Thumb sucking should be eliminated as soon as possible and it is accepted that it should never persist past the time that the child's permanent teeth start to erupt.
At Dr. Gray's office, we like to begin by facilitating the child to eliminate the habit using proven behavior modification techniques. This is a delightful process. It builds self-esteem and eliminates the harmful habit. We have helped so many children that you could never believe it. Our successes amazes many parents and we still find it remarkable as well!
Another method is to place an orthodontic habit appliance in the palate that is attached to the molars. It is effective, though potentially problematic. We can discuss this option with you if necessary.
Have you ever noticed how a seaside oak tree is bent from the effects of the constant onshore breeze? The trunk and branches are prematurely deformed as the result of the pressure of the wind.
Applying pressure to the teeth changes the bone that holds the teeth. That is how orthodontic tooth movement is accomplished. Thumb sucking is a very effective orthodontic pressure. Unfortunately, these pressures are the wrong direction!
Just like the tree that is deformed, the upper jaw is adapted to the forces of the thumb sucking. The upper jaw narrows and a narrow jaw has less room for the teeth. This results in crowding of the teeth. The palate becomes high and the face becomes long. Lips may not comfortably meet at rest. The upper front teeth may protrude. A crossbite is often created. A crossbite can cause a bite interference which will force the movement of the lower jaw to one side so that the teeth will fit. This condition encourages the teeth to fit together at the expense of the developing jaw joints (TMJ’s). A crossbite with a functional shift will create a muscle imbalance. I have seen TMJ disorders in patients as young as seven years.
With thumb sucking, the tongue, which normally occupies the roof of the mouth, drops to the floor of the mouth to make room for the thumb. The swallow pattern that usually changes from a tongue thrust swallow to an adult swallow about age six, does not change. Even with the elimination of the thumb habit after that age, the tongue thrust swallow usually persists and will create abnormal pressures on the teeth and bones.
The muscles of the face and jaws function differently with thumb sucking than in individuals without the habit. The lower lip is overly active as it participates with the tongue thrusting and thumb sucking. This creates pressure on the lower teeth. Even with the elimination of the habit, this hyperactivity persists. This adversely affects lower tooth position and the stability of any orthodontic correction. (it changes the normal equilibrium). In other words, long term thumb sucking contributes directly to a group of facial conditions. The severity of change is related to the existing facial form (the genetic pattern – is there already a long face tendency?), the presence of mouth breathing (chronic mouth breathing creates similar disturbances in facial growth), the duration (how old is the patient?), the intensity (how vigorous is the habit?), and the incidence (how often does it occur each day?) of the habit.
By age eight 80% of facial growth has occurred; by age twelve 90%. If a child has an intense thumb sucking habit which occurs throughout much of the day for a long period of time, you can now understand the facial bone change and aberrant swallow and tongue function that will happen. Some bone and tooth change may be subtle, some gross.
Orthodontic treatment regimens and treatment success for these conditions will vary with treatment of adverse changes. In general, palatal expansion, long term growth modification appliances (headgear or Herbst) therapy and eventually full braces are needed. The younger the patient is, the more effective the treatment for these conditions. There have been many instances where the extent of bone change was so extensive that corrective jaw surgery was needed.