Is my maxilla recessed?

[jawprobs16]

Hello everyone,

So about 4.5 years ago, I had lower jaw surgery (BSSO) for an underbite and alight crossbite. I only received the lower jaw, but ever since this surgery I believe that DJS would have been better because I think my maxilla is recessed. My surgeon claims that moving me forward wouldn’t have been good for me as he believes it would have made me look chimp like because I have normal projection but I don’t think that is true. I feel like my mid face is flat and my face is still long and that could be due to having a recessed maxilla. What do you all think? I’m really considering revision but everyone keeps saying I shouldn’t. I attached pictures below. First picture is a ceph of my jaw prior to surgery

[InvisalignOnly]

I think you look great. I would not do anything.

[kavan]

NO. Your maxilla is not recessed.

Your maxilla is sufficiently advanced but your chin has extra length to it, has some recession and you have a somewhat 'flat' curve between lower lip and chin. That might be what is making your face look long to you. Perceived extra length would not be due to any maxillary recession.

That could be corrected with a SLIDING genio which both shortens and advances the chin in addition to giving curve to where you have flatness under the lip.

NOTE: Morph is to share an aesthetic vision and to also resolve it to the TYPE of procedure to look into. But not to discuss 'exact' mm measures. Here the advancement is about/approx. equal to the shortening. So, good candidate for sliding genio.

[Post bimax]

Chimp lip is real and your maxilla is not recessed.  I strongly advise against maxillary advancement.  The LF1 does NOT replicate the natural skeletal 'forward growth' pattern.  It only moves a piece of your face, which can generate other imbalances.  Trying this for aesthetic reasons when your maxilla is in the normal range is a recipe for disaster.

I second Kavan's suggestion on the SG

[Tom199358]

Looking at your profile, I'd say there is there is a good balance between your maxilla and mandible. Both of them based on my rough calculations are within normal ranges. See attached link for SNA (maxilla) and SNB (mandible) angles. If your maxilla was recessed, you'd see numbers below the 81* average. I wouldn't even think about maxilla advancement. Your surgeon is right, even a few mm can cause issues with your top lip and your lips have a good shape to them. It's not worth the pay off.

https://imgur.com/a/0ybnRNM

[PloskoPlus]

Looking at your profile, I'd say there is there is a good balance between your maxilla and mandible. Both of them based on my rough calculations are within normal ranges. See attached link for SNA (maxilla) and SNB (mandible) angles. If your maxilla was recessed, you'd see numbers below the 81* average. I wouldn't even think about maxilla advancement. Your surgeon is right, even a few mm can cause issues with your top lip and your lips have a good shape to them. It's not worth the pay off.

https://imgur.com/a/0ybnRNM

I've always wondered how those standard numbers were derived.  Do standard SNA and SNB values apply to both sexes and all races?  Here is a case where the patient started with SNA/SNB of  92.4 and 94.3 and ended up with 94.7 and 95.5.  Normalising the values in his case would've been disastrous, IMO.

https://www.researchgate.net/publication/325052253_Alteration_of_Occlusal_Plane_in_Orthognathic_Surgery_Clinical_Features_to_Help_Treatment_Planning_on_Class_III_Patients

OP's protrusive lips may be due to protrusive teeth rather than prognathic jaws.

[kavan]

I've always wondered how those standard numbers were derived.  Do standard SNA and SNB values apply to both sexes and all races?  Here is a case where the patient started with SNA/SNB of  92.4 and 94.3 and ended up with 94.7 and 95.5.  Normalising the values in his case would've been disastrous, IMO.

https://www.researchgate.net/publication/325052253_Alteration_of_Occlusal_Plane_in_Orthognathic_Surgery_Clinical_Features_to_Help_Treatment_Planning_on_Class_III_Patients

OP's protrusive lips may be due to protrusive teeth rather than prognathic jaws.

With SNA, SNB, they can altered to get a desired ANB (class 1) relationship. (SNA-SNB=ANB).

