Increased orthodontic retention and tongue posture

Editor’s intro: Tongue posture is just one aspect of myofunctional therapy.  During all phases of treatment, myofunctional therapists work with orthodontists as a multidisciplinary team to achieve long-term orthodontic stability.  

Sarah Hornsby, RDH, discusses the benefits of myofunctional therapy as a multidisciplinary part of the orthodontic practice

Most patients assume that the results of their orthodontic treatment will be permanent. But as dental professionals, we recognize that orthodontic relapse is a common occurrence.

In many cases, the patient has not been compliant with retainer use, but there are other variables that we can identify as well — third-molar eruption, latent mandibular growth, genetics, and mesial drift, for example. We also see those “perfect patients,” who seem to have none of the possible factors that contribute to relapse, and who are incredibly diligent with wearing their retainers, yet they still experience occlusal changes. So, what else could be going on?

Tongue posture

From the anatomical and anthropological perspectives, we know that the tongue should rest in the palate. The posture of the tongue can have a significant impact on orthodontic treatment and retention. For example, if the tongue has an interdental resting posture, we can see the impact of tongue position on occlusion in anterior and posterior open bites.

For optimum orthodontic stability, the body of the tongue should fill the entire space of the oral cavity. The tip of the tongue should rest on the incisive papilla or the alveolar ridge area, and the dorsum of the tongue should make contact with the hard and soft palate.

Causes of incorrect tongue posture

When the tongue drops from the palate, we may begin to see changes in occlusion. In the above example of the anterior or posterior open bite, what we often fail to understand is that the tongue has lost contact with the palate. It has dropped to the floor of the mouth and, as a functional compensation, has begun to rest between the teeth and push forward or laterally during swallowing. We can identify this clinically as a tongue-thrust swallowing pattern.

So, what would cause this postural change to the tongue? Possible reasons for this type of compensation are a retained infantile swallowing reflex or oral breathing. When our patients breathe through the mouth, it’s not physiologically possible to keep the tongue in the correct position.

Another reason that the tongue may lose contact with the palate (or never achieve it in the first place) is ankyloglossia. Ankyloglossia is a congenital anatomical condition that restricts the lingual frenum and function of the tongue. This condition can interfere with breast feeding, speech, oral health, and of course, orthodontic treatment and stability.

Identifying these specific postural and functional problems with the tongue can be the first step to an increased likelihood of orthodontic retention.

How to identify a low tongue

Ankyloglossia (or tongue-tie) occurs on a spectrum. We typically think of ankyloglossia as the tip of the tongue being fully attached to the floor of the mouth. However, even a small amount of lingual restriction or tension can prevent the tongue from making contact with the palate. There are a number of protocols for identifying and classifying ankyloglossia. A skilled myofunctional therapist will be familiar with these protocols, so a referral may be necessary.

Patients who mouth-breathe may be easier to identify. Anyone with a history of allergies, asthma, large tonsils and adenoids, deviated septum, large turbinates, or sinus infections will be very likely to breathe through the mouth. Even if the mouth breathing occurs only during the night, the hours spent with a low tongue posture have a cumulative effect on orthodontic stability, especially if patients do not wear their retainers.

A possible solution

Myofunctional therapists teach patients exercises to increase the tone and coordination of the tongue so that it can rest in the palate and function optimally for chewing, swallowing, speaking, and breathing. The goal of the myofunctional therapist is to teach correct tongue posture during the day and at night, which can be a perfect complement to orthodontic treatment.

In my practice, I work closely with orthodontists during all phases of treatment. In fact, they’re my most active referral partners, and working together as a multidisciplinary team, our patients achieve optimal results and long-term orthodontic stability.

Besides tongue posture, myofunctional therapy has benefits for malocclusion and OSA. Read Dr. Daniel Klauer’s article, “Myofunctional therapy plays a key role in the orthodontic practice.”