When does class 1 end and class 2 or 3 begin?

[Mark32]

Hi all

I've just joined the forum as I'm considering having something done to my jaws. But I only know a small amount about all this stuff so I'm keen to learn a bit more.

One of the things that I've been wondering about is when does somebody stop having a class 1 type jaw relationship? I've read the explanation that such a bite involves the front outside (mesio-buccal?) cusp of the first upper molar being aligned with the buccal grove of the first lower molar. Don't know if those terms are right?!! But is that position just the exact mid-point in a range of jaw relationships that are grouped together as class 1?

Can this cusp/grove alignment be a few millimetres out either way before you'd be considered a class 2 or 3? Or maybe the whole class thing is way more complicated than this.

[Mark32]

one bizarre interest I have is looking at the teeth of celebrities. and it's from such pics that i'm left wondering if there's a range - albeit small - of skeletal jaw relationships within the class 1 group. I dunno if this makes sense but many of the famous people I have in mind have nothing class 2 or 3ish about their facial shapes. however, when you see a pic of their teeth - especially when clenched - some seem to have more ?anterior? lower canines and/or more crowded lower incisors than others. Others are in the other direction and almost seem to have a very slight overjet. Yet all these people would seem to have good facial balance and be within the class 1 group.

I know the front teeth can't tell you that much about the skeletal relationship but can't they maybe hint at how the jaws meet.

also, aren't most physical characteristics, like height and weight, distributed across a group in a way that plots a bell curve on a graph. it's called normal statistical distribution, I think. wouldn't that mean that there'd be a ton of people slightly to one side or other of the average measurement but who'd still be so far away from the tails of the curve that they'd be considered 'normal'.

aren't 70% plus of people in the class 1 group but couldn't a good chunk of those fall out towards the class 2 or 3 side of the average, 'ideal' jaw relationship? that would make sense of how people who seem to be class 1 still seem to vary slightly in an anterior/posterior alignment of how their jaws meet.

am I making any sense or have I just lost the plot

[PloskoPlus]

I keep looking for class iii celebrities and can't find any.  Michael Phelps?  But he's an athlete.  For a while I thought Sammy Davis Jr was, but I think that people often mistake a heavy chin for class iii.

[Mark32]

what do you think of the bites/jaw relationships of these celebs (some dead):

Jay Leno
Fred Gynne (Herman Munster)
John Lithgow
Bob Hope
Michelle Obama
Robin Williams
Seth MacFarlane (Family Guy)
Michael Douglas
Ronald Reagan
Rob Lowe
Kevin Spacey
Alan Ruck
Stephen Colbert
Bill Clinton
Drew Carey
Arnold Schwarzeneger
Gregory Hines
Cenk Uygur (Young Turks)
Reese Witherspoon
Jack Black
Ron Perlman (Hellboy)
Sigourney Weaver
Jon Stewart
Ed Helms
Daniel Day Lewis
Jerry Lewis
Bill Cosby
Kelsey Grammar
George Clooney
Seth Green
David Zayaz
Josh Brolin
Debra Messing

with the possible exception of maybe Jay Leno I don't think anyone on that list would fall into the full class 3 group. but if you look at close up pics of their teeth or just notice their lower facial balance I think that many of them, while being class 1 i'm sure, would have a class 3 tendency if such a description exists. quite a few seem to have an edge to edge incisor relationship despite appearing to have already had orthodontic correction/veneers. others might be edge to edge but for orthodontics or might have had excessive lower incisor crowding. many have too prominent a lower lip area I think.

I suppose what might show this thing about a range in class 1 are Charlie and Martin Sheen. both are/were attractive men that are no doubt considered to have class 1 jaw relationships. however, Charlie's lower jaw seems further forward or upper jaw further back (either/both) with his incisors just overlapping vertically. by contrast, martin's upper incisors are much more prominent in relation to the lower ones. do you think could the father be on the class 2 end of a class 1 spectrum and the son on the class 3 end?

do you know of any papers/publications that might go into whether there's an anterior/posterior variation in the class 1 jaw group?

[PloskoPlus]

Only Jay Leno.  A lot of these people have a so called ante face - the jaws are heavily projected forward often with a sloping profile.  But they are all class I.  All of them.

[Mark32]

I see what you're saying about the jaws projecting forwards. I suppose that would make the lower teeth more prominent relative the rest of the face as well. but do you still not think that many of those could have some sort of class 3 tendency even while being class 1s? after all, there are different degrees of severity in class 2 and 3 conditions. so couldn't there be a range of class 1 alignments too? I think I remember reading about inadequate overjet in some orthodontic material...

wouldn't you think that Michelle Obama, John Lithgow or even Seth MacFarlane have lower teeth (maybe jaws) that are too prominent?

[PloskoPlus]

wouldn't you think that Michelle Obama, John Lithgow or even Seth MacFarlane have lower teeth (maybe jaws) that are too prominent?

Maybe... But in any case, all this sounds like some kind of bro science.  What is not bro science is that soft tissues sags with age.  So both the upper and lower lip droops.  That's why older people have less upper tooth show and more lower tooth show.  Maybe that's what you are seeing.

[Mark32]

that's interesting about soft tissue sagging to change the way in which the teeth are revealed. I think that must be going on with my dad. he doesn't reveal much of his upper teeth when smiling but in old pics his front teeth are more visible. as for the celebs, it is difficult to tell all that much from photos

I suppose the reason that i'm always looking for famous people with slight jaw imbalances is that I think that that type of bite might more reflect my own situation. I think that I fall more into the tendency bracket (if there is such a thing) rather than a much more pronounced class 3. I also think I might have a slight open bite tendency. so I suppose i'm really in search of advice on what to do when less correction/movement is required.

what is bro science?