Preliminary plan -- CCW or CW? Maxilla advancement?

[logan]

Hi all,

So I posted several months ago (http://jawsurgeryforums.com/index.php/topic,8068.0.html) and have since decided to go forward with bimax (+maybe genio) surgery. I'm still stuck on the surgeon tho -- Dr. Neugarten (NYC) or Dr. Steinbacher (Yale).

The new information I have is a preliminary plan from Dr. S. It is preliminary because it was created from a CBCT taken BEFORE pre-surgical invisalign, but it's better than nothing. I'm having a hard time reconciling it with the advice I received here, and with the (verbal only) plan from Dr. N. Can anyone make sense of it?

Dr. S's plan (attached; mandible first) looks like CCW rotation, with more impaction in the front than the back (1 mm impaction posteriorly and 2 mm impaction anteriorly, if I understand the diagrams.) My question is that I thought that I needed CW rotation with more impaction in the back than the front (e.g. Kavan's comment in my linked post), in order to correct my posterior gummy smile. Is there something I'm missing here? Does the plan seem reasonable?

Also, it looks like Dr S's plan doesn't do much maxilla advancement (only 0.5 mm?), whereas Dr. N verbally proposed about 4 mm of advancement, which sounded like a good idea to improve facial soft tissue support. Why the discrepancy?

I asked Dr. S these questions and he emphasized that this was preliminary and could be adjusted based on gum show after invisalign. But he won't do more work on my case until I decide to go forward. Similarly, Dr. N won't give me any more plan details before I decide to go forward with him... What to do, what to do

[GJ]

I've never see diagrams like that, but it does look like a net CCW movement.

I stick by what I wrote in the first thread: Seems the best plan would be to impact/level the maxilla and then rotate the entire complex (both jaws) slightly CCW.

I think the posterior gummy smile can be handled via the impaction. If the entire maxilla is impacted, and then the entire complex rotated CCW, seems the best outcome to me.

[SMSOMS]

You have, as most have pointed out,  a high mandibular and occlusal plane.  If you look at the lateral ceph there actually two occlusal planes.  The anterior teeth are on one and the posterior teeth on another.  When you smile you really do not see the first and second molars which is good.  Bringing them down a few millimeters will never be seen but that is used to get the CCW rotation that is needed to take the convexity out of the face and get the chin where it needs to be.  The combination of an anterior impaction and a posterior downgraft or inferior repositioning of the molars (same thing) flattens the occlusal plane. Additional inferior repositioning of the molars increases the CCWR.
 
The majority of the impaction to get the autorotation that has been spoken of will occur at the premolars as they are lower than the molars and incisors.  The maxilla absolutely must be segmented to get the differential movements to develop the smile line.  The amount of CCW rotation can then be accomplished by bringing the second molars down to magnify the forward rotation of the chin (or CCW rotation) and putting the chin in a position of desirable esthetics.

That make sense? 

[SMSOMS]

One more quick observation the IMPA or lower incisor angle to the mandibular plane is high.  It is best if the incisor angle is 90-95 degrees to the mandibular plane.  Every 3 degrees of overangulation costs you 1mm of mandibular advancement and often eliminated the need for a genioplasty if the chin shape is good. With a the proper amount of CCWR and incisor decompensation it is possible to avoid a chin procedure. 

A technical note is you can advance the incisors the same amount of the molar inferior repositioning and with the CCWR the base of the nose is unchanged and the Lefort cut goes right back to its point of origin.  So, 5mm of incisor edge advancement and 5 mm of second molar inferior repositioning yields 10mm of chin advancement in a class I patient and no discernible base of nose change.  So if you have 5 mm of class II over jet to add to that you get 15mm of chin advancement.   

[logan]

When you smile you really do not see the first and second molars which is good.  Bringing them down a few millimeters will never be seen but that is used to get the CCW rotation that is needed to take the convexity out of the face and get the chin where it needs to be.

Thanks for the reply!

Could you clarify why it is good that you can't see the 1st and 2nd molars? My posterior gummy smile really bothers me and I'm not seeing how CCW rotation of the maxilla/bringing them down a few mm would improve that

Can there be a disconnect between skeletal ideals and soft tissue considerations like this?

I do understand that my mandibular plane & both occlusal planes are high, but I thought (from previous discussion, and Dr. N) that more posterior impaction --> autorotation of the mandible --> reducing the mandibular plane angle, reducing overall length of my face, and partially increasing chin projection

[logan]

One more quick observation the IMPA or lower incisor angle to the mandibular plane is high.  It is best if the incisor angle is 90-95 degrees to the mandibular plane.  Every 3 degrees of overangulation costs you 1mm of mandibular advancement and often eliminated the need for a genioplasty if the chin shape is good. With a the proper amount of CCWR and incisor decompensation it is possible to avoid a chin procedure. 

Good to know! I would be happy to avoid/reduce genioplasty if possible, many of the "good" examples I see on women come out too boxy/prominent for my preference

I'm actually most of the way through invisalign at this point (I know, I should have decided on a surgeon already, but both seemed to want the same thing and my ortho has a ton of experience working with surgical patients and did discuss the initial plan with Dr. N. And I'm apparently incapable of making big life decisions until I absolutely have to.)

The good news is that my lower incisors have definitely been decompensated, and maybe angled back? I don't have good photographs but apparently things look good/as expected from the treatment plan (attached). I'm also amazed at how much my two-part occlusal plane seems to be flattened. Not bad, right?

