Thanks a lot. I'll probably avoid bimax as I really like the look of my upper jaw. I'll be looking into ccw.
How do you determine how much to move the mandible and the chin? As in 7mm bsso and 3 mm genio or 5 mm each.
How do you tell if the deformity is due to a recessed mandible or chin?
This result got me excited about the diagonally placed genioplasty since my profile looks similar. I'm not sure if an isolated genioplasty would be an ideal fix or a camouflage. I was told my occlusion is good.
Everything starts with having good capacity for understanding basic geometrical relationships.
That's the foundation needed to relate to what's going on in maxfax or at least the one I use to understand things myself. I'm going to provide one last entry here as to BIMAX advancement with genio.
With linear advancement, (in an aesthetics case) you only do it as MUCH as the maxilla can be moved out to give better support to the upper lip and base of the nose area. But you don't move out the maxilla AS MUCH as the mandible COULD be moved forward which could result in the maxilla being too forward to look good.
The illustration is one where the horizontal red line is parallel to your maxillary plane (ANS-PNS) and where the diagonal green line is parallel to the mandibular plane. (The mandibular plane angle is the angle the green line makes with the horizontal.) The point here is that with linear advancement, one is just moving along the lines that define the maxillary plane and the mandibular plane. There are no rotations.
So, let's say things could look better with the mandible moved further out than the maxilla. In that case, extractions to the lower jaw pre-molars could be used to push the front lower teeth backwards to create more of an overbite which will allow for more lower jaw advancement. In that case, the mandible still pretty much moves along the diagonal line AND the chin moves in the same direction.
But STILL, in BOTH scenarios, it's BIMAX surgery. As to the chin, it's going to be moving along the same downward diagonal line as the mandible. Hence, there is chin advancement WITH the bimax. The chin goes along with the 'ride' and on the SAME PATH the mandible is moved 'forward and it's moving 'forward' on a diagonally downward path. A genio can be ADDED to that.
Personally, I think you would benefit more from BIMAX surgery WITH a genio that can be adjusted to the mandibular displacements than you would with genio alone. It would tend to yield more over all soft tissue support than genio alone. In fact, when the cranio guy suggests a genio alone and tells you it will vertically elongate and horizontally advance the chin, that's basically the same/similar diagonally downward direction that advancement of the lower jaw would yield in a BIMAX scenario where where both jaws were moved linearly the same amount and/or a scenario where the lower jaw was advanced MORE linearly than the upper jaw.
If your occlusion is good, then you could have bimax EQUAL linear advancement but ONLY to the extent where it would improve the soft tissue support to the base of the nose and upper lip. To that the the diagonally downward genio could be added. But LESS so given the mandibular advancement will move out the chin point in the the same/similar direction that a diagonally downward genio would.
ETA: diagram included with this post.
