I too started out with a 9mm overjet/overbite issue. I also had a super gummy smile. Make sure you get multiple opinions. Just don't talk to the one surgeon your ortho is pushing you towards. I didn't get a genio with mine (although one of the five surgeons I had seen did recommend it), and I am really glad I didn't. All the genio would have done for me is mask the fact that my lower jaw wasn't brought forward enough.
Long story but my initial surgery went to hell. I had to have a revision two years later, and that just happened in Feb 2016. Here is a progression of records starting at the top in 2013 before I got braces on, second row is 6 weeks post op from first botched jaw surgery, third row is 6-7 months post op from botched surgery and beginning of treatment with my new revision ortho, fourth row is 2 months shy of two years post op from that first surgery and about 2 weeks pre op to revision, and bottom is 5 weeks post op from revision. First surgery I was supposed to have my lower jaw come forward about 5-6mm, and upper jaw impacted and moved forward a hair. They ended up moving my upper jaw forward a whopping 4mm (without my knowledge or consent) and my lower only came forward 3mm, so I was left class II still with severe lip incompetence (on top of them twisting and canting both jaws severely... it was a mess!). So, in revision my upper jaw went back almost 3mm to where it started with and lower jaw came forward another 3mm to where it should have been to begin with. Big difference in my profile! So yes, your profile will definitely change!
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