Author Topic: Mandible first movement?  (Read 1477 times)

Dopesaint

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Mandible first movement?
« on: December 07, 2020, 10:28:19 AM »
Hi guys,

I got my surgical plan today (BSSO, LF1, CCW + Genio for overbite) and I noticed it's a mandible movement first.

My surgeon typically does maxilla first and I know some surgeons like to perform maxillary driven planning for esthetics.

Is this typical? Does it matter if it's mandible or maxilla first or am I overreacting? Any comments will be appreciated.

PloskoPlus

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Re: Mandible first movement?
« Reply #1 on: December 07, 2020, 01:49:03 PM »
If rotation is involved, mandible first is "best practice". Puts a lot of pressure on the surgeon to get the planning perfect, lol.

Dopesaint

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Re: Mandible first movement?
« Reply #2 on: December 07, 2020, 02:13:24 PM »
If rotation is involved, mandible first is "best practice". Puts a lot of pressure on the surgeon to get the planning perfect, lol.

Yes CCW is involved

GJ

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Re: Mandible first movement?
« Reply #3 on: December 07, 2020, 05:33:43 PM »
Mandible first is standard.
Millimeters are miles on the face.

SMSOMS

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Re: Mandible first movement?
« Reply #4 on: December 07, 2020, 06:02:40 PM »
With CCWR doing the mandible first is essential.  Large CCW rotation will translate the condyles forward because the intermediate splint will be as thick as the amount of inferior repositioning of the posterior maxilla needed to attain the rotation.  Some surgeons do this but this often means that when the condyles are seated when finally doing the mandible the forward translation results in the maxilla/maxillary incisors often not coming as forward as planned or staying in the same position if that was desired. 

Furthermore virtually all Class II and Class III patients habitually posture the mandible forward, on average 2mm, to either avoid interferences with the teeth or in the case of Class II, they look better with less overbite. That posturing if missed can mean that if doing the maxilla first the positioning will be off by the amount they posture forward and the result is a maxilla further back than planned.

Doing the mandible first in CCW rotations precludes that from happening because the only thing that happens intra-operatively is you well see that the amount of advancement is slightly more than expected but consistent with the plan.     

Dopesaint

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Re: Mandible first movement?
« Reply #5 on: December 07, 2020, 06:17:08 PM »
Mandible first is standard.

Thank you for your reply!

With CCWR doing the mandible first is essential.  Large CCW rotation will translate the condyles forward because the intermediate splint will be as thick as the amount of inferior repositioning of the posterior maxilla needed to attain the rotation.  Some surgeons do this but this often means that when the condyles are seated when finally doing the mandible the forward translation results in the maxilla/maxillary incisors often not coming as forward as planned or staying in the same position if that was desired. 

Furthermore virtually all Class II and Class III patients habitually posture the mandible forward, on average 2mm, to either avoid interferences with the teeth or in the case of Class II, they look better with less overbite. That posturing if missed can mean that if doing the maxilla first the positioning will be off by the amount they posture forward and the result is a maxilla further back than planned.

Doing the mandible first in CCW rotations precludes that from happening because the only thing that happens intra-operatively is you well see that the amount of advancement is slightly more than expected but consistent with the plan.   

Thank you so much for your detailed reply, it makes sense being that my mandible will be anteriorly moved 14.1mm + a 5mm genioplasty.

SMSOMS

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Re: Mandible first movement?
« Reply #6 on: December 08, 2020, 10:49:07 AM »
I am always cautious with genioplasties.  They should be reserved to do nothing more than change the shape of the chin and provide a natural chin shape.  A genioplasty is never a substitute for getting the mandible in the correct A-P position in the first place.  Any genioplasty in a well shaped chin can deepen the labiomental fold more than can be tolerated and make it look overdone and knobby.  Only 20% of my 130-150 DJS per year get genioplasties.

PloskoPlus

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Re: Mandible first movement?
« Reply #7 on: December 08, 2020, 11:31:15 AM »
I am always cautious with genioplasties.  They should be reserved to do nothing more than change the shape of the chin and provide a natural chin shape.  A genioplasty is never a substitute for getting the mandible in the correct A-P position in the first place.  Any genioplasty in a well shaped chin can deepen the labiomental fold more than can be tolerated and make it look overdone and knobby.  Only 20% of my 130-150 DJS per year get genioplasties.
So what is the reason genioplasties are so common? Inability to perform CCW-rotation to get enough advancement?

SMSOMS

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Re: Mandible first movement?
« Reply #8 on: December 08, 2020, 12:42:07 PM »
In short,  large CCW rotations are not for the faint of heart and the genio gives you the added chin projection but it changes the shape of the chin sometimes in a bad way. It is also added because it is a non-covered benefit with insurance so that surgeons who participate in insurance plans and get paid on average 15-20% of the billed charge for the surgery can collect full fee for the chin. Some surgeons add in cheek and angle augmentation for the same reason but that is a whole other topic.  A really good reference is a book devoted to just genioplasty by my good friend Johan Reyneke.  Hope that helps

PloskoPlus

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Re: Mandible first movement?
« Reply #9 on: December 09, 2020, 02:09:01 AM »
In short,  large CCW rotations are not for the faint of heart and the genio gives you the added chin projection but it changes the shape of the chin sometimes in a bad way. It is also added because it is a non-covered benefit with insurance so that surgeons who participate in insurance plans and get paid on average 15-20% of the billed charge for the surgery can collect full fee for the chin. Some surgeons add in cheek and angle augmentation for the same reason but that is a whole other topic.  A really good reference is a book devoted to just genioplasty by my good friend Johan Reyneke.  Hope that helps
No surgeon in my city performs CCW-rotation, claiming it's unstable.

SMSOMS

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Re: Mandible first movement?
« Reply #10 on: December 29, 2020, 03:35:17 PM »
No surgeon in my city performs CCW-rotation, claiming it's unstable.

There is plenty of literature to the contrary regarding stability of CCWR.  Reyneke did his PhD Thesis and it was published in the British Journal of OMS in 2006.  In the USA Wolford started doing them in 1988-90,  Sullivan in 1990, Arnett 1995 and after that more surgeons began doing them.  A surgeon who does not do them is a dabbler in my view. 

PloskoPlus

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Re: Mandible first movement?
« Reply #11 on: December 30, 2020, 06:43:58 AM »
There is plenty of literature to the contrary regarding stability of CCWR.  Reyneke did his PhD Thesis and it was published in the British Journal of OMS in 2006.  In the USA Wolford started doing them in 1988-90,  Sullivan in 1990, Arnett 1995 and after that more surgeons began doing them.  A surgeon who does not do them is a dabbler in my view.
That would make it every surgeon in Melbourne, Australia.

Vincent999

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Re: Mandible first movement?
« Reply #12 on: January 03, 2021, 03:58:27 PM »
That would make it every surgeon in Melbourne, Australia.
My Australian surgeon performed CCW, albeit maxilla first.

FWIW Arnett advises mandible first.