How to Tell an Underbite?

Actually, you need to have him evaluated by an orthodontist, not a dentist. The evaluation appointment is usually free, so you have nothing to lose. Go talk to an expert.

He's growing, his mouth is still forming. Teeth move incredibly well with slight by constant pressure (according to my son's orthodontist back in the day), and techniques have changed exponentially in the past 5, 10, 15 years. Lots of adults are getting adjustments to their bite well after their growth is done.

You don' know what you're looking a until you talk to at least one orthodontist.

Don't beat up on yourself. You're not a dentist. The pediatrician didn't notice either, right? Or noticed but didn't think it was urgent.

You have time to look at and consider options. You do not have to make a rash decision. If you don't have a dentist, get one. (Ask friends, ask your pediatrician.) If you need a pediatric dentist, get a referral. You'll get an assessment and a set of x-rays, and a timetable. If you want a second opinion, get one. Anyone who tries to rush you into any treatment without some compelling evidence is suspect. I'm sure this will work out if you just take it step by step.

An underbite is when the bottom jaw (and/or teeth) jut out in front of the upper teeth.
Yes see a dentist but most importantly - get a referral to an orthodontist.
Much is going to depend on what the exact problem is.
In some cases - an expander on the upper jaw will increase the space enough to correct for it - and it's important to start this BEFORE the soft palate calcifies and hardens.
It's easier to do when the jaw is naturally growing.
Our son had expanders - they are easy and much less painful than braces started at a later age.
I only wish it had existed when I was a kid.

In other cases - lower jaw needs to be broken and re-positioned.
The only way to know for sure is to see to an orthodontist.
You don't want to put this off.
See one as soon as possible and they will tell you if you can wait a year or two or if you need to start doing something right now.

Teeth are things that the sooner you start correcting a problem - the shorter the treatment time will be.

Our son had expanders for 6 months and then 3 years of braces - he was finished before he finished 6th grade.
His teeth are beautiful.

I started braces in the 4th grade - and had braces for 7 long years and 8 adult teeth extracted - back in the day if your teeth didn't have room to fit - they removed some and moved the rest around.
Let me tell you it was a long painful process and I thought I'd never get all the hardware out of my mouth.

Hi M., my 5 year old son also has a slight underbite. His teeth come down on top of each other, instead of the front teeth coming down just in front of the lower teeth, so the dentist considers him to have a malocclusion. You can visibly see the wear on his front teeth from them hitting each other . They do now recommend to start treatment for this earlier rather than later, as it is easier to move the jaw in younger kids as opposed to older kids. My son is having an appliance put in his mouth which will hold the headgear to pull his upper jaw forward; he only has to wear this at night, not to school or anything. It's not braces, it's a palate expander that sits on the roof of his mouth. We decided to do this now, before his permanent teeth come in and start getting worn down the way his baby teeth already are.

You might be able to see for yourself if your son has an underbite, but you really need to take him to a dentist or orthodontist that can give you a real diagnosis. If you want to get an idea for yourself first, have him close his mouth naturally (without smiling etc). Look at his profile (view face from the side), you should see the upper lip protrude slightly over the lower lip in the case of a normal bite. If the lips are entirely parallel (as in my son's case), or the lower lip is protruding out from under the top lip, then he likely has a bite issue. In any case I would still have him evaluated by a professional and see if he needs treatment. They will take xrays and examine his jaw, it's not much outside of what you'd get at a normal dentist visit. Don't feel bad for not noticing or doing anything sooner, he is still really young and has a lot of time to correct this! That said, the younger he is when you treat it, the easier it will be and the less time it will take.

Just have him close his mouth and then open his lips. If the bottom teeth cover or mostly cover the top teeth, he has an under bite. It's not a huge deal. If he gets regular dental care, he dentist will probably refer him for an ortho consult after his 6-year molars come in. If the under bite is still there, ortho treatment at age 7-8 is simple and effective. One of my sons just needed braces that pushed his top teeth forward and pulled his bottom teeth back and it was enough to correct the under bite. The other needed a palate expander to widen the upper jaw. Both are 12 and 14 now and the prior work has held up so far. We expected that, depending on growth, they might have needed additional work after their 12 year molars came in and maybe a final round as young adults but so far, so good. FWIW, I had the same under bite that my kids have and it wasn't noticed until I was in high school. At that point I tried braces and a palate expander but required jaw reduction surgery (which is major surgery with a night in ICU and a stay of several days in the hospital) to really correct the problem.

Don't feel bad or worry about it...talk to your dentist at the next appointment and see what she or he says. I found it helpful to have an idea of what to plan for well in advance so that I could increase my health savings account election the years the work was done, which helped with my budget, but it's really not something to stress about in advance.

My son has a pretty severe underbite and the dentist has been speaking to me about it since he was 3. So I'm concerned that your dentist hasn't said anything. I would start there. The therapies are intense but breaking his jaw when he's 18 is worse, so I'd start early and try and avoid that. The ortho can't do much until he loses certain teeth and possibly until his molars come in. I would ask your dentist for a referral to an orthodontist he/she trusts.

Do you regularly take your child to a pediatric dentist? If so, s/he should be keeping an eye on it.

what does the dentist say? i work with my child's dentist and orthodontist to make sure my child gets the necessary dental care so that he has the care necessary for the best possible outcome of straight teeth. (he is missing 8 of his adult teeth and will require braces and partial dentures to be able to eat when hes older)