Author Topic: Occlusal plane tipped down  (Read 651 times)

secondtimearound

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Re: Occlusal plane tipped down
« Reply #15 on: January 02, 2018, 08:47:46 AM »
If the maxilla is rotated 4 degrees CW, I would need a mandibular setback if I understood correctly, right?

You said that the lower jaw would come back a bit from the rotation, but it would also need to be cut and setback, right?

I still dont understand why my occ plane got so tilted up (10 degrees) if my maxilla was CCW rotated approx 4 degrees.

If the maxillary plane was brought back to a straight plane, would that close much my airway? Im concerned about that.

Yes the lower jaw has to be cut as well. I can't really comment any further until you figure out why your ceph is so distorted and get a proper one. It's impossible to judge anything with these images.

Talk to your surgeons office and show them the overlay I made of the ditortion.

See what they have to say.

You need at least slightly comparable cephs to work with here.

secondtimearound

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Re: Occlusal plane tipped down
« Reply #16 on: January 02, 2018, 09:14:48 AM »
I think the problem is head position. It looks completely different in pre and post op cephs.

Yeah which makes it worthless. Cephs are supposed to be standardized position.

Also, I submitted a new image to cephx and they're saying they won't trace it because I'm not a orthodontist or surgeon. Wtf? How did you get yours done?

They did mine previously.

kavan

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Re: Occlusal plane tipped down
« Reply #17 on: January 02, 2018, 10:07:03 AM »
Yeah which makes it worthless. Cephs are supposed to be standardized position.

Also, I submitted a new image to cephx and they're saying they won't trace it because I'm not a orthodontist or surgeon. Wtf? How did you get yours done?

They did mine previously.

To the best of my knowledge, exact head orientation is a very common issue in taking the cephs. Consider that even when they line up with the 'Frankfort horizont' or try to, the FHL is NOT actually horizontal in some people. IMO, they would need some kind of technology to actually SEE the actual bony landmarks to make a consistent line up as in seeing the X ray BEFORE the final shot of it was taken. But that would involve too much exposure to X ray radiation.
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kavan

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Re: Occlusal plane tipped down
« Reply #18 on: January 02, 2018, 10:08:18 AM »
I think the problem is head position. It looks completely different in pre and post op cephs.

Yes. See my post on this string to that regard.
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secondtimearound

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Re: Occlusal plane tipped down
« Reply #19 on: January 02, 2018, 10:21:02 AM »
To the best of my knowledge, exact head orientation is a very common issue in taking the cephs. Consider that even when they line up with the 'Frankfort horizont' or try to, the FHL is NOT actually horizontal in some people. IMO, they would need some kind of technology to actually SEE the actual bony landmarks to make a consistent line up as in seeing the X ray BEFORE the final shot of it was taken. But that would involve too much exposure to X ray radiation.

So basically ceph surgical planning is a crapshoot, and we need CT planning if we want to be sure it is going to be remotely accurate.

secondtimearound

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Re: Occlusal plane tipped down
« Reply #20 on: January 02, 2018, 11:04:15 AM »
Cephx.com just did both my diagrams, I didn't do anything special.

So are my diagrams not valid? Or is it just difficult to compare both diagrams because of the different head position, but they are both valid separately?

At least one of them is not valid. Cephs must be taken from a standard position and angle for the analysis to be valid. One of these at a minimum is worthless and cannot be analyzed correctly.

CCW

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Re: Occlusal plane tipped down
« Reply #21 on: January 03, 2018, 04:48:26 AM »
Post actual pictures of your face. The profile looks good and went from convex to normal.

kavan

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Re: Occlusal plane tipped down
« Reply #22 on: January 03, 2018, 01:20:08 PM »
Well both of them make sense to me. Everything that is said on both analysis seems to be true.

Why does the head position matter, it the analysis is made taking into account points that are just there no matter the head position?

I understand that over positioning the diagrams would not work if the head position is different, but dont understand why each are not not valid separately.

You can say they both 'make sense'  independently which they do independently. But you can't use them for an exact INTERdependent differential which is what you seem to be doing such as subtracting one angle from the other for a differential angle change. Last I checked the SN line relative to a horizont was 15 degrees away in one but 12 degrees away from the horizont in the other which could be a matter of the 'exact' head position was not consistent in both which by the way, is a common thing any time 2 different cephs are made.

There is also the factor of  the doc being able to make adjustments when the SN line deviates MORE than 7 degrees away from a horizont which seems he did a good job at doing.

