The gonial angle in relation to maxilla rotation

[000]

When you rotate the maxilla CCW by some x°, does this make the gonial angle x° smaller?

 

[hairyballscel]

if the jaw follows then yes

but i don't think its thats simple

 

[Asetric]

Yeah it goes lower

Jut the jaw like this and look from that angle if the occlusal plane is inward

 

[ScramFranklin]

Neither BSSO or Lefort 1 alter the gonial angle. Even during various rotations of the mandible via BSSO, the gonial angle is the same. Because the cut is made anterior to the gonion.

Chin wing, fillers, or implants can alter the gonial angle.

 

[000]

Neither BSSO or Lefort 1 alter the gonial angle. Even during various rotations of the mandible via BSSO, the gonial angle is the same. Because the cut is made anterior to the gonion.

Chin wing, fillers, or implants can alter the gonial angle.

But what about theoretically in kids when they facepull?

 

[Asetric]

You are talking about rotating it and not moving it forward so it's gonna decrease the vertical height in both jaws

 

[000]

You are talking about rotating it and not moving it forward so it's gonna decrease the vertical height in both jaws

So then when measuring the new facial height difference (top of forehead to bottom of chin), it wasn’t only the lower gonial angle making the face shorter, it was also the maxilla shortening? Or do you only take the lower gonial angle into account?

 

[Asetric]

The entire skull becomes more compressed and smaller unless the bone is cut apart with surgery

Where the tmj is that will shift lower and the gonial angle goes closer to 90 degree

 

[ScramFranklin]

But what about theoretically in kids when they facepull?

Facepulling in children is completely different, and I am not knowledgeable on things that would help children.

 

[ScramFranklin]

The entire skull becomes more compressed and smaller unless the bone is cut apart with surgery

Where the tmj is that will shift lower and the gonial angle goes closer to 90 degree

Well it's not like a rotation is done without cutting the bone. You are correct that CCW rotation shortens the vertical height of the jaws, but he's just asking about the gonial angle. That won't change. However, the MANDIBULAR angle will change.

 

[000]

Well it's not like a rotation is done without cutting the bone. You are correct that CCW rotation shortens the vertical height of the jaws, but he's just asking about the gonial angle. That won't change. However, the MANDIBULAR angle will change.

Aren’t those the same thing

 

[ScramFranklin]

Aren’t those the same thing

I should have said Mandibular plane, not mandibular angle. However, during BSSO, since the cut is made past the gonion, it won't affect gonial angle... as that is only a measure of the angle AT the gonion. So even if the mandible is rotated whatever-which way, the cut is made well past the gonion.