Counterclockwise rotation of mandible only?

[jawsaw]

is it possible to rotate the mandible counter clockwise while impacting the maxilla without rotation? This doesn't seem possible without some kind of wacky decompensation of bottom teeth. Any thoughts?

[kjohnt]

Your question doesn't make sense because CCW rotation refers to the occlusal plane.

If impacting the anterior maxilla, ccw rotation occurs and the mandible follows.

If impacting the entire maxilla evenly, no rotation occurs, but mandible will swing up that much more to close bite.  Occlusal plane stays the same.

If open bite, mandibular occlusal plane is CCW rotated to allow for closed bite, unless the posterior maxilla is impacted, in which case maxillary occlusal plane is CW rotated.

[jawsaw]

Thanks for the sort of clarification.

impacting the entire maxilla evenly, no rotation occurs, but mandible will swing up that much more to close bite.  Occlusal plane stays the same.

This could possibly be what I am after.

So with straight impaction, the mandible just swings up more? It seems like that would mess up the occlusion.

If what you are saying is true, wouldn't this be a method of flattening a steep mandibular plane? Which should create more room between neck and chin?

[Vic]

With straight impaction the mandible will move up and back

[kjohnt]

Vic is correct but only if the mandible is left untouched.  That won't happen.

With straight impaction, the resulting mandible will go up and forward via more room to swing and bsso to advance, and the occlusal and mandibular planes will not change relative to horizontal.  Let me explain.

Imagine a perfect class I occlusion with perfect occlusal plane but with vertical maxillary excess.  Impaction is needed.

First think of the maxillary occlusal plane.  Nothing changes.  The entire maxilla is evenly shortened vertically.

Then think of the mandible.  If untouched, it would swing more ccw, the planes would become flatter, there would be more space created between the lower and upper incisors (more overjet), and the molars would not contact properly (think reverse open bite).  So as part of the bsso, the part of the mandible anterior to the fractures on either side is rotated up (cw) to adjust so the molars contact again (mandibular occlusal plane moved to match maxillary occlusal plane), and also advancement is done to cover the overjet.

[kjohnt]

If more room between the neck and chin is needed but the occlusal plane and occlusion are both fine, straight bimax advancement.  If plane is fine but class II, then more relative mandibular advancement.  In either case there could be chin deficiency and sliding genioplasty is indicated.

But more likely there is a steep occlusal plane so ccw rotation.  If excess gum show, this is accomplished by anterior impaction.  If gum show is good, this is accomplished by posterior maxillary downgrafting.  Many cases probably use some combination.

Edit: and actually, as explained in my post above, straight impaction and the necessary bsso to go with it will result in slight mandibular advancement, so more space between neck and chin.  Again, no rotation occurs (more ccw swing at joints, but no change to occlusal or mandibular planes).

[jawsaw]

This is what I don't want

So as part of the bsso, the part of the mandible anterior to the fractures on either side is rotated up (cw) to adjust so the molars contact again (mandibular occlusal plane moved to match maxillary occlusal plane),

Reason being: cw advancement
What I am trying to achieve is a flattening of the mandibular plane without changing the occlusal plane.

The resulting malocclusion of impaction without cw rotation of mandible, but only advancement to address the overjet could potentially be fixed with orthodontics? ( molars not touching etc)

Does this not make sense? Theoretically?

Regular ccw is not an option because my occlusal plane is already flat. I'm looking for a way to flatten pitch of mandible without changing pitch of occlusion.

[kjohnt]

I was just referring to my example.  There is no rotation involved at all with even/straight impaction.  Maxilla is shortened and mandible anterior of the split moves straight up to follow.

You cannot alter the mandibular plane without altering the occlusal plane except for maybe mildly with genio.

It sounds like you want more vertical posterior mandibular bone volume (which would be there if longer ramus).  Not possible as far as I know.  The lower molars can be extruded but IDK by how much, not a lot.

You have a ceph radiograph to share?

[jawsaw]

No ceph at the moment. I don't want a longer ramus or an Arnold Schwarzenegger chiseled jaw line. Lol, this scheme I am brewing has very little to do with looks honestly.

I just had jaw surgery, I am happy with the results, except for one important result that is important to me that was not achieved.

I could try to go more in depth, but the gist is that want to flatten my steep mandible because it constricts my neck when I stand with proper posture. If this is not possible I guess I will look into more advancement. But I think that would be overkill. The only point of discomfort is directly behind my steep mandible. When I posture my head up or forward, then i don't feel constricted. But this causes me a lot of back, neck, and shoulder pain. When I stand tall, like I want to, it takes the pressure off of my neck, back and shoulders but my mandible is to close to my neck. It feels constricting and I look kind of silly.

Ideally I want orthodontic decompensation on the teeth on my mandible in preparation for a second surgery. I don't know if it is possible, but just try to imagine. Decompensation to steepen the hell out of my mandibular occlusal plane to match, or at least approach the steep angle of my mandible, resulting in an awful open bite and teeth that are parallel to the pitch of my mandible. Then the bsso could be rotated up to meet my maxilla, flattening the mandibular plane, which would creating a lot more space between my neck and chin. Get it?

I refuse to believe that of all the jaw problems in the world, I happen to have the one that isn't solvable by means of current medical technology.

[kjohnt]

I understand but honestly would have to see a radiograph to see the bone structure.  I'm certainly not saying your concerns are imagined or are overanalysed; I just haven't seen an overly-steep mandibular plane with a good occlusal plane and wonder if something else is at play.

[jawsaw]

See what I am talking about

[attachment deleted by admin]

[jawsaw]

In relation to the orientation of the image, when I stand comfortably, my head is rotated slightly more clockwise than what it is in the image.

The steep mandible constricts my neck. If I steepen the teeth on the mandible to match the steepness of the mandible and had it rotated up to meet a straightly impacted mandible I would be relieved from this problem.

[jawsaw]

i basically want to make my occlusion similar to this. Then from there have surgery to rotate the mandible and fix this problem.

This pic was taken from the thread titled "Steep Mandibular Plane Angles?"

[attachment deleted by admin]

[jawsaw]

There are some measurements of the distance between the bottom of the roots of my lower incisors and the incision mark of the genioplasty. I have roughly 6mm between roots and genio. I feel optimistic. How can this not be possible?

If the brackets of my braces on the mandible were reformatted; The brackets on my lower incisors placed at the very top of the front face of the tooth, and the placement gradually descends from tooth to tooth going back towards my most posterior molars. Over time this would slightly push up my molars while pushing down the incisors giving the desired open bite decompensation.

What do you guys think? I am going to bring this up to my ortho this week.

[jawsaw]

Anybody? Ortho said lower teeth can't be moved to match steep mandible. I am very frustrated and sad. He said my flat occlusion is the result of my prior orthodontics. My prior orthodontics put me in this mess. I need ccw bad to open up the space behind my mandible. My ortho does not think the constriction is due to the mandible. I am certain it is. It is so ovious. You can see the soft tissue bulge out of the sides. I respect the scientific notion that my report is subjective, but it is ovious when you look at me.