Friday, March 24, 2006

Permanent Teeth Coming in Behind Baby Teeth

I see this every day. A child comes in with his permanent lower incisors coming in behind the baby teeth. We sometimes call it "Shark" teeth. The baby teeth have not come out like they were supposed to. It is most common with the lower front teeth when the child is six years old and then the upper back molars when the child is around eleven years old. A common "emergency" is when a parent notices a permanent tooth coming in behind a primary (baby) tooth. It's not really an emergancy, but needs to be addressed.

In the normal course of events, the permanent teeth slowly dissolves the baby tooth root as it comes in up under the baby tooth. Finally, there is not much root left. The baby tooth gets loose and eventually falls out. The permanent tooth then comes in where the baby tooth used to be. Well, it doesn't always happen just like that.

If the child doesn't have enough room for the permanent teeth, then the permanent tooth may not come in right up under the baby tooth. Even when there is lots of room, the new tooth may not be able to resorb the baby tooth root fast enough. It then takes the path of least resistance, which is to come in behind the baby tooth. That means there is nothing "pushing" the baby tooth and there may be quite a lot of baby tooth root left.

The good news is that the permanent tooth will tend to move forward into the correct position on it's own IF there is nothing in the way and there is enough room. That usually means the dentist will need to remove the retained baby tooth and make more room by removing the adjacent baby teeth or making the baby teeth more slender by "disking" them. If the new tooth hasn't come in very much (you haven't waited too long), then the new tooth will slowly move forward. This takes a few weeks or months to move forward into a better position. They may even straighten out a little if they were coming in crooked.

Often teeth come in pairs, so if one tooth is not coming in correctly its partner on the other side won't either. A lot of parents hold out hope the baby tooth will fall out on it's own. Some children are very aggressive in wiggling their teeth. Some just let them hanging there. Remember however, that there may be more root on that baby tooth than you think, otherwise it would have come out by now. Most of the time the dentist has to get in there and get the tooth. Even if you can get that tooth out, is there enough room for it to come forward? Many times teeth come in funny because there is some inherent crowding. If the dentist needs to get it out, it's not a big deal. Most kids do quite well for this. Plus, they get to have their tooth to put under the pillow for the tooth fairy!

For more info click home or here:Pediatric Dentistry

29 comments:

Anonymous said...

My daughter is five and her dentist wants to pull two of her baby teeth because he says she had crowding. I'm worried because she already is already missing her two front teeth and he wants to pull out the other two. She won't have any teeth in front on the top! I feel this is a little extreme, is it necessary?

Dr. Dean Brandon said...

I have no idea if it's extreme...All this kind of thing revolves around is how big are the new teeth coming in, is there enough room for them to come in properly, at what stage of eruption are the new teeth, etc. etc.

Anonymous said...

Thanks for an interesting article. My 4 year old daughter has the left lower center tooth coming in behind the baby tooth, it is coming up a little crooked,and the front left corner is touching the back of the 2nd left tooth. the baby tooth it is replacing is wiggling since a few days ,and we only spotted the tooth today. I see nothing on the other side, so it seems only one tooth is coming. i doubt two teeth like this one will fit in the space occupied by the two babies...should we just wiggle loose the baby tooth, or is there course for alarm. btw, how common is it for 4 year olds to have this happen, seems like 1.5 years early( she is however an early developer...?) Olof

Anonymous said...

my tooth hasn't come in yet

SafeTinspector said...

Well, this is exactly what my daughter has going on. Thanks for a very informative article, and I guess we'll be calling Dr. Steingold!

Anonymous said...

I just returned from the dentist where my 6 yr old had his front tooth pulled because of his permanent tooth coming in behind. I was wondering if I had done the right thing. I finally looked at the tooth - the root is very long & crooked. I googled & found this site. I feel better after this article. Thank you!

Anonymous said...

I am 21 years old and I have a full grown adult tooth behind another adult tooth that used to have a baby tooth when I was younger. The dentist told my mother not to worry about it,that the baby tooth will fall out on it's own.Well thats not the case hear I am at 21 and that back tooth wants to move in. Hurting my gumes. Now I am trying to find a dentist that will finally help me.
When they insist on waiting for your childs baby teeth to fall out on it's own keep an eye on it.

Anonymous said...

Hi! I have a 6 year old daughter she loose her 2 front upper teeth by accident last October 2007 and I am worried because its been almost 3 months and her permanent teeth did not come out yet. Is this normal?

Dr. Dean Brandon said...

Yes, it can be up to 6 months before I see permanent teeth erupting when they fall out normally--could be longer with knocked out teeth. Normal time for upper front teeth to come in: 7-8 years of age.

Anonymous said...

My son is seven and a half and has not lost a single baby tooth yet.(Nothing is even loose).Today I noticed that a permanent tooth came in behind the baby tooth on the bottom left.The dentist says this is perfectly normal and that we need to just wait for the baby tooth to fall out.Is there something to be concerned about?Should I get another opinion?

