A new study on pre-formed myofunctional appliances done in Syria provides interesting results.
Every now and then someone does a great study. A team in Syria did this study and publication has been delayed because of the Syrian Crisis. It is well worth a read.
This trial addressed the controversial treatment of myofunctional orthodontics. This treatment philosophy is based around early treatment with pre formed appliance and muscle exercises. A company based in Australia called Myofunctional Research make these appliances. Proponents claim that they are treating the cause of malocclusion and that the appliances are more effective than conventional treatment. Furthermore, the outcome of this treatment is more stable than conventional orthodontic care. In theory, this has some logic. However, despite widespread promotion by Myofunctional Research, evidence regarding these claims is lacking. I have posted about this before and had an interesting discussion with the scientific advisor to Myofunctional Research. Initially, they appeared interested in carrying out some research with me as an advisor, but when I asked him if he was prepared to do a study in which patients were randomised to conventional and myofunctional treatment, the silence was deafening.
A team in Syria did this study. It is an example to all those who resist carrying out trials into their products.
Ghassan Idris et al
European Journal of Orthodontics, 2018, 1–8 doi:10.1093/ejo/cjy014
“What are the soft and hard tissue effects of an activator and a pre formed myofunctional appliance”?
What did they do?
The PICO was;
Participants: 8-12 year old children with overjets greater than 4mm. They recruited the patients via a screening programme.
Intervention: Myofunctional Trainer for Kids (T4K). This is a pre-formed appliance. The children were asked to wear this for two hours a day and when sleeping. All participants had soft trainers for the first 6 months, then hard trainers were used for the remaining period of the treatment. They also did a series of daily muscular and swallowing exercises.
Comparator: Conventional activator worn for 15 hours a day
Outcome: Cephalometric analysis at the start of treatment and 12 months later.
They carried out a good sample size calculation. They based this on a difference in ANB of one degree. This is rather small and I wondered if the study was over powered. However, it showed that they needed 30 participants in each group. This reduced the problem of a small study reporting spurious effects.
They used a pre-determined randomisation and concealed their allocation with sealed envelopes. Unfortunately, it was not clear whether patient enrollment was done before the allocation. This does put the trial at some risk of bias.
What did they find?
They randomised 30 patients to each of the interventions. At the end of the study, 2 of the activator and 4 of the T4K groups dropped out.
They presented a large amount of cephalometric data and this was a little confusing. As a result, I have just selected some of the most important final treatment outcome measures in this table.
|ANB||4.53 (1.69)||6.21 (2.04)||0.001|
|Wits||1.57 (1.44)||2.50 (1.69)||0.2|
|Overjet||4.20 (2.1)||4.61 (2.14)||0.001|
They concluded that a 12 month treatment with an activator resulted in better skeletal change than the T4K. Furthermore, the activator was also better than the T4K in reducing the overjet and normalising the soft tissue pattern.
In their discussion, they suggested that this may have occurred because of the greater wear time of the activator. They also pointed out that the T4K was rather flexible and did not hold the mandible forwards as much as the activator.
What did I think?
I thought that this was a well carried out interesting study. The good points were:
- They investigated a clinically relevant question
- The trial had an adequate number of patients and there were few drop outs.
- Randomisation and concealment were good.
- They recorded and analysed the data blind.
These issues were potentially problematic;
- It was not clear whether they allocated the treatment after they enrolled the patients into the trial. This means that there is potential for bias. Nevertheless, the groups were similar at baseline.
- They only measured cephalometric data. Furthermore, the differences between the two groups after treatment were rather small. I did not feel that they were clinically significant.
If we put all this together. I feel that this papers provides us with useful clinical information and suggests that the there are no real clinical differences between activator and T4K treatment.
We now need to consider whether there is an advantage of the T4K because it is pre-formed and can be fitted without impressions. I think that this is a considerable benefit of this type of appliance. I would also like to see further research on the end of treatment results with this appliance.
Finally, I would like to consider whether the results of this study and an earlier study by Emina Circic support the advertising claims made by Myofunctional Research. I have looked at their website and they make claims about improving breathing, arch development, better jaw growth and long term stability of their treatment. This study does not support their claims. Perhaps they should do some research into these claims before they make them. After all a team from Syria has managed to research into their product….
However, it does appear that the myofunctional appliances that have been tested in the two trials produce similar results to conventional activators. This could be a great selling point to orthodontists. There would be no need to promote their appliances by making reference to magic claims. I wonder why they don’t do this?
Let’s have a good discussion, but before you make a comment, please remember the pyramid of denial..
Emeritus Professor of Orthodontics, University of Manchester, UK.