Dr. Moon’s Presentation

On Saturday I attended a live Zoom webinar/workshop with Dr. Won Moon, inventor of the MSE. Here are my thoughts. I wrote this while watching the presentation, so it’s not incredibly organized. I’ll give a disclaimer that I am a patient and not an orthodontist, so what I write here is my own understanding of the issue. You’d think that is obvious, but there seems to be a lot of weird misinformation about adult orthodontics, and I don’t want to contribute to that.

1. World-class orthodontists also struggle with using Zoom.

2. If you look closely, Dr. Moon’s palate seems narrower than I would have expected, and he has dark buccal corridors. I wonder what his orthodontics history is. Has he had palatal expansion? Extractive rectractive orthodontics? If you are best orthodontist in the world, does that mean you don’t trust anyone to treat you? Was he too old for MSE treatment by the time he invented it? Or does he not trust his own device in his own mouth? Or has he come to peace with his mouth the way it is? Maybe I’m really overthinking this, and I don’t really care about his orthodontic history as long as his device can help me.

3. Dr. Moon showed a lot of nice pictures and X-rays of people being successfully expanded at all ages. What he didn’t have was stats about chances of success or rates of complications at different ages.

4. Most MARPEs are placed where the palatal bone is the thickest, MSE goes where it exerts the most force against the lateral resistance. I know that TAD drifting through the bone is a risk with MSE, I wonder if other MARPEs have lower drift rates.

5. The pterygopalatine suture must be overcome. The CBCT’s show that it is actually pulled out of the pterygoid notch in a forward movement. From what the pictures look like, there is a form of joint at the back of the maxilla, and the maxilla is actually pulled out of the joint. Is that the 1–3mm forward expansion that everyone talks about?

6. Dr. Moon mentioned that the existence of multiple MARPEs that have different expansion patterns and protocols has led to confusion about what bone-anchored devices do. I have seen that on the Facebook groups, people seem to use MSE as a generic term for almost any expander.

7. He addressed torsion from the expansion bending or twisting the MSE, leading to failure. He said that the arms help anchor the device so that there is less twisting. I wonder if I had a bit of that. My orthodontist removed the arms after I had a successful split, she said that once I had the split I no longer needed the arms.

8. He said that hand-driving the implant into the bone is best because it puts less pressure on the screw and it is easier for the orthodontist to know where the screw is in the bone. I like that, I’ve done a bit of woodwork with fancy hardwoods, and we do the exact same thing.

9. Slow expansion means 1mm or less per week. So doing one turn a day of MSE is .91mm a week. Turning once a day is slow expansion, twice a day is rapid.

10. Slow expansion relies on biological processes, but the initiation of the expansion requires force.

11. He described MSE as a back-and-forth of mechanical force and biological factors. Every time the screw is expanded, the mechanical force triggers biological processes that should loosen the suture. So MSE is not just brute force.

12. Rapid expansion with MSE has a higher failure rate, but a higher chance of skeletal expansion. Slow expansion has a higher rate of success, but is not as good as loosening up sutures. So if someone wants maxillary protraction, rapid is better. It seems to be a tradeoff.

13. There is a lot that happens on the orthodontist’s side that we, the patients, do not see. The placement of the MSE, the turn protocol, and when to change the protocol or when to wait a bit are all individualized. So MSE treatment requires a lot of professional knowledge on the orthotodontist’s side. Patients can exchange their personal experiences of turning and protocols, but we can’t see most of the important information. I have gotten a lot of questions about why my ortho did certain things, and some seemed mildly judgemental, as if because my ortho does things differently she is somehow doing my treatment wrong. I don’t think that is right. I have regularly questioned some choices of hers, but it doesn’t mean that her professional judgment is wrong.

14. There are four sizes of MSE, but the larger ones can be hard to fit in a patient’s mouth. Dr. Moon says you can actually slightly press the expander into the soft tissue to fit a bigger one in, it could be uncomfortable but effective. If an orthodontist wants to do that, they need to grind the cast of the mouth that they use to fit the MSE.

15. Overexpansion of skeletal structure is not done with MSE. Any overexpansion is only dental.

16. The MSE III and IV will be available in June if they approved on schedule. The MSE III has a replaceable screw so if you max it out you replace the screw. I’m interested to see if that could work for me.

17. Dr. Moon is working on a surgical guide for surgical assist MSE to help surgeons who are new to it. I want to see if I can get the guide and shop around with it. The cuts that are used are not new or revolutionary, but the overall combination of MSE and surgery is relatively new.

18. it seems that forward protraction of the maxilla is always possible, even with adult men. It may not be enough to fix a Class 3 malocclusion, but it is something.

19. MSE widens the nasal cavity and increases the size of the pharyngeal airway. The mechanism that opens the pharyngeal airway is not yet clear, since MSE should be a lateral expansion and not too much forward expansion. Dr. Moon is now looking into that. He thinks it could be a minor forward pulling of soft tissue by the soft advancement. They had studied tongue posture changes from MSE and concluded that tongue posture changes were not sufficient to explain the change in airway.

That is all that I have from the study. I may do a second article where I extract certain interesting things from the slides, I just want to find out what the copyright issues with images are.

30 year old male, undergoing MSE and maxillary protraction for Class 3 malocclusion. Never had orthodontic work before, have all 32 teeth.