Orthodontics: Tongue thrust and how it effects treatment

Please note: this information is about kids. Not adult abnormal swallowing habits.

Tongue (abnormal swallow) thrusting is the abnormal habit of placing the tongue between the teeth before and during the act of swallowing. During a normal swallow, the mid-tongue should be placed on the roof of the mouth, not between the teeth. Placing the tongue between the teeth pushes the teeth apart and out.

Tongue (abnormal swallow) thrust and abnormal facial muscle habits are all part of a complex myo-functional environment which produce many of the problems associated with orthodontics and braces. Unless we successfully treat the myo-functional problems, orthodontic treatment will be much more likely to fail.

Swallowing occurs 24 hours per day and about 2000 times per day. During each swallow, the tongue can exert momentary pressures of 1 to 6 pounds on the surrounding structures of the mouth. This pressure will push the teeth and bone forward or apart. An abnormal swallow will move teeth into abnormal positions and cause growth distortions of the face and teeth.

It is natural for infants to swallow with the tongue between the gums, but a transition should be made about age seven where the tongue is placed on the roof of the mouth and the teeth are in full contact during the swallow. If the tongue is placed between the teeth during the swallow like an infant, the muscles surrounding the teeth and lips are used to gain suction rather than using the muscles of the throat.

Lip puckering and lip licking prior to a swallow are easy signs to look for when a child is swallowing with the tongue between the teeth. The result of the forward tongue position is an open bite where the teeth do not touch. There is usually a protrusion of the upper front teeth and constriction of the dental arches.

Lip biting or sucking can be a major factor in moving the front teeth. The cracked and swollen lower lip is a prime indicator of a lip habit.

The majority of patients we treat for protrusion of the upper teeth have a forward tongue positioning thrust! There is also a type of thrust which is to the sides of the mouth (lateral thrust) and is almost untreatable unless normal arch form is established early in treatment.

If the front teeth are brought back into alignment, but the thrust habit is not broken, the teeth may be moved back out after treatment. So, what can be done to stop this habit? Habit correction (myo-functional therapy) by a speech therapist may be necessary if the exercises which we recommend during treatment are not followed. Finding a knowledgeable speech therapist is very difficult. They all know what it is, but few know how to effectively treat it.

In situations where the habit is severe, a removable appliance may be used to block the tongue away from the front teeth. Unfortunately, some thrusters are never corrected due to lack of parental support or lack of cooperation (or denial) on the part of the patient. In either case, orthodontic treatment is sure to be negatively effected.

See the page on oral habits of compulsion for additional information on related habits which adversely effect treatment.

If you detect an open bite, where the front teeth don't touch, then the child should be seen around age seven for a preliminary orthodontic exam.

During a normal swallow: the tongue is on the roof of the mouth and behind the front teeth. The front and back teeth touch during the entire swallow and do not protrude. The tongue is not between the teeth at any time during the swallow and the lips contact normally.

During an abnormal swallow: the tongue is between the front teeth, the lower lip is licked prior to the swallow and the lower lip is usually swollen, red, and cracked due to constant licking. There is pursing of the lower lip and chin during the swallow. The abnormal swallow pushes the upper teeth forward and keeps them apart in the front of the mouth, causing an open bite.

The damage done by the tongue to the skeletal features and teeth can be seen in this x-ray which shows the back teeth in full contact while the front teeth are completely wide apart and forward. This is an open bite due to an abnormal swallowing pattern.

Click the x-ray to enlarge it.

Severe thumb habit often lead to an abnormal swallowing pattern. The distortions caused by the thumb or a finger habit will severely distort the teeth and bone positions.

In the lower photo, you can see the distortion caused by the thumb position shown above. This patient has just had the braces placed to move the teeth back into position during a Phase One treatment.

Why do you want to stop the abnormal swallow? Because thrusting delays completion of your orthodontic treatment by forcing the teeth apart or forward. After the braces are removed, thrusting will ruin the results. It is a habit, just like sucking the thumb. Thrusting is a negative force. Thrusting will destroy your straight teeth.

ABNORMAL SWALLOW & TONGUE THRUST