What does posterior downgraft during bimax actually do aesthetically?

[bysontallou]

Hi all, I've been researching bimax and as I understand it there are two ways of doing CCW during bimax - posterior downgraft and anterior impaction. I do not have a gummy smile so will not need anterior impaction. I am struggling to actually understand what posterior downgraft does - there don't seem to be any video simulations of it online.

Can someone please explain to me what it does, especially aesthetically? Does it affect how parallel your mandible is to the floor, for example? Does it affect the lips/philtrum? Whereas anterior impaction moves the front of the maxilla up, it seems like posterior downgraft moves the back of the maxilla down, which doesn't sound like it would create an aesthetic outcome.

Lastly, would it have any impact on the size of the airway (accompanied by the BSSO, of course), assuming the maxilla wasn't moved forward very much?

Thanks for the help.

@Sergio-OMS
@RealSurgerymax

 

[Deleted member 399]

Man this is a good post. I wish I had more knowledge to answer your questions.

 

[Deleted member 5634]

The breathing will get better because of your paranasal area but i do have this doubt too

 

[bysontallou]

@DatGuyYouLike
I know you had this done - was wondering if you could shed some light on this for me.

 

[Deleted member 4797]

@DatGuyYouLike
I know you had this done - was wondering if you could shed some light on this for me.

It looks better, mandible and teeth will be more parallel to the floor. Ramus will look a bit weaker tho, since that gets left behind and too high compared to the new mandible position.

CCW usually improves the lips, so long as the forward projection of the upper jaw is not too much (I'd say above 4mm starts to ruin your philtrum shape, which affects the lip aesthetics)

 

[bysontallou]

It looks better, mandible and teeth will be more parallel to the floor. Ramus will look a bit weaker tho, since that gets left behind and too high compared to the new mandible position.

CCW usually improves the lips, so long as the forward projection of the upper jaw is not too much (I'd say above 4mm starts to ruin your philtrum shape, which affects the lip aesthetics)

So does the gonial angle look smaller (I know the angle of the bone itself won't change) when viewed from the side? Lifefuel tbh.

I remember you got slight anterior impaction too despite not having a gummy smile - I'm wondering if your current smile has ideal tooth show, or if you wish you had more tooth show?

Also do either anterior impaction of posterior downgraft reduce the height of the lower third? From what I've read online it seems anterior impaction does but posterior downgraft doesn't - does that sound right? I'm a bit worried about making my lower third shorter tbh, I already need a vertical genioplasty due to short chin.

Thanks for the help as always.

 

[Deleted member 4797]

So does the gonial angle look smaller (I know the angle of the bone itself won't change) when viewed from the side? Lifefuel tbh.

I remember you got slight anterior impaction too despite not having a gummy smile - I'm wondering if your current smile has ideal tooth show, or if you wish you had more tooth show?

Also do either anterior impaction of posterior downgraft reduce the height of the lower third? From what I've read online it seems anterior impaction does but posterior downgraft doesn't - does that sound right? I'm a bit worried about making my lower third shorter tbh, I already need a vertical genioplasty due to short chin.

Thanks for the help as always.

Well impaction does reduce lower third height yes but very slightly, and downgraft doesnt make it taller just at the back, the front stays same.

Naturaly the more you bring the jaws forward, this will also make your lower third taller. Thats because even after CCW, your jaw wont be exactly parallel to the floor, it will still aim diagonally down slightly, so the more it comes forward the more it moves ahead diagonally, forward and down.

Teeth show stayed the same, didnt get better or worse. Ideally I would have more teeth show but it didnt happen, I guess it wasnt possible to improve my teeth show due to the fact I needed so much CCW. If I didnt have the impaction my teeth show wouldve been better but then I couldnt have as much CCW as was needed, so it was a compromise.