. A new tooth that is only half through collects food around it, so brushing needs your eyes on it, not just a reminder.

5. 5

   Regular check-ups, with the changeover as part of themAt every check-up we follow how the jaws are growing, how the teeth are coming through and how they meet. So there is no need to wait for something to show before you come in.

Questions people ask