Please help with my case - 11mm overbite with a big lower jaw

[palacsinta4]

After 3 years of failed braces treatment (they fixed my gummy smile with TADs, but didn't help my overbite), I was told that I can get jaw surgery if I want to fix my bite, but the suggested movements seem off to me.

I was told lower jaw advancement and upper jaw clockwise rotation (but no movement)

My lower jaw seems big to me already while my midface is flat, and I can't really find cases like mine online. I'd really appreciate some thoughts: https://imgur.com/a/0nHdEz0

[kavan]

Suggested movements seem appropriate to me.

CW rotation at the maxilla around the Insisor point will bring ANS (anterior nasal spine) forward and the soft tissue at base of nose will go forwards. So that part would tend to improve some flatness you cite as an issue.

The CW rotation also rotates the jaw backwards and down. So, that would give a better angle of inclination to the lower jaw to bring it forward for a better bite. Included is an illustration.

Imádom a nevedet.

[palacsinta4]

Köszönöm : )

But should they not at least tip the top teeth back at first and extract teeth? My upper teeth are very tipped forwards, and honestly from what I see both jaws are recessed and not just my lower jaw



I have no idea if they'd rotate around the ANS or incisor point, I only know that they'd move the back of my maxilla upwards. But can my face really handle a big mandible advancement?

[kavan]

Köszönöm : )

But should they not at least tip the top teeth back at first and extract teeth? My upper teeth are very tipped forwards, and honestly from what I see both jaws are recessed and not just my lower jaw



I have no idea if they'd rotate around the ANS or incisor point, I only know that they'd move the back of my maxilla upwards. But can my face really handle a big mandible advancement?

Your lower jaw  gets rotated with the rotation at the maxilla. The rotation at the maxilla will give your lower jaw a better angle of inclination to advance it over. If the lower jaw were not rotated via the rotation at the maxilla, it would look too advanced. A rotation at the incisor point moves the back of the maxilla upwards but it also will move the soft tissue near the nose more forward (where you feel it's recessed). So, the doctor's suggestion is appropriate. Feel free to cross reference what I said here with your surgeon.

[kavan]

So, you've introduced a new piece of information which would have been better  introduced all together with your first post. So, we will try the other CW-r rotation point.

OK, the CW-r could be one or the other rotation point. Neither of us know for sure which rotation point is to be used for the CW-r. What both rotation points have in common is that the chin point (lower jaw) will rotate backwards and down and the back of the mandible will move up with CW-r around EITHER of rotation points (ANS or insisor).

 Let's try ANS as the rotation point. With that rotation point, the soft tissue of the lips and also the frontal incisors will go backwards with that rotation point.
In that case. In that case, the excess angle of inclination of the incisors and also their protrusion  will be REDUCED. So, maybe he chose that rotation to reduce the excess angle and and extent of protrusion of the upper incisors.

Your midface could look flat to you via RELATIVE COMPARISON of the excess angle and protrusion of the upper incisors. It isn't flat or recessed in terms of some other angle measurements maxfax surgeons use (SNA norms).

With rotation around the ANS point (CW-r at the maxilla), the (chin point) at mandible also rotates down and backwards along with the rotation at the maxilla. However, the rotation allows for advancing the mandible along a better angle of inclination relative to a horizontal plane which makes it possible to advance it without the chin point 'sticking out too much' or looking 'over advanced'.

As is obvious from the ceph, the mandible needs to come forward to correct the bite.
What may not be obvious to you is that the surgeon is looking at a TRIANGLE made from 3 points and seeing that rotating it CW-r is the optimal rotation for your case. However, I can't draft out a long geometrical tutorial in the event the rotation of a triangle is not a concept you are familiar with.

So, all I can offer here is WHY I think your surgeon's proposal is on target with correcting your bite and also mitigating the excess 'stick out' area of the upper lip. The general concept of what he's proposing rings right (correct) to me and there is NOTHING in the information presented to opine on the extent of the mandible advancement that you say is a 'big mandible advancement'.

[palacsinta4]

Okay I get it now, thanks a lot for your help. I have no idea about the exact movements yet, but my teeth won't really be moved now, so I assume it's a pretty big mandible movement.

Do you think it's relevant that my front teeth were all moved upwards by a different ortho to fix my gummy smile? It made my bite flatter https://imgur.com/a/v0VN2Pn

[kavan]

Okay I get it now, thanks a lot for your help. I have no idea about the exact movements yet, but my teeth won't really be moved now, so I assume it's a pretty big mandible movement.

Do you think it's relevant that my front teeth were all moved upwards by a different ortho to fix my gummy smile? It made my bite flatter https://imgur.com/a/v0VN2Pn

What is relevant here is what I mentioned prior. A surgery (and surgeon doing it) would take into consideration where your teeth are NOW.