A myofunctional trainer, as its name suggests, is an appliance used to train a particular function – such as tongue position at rest, swallowing and breathing. These appliances help to correct harmful habits and, if the jaws are still growing, support their proper development. If a trainer is worn by a patient who has no harmful habit, what we can expect as a result is that the teeth coming through will be guided into their correct position. A trainer on its own cannot solve the problem of a harmful habit. It can ‘show’ the tongue where its correct place is and, by keeping the mouth closed, direct air through the nose when breathing. This appliance is suitable to use while a speech therapist works on the tongue problems with exercises.
This answer is for general information. Your own case needs an examination by an orthodontist.