Dr. Lynskey's Invisalign & Braces Blog

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When Adult Teeth Come In Behind Baby Teeth March 28, 2012

There are many parents who are petrified when they see a permanent tooth erupting behind the baby tooth. They wonder whether this is alright as permanent teeth only need to erupt once the baby teeth have fallen.

But, in reality it is quite okay for the permanent tooth to erupt before the milk tooth has fallen. The way it goes on to work is that the permanent tooth will make the roots of the baby tooth weaker and the baby tooth will fall off on its own. This space will be then occupied by the permanent tooth. Although, this is not the course of event followed all the time.

The thing is that if there is not enough space available in the child’s mouth then the permanent tooth will start erupting behind the baby tooth. There might be enough space but still this might occur as the new tooth might not be able to reabsorb the baby tooth at a fast rate. This means that it takes the easy way out of growing behind the baby tooth. The permanent tooth grows behind the baby tooth which is the path of least resistance.

The baby tooth will still be in the mouth and then the permanent tooth will erupt. This is most commonly seen in kids who are six years old and in the lower front teeth. The technical term for this is lingually erupting mandibular incisors. The other name that it is known by is shark teeth or simply permanent teeth erupting behind the baby teeth. This can also happen to the upper molars when the child is 11 years old.



    Is there a reason why do permanent teeth grow behind the baby teeth?

The main reason behind ectopic and lingually erupting incisors is not being placed well. There are quite a few reasons why shark teeth might occur.

  1. There are dentists who say that when the roots of the baby teeth don’t dissolve like normal, then the permanent teeth are bound to come from behind. This is the place that has the least amount of resistance to it and they find it easy to emerge.
  2. On the other hand, there are dentists who think that permanent teeth start growing from behind because of too many teeth and overcrowding that takes place in the jaw.
  3. Then, some say that permanent teeth go on to grow behind the baby teeth as this is a deviation and this ensures that they aren’t going to grow normally.

Is it a threat if there are permanent teeth growing behind the baby teeth are the question?

This is a common occurrence in children to find permanent teeth growing behind baby teeth. In fact, almost 10% of kids will encounter this.

Having said that shark teeth do not need much assistance from a dentist as they can find their own answer since over time the baby teeth has to fall. But, there are times when they don’t have a resolution as the baby teeth do not fall on their own. This then gets termed as retained baby teeth. If this happens then a dentist has to help to manage the permanent teeth coming in behind the baby teeth.  They must ensure that the correct position and there is ample of space for the permanent teeth to erupt perfectly. For that they might have to remove the baby teeth.

The Help a Dentist Can Render to Manage Permanent Teeth Coming In Behind Baby Teeth

If you find that your child has shark teeth then what you do need to do is to watch it for a few days or weeks and see if it gets resolved on its own. It is certainly a great idea to consult a dentist about it. This is when the child’s dentist will recommend whether you do need to remove the baby teeth or wait and watch. This will ensure that you are able to get the right resolution for the problem.

The dentist may remove the baby teeth behind which the adult tooth is growing and this will go on to give the permanent teeth enough space to come forward. There is also a procedure called disking wherein a part of the adjacent baby tooth enamel is removed so as to give enough room for the permanent teeth to grow into its final position. This does not require your child to go through extraction of the adjacent baby teeth right away. However, even after disking if the permanent teeth seem to have no space to move forward and grow well then the dentist will be forced to remove the adjacent milk tooth to have extra space in the mouth.

The new tooth will then go on to slowly and gradually move forward and take the place of the milk teeth. This might take a long time and the effects can be seen in months or weeks. You will notice that the permanent teeth have a straighter look to them as they move into the final position.

A thing to keep in mind is that there is enough space in the mouth for the adult teeth to erupt. This will ensure that your child has a good smile and effective chewing for a lifetime.


The thing to remember as a parent is that shark teeth are not abnormal. Almost 10% of children have it and the milk teeth will either fall on their own within some time. If they don’t fall even after some weeks, then intervention of a dentist is required. If the baby tooth falls out on its own then you are surely spared the hassles. If it does not then you need to consult a dentist who will recommend a solution. The baby tooth is pulled out in such situations. It is a simple thing and you need not worry needlessly about it. This will make enough room in your child’s mouth for the permanent teeth to emerge.


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