Protraction Facemask: Flattering to deceive?
I read a fascinating discourse on Ravi Nanda’s Facebook Group group about expansion, which became a little side-tracked, delving into the effects of maxillary protraction or facemask therapy. The discussion included a debate from some of the best and most experienced thinkers about the relative impact of including RPE or Alt-RAMEC as part of the protocol. This led me to think about my use of protraction.
I have used protraction for years and am rarely disappointed (and often flattered) with the occlusal effects. What is far less certain are the prolonged skeletal effects.
Let’s look at a study.
Many of you (particularly those based in the U.K.) will be aware of a fantastic multi-centred clinical trial by Nicky Mandall. I thought it would be helpful to summarise the study and include my own (likely contestable) interpretation.
The study involved two groups- an untreated control and an active treatment group allocated to protraction facemask therapy. Participants were under ten (7 to 9 years) and evaluated at 18 months, three years, and six years. The link to the latter is here.
Skeletal effects
The findings are fascinating. Let’s look at the skeletal impact first – ANB improved by 2.1 degrees with treatment and worsened by 0.5 degrees in the control after 15 months. What happened after six years? This difference dissipated to just 0.7 degrees. Does that sound familiar? And perhaps remind you of the long-term effects of functional appliance therapy?
Dental effects
And what about the dental effects? Maxillary incisors remained proclined in both groups (about 7 degrees). The lower incisors had retroclined a little more (2.7 vs. 0.4 degrees) in the treatment group at six years. There were no statistical differences between the groups here.
The big difference, however, between the groups was at the occlusal level, with the overjet being improved in both groups over the six years (This ties in with my feeling that Class IIIs can get worse but typically don’t. And rarely do so in the presence of mild skeletal discrepancies or positive overjets in early adolescence). The overjet, however, was 3mm more positive in the active treatment group and 1.7mm more in the control group after six years. So, if protraction headgear has a sustained benefit, the safe bet would be to pin this to occlusal rather than skeletal effects.
You may think some of these findings are incongruous- no skeletal distinction? Or difference in incisor inclination? So why the difference in overjet? It seems to relate to occlusal plane rotation with more clockwise rotation of the maxillary occlusal plane with facemask therapy. There is a knock-on effect on the mandibular occlusal plane and, indeed, in the position of B point.
Need for orthognathic surgery
But the most exciting finding is that a panel of expert orthodontic raters adjudged the need for surgery to be appreciably reduced (from 66% to 36%) in the protraction group at a 6-year follow-up. The panel made this assessment based on radiographs, models, and clinical photographs. Remember, the groups were essentially identical at the skeletal level at this point. Like me, it appears that these orthodontists may be ‘flattered’ by occlusal change.
How do I use this information?
I use it to inform the ongoing use of protraction headgear in a subset of my patients. I also use it during explanation and consent to suggest that protraction will likely lead to an improved bite long-term but that we know less about the effects on the jaws. I also use it to inform thoughts around the potential remit of skeletal-borne protraction. I am, I’m afraid, much less enthusiastic than many and fear that the invasiveness that is becoming routine in this respect might flatter many in the short term with long-term results likely undershooting (I will post on the fledgling evidence on this topic soon). Of course, I look forward to being proved wrong!
Professor of Orthodontics, Trinity College Dublin, The University of Dublin, Ireland
Facemask therapy is more effective the earlier you use it. I have had the greatest maxillary effect on 4-8 year olds.
Dear Jeffrey
I have similarly found that treating young children(less than age 7) with maxillary skeletal (sagittal/transverse) hypoplasia, at the earliest ‘feasible’ (per financial constraints, geographical challenges, caregivers’ acceptance/non-acceptance of Rx,, etc.) stage of their dento-facial development, is the most effective strategy in my hands.
Also, per one of McNamara’s conclusions (please see below) about the most frequently observed maxillary skeletal position in class II pts. as being neutral to retrognathic (rel. to ACB) from his published (Angle Orthod. 51(3):177, 1981), I will often also Rx: nighttime facemasks as an adjunct to RPE in kids who might present at T-0 with Angle Cl I and/or Cl II, but only when A-point to N-perp., SNA, PNS distance from Ptm, and negative Witt’s appraisal might be supportive of a Dx: maxillary skeletal insufficiency in the absence of a Dx of Cl III with or without an anterior dental cross-bite.
Kev
Conclusion 2. ‘Only a small percentage of the cases in this study exhibited maxillary skeletal protrusion relative to cranial and cranial base structures. On the average, the maxilla was in a neutral position, and when not in a neutral position, it was more often in a re-truded than protruded position.’
‘Of course, I look forward to being proved wrong!’
This statement of yours reflects not only your personal integrity….but also. especially, your keen understanding, mastery actually, of Karl Popper’s hypothesis regarding the development and testing of a newly-proposed hypothesis, that might be worth developing and testing in the first place.
Thank you Paddy
Slainte!
