Introduction:
Tongue thrust is the habit of placing the tongue forward between the upper and lower anterior and/or posterior teeth when a person swallows. Anterior tongue thrusting is when the tip of the tongue is placed between the incisors during swallowing. Tongue thrusting might be a major cause of malocclusion , or it may be associated with skeletal open bite as an aggravating factor. It may be associated with children with long term thumb sucking habit.
How Is Tongue Thrust Habit Classified?
The tongue thrust habit is classified into:
I) Primary and secondary.
II) Anterior, lateral, and complex.
III) Endogenous, habitual, and adaptive.
What Causes Tongue Thrust?
There are different schools of thought explaining tongue thrust:
According to Graber - According to this theory, tongue thrusting is because of retained infantile swallow. Whatever may be the cause of tongue thrusting habit, be it size, posture, or function, it serves as the effective cause of malocclusion.