Thanks for this exchange. It's useful for me to hear different perspectives.
To be clear: I sought out the orthodontist, I sought out the surgeon -- I have been driving this whole process. The surgeon expressed skepticism about the benefits. He was (and is) pushing me away from surgery, not towards. But if I insist, he said he could do it.
I told the surgeon I was unsure whether hard or soft tissue was the issue. I asked him: imagine you saw the CT scan only and not my face. Would you see anything wrong? From the CT scan, would you think I have a gummy smile? He said the hard tissue all seemed within the range of normal and attributed my gummy smile to muscular issues.
The orthodontist is a bit more nudging towards surgery, but only a bit.
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What I'm trying to unpack with this thread is whether there is a clearly "fixable" problem that merits jaw surgery. I've learned is that there is multidimensional input and output of the surgery, rather than just being a binary fix of one thing from good to bad. This means that in addition to the cost, recovery, and standard surgical risks, I also need to factor in undesirable unintended aesthetic consequences. This is not something I've given much thought to before.
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To expand on the concern I mentioned in the earlier photos, I've attached a photo of my smile in more of a profile. I perceive my philtrum to be rather short during smile, especially in relation to the projection of my nose. Compare that ratio to here:
https://www.pinterest.com/pin/327918416592959004/Imagining post-surgery my upper teeth starting where my philtrum ends when smiling ... that seems like a bad look at could result from any impaction (even if it's not considered "overimpaction").
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Regarding BDD, appreciate the concern. There is a certain degree of objectivity regarded the optimal gum display during smile, and I am several standard deviations from the norm, especially during "full" smile. Some people may be less bothered by this sort of thing than others. I'm on the "more bothered" side of the spectrum. Whether this is merits psychological treatment or evaluation, I'm not sure. Perhaps therapy could be appropriate.
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So my current plan is to get botox and see how I feel in a bit. I've had it before and liked the result. I just didn't like that it was temporary and that (in my understanding) it didn't fix the "root cause". However, if the root cause _is_ muscular, or at least the muscles are a strong contributing factor, then botox actually does address the root cause. That reframing might be sufficient for me.
This is a lot of new information in the last week, so I'm still processing. Thanks again.