Kev
Thanks, Pad, for this timely discussion. I would like to add the concept of the patient’s journey length – the interception treatment and the follow-up management will likely take at least 5 if not more, years. The occlusal improvement may be enough for mild skeletal cases to obtain a relatively balanced management result. Still, for moderate or severe cases, a solution of, let’s say, 25% of a problem does not really address it – plus, in the journey, some incisors may finish in unflattered aesthetic and questionably periodontal positions. Wrapping up this commentary, it is good to remind that the caregiver makes the call based on how we present the information. This could be biased in so many directions. At the end of the day, it is their prerogative to make the call, but it is also ours to provide only reasonable healthy options. Sometimes observing and letting nature follow its course is a wise decision.
Padhraig, I agree with you 100%. I am always skeptical of studies which show results for one or two years after treatment. Dental results and clockwise rotation helps in many patients to resolve Class III’ ‘look’. I published a paper on modified protraction paper in early 80’s in AJO with small number of patients but results are still valid after all the fancy studies of recent years. Incidentally, in current environment my 80’s paper would never be accepted in a reputable journal due to sampling and associated issues 🙂
Padraig – I agree with you and treat similarly… my ‘missing information’ is what is the growth state by 18 ie end of growth.
Unfortunately Mandel et al so far has not followed up their cohort as the 6 year follow up of the 7-9 yrs being published in 2016 was hen they were 12-14yrs and yet to complete their growth to… the cohorts will all now be in their 20’s and the follow up study is IMHO needed
In the small city of San Sebastián this year I am going to operate my 500th orthognathic surgery case along with my surgeon.Since the majority of my cases are Class III I have probably done maxillary advancements in 90% of the cases. The majority bimaxillary cases the rest monomaxillary cases.After looking at my cases I came to realize that we were advancing the maxillaris an average of 5-8mm for functional and ESTHETIC results. Can we do this with face masks??? Let’s not loose sight of the goals
Dear Domingo
If you are asking, can one advance non-growing adult maxillas 5-8 mm w/ face masks alone, the answer would be much different from what might happen w/non-surgical distraction w/FM Tx in a growing child, say, under 7 years old. Please give me an opinion if you might…..what percentage of your 500 (non-syndromic, non-Cl III) pts who’d received MMA or LeForte-only surgery were: 1. also maxillary skeletal transverse deficient; 2. had a pre-surgical Angle class I or II skeletal Dx(i.e., NOT Cl III); and, 3. might have been identified as having had reliably-persisting (non-self correcting) antecedent malocclusion traits (e.g., transverse and sagittal hypoplasia) whilst they’d been say, under 7 years old?
Thanks for considering my questions
Kev
I agree that growth will continue after the final records were taken and that assessing the patients older than 18 might be interesting. However, I think it would be an ethical problem to postpone further treatment into the patients’ late teens and 20s. I suspect patients would leave the study so they could have more treatment without the delay required by staying in the study.
Dear Spencer
I think that it would indeed, as you state, ‘….be an ethical problem’ to actually withhold a (published/documented btw with myriad case control, retrospective observational studies) therapeutic regimen from a group of afflicted individuals for the sole purpose of establishment of a comparative control cohort. That is, the rigorous Institutional Review Board (IRB) process, largely created after the WW II Nuremberg Warcrime Trials, simply would (should?) not allow it I’d say.
I think this study is most valuable in showing how things change post treatment, which to me says I need more overcorrection during with RPHG since much is lost.
My biggest concern is how they determined when to stop treatment. they stated:
The clinical end point was established as the end of active protraction facemask treatment. This was defined as achievement of either a class I incisal relationship or a positive overjet with no anterior crossbite, and a correction of the class III skeletal pattern to a clinically apparent class I skeletal relationship.
First, they did not define what constituted a “clinically apparent class 1 skeletal relationship”. If this was just an eyeball judgement of when the face looked good, I think this is a weak point. I am more often fooled by class 3’s than class 2’s if I just judge from the face.
Second, Initial incisor angulations run the gamut in young class 3 patients. From full camouflaged looking incisors (retroclined lowers/proclined uppers, typically low angle no crossbite cases) to exactly the opposite (usually cases in full anterior crossbite). Using incisal relationships to judge when enough correction was obtained is not a good standardized measure of when the underlying skeletal relationship was corrected.
This does not diminish the findings of the significant changes that occur post RPHG. I just am concerned that since this was such a well controlled study, the results numbers will be seen as limits to possible correction when I don’t think that is necessarily the case.
Domingo, totally agree with your appraisal. We do have a large surgical patient pool. Unfortunately, on opportunities the Class III kids we thought we “solved” at 8 years with a bonded expander and a facemask. Come back to our office when they are at 18 years. Being now a maxillary surgical advancement plus a mandibular setback case. I have this happened at least a dozen times in 28 years. So is important, to talk straight with parents and don’t offer them a “full cure” solution for early Class III interception with expansion and facemask. All best, Miguel