[SMSOMS]

The issue with a posterior gummy smile needs to be determined.  Is it because tooth crowns are short or are you skeletally long.  If it is the former then gingival recontouring is the treatment.  If you are skeletally long then posteriorimpaction is the answer.  A high angle case where the anterior face is disproportionately long like you posterior impaction will shorten the posterior facial height with minimal effect on the anterior facial height even with a small impaction. 

Yes you get auto rotation but it does nothing for the high mandibular plane which gets camouflaged with a CCW rotation by flattening it somewhat.  You need some anterior impaction but your central incisors are longer than the laterals....is this because the gingiva covers more of the other teeth is the question. 

I agree with you view on genioplasty that is not judiciously done women can have undesirable results.  It is usually because the mandible was not in the correct position and the chin is done to make up for it

[kavan]

The read out doesn't list all the things that he shows on the diagram. For example, the read out doesn't list the PNS where the illustrations seem to convey a very minor displacement of the posterior maxilla. So, looks like the over all net rotation would be from anterior impaction CCW even if some of it included either a very small amount of posterior impaction or downgraft. TBH, I'm not really familiar with the type of diagrams you got that don't cross reference the the illustrations with the read out.

The illustrations convey different extents of cuts from either side of maxilla which would resolve most likely to multi segment lefort 1. The genio illustration is covered up by a measurement over it making it hard to see the amount that 'sticks out' But from the 'negative space' left behind on the illustration showing the genio, the chin displacement looks modest to minor as in something subtle to help give overall appearance of CCW and not something to fret about as in something dramatic to give appearance of masculine chin.

[logan]

Additional news and information!

First, I decided to go with Dr. N, honestly because I just had to choose and he is closer to me and gets marginally better reviews online.

So, I just got Dr. N's plan (and I have about 24 hours to accept it or suggest changes before titanium plates get 3D printed)

It is another strange format. But it's enough to roughly compare with Dr. S's plan above (note, the starting point is slightly different because I am now post-Invisalign and teeth are decompensated/occlusal plane somewhat flattened).

Overall I am reassured because the plans are similar. They both propose CCW rotation, with the net effect of advancing the upper incisors, advancing the mandible, and a sliding genioplasty

Main differences are that Dr. N is planning a bit less CCW rotation (yay, given gummy smile concerns?) but also a larger genioplasty (boo?)

My question about posterior gum show still hasn't been answered despite asking both surgeons if the suggested CCWR would fail to improve it, since molars are not moving up by much. N seemed to agree that we might consider just linear advancement instead of CCW when I suggested it. I still have no idea which is better tho. Goals are both reducing gummy smile (equal impaction better?) AND correcting the main issues of VME + other aesthetic considerations (CCW better?).

I am optimistically wondering if the maxilla advancement through CCW will improve lip support and reduce gumminess automatically (my upper lip is currently very thin when I smile, if I push on the skin above the lip it rolls out and covers some gum). Has anyone heard of that happening? Any examples you guys know of a VME case with posterior+anterior gummy smile who got net CCW, with mm amounts moved? It feels like we should have the data somewhere to make reasonable soft tissue predictions even if they are not intuitive

Separate from the issue of CCW or not, I am worried about overdoing anterior maxilla impaction -- I'd rather keep 0-1 mm of gum showing, since aging lengthens the upper lip. I measure 2 mm anterior gum show when I smile, yet Dr. N has the upper incisor moving up by 3 mm. So I am thinking of asking him to reduce that to 2 mm. Does that make sense?

I'm also planning to ask him to reduce the genioplasty by 1 or 2 mm (it's currently +5 mm anterior) because it looks a bit extreme

[logan]

The issue with a posterior gummy smile needs to be determined.  Is it because tooth crowns are short or are you skeletally long.  If it is the former then gingival recontouring is the treatment.  If you are skeletally long then posterior impaction is the answer.  A high angle case where the anterior face is disproportionately long like you posterior impaction will shorten the posterior facial height with minimal effect on the anterior facial height even with a small impaction. 

@SMSOMS, I'm not sure if it is skeletal or gingival -- any way to check? I asked my orthodontist about gum recontouring for this and got an unenthusiastic response but I'm not sure why

[kavan]

The surgery proposal (the one with the READ OUT and the skeletal illustration facing to the right) closes the open bite and balances the profile bone structure via:

a: A CCW rotation to the maxilla with minimal advancement. The read out chart conveys the ANS is going UP and the PNS is going DOWN. Hence, CCW rotation to the maxilla.

b: The CCW rotation to maxilla allows for advancing the mandible over a decreased MPA.

c: The genio that moves the chin out and up also contributes to decreasing the overly steep MPA.

The net (positive improvement!) cosmetic effect is to decrease the 'longness' to the ANTERIOR face and to also increase the projection of the lower face.

 ETA: With LESS CCW-r to the maxilla, more outward and upward displacement with the genio would be needed to decrease the steep MPA and the look of the 'longness' to the anterior facial height. The relationship is like this: The MORE CCW-r, the LESS they need to recruit the genio to decrease the anterior facial height and decrease the overly steep MPA.

They elected NOT to decrease posterior gum show (via posterior impaction) because that would NOT have decreased the LONGNESS of the ANTERIOR face. It would mean the the longness to your face, as viewed from frontal was a key detractor to aesthetics and much more so than some posterior gum show. So it means that the NET POSITIVE AESTHETIC effect to the look of the FACE would outweigh a possible 'trade-off' of a little more posterior gum show.