Can structural changes be promoted by myofunctional orthodontics with preformed appliances?

To answer this question, I need to make a small premise.

Every individual is unique: we are born with a genetic potential, known as a genotype, that is passed down through generations. In an ideal world, where everything goes according to plan during pregnancy, birth, postpartum, breastfeeding, growth and development, we should be able to express and realise this genetic potential and become the best ‘us’ we can be. But in the ‘modern world’, the environment around us, the air we breathe, the type and quality of food we eat, and the bad habits we may have, almost never allow us to fully express this genetic potential, leaving us in a state of compromise known as the ‘phenotype’. The fact that a genetic trait has not been fully expressed does not mean that the trait has disappeared or no longer exists. It simply means that certain patterns of behaviour have suppressed its expression. The science that studies this phenomenon is called epigenetics.

Now I have to generalise, because what you are about to read cannot be universally applied in cases of severe genetic abnormalities, trauma or structural and/or surgical interventions that have caused irreversible changes.

There are 2 schools of thought.

One, more traditional, says that the damage has already been done and that mechanical force is needed to reverse it. This is the world of orthodontics, which uses ‘fixed braces’ attached to the teeth. Pressing on the teeth forces an enlargement of the arch, usually the palate, but a similar argument can be made for the jaw. In practice, you are forcing a system that has never developed according to its genetic potential, due to a non-physiological way of breathing, an incorrect position of the tongue and other postural and muscular dysfunctions during growth and development, by trying to restore the correct proportions by anchoring on the teeth and acting mechanically.

The other school argues that the genetic potential still exists and that the arches can and must be ‘encouraged’ to develop in this direction by applying very light forces to the arch itself – not to the teeth, except to a lesser extent – and by removing the obstacles that have prevented its full expression, i.e. by first (or simultaneously) addressing the patient’s functional and muscular problems. Sometimes these “obstacles” may be outside the oral cavity and require the intervention of other specialists.

Personally, I find the concept of ‘encouraging the development of the arch’ much more sensible than ‘forcing the expansion of the arch’, but there are cases where the damage is so severe that forced intervention is necessary. Even in these cases, I prefer, if possible, to do a functional and muscular rehabilitation programme to support the treatment, even if it is ‘limited’ during the use of the fixed appliance. Or better still, if the case lends itself, use a fixed appliance that works with the preformed devices and does not interfere with myofunctional therapy, but rather helps it to achieve its goals.

It is always important to diagnose the cause of the malocclusion before embarking on rehabilitation, because if you do not address the cause of the malocclusion, you are just fighting the way the body has decided to work in order to survive. Malocclusions are usually the result of dysfunctions in the rest of the body that manifest themselves in the mouth. Of course, they need to be corrected in the mouth – by dentists and orthodontists – but stability or balance is unlikely to be achieved unless the underlying causes are also addressed.

To return to the original question, from my training and the clinical evidence I have seen directly in patients I have treated and am treating, the answer is yes. Myofunctional orthodontics with preformed appliances promotes structural changes if a strategy is implemented that addresses the functional and muscular problems that led to the malocclusion. If you put myofunctional therapy at the centre of the treatment and follow the patient through a rehabilitation pathway, consisting of functional and muscular exercises and preformed and/or fixed appliances that strengthen the active part of the treatment and condition the functional matrix, i.e. everything around the teeth and jaws, it is possible to unlock the genetic potential and promote the harmonious development of the arches.