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Merlix
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I'm in the process of designing custom cheek and jaw/chin implants so I'm trying to figure out what principles I should use to determine the right projections. In all cases I'm using the bone 3d CT scan without a soft tissue overlay.
I'm sure the doctor will have his own ideas but I wanted to go into it with scientifically proven principles so any help with this would be appreciated.
For cheek:
Increase lateral projection such that the FWHR ratio is maximised (up to 2) but the ES ratio doesn't fall below 0.42. Err on the side of underprojecting to account for variability of soft tissue change (and likely less than 3.5mm in any case).
Anterior projection around 3.5mm maximum.
Zygomatic arch enhancement should wrap around entirety of lateral cheek all the way to ear. Aim for sayan-like shape.
For jaw/chin:
Increase chin width to at least the distance between canine teeth but potentially more, to around mouth width (can't see mouth with bone scan though). Chin should have some flanging on corners to square chin and avoid rounded chin.
Increase chin height such that the chin height to philtrum ratio is 2 using bone scan, which would go even higher after accounting for soft tissue overlay at bottom of chin, but no greater than 2.25. Also accounting for increase height, the lower third should be no greater than 10% more than midface third, else long face will develop.
Increase chin projection such that tip of chin vertically aligns with at least bottom lip (which in turn is slightly behind my upper lip) erring on side of greater projection but no greater than vertically aligning with top lip.
Gonions should be horizontally at mouth opening level, erring on slightly lower but no lower than horizontally below bottom lip (will need to estimate based on bone scan). Gonial angle will then be determined based on this level and chin height but should be around 120-130 degrees, ideally 125.
Jaw width should be around 92-95% of cheek width, erring on higher but no higher than 100% in any case (will need to be estimated based on bone scan and variability of soft tissue changes).
Generally speaking, since I have big lips and mouth I think I can generally err on too large a chin and jaw since it won't look strange.
Any opinions are welcome. Thanks.
I'm sure the doctor will have his own ideas but I wanted to go into it with scientifically proven principles so any help with this would be appreciated.
For cheek:
Increase lateral projection such that the FWHR ratio is maximised (up to 2) but the ES ratio doesn't fall below 0.42. Err on the side of underprojecting to account for variability of soft tissue change (and likely less than 3.5mm in any case).
Anterior projection around 3.5mm maximum.
Zygomatic arch enhancement should wrap around entirety of lateral cheek all the way to ear. Aim for sayan-like shape.
For jaw/chin:
Increase chin width to at least the distance between canine teeth but potentially more, to around mouth width (can't see mouth with bone scan though). Chin should have some flanging on corners to square chin and avoid rounded chin.
Increase chin height such that the chin height to philtrum ratio is 2 using bone scan, which would go even higher after accounting for soft tissue overlay at bottom of chin, but no greater than 2.25. Also accounting for increase height, the lower third should be no greater than 10% more than midface third, else long face will develop.
Increase chin projection such that tip of chin vertically aligns with at least bottom lip (which in turn is slightly behind my upper lip) erring on side of greater projection but no greater than vertically aligning with top lip.
Gonions should be horizontally at mouth opening level, erring on slightly lower but no lower than horizontally below bottom lip (will need to estimate based on bone scan). Gonial angle will then be determined based on this level and chin height but should be around 120-130 degrees, ideally 125.
Jaw width should be around 92-95% of cheek width, erring on higher but no higher than 100% in any case (will need to be estimated based on bone scan and variability of soft tissue changes).
Generally speaking, since I have big lips and mouth I think I can generally err on too large a chin and jaw since it won't look strange.
Any opinions are welcome. Thanks.
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