With SNA, SNB, they can be altered so than points; 'N', 'A' and 'B' are found (pretty close) along a vertical line.

What is important is the ANB relationship for the class 1 and sometimes a relationship where; N, A and B have a better line up relative to a vertical dropped from the N point.

So, it's not a thing where they aim or otherwise prioritize giving someone an SNA and SNB angle within a reference range if bringing them BEYOND that range gives a desired ANB angle relationship and more of a vertical alignment of points; N, A and B.

The S point in SNA and SNB was used by Steiner because the S point is readily seen in the ceph.

Although her post surgery ceph clearly show that she has protrusive LIPS , they are neither resultant from her maxilla position nor tooth position. They are due to soft tissue THICKNESS which is pretty much normative for her race.

[jawprobs16]

I've always wondered how those standard numbers were derived.  Do standard SNA and SNB values apply to both sexes and all races?  Here is a case where the patient started with SNA/SNB of  92.4 and 94.3 and ended up with 94.7 and 95.5.  Normalising the values in his case would've been disastrous, IMO.

https://www.researchgate.net/publication/325052253_Alteration_of_Occlusal_Plane_in_Orthognathic_Surgery_Clinical_Features_to_Help_Treatment_Planning_on_Class_III_Patients

OP's protrusive lips may be due to protrusive teeth rather than prognathic jaws.

So are you saying that my maxilla is recessed?

[PloskoPlus]

So are you saying that my maxilla is recessed?

No. By the standards it's right where it should be. But I'm questioning the standards themselves. If average SNA and SNB values were obtained by surveying a "few hundred white college students without dentofacial deformities in 1953" (disclaimer - I'm not saying this is how they were obtained, just a suspicion), what relevance do these numbers have to an African face? It's no secret that Africans in general have more prognathic (forward) jaws. Maybe different "standard" cephalometric values should apply.

[jawprobs16]

No. By the standards it's right where it should be. But I'm questioning the standards themselves. If average SNA and SNB values were obtained by surveying a "few hundred white college students without dentofacial deformities in 1953" (disclaimer - I'm not saying this is how they were obtained, just a suspicion), what relevance do these numbers have to an African face? It's no secret that Africans in general have more prognathic (forward) jaws. Maybe different "standard" cephalometric values should apply.

You make a very good point. This was something I actually brought up to my surgeon and I asked if he was keeping my race in mind and he said that was all brought into consideration. I agree about the standards...when looking at for example people of African descent, degrees may be higher just due to our overall facial structure. It’s good to hear that I’m not recessed though because I really do think a recessed maxilla affects the beauty of the face. Do you think I should consider a sliding genio as posited by someone on this?

[Tom199358]

Plosko makes an interesting point and it's something I've been thinking about during my jaw surgery journey. I think even between the sexes there are differences when it comes ideal angles. I'd say there would be deviations cross races and sexes. However, I think in your case you have a good profile and both jaws compliment each other. Your ANB angle is solid and you have great forward projection. I've had a sliding genioplasty years ago, and the recovery time and pain is not too bad. End of the day, jaw surgery can lead to complications and unpredictable soft tissue changes, and I don't think going back under and moving your jaw would benefit you aesthetically. The above comments about sliding genioplasty would be the direction I'd go with if I was in your shoes.

[ODog]

I’ve wondered this as well, why the normative SNA and SNB angles don’t differ between the sexes, but perhaps since these are numbers relative to the rest of the skull structure perhaps men and women do indeed have similar SNA and SNB angles afterall. Absolute jaw length is obviously a different story.

Do SNA and SNB angles even mean anything? Isn’t the best way to determine jaw position just to see how the lips and chin line up with the TVL dropped from subnaison?

For example my SNA is 81.84 and SNB is 81, which could indicate that I could use some more projection, but my lips and chin line up with the TVL pretty well, so further projection could skew proportions in relation to my nose.