THE EDITOR'S CORNER
Tongue thrust has been a subject of controversy in orthodontics for at least the last fifteen years and the more general subject of myofunctional therapy for quite a bit longer than that. A cause of the controversy is that these therapies have had strong advocates who created whole sets of rules and treatment procedures without necessarily having identified that there was a problem which required treatment or that the treatment resulted in a specified gain for the patient. Some may feel that they have identified both to their satisfaction. However, it is inherent in the very name of science that we must know and not feel. Fifteen years is not a long time in the history of science and perhaps it was not enough time for the development of meaningful research programs. However, orthodontists ought not continue to support therapeutic ideas which have no basis in proven fact.
The question would not seem to be whether a person has a tongue thrust or not, but whether the tongue thrust, if there is one, is doing any harm sufficient to require its treatment. This, in itself, is not a simple concept because what one person sees as a thrusting tongue causing an open bite, another might see as a thrusting tongue caused by an open bite; what one person sees as an orthodontic relapse caused by a thrusting tongue, another might see as a thrusting tongue and a relapsing orthodontic result co-existing; what one person sees as improvement in an open bite due to tongue thrust therapy, another might see as improvement with the passage of time. The coincidence of two events does not establish that they have a relationship. The succession of two events does not establish a cause and effect relationship.
Most of the reports in the literature concerning myofunctional therapy and tongue thrust therapy have been based on opinion, repetition of past published opinion, and poorly drawn studies. Nevertheless, we have had many orthodontists who would not start to treat a case orthodontically until the tongue thrust swallow had been treated and they might identify up to 80% of prospective patients with tongue thrust swallow. There are many practitioners who never refer a patient for tongue thrust therapy. Both groups of orthodontists may feel that they are getting satisfactory orthodontic results and, indeed, they may be. Of course, if they are, it would tend to invalidate tongue thrust therapy. Unless it can be proven that tongue thrust therapy or any other myofunctional therapy is valid, I think little kids have enough problems already and enough things for parents to nag them about, and that parents have enough to do without an additional supervisory task and also enough on which to spend their money. We would not recommend orthodontic treatment for a child on the basis that it wouldn't do them any harm or if we didn't think that the time, effort and money could be justified by the amount of benefit from treatment. The same rule should apply to adjunctive therapies.
It has only been part of the problem that some of us have given adherence to unproven ideas, that the research has been conducted almost entirely by people not trained in research, that this has resulted in dissemination of information which may be compelling to them and to others who do not subject the material to even elementary rules of scientific investigation. In addition to studies in the field being conducted by people not trained in research, they have also been conducted by people not adequately qualified to make the investigation. Thus, you have orthodontists untrained in speech therapy, dentists not adequately trained in orthodontics or in speech therapy, speech therapists untrained in orthodontics. You have a whole mix of unqualified people who are working clinically with myofunction, especially with tongue thrust, and who may honestly believe that they are absolutely correct or be compelled by evidence which is almost totally inadequate.
A speech pathologist may conduct a study on tongue thrust with regard to speech, but not with regard to orthodontic effect. That is solely within the orthodontists' province and we would do well to keep it in mind.
