THE EDITOR'S CORNER
If there is one area that I have felt is really confused in orthodontics, it is our understanding of oral habits. We classify them as habits when many of them are not habits at all. Some are necessities dictated by requirements of structure and function in the individual, such as the need to breathe.
If an individual cannot breathe through his nose, he will open his mouth to breathe in order to survive. Yet, we have had advocates of the positioner appliance and the oral screen say that they cure a mouthbreathing habit. More often I think they may wind up with unsuccessful treatment because the patient physically could not cooperate in wearing the appliance because of his need to breathe through his mouth.
If you look back in our literature you can find that the statement that a mouthbreathing habit causes high palatal vaults has been repeated for a hundred years or more. Isn't it more logical to recognize that the roof of the mouth is the floor of the nose and that a high palatal vault intrudes on the nasal area using up breathing room in the nose and that this can cause mouthbreathing?
Another "habit" that I believe is usually misunderstood is lip-biting. It is said that a habit of biting the lower lip results in protrusion of the upper anterior teeth. Is it not more logical that the protrusion caused the lip-biting? Where else is the lower lip going to go? True, lip-biting can exaggerate a protrusion of upper anterior teeth, but I would question whether it causes it. The fact is that the lip-biting disappears with the reduction of the protrusion and does not recur.
The furore over the tongue-thrusting, reverse-swallowing habit has subsided to some extent in recent years, but there is still a marked tendency in orthodontics to misinterpret and overstate this problem. There is probably more than one kind of tongue-thrust. There is the lip-wetting kind that may not be related to any demonstrable tooth problem. If there is no problem clinically, then what is the significance of a swallow that doesn't go according to the book, and how much time, money and effort should go into trying to correct it? I think the answer is none.
What about reverse swallows and tongue thrusts that are associated with tooth problems such as anterior open bite? Most of them are akin to the lip-biting habit. They are necessary rather than habitual. Try to swallow with your teeth apart. An individual with an anterior open bite usually must close the system by thrusting the tongue into the space in order to swallow and to make certain speech sounds. In addition, the tongue will sometimes lay in the space just because it is there. Most of these are amenable to treatment that itself closes the system and prevents the tongue from thrusting through. In most of these cases, that is all that is needed to reduce the open bite and it rarely opens again. This is especially true if this treatment is done at a young age (around the time of the eruption of the permanent upper laterals).
A number of these may also respond to tongue retraining. I think this is the hard way and I haven't seen it succeed very often. Usually the patient does not persist in his prescribed exercises. It is said that most tongue thrusters never get to see an orthodontist or a speech therapist and that the tongue thrust is lost by the majority of them somewhere along the way. This could be part of physical and social maturation.
In summary on tongue thrusting, I have rarely seen one that I felt was a habit that prevented me from achieving a planned result or which upset the occlusion following retention.
I, therefore, do not classify most mouthbreathing, lip-biting, or tongue thrusting as habits. If you can eliminate the physical cause and eliminate the phenomenon and its symptoms, I do not call that a habit. 
