Case 1 Prompt 7

[Chad Carter (Course Director)]

Very astute! Yes in a straight wire mechanics / closure that is a side effect.

The difference here is stating objectives vs. treatment plan / mechanics. So since our objective is to maintain the overbite then we state our objective as “maintain vertical max/man incisors”. This is a Domain 2 question – objectives. Now if they asked a Domain 3 question – “how to prevent bite deepening during treatment” then we would dive into mechanics of expected effects and how we counter/correct/manage them.

[Alyssa Domico]

I have a follow up question to prompt 7 of module 1 (Assuming an ideal tx plan, what are the tx objectives for the maxillary and mandibular incisors?). Is the reason we are reducing maxillary/mandibular incisor torque and retracting incisors due to the fact that the extraction plan would be most ideal for her and/or to help reduce the lip procumbence/fullness? (Ie. is this question first requiring you to recognize that extractions are most ideal, so then that’s why ideally you’d retract/retrocline incisors as a result?) When I first looked at the ceph values, the U1-SN and IMPA seemed reasonable, and the U1/L1 to NA were both less than 4 already… but I understand the numbers aren’t the full picture. Thanks in advance for the help!

[Chad Carter (Course Director)]

Alyssa, Great to have you on board!

Yes, I think you’ve got it. Recognize the treatment and then the mechanics and reasons to accomplish it.

Thanks

Carter

[Lily Etemad]

Hi Chad! Jumping in on this thread. I am still confused on this based on what Alyssa mentioned above. I understand the treatment plan assumes extractions but why would we want to retract and retrocline incisors when they are ideal right now based on ceph numbers provided. Wouldn’t we want to try to maintain the current inclination and position? If the question states treatment objectives and we are extracting shouldn’t we want to attempt to maintain, although I understand we may likely get some retraction/retroclination. I am a bit confused on the wording of this type of question. Thank you for the clarification!

[Chad Carter (Course Director)]

Lily, Good question and observation. Yes, the numbers are in norms. For the telling part is the soft tissue – she’s so full with protrusive lips that that I want to help soften that up. So retracting helps get us there for her soft tissue paradigm and stay in the range of normal angles.

Have you seen some of the ABO examples where is shows multiple options… I could see it saying for this:

Acceptable Answer May Include: Maintain or Retract Incisors

Unacceptable Answer: Procline Incisors to resolve crowding and ectopic premolar.

Is that a bit better?

Thanks, CBC

[Maria]

Jumping here in this topic because I had a hard time with prompt 7.

I agree just by looking to her profile I would like some anterior teeth retraction to improve lips position and convexity, as well as mentalis strain. But I get very confused when in some questions seems like ABO wants us to be guided by ceph norms and in other questions to be guided by our observation, so when I try to train myself to answer to their standards I end up like missing things like this, because I question myself thinking they will not want to read my clinical observation, but more likely the answer should be guided by the standard cephalometric norms. Does that makes sense?

Also, considering the ideal treatment plan with extractions, wouldn`t we want to maintain upper and lower incisors torque and have more a translational movement for retraction? The inclinations of those teeth look good.

Thank you!

[Chad Carter (Course Director)]

Maria,

Let me make sure I’m understanding your question.

1) Soft tissue paradigm is widely accepted as the standard. We may diagnose with ceph numbers but we TREAT to the face. We then also use the ceph numbers and superimpositions to verify if we met our treatment goals (maintain, procline, upright, translate, etc.). Are you asking if there is a favoring of L1-MP at 90 degrees like the Tweed days? I think that ship has sailed.

2) So for your mechanics comment…. Yes you could aim for retraction. How would you do that mechanically? What side effects would still be present? How would you minimize those side effects for your treatment goal?

[Maria]

Thank you for your answer!

1- Yes I agree we treat guided by the face and our clinical observations. That is the goal. But specifically for answering in the ABO exam in some questions I have answered before (taking this case as an example) that we should retract the incisors, but according to the ceph numbers those incisors were well positioned (contradicting our clinical observations), so the ABO answer could actually not include retraction. Just a hypothetical scenario here, because I had that issue studying for the exam before. But I totally understand and agree with the thought process in this case and I wonder if in the real exam we should include an explanation in the answer for our thoughts on retracting incisors when the ceph values portrait another view.

2-I meant because the answer key for this question specifically states in another bullet point to change the torque of the mandibular incisors and I was wondering the rationale of including that in the answer if the measurement of mandibular incisors inclination is good L1-MP. I agree on the retraction that is another bullet point. But wondering if we had to include both? Also agree that of course is nearly impossible to achieve completely translational movement when retracting even with full size wire, segmental mechanics, TADs anchorage, etc , but question asks our objectives so I thought we should aim for that in my perspective.

[Chad Carter (Course Director)]

1) Ceph numbers are surely helpful. The incisor angulations though are based on Class I skeletal relationships. When compensating Class II and Class III skeletal patients there is a compensation of that angles that will not be the same as the Class I. That is acceptable to building a functional occlusions.

2) For the retraction, torque answers etc. Our goal for ourselves and for demonstration purposes is getting used to the format of creating bulleted and separate responses so you can score as many points as possible. Again the examples from the ABO give “high points” for items which “must be included” for a correct response. There are a myriad of other items which can also help. The only caution here is to not put contrasting responses (e.g. Retract Maxillary Incisors and Advance Maxillary incisors)

[Emi]

I think this case cranial base is flatter then normal, U1 to SN is actually 107, L1 to SN is 96. So that is make sense…?

[Chad Carter (Course Director)]

I agree it is a flatter cranial base (4 degrees)

[Chinyere Mbadiwe]

for the lower incisors, can we say relative extrusion to improve OB?

[Chad Carter (Course Director)]

Chinyere, I like that descriptor and I believe it’s universal in ABO language.

(I laugh because in my residency class there was always a debate over relative vs absolute extrusion/intrusion)