Myofunctional therapy is treatment aimed at changing muscle (Myo = muscle) function and possibly influencing jaw growth and the position of the teeth. Myofunctional appliances have been around in various forms for many years. These can include lip shields and screens, eruption guidance appliances and the T4K™. Although claims are made that they alter muscle function resulting in improved facial growth, better alignment, and more stable results, what evidence is there to support these claims?
There are a number of studies examining the clinical effects of the eruption guidance appliance and the T4K™ and they provide clinical evidence as to the compliance and effect of these appliances.1-5 These appliances are available in a small range of sizes where one is selected to suit an individual rather than being custom made from an impression/scan. Possibly due to this generic fit, one study found 31% of patients did not wear the appliance.1 A randomised trial of the T4K™ vs. a custom made Activator appliance found the Activator caused less discomfort than the T4K™ and was more acceptable.6 All five studies showed that treatment at age 5-9 was quite long (13-36 months) and protrusion of the top teeth was reduced by only a small amount (1.5-2.5mm).1-5 A study of the T4K™ appliance showed it had no growth effect.3 Another study on the eruption guidance appliance followed patients over time and found the small 2mm improvement in crowding relapsed to the initial state which shows it is not stable.4 A 2mm improvement in bite depth was also unstable and relapsed leaving only 0.5mm of change.
A 2mm change is considered a minor improvement and could be treated once all adult teeth have erupted (~age 12-13) in one phase of treatment. This results in a reduced overall treatment time as well as potentially less cost than doing two or more phases of treatment. Clinical trials in the both the USA and the United Kingdom where patients were randomly assigned to early or late treatment have shown that when patients were treated early for much more severe protrusions (7mm rather than 2mm) they could be treated equally as well by delaying treatment until all the baby teeth had been lost.7,8 The result of treating later (~ age 12-13 years of age) was a shorter overall treatment and less cost. However a case can be made for early treatment to reduce protrusive teeth when the appearance or function is concerning the patient or for a small reduction in the risk of trauma to the front teeth (see my previous post on trauma).
So if you are unsure about whether early treatment is required for your child, consult your orthodontist. Some problems such as crossbites and impacted teeth can be detected and treated more effectively if found early. Your orthodontist is an expert in growth and development and can best determine if early treatment or simply monitoring your child is indicated to achieve the most efficient and cost-effective treatment at the most appropriate time.
References:
1. Keski-Nisula. American Journal of Orthodontics & Dentofacial Orthopedics 2008;133:254-60
2. Methenitou. Journal of Pedodontics 1990;14:219-30
3. Usumez. Angle Orthodontist 2004;74:605-60
4. Janson. American Journal of Orthodontics & Dentofacial Orthopedics 2007;131:717-28
5. Myrland et al. European Journal of Orthodontics 2015;37:128-134
6. Idris. European Journal of Paediatric Dentistry 2012;13:219-24
7. Tulloch. American Journal of Orthodontics & Dentofacial Orthopedics 2004;125:657-67
8. O’Brien. American Journal of Orthodontics & Dentofacial Orthopedics 2009;135:573-9
Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and teaches orthodontics part-time at the University of Queensland and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'. Importantly, he has no financial interest in any products discussed in these Blogs.
Claims of faster treatment are easy to make and we would all like this but is it realistic? In the 1960's and 70's Begg braces/brackets were very popular and were thought to provide faster treatment as they allowed very rapid tipping and alignment. However this was at the price of less control over the root position which took more time to recover later and so they are seldom used nowadays. Other bracket designs that allow tipping have been shown to actually be slower than conventional brackets when closing extraction spaces.
More recently self-ligating brackets such as the Damon bracket, Smart-Clip, In-Ovation, Quick and more were introduced with claims of faster treatment. This was marketed well and became quite popular but with little evidence to support the claims. Dr Miles conducted the first prospective clinical trial and found there was actually no difference during initial alignment which was later confirmed by other researchers. The most recent evidence suggests that despite the claims of faster treatment, the self-ligating brackets may actually be slower than conventional #braces by about 2 months! Braces claiming to be fast are use brackets and wires just like conventional systems and so would not be expected to be any quicker. They claim lower friction but this allows the greater tipping and lack of control seen in earlier systems that proved to be slower. Let's look at an analogy - when you build a house the frame goes up quickly but then seems to slow when the smaller jobs are taking place such as the painting, tiling, etc. - but you don't want to move into your new home without this done do you? The same with braces - the initial alignment of teeth can be quite rapid but these are the simple tipping movements and the roots have not been moved into their correct and more stable positions. Your bite may need correction with elastics or other techniques and this is also a slower movement. These are the ‘detailing’ stages of #orthodontics and are slower and less obvious but very important for the most aesthetic and stable result possible.
The skill of the practitioner in placing the brackets as accurately as possible and using the correct wires, mechanics and appointment intervals affect your treatment duration. However treatment time is also affected by patient cooperation (e.g. are you wearing your elastics as directed?) and biological variation – everyone is different and their teeth move at different rates and respond in varying amounts. The same wire and adjustments will have differing responses in different people and your orthodontist will adjust your treatment based upon what they observe. Even extremely precise methods of bracket positioning using computer-aided design and manufacture, or robotic wire-bending are prone to the same problems of variation in response. Orthodontists are aiming for the best outcome possible for you and this variation is why your #orthodontist cannot give precise times to the eternal question; "When am I getting my braces off?".
Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and teaches orthodontics part-time at the University of Queensland and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'. Importantly, he has no financial interest in any products mentioned in these Blogs.