At this point, I really think you need to disclose to people you ask for feedback that your salient issue is that you are upset because you don't look like the yourself that you were USED TO seeing and you don't care that OTHER people (on here) who have seen these changes are like WOW impressed at the dramatic difference and ultimately you are just wanting validation that you 'should be' upset due to the doc 'doing you wrong'.

I mean there are people on this board, your's truly, is one such who can explain in terms of geometry or mechanics but that goes NO WHERE because ultimately your question resolves to an EMOTIONAL one of 'Why did he DO THIS TO ME?' So any analytical explanation is just going to elicit a BLOCK of 'Why did he do this to me?' and can become an exercise in futility for the mathematically or mechanically minded people to answer. Add to this that even when you show your pics the people who say 'Wow! That looks great.' are saying what you DON'T want to hear and that just ends up inflaming your emotions because you need them to understand how he 'did you wrong' by removing you too much from the 'identity' you 'identified' with even WHEN the change was one most people on here would be ELATED if they got. 10 to 1 if you showed your photos to CCW (who has asked for them on this thread) and also 'secondtimearound', the response would be WTF.

Just your question of 'Why does the head position matter?' is an irrational and emotional one resolving to the 'Why did he do this to me' meta program in your head. Reason being is that you already YOURSELF noted that the lines being askew were due to HEAD POSITION. So on a LOGICAL level, you KNOW why it matters. But the EMOTIONAL level elicits the irrational question of 'Why does the head position matter?

Now I understand you are emotionally upset due to 'identity issues' and I understand those things exist with some patients. I also understand that doctors KNOWN for kicking up the most dramatic changes in accordance to an aesthetic that a LOT of people specifically seek out those doctors for are the docs who, here and there, get the totally unhappy patient who's grounds for discontent is that they are upset being modeled in accordance to an 'aesthetic ideal' of the doctor and 'miss' the look they IDed with. But I think you need to clarify more to others you are seeking feedback from that this is the salient issue and not one of the doctor having poor judgement in terms of aesthetics.

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PloskoPlus

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Re: Occlusal plane tipped down
« Reply #23 on: January 03, 2018, 01:45:56 PM »
I actually think it went from concave to convex. It was rotated too much for my liking and my nasolabial angle was closed. I look better post up, but too different and prognathic in my opinion. Dont eant to post my pics here though.
Your terminology is off. Rounded upper lip - convex. Sunken - concave.

kavan

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Re: Occlusal plane tipped down
« Reply #24 on: January 03, 2018, 03:47:35 PM »
I know I look better, but I did not want such a dramatic change. On top of that it is true that I was left class III, and I don't like that. I feel that I would have looked better and not have these ID issues if I had a linear advancement instead of CCW considering that my occlusal plane was flat. I no longer think my surgeon did something 'wrong', he just gave me a too dramatic change without me knowing it, and I don't like it, although you think that I look good. I dont think my doctor has poor aesthetic judgement. I just don't like my result because I went from retrognathic to prognathic, although I look good. Is that irrational? As well as some people have said that I look much better, others have said that I do look prognathic and they understand that I dont like it nor identify with it.

As for the head position on my cephs. I emailed Cephx.com about it. Here is their answer (seems I wasn't being emotional about it ;):

Our program adjusts the ceph so that it is straight.
I have just checked both cases in your account and they are straight.
This should not effect the results of the analyses in any way.
Let me know if you need anything else.

I sent them secondtimearound's overlay of the diagrams and asked about the distortion. Will post their answer.

Plosko, sorry I meant concave, but I was actually referring to my profile, not my upper lip


What it affects is doing a comparative DIFFERENTIAL where you can't use to claim an 'absolute' angle change based on subtracting one number from the other in both read outs.

For example, the SN line in the before is 15 degrees away from a horizont and the SN line in the after is 12 degrees away from the horizont. The Frankfort horizont is about 3 degrees away from a true horizont in the before and about 8 degrees away from a true horizont in the after


 ALso, if you look at BOTH the cephs, you see that the Ottoman saddle shaped figure (Sella Turica, where they put the 'S' point) has a totally different orientation. So, if those things are not CONSTANT in the poses/head postures for the cephs, you can't go around assuming you can use both to come up with an absolute differential as to how many degrees he rotated your OP or how many degrees the nasial labial angle was changed.

