No the chin wasnt touched at all. Let me ask you since you seem to know about this. I feel like I still have some lip incompetence, mostly from the lower not coming up far enough to cover my lower teeth(I still show some upper teeth at rest but according to my orthodontist that is normal and a good thing given that the upper lip droops with age) . Do you think that genioplasty plan would help with that? To be honest, I am hesitant and want to wait until I see Gunson in June before I do anything that would complicate things further but it does seem like most long face syndrome patients have a genioplasty performed. In my case the surgeon never mentioned it.
Well, in general, lip incompetence is from chin muscle (mentalis strain). The strain is made less when the movement of the muscle is more on a VERTICAL plane and not on a diagonal. If the chin is too backwards, then the orientation is backwards diagonal. Think of a right angle where the distance of the hypotenuse is longer than the distance of the vertical leg. So, one drops a vertical line from the lower lip and advances the chin 'somewhat to slightly' posterior to the line so the mentalis orientation is more vertically aligned which makes less the strain associated with lip incompetence.
This is from a mechanical geometric perspective. I'm not a doctor. However, the mechanics or geometry of it pretty much explains why chin advancement is done to ease that type of strain. However, IF someone has a very recessive chin, there's also a mechanical 'limit' as to how far it can be advanced without stretching the mentalis muscle which is yet another strain on it.