Orthotown March 2020 - 26

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I agree that further closure will express the Class III, but couldn't it be camouflaged with
extractions? I get that keeping the spaces closed will be tough, but what if I had very good informed
consent and placed a fi xed retainer (even 5-5) and an overlay Essix?
David, if you aren't thinking surgery, what are you thinking? ■
1/7/2020

davidharnick
Member Since: 08/28/02
Post: 7 of 22

Since vertical dimension seems reasonable and so are the aesthetics, I don't think surgery is
that good of an idea. Stability might be quite an issue. Maybe Fen could help, but my recollection
of surgery success is to measure OJ/OB and if the front teeth are touching. So in our literature,
this would be included as a surgery success despite the shortcomings of the occlusion.
I thought this was such a good teaching case I went over it with my daughter yesterday before
we left. First of all, we both agreed it was an amazingly stable correction for such an open bite. We
do a lot of IA and tackle these kind of cases with the same surgery recommendation and informed
consent. We concluded that we would send her to a DDS who would make an orthotic that
stabilized her occlusion and she would wear it full time. We personally would not do the orthotic.
If successful, we both felt any ortho had such an unknown prognosis that we felt a more
permanent orthotic, such as a partial denture designed not to interfere with the occlusion but
simply stabilize it, with a heartier appliance than just acrylic, would be necessary. So for us, this
is not an ortho case because of the poor prognosis. ■
1/8/2020

justinudm
Member Since: 09/29/14
Post: 8 of 22

A couple of thoughts in addition to what David has said. I agree that treatment should not
proceed until the joints are stable. This could mean splint therapy, but degenerative joint disease
should also be ruled out. What concerns me is the new information that the open bite progressed
over time. (Patients are not great historians, but you saw pictures.) I don't think you would get this
much of an open bite with just Class III skeletal growth. That would manifest as an AP change in
the bite unless the jaws were growing divergently. So I think ruling out joint damage and possibly
asking questions about significant weight gain are in order.
The weight issue would likely change tongue posture and could lead to dramatic changes in
the bite. Profit has this in his textbook: A patient gained significant weight and it caused a severe
change in the mandibular transverse. I cannot remember if it caused an anterior open bite? But
the patient likely had sleep apnea and the tongue probably dropped to the floor of the mouth to be
able to mouth breath day and night. So the bite may have changed with significant weight gain.
As to jaw surgery stability, remember that all the UNC data on jaw surgery stability was
collected before the contemporary internal rigid fi xation methods were around. The surgeons tell
me that all the orthognathic stability literature needs to be redone using cone beams and the new
internal fi xation techniques, and that things are much more stable with contemporary plating
methods. Sean Edwards at U of M has been working on this. I will have to ask him if he has
published anything. This is analogous to Little's irregularity index research needing to be redone
using the WALA ridge and accounting for original mandibular arch form when using wires. ■
1/8/2020

davidharnick
Member Since: 08/28/02
Post: 9 of 22

Great thoughts. My understanding was that degenerative joint disease was ruled out, as it
was my first thought. Then due to the unusual occlusal changes, it swayed me not to attack this
particular case orthodontically. As to stability of surgery, my thought is that it is not measured
other than how the anterior open bite has been maintained. As to real-life stability, I would suggest
following the open bite study I was part of. I think the main author was Greg Huang, who has
presented at the last two AAO meetings and has published in the AJO. Also, my idea was not to
place a typical splint but a custom one that fills in only the lacking posterior occlusal contacts. ■

1/8/2020

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