Ditto what Hell On Heels said regarding not being told about this any sooner. Has he not lost ANY of his baby teeth?
My daughter just turned 12, and last summer (around her 11th birthday) was when we scheduled her with the orthodontist. Mainly, b/c our older son needed some work done and they said we could schedule them both at the same time. They both have/had overbites that were enough that correction is needed. Daughter also has a history of screwy teeth. Shark teeth. Teeth not falling out easily. Teeth coming in sideways, etc.
She needed 4 teeth removed, and yes, the regular dentist is the one who pulled them. But the ortho is really the one who looks at the xrays into the gumline to see what is most important to deal with first. Then they will refer you back for having the actual removal done.
We happen to have a great relationship with our dentist, and they were able to get us in the very next day (to have 4 teeth pulled all at once... ouch!). It might've been a few weeks, like you mention, but our ortho told us it was important to get them out ASAP, and when we called our dentist, they were able to accommodate us. If we hadn't been able to come at the one opening they happened to have, it WOULD have been at least 2 weeks. (The office closes for at least a week annually to go to South America to do volunteer dentistry work).
I don't think your dentist is necessarily WAY off on the age, but more so the fact that your child hasn't been losing any teeth. Our daughter was losing teeth. Just not as frequently or "normally" as most people. She had had 4 shark teeth. And one of those baby teeth eventually just had to be pulled because it was NOT coming out and the permanent one was almost fully in and she couldn't clean well in between.
She had those 4 pulled last summer, lost 2 more on her own (on the very same day!) about 6 months ago, and hasn't lost any since. And none of the 4 that were pulled have the adult tooth grown in yet. We just had them xrayed this past week at the ortho, and they have dramatically shifted and hopefully will not cause any permanent problems. One is still on the iffy side, but we are hopeful. Teeth move. Even when they are grown in. It's why you'd need an implant if you lose a permanent tooth. Not because you can't live without it or eat without it, but because the space encourages the remaining ones to shift around and you need something there to keep things where they belong (and to keep the jawbone from deteriorating as well).
Good luck with your child.
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The thing is, regular dentists may xray your mouth (or your kid's mouth) once a year or whatever, but they are normally just taking bitewings. Those don't show the underlying structures, just the teeth and their roots. So they wouldn't see the permanent teeth beneath the roots of the baby teeth. They are not trying to (bitewings are not made to do that). An orthodontist, that is the first thing they do. Take panoramic xrays of the entire mouth structure.
Until your son complained, your dentist was likely unaware of any underlying problems, except that maybe your son wasn't loosing teeth at the normal rate. Which is why I say I'm surprised nothing was said about him not loosing many teeth. That would be a flag in my mind. But since your child is going to need to go to the orthodontist, they will wait and let the ortho take the panoramic xrays there, because they will retain them for comparison purposes later, to see how things are moving/changing and how to best treat whatever is going on as time progresses.
Regular dentists do not do the same things as orthodontists. Just like orthodontists and regular dentists don't do the same thing as oral surgeons. I'd bet you won't find a "dentist" who will do a tooth implant. It is a specialty. And orthodontics is also a type of specialty.
Does that help clear anything up?