Let’s talk about myofunctional orthodontics…..
Let’s talk about myofunctional orthodontics….
In this post I would like to provide my academic opinion on the interesting, yet controversial, area of myofunctional orthodontics. I have been prompted to do this following feedback on previous blog postings from those who have developed and promoted the concepts of orthotropics and myofunctional orthodontics. I have also spent some time researching the back ground of this subject and I would like to discuss these, interesting, related concepts together in one post.
Where do we start?
A good place to start is to consider that if malocclusion is a disease (and I am not even sure if this is correct) then orthodontic treatment should be directed to correct its aetiology. But as we all know, the aetiology of malocclusion is not clear and the most widely accepted theory is that malocclusion has a genetic and environmental aetiology. For example, if we consider a person with a skeletal II malocclusion, we suggest that the skeletal component is genetically determined and the position of the teeth is modified by the environment of the soft tissues. This whole concept is covered in standard sources and particularly well by Bill Proffit in his classic paper “Equilibrium theory revisited”. I have discussed this in this post.
While this may be accepted knowledge and appears to be logical; the strength of evidence underpinning this concept is not high and is mostly supported by personal opinion and theory. I still remember the many hours I spent trying to understand Moss’s functional matrix and Bjork’s papers on facial growth! As a result, other theories exist. One of these is that the influence of the environment is the major (or only) aetiological factor. In effect, the environment has influenced the position of both the skeletal bases and the teeth. This leads to the hypothesis that it is possible to “cure” malocclusion by correcting the environment. This may be achieved by providing treatment when patients are young with the aim of changing the soft tissues and the airway. Furthermore, because the cause of the malocclusion has been removed the treatment will be stable. Proponents of this philosophy suggest that this is different from treatment with fixed and functional appliance therapy, which merely masks the malocclusion by moving teeth and the actual cause of the malocclusion is not addressed. In many ways, this concept has a degree of logic But before you start thinking that “he has lost the plot” then read on…….
Is this a new concept?
It is important to remember that little in orthodontics is new, and many ideas and concepts are simply recycled from time to time. It is certainly established practice in some countries to provide orthodontic treatment with muscle exercises. Indeed, the whole concept of Frankel’s treatment was based around altering the muscle balance around the teeth. But let’s look at these treatments in more detail. I am going to discuss orthotropic and myofunctional braces together because I feel that the concepts are related, nevertheless the appliances are different.
This form of treatment was developed by John Mew in London, South of England. Over the last 15 years I have had many discussions with John about his ideas and treatment, and he has given a seminar to the specialty trainees at Manchester. There is no doubt that his ideas have not been accepted by UK orthodontics and there may be many reasons for this and I do not want to go into them now. He has recently been joined by his son, Mike, who is a specialty trained orthodontist and these ideas are being put forward in a concise way. Details of this treatment are on their website.
In brief, orthotropics is based around the theory that different forms of removable appliances, along with relevant muscle training, correct the soft tissue behaviour and oral environment. This then results in the development of the skeletal bases and change in the position of the teeth. I have looked at the evidence that has been published and unfortunately I could not find any sufficiently powered prospective studies. He illustrates successfully treated cases in papers, a recently published book and on the website. But some of these look a little dated. This is perfectly reasonable because John has been working as a single handed practitioner for many years with limited resource. Nevertheless, there is not doubt that some of the results are impressive.
This is a relatively new treatment, that has been influenced by the thinking of John Mew, and again this is based on correcting the soft tissue pattern early. One of the largest providers of this treatment are Myofunctional Research Co. The really interesting aspect of this treatment is that different appliances are used for different malocclusions and ages of patients and the appliances are not custom made. They are “taken off the shelf”. I think that this is a really interesting concept. Their website is very well presented and professionally built, and can be found here. They show many treated cases and highlight several publications that support their treatment concept and philosophy.
When I reviewed the cases, I thought that they were interesting, but most of the photographs were confined to anterior and occlusal views, there were only a few with buccal shots illustrating the posterior occlusion. The papers that they included were, in my academic opinion, mostly low scientific quality retrospective studies that measured muscle force or cephalometrics. They were chararactised by lack of power calculations, inappropriate statistics, multiple comparisons and discussions about small effect sizes. Nevertheless, these were published in refereed journals such as the Angle Orthodontist and the European Journal of Orthodontics. While I may be critical of the methodology etc, there is no doubt that the quality of these studies are at the same low level as some published research into more conventional orthodontic treatment. However, one paper could be important and this was the study by Keski-Nusala et al. in which they used an eruption guidance appliance. I have previously reviewed this paper and found it very interesting and relevant.
Finally, when we consider that the appliances can be fitted without impressions, this makes them readily accessible to the general practitioner.
So what do I think?
This is difficult, mostly because of the “white noise” and confusion surrounding these therapies. If I could treat my patients with removable appliances and achieve results that were more stable with a lower failure rate than fixed appliances I would embrace this concept completely. If the treatment could be provided by general practitioners this would be even better, as it would increase access to orthodontic care. But I will not be convinced that this is an effective treatment until I have seen studies that report a higher level of evidence. I am also more interested in studies that provide information on the alignment of the teeth, the burden of care, co-operation rates and the final results of treatment, as opposed to muscle forces or proximal cephalometric measurements.
I fully appreciate that the evidence underpinning fixed appliance treatment is not high; yet there are trials of different brackets and functional appliances etc. I would also like to point out that we must remember that “conventional” orthodontists adopted self ligation treatment, Invisalign and TADS with little critical analysis.
Is there a way forwards?
Putting these thoughts aside, I cannot help thinking that there might be something to this concept. We need to move forwards and stop endlessly arguing the issues. We could do a study! At this early point this could be a cohort study, in which a consecutive sample of patients could be enrolled; data would be collected at the start and end of treatment. All patients regardless of co-operation would be analysed and any failures would be recorded. Is this difficult to prepare? No this is a straightforward, I could write the protocol in a couple of hours. Ethics would not be a problem.
So a challenge to those supporting these concepts is get in touch with me. I will work with you to write the study, we may be able to find funding (or this could be funded by the proponents of the methods). We will then remove all the uncertainty and argument. I will also give you the right of reply, if you feel that I have misunderstood anything, and offer you a blog posting of about 1,000 words that I will publish in the next few weeks. It’s over to you….
Emeritus Professor of Orthodontics, University of Manchester, UK.