Although we CAN measure those angles on BOTH and most of my angle measures with a hand held protractor and some geometry were basically consistent with each read out, the numbers and angle measures in the read out can't be subtracted from each other in an attempt to say with 'absoluteness' the number of degrees he changed the planes.
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PloskoPlus

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Re: Occlusal plane tipped down
« Reply #25 on: January 04, 2018, 12:34:50 PM »
You should have gotten a CD from the place that took your cbct.

kavan

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Re: Occlusal plane tipped down
« Reply #26 on: January 04, 2018, 01:53:31 PM »
Well, a CEPH usually shows the cephalostat at the root of the nose/cranial base on the ceph. On it is a 'true vertical' (and sometimes linear measures on it too) such that REFERENCE lines can be assessed. https://en.wikipedia.org/wiki/Cephalometric_analysis

It sounds like one of your 'cephs' was not a true ceph but rather a slice from a 3-d type program used to simulate a surgery and they had to estimate where the Sella Turcica was which is a landmark that is highly visible in a CEPH but might not be in a sagittal cross section coming from a 3-d program.

AS to these DICOM files and other SOFTWARE to 'extract' things, that sort of computer stuff is beyond me. However, ditterbo is a computer genius for programs and software and perhaps could shed some light on that.
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kavan

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Re: Occlusal plane tipped down
« Reply #27 on: January 04, 2018, 07:19:08 PM »
Thanks secondtimearound. I had little tooth show preop, and now I show some gum, which I dont like. My smile was not ideal preop, but I didnt want to change it. I would like to remove the whole downgraft altogether, anterior and posterior, and leave my occlusal plane as it was. Also, my maxilla was advanced 10 mm, so that would have been enough to give me a little more tooth show.

What I do not understand is why can't I rotate the maxilla CW without BSSO? Doesnt the mandible just rotate WITH the maxilla? Maybe im missing something here. You mean I would need a mandibular setback to match the maxillary rotation?

Also, why are you saying I now need only 3-4 degrees of rotation? I was rotated 10 degrees and my occlusal plane was already flat. Wouldn't I need to derotate 10 degrees?

It really sucks my friend. Horrible to have to think about the surgery again. The agony before the surgery not knowing if everything will go well, the horrible recovery...

Where did you come up with the assessment that your OP was rotated 10 degrees? Your after ceph read out (even if it was for a non ceph but rather a CT cross section) said it was about 5.9 degrees. Even if you thought both were correct read outs in their own right and knew your OP was 'flat' in the before and your read out said it was 5.9 in the after. How did you conclude a rotation of 10 degrees?
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kavan

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Re: Occlusal plane tipped down
« Reply #28 on: January 05, 2018, 04:56:17 PM »
According to Steiner analysis, my occlusal plane to SN was 15,98 pre-op and 5,67 post-op. Thats why I said 10 degrees.

So, you made this conclusion by subtracting the after number the ceph read out gave you from the before number.

Do you still think the NET change in OP angle was 10 degrees?
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kavan

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Re: Occlusal plane tipped down
« Reply #29 on: January 05, 2018, 06:43:28 PM »
I have no idea to be honest. But I suspect it is not. I don't know how to get the change in OP.

Anyways the after ceph is not valid, right? Ill get a proper ceph done on Monday.

I used 6th grade geometry to cross reference your ceph read outs.

First thing I did was measure an angle that they DON'T give which is the angle the SN line makes with a 'pure' horizont.

Since the before showed the SN line was angled about 16 degrees away from a horizont and the OP line was 'flat' (about 0 degrees from a horizont) it was self evident that the Steiner 'op plane angle' (SN-OP angle) said 16 degrees away on the before.

In the after, it was also self evident to me that the SN-OP angle was 6. (Done by taking a line segment from the OP line and transferring it to the SN line to where the 2 meet form the apex of an angle and measuring the angle.)

So, what ever both ceph read outs said for the SN-OP angles were self evident to me. However, I knew NOT to subtract the after reading from the before reading (numbers in ceph read out). There was a reason I knew not to subtract the reading from one ceph read out from the other

Instead, to get the approximate NET angle change for the OP, I drew HORIZONTS. OP of before was 'flat' (0 degrees from horizont). OP of after was 6 degrees away from a horizont. Therefore NET angle change of OP was 6 degrees. So,  and got 6 degree change. NOT '10'.


That is REAL (simple) 'analysis' using only elementary geometry concepts and a protractor to measure angles.
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