Dr. Dean Brandon said...

Sometimes it does not fall out fast enough. If they are loose and fall out within a couple of weeks I don't worry. You can read my opinions here.

Anonymous said...

My daughter is 17 months and she have 6 teeth on top the one on the back right is in but there is one comming in right behide it ,what should i do?

Anonymous said...

My daughter is 5 1/2. I just noticed today morning that she is getting "extra" or "permenant" teeth behind her baby teeth. Your article is very helpful and educational. Thanks, I will have to call dentist right away.

Shannon said...

My daughter is 5 and a half and has two teeth growing in behind her bottom baby teeth. The dentist says even though the tooth is loose, the gums don't seem to move underneath. He says that he will need to extract them with anaesthesia. I made an appointment for 1 month from now. One of the permanent teeth is halfway in. Is a month too long to wait?

Dr. Dean Brandon said...

Seems like an ok timeframe to me.

Kathryn Crouse said...

My sons baby teeth (all four) did this. They all eventually moved forward except one front top tooth. I repeatedly asked the dentist to PLEASE pull it, but he kept refusing. Now he is sending me to an orthodontist because it's not coming forward. I am pretty frustrated. He keeps telling me it wouldn't have made a difference. I beg to differ. What do you think?

Anonymous said...

My 5 1/2 year old daughter's bottom front tooth came out yet the permanent tooth had already begun to come in. Only the top of the permanent tooth had come through, but it is VERY crooked: almost lying at a 45 degree angle to the tooth next to it. Might this be caused by roots still in her gums? The baby tooth next to it is very loose, but no tooth appearing behind it yet. Is it too soon to see the dentist? Will they have to pull it? All I can think of are braces!

Dr. Dean Brandon said...

It's not too soon to see the dentist. Have them take a look to relieve your concerns. It's not an uncommon occurrence.

Anonymous said...

Hi there...I was curious to know how long do you leave the "shark teeth" before taking action and getting them removed?
Thank you

Dr. Dean Brandon said...

Good question: If a patient presents with this, I usually say if you can't get it out (the baby tooth or teeth) in a couple of weeks (two or three), then we need to get it out for you.

Anonymous said...

My daughter turned 5 in January, 2008 and has two front lower permanent teeth coming behind her baby teeth. Her dentist said we do not need to worry about it...she can wait until she turns 6 to lose the baby teeth. They are a little wiggly already. Should we let the baby teeth fall out on their own or let her wiggle them until they fall out? We are concerned that if we wait another 8 months and the babyteeth are still there, would the permanent teeth grow crooked.....Please help us...

Dr. Dean Brandon said...

I usually don't let the baby teeth stay there too long. I give the kids a few weeks to get them out if the new ones are erupted. The longer a permanent tooth stays out of place the less the chance it will move into a proper position on it's own. still your pediatric dentist is the one who looked at it, so I cannot advise.

Anonymous said...

Dr. Brandon,

My 14 year old had 4 baby teeth extracted to make way for the permanent teeth and braces. After 2 years, one of the permanent teeth have not erupted. The orthodonist says the tooth is lying sideways in the gum and does not have a developed root. They suggest we do oral surgery to remove it and at 18, implant a tooth. Is this sound advice? Is it possible the permanent tooth was damaged in the extraction process? Does that ever happen? THANKS SO MUCH!

Dr. Dean Brandon said...

I do see malformed/malpositioned teeth from time to time. Some don't form at all. One way to treat a missing tooth (it basically is not from what you say), is as you say. Another way is to close the space with braces. Your orthodontist will advise on the best for you.

mom2twins said...

My son is 6 and has lost 7 teeth with no sign of a permanent coming in. Its been about 7 months since the first one came out. When should I be concerned about this?

Oh, he was a 26 week preemie, i have been told this affects teeth sometimes? Have you heard this? He was on o2 for 4 months and intubated for 6 weeks?

Michelle

Dr. Dean Brandon said...

It can be a while till some teeth come in after they naturally fall out. An x-ray might be recommended by your dentist if you are concerned. I would have your dentist take a look to give an informed opinion and to rule out other conditions as well.

Anonymous said...

Today, the dentist removed my 6 yr old's two bottom and its apparent that there is not enough room for permanent teeth to make there way to the front. She did not want to remove the other two teeth for fear of too much space. I was told to wait to see how they turn out. What's the likely hood of the other teeth shifting and making room for the newcomers? I wonder why they didn't mention "disking" as an option. Should we start saving for the orthodontic fund?

Dr. Dean Brandon said...

Well, removing baby teeth (or disking--and sometimes disking is not needed) makes more room in the front for the erupting teeth. However, the inherent crowding is still there and usually must be resolved with some kind of treatment later on. So, if crowding is the reason teeth were removed, then it is likely that braces might be needed later on.

Dr. Dean Brandon said...

I know this is a common problem and there are a lot of comments on this subject here, so I am temporarily discontinuing comments on this post. I hope you can find the info you need here and elsewhere on the blog.