CASE 2 PROMPT 4

[Chad Carter (Course Director)]

Elizabeth, good way to dig into this case. I had to pull it up and zoom on the pictures to remind myself of the details.

Prompt 4 is a good example of a “Case Management” question for the boards [Though they could show things that are WAY OFF THE RAILS!]

So for Case Management I would look at 1) What skeletal / dental problems still exist? 2) What is the objective to correct those? 3) They already told us surgery is the answer, so then what surgery gets us there?

What would you briefly answer are the skeletal/dental problems that still exist at Prompt 4 of this case?

[Side note: 100degree incisors in a patient of African ancestry is not concerning to me in this case – the incisors started there – there was spacing, we have no proclined them, I don’t see the “ripples” showing in the man antr vestibule that concern me about bone – so if we have maintained things that is best for stability.]

[Maria]

Bringing up this topic here for discussion.

I did not think about extractions to increase overjet, but I agree overjet is tight for a BSSO.

1) Would you say in this case the BSSO would include counterclockwise rotation of the mandibular plane, so maybe we could go with the overjet she currently has?

2) For me, this patient has small maxillary lateral incisors, Bolton discrepancy, and since she also has a cant wouldn`t she benefit of a 3-piece maxilla surgery as well? Because that was my thought process I included in the answers we should leave spaces distal to maxillary laterals prior to surgery. Would that be correct?

3) When question asked what steps are necessary to ensure patient is ready for surgery, I thought about taking impressions for study models for checking occlusion and any adjustments necessary, also placing heavy stainless steel wires and crimpable hooks between brackets. I could not see the torque or rotations adjustments included as the answer keys, I guess because the photos are so small, even after reading the answer I had hard time seeing those.

[Chad Carter (Course Director)]

Maria,

Replying to each question here.

1) Would you say in this case the BSSO would include counterclockwise rotation of the mandibular plane, so maybe we could go with the overjet she currently has? – Yes there is more to her BSSO that just an AP movement so the rotation is helpful. Sometimes the jaw will autorotate to the position you want but for her it’s about coordination.

2) For me, this patient has small maxillary lateral incisors, Bolton discrepancy, and since she also has a cant wouldn`t she benefit of a 3-piece maxilla surgery as well? Because that was my thought process I included in the answers we should leave spaces distal to maxillary laterals prior to surgery. Would that be correct? – I do not see an indication for a multi-piece LeFort. A 2-piece LeFort for Transverse is useful up to 6mm of expansion (stability). A 3-piece LeFort is most common for multi-plane occlusion. Remember from the hierarchy of surgical stability – these multi-piece options come with risk. The maxilla can also be moved in all planes. In her case it is a roll (review – pitch, yaw, roll for surgery) and comes with a mild advance just to clear the plates.

3) When question asked what steps are necessary to ensure patient is ready for surgery, I thought about taking impressions for study models for checking occlusion and any adjustments necessary, also placing heavy stainless steel wires and crimpable hooks between brackets. I could not see the torque or rotations adjustments included as the answer keys, I guess because the photos are so small, even after reading the answer I had hard time seeing those. – Yes the photos are small and a limitation on this delivery platform. Ideally 3D casts to review would be great for this question. I agree the premolar rotation is challenging to see (I have to increase the display of browser for these. The clue on the molar is how the band is viewed (see more lingual surface and excess torque based on how the mesial band looks.

Good luck!

[Maria]

Thank you!

Great to think about the yaw, pitch and roll. Would you say in this case that if we want to expand maxilla in surgery plus correcting her cant (roll) we can go with just 2 piece Le Fort?

[Chad Carter (Course Director)]

Yes, I think a 2 piece would be adequate if there is a transverse.

Just remember the article from boards reading list on Transverse limits and when a SARPE is needed:

Surgically assisted rapid palatal expansion: A literature review

Lokesh Suria and Parul Tanejab

One of the surgeons I work with says that there are many orthodontist who send him “multipiece LeFort cases and ask for something like 10-12mm of expansion during the LeFort”. This is 100% unstable! A SARPE is needed for transverse over 5mm (or MARPE/TAD something skeletal). A LeFort expansion greater than 8mm (according to article) but by surgeons guidelines greater than 6mm decreases in stability and results in poor bone bridging at the gaps were the cuts are made (I believe proffitts surgical textbook shows the cuts if you’re not familiar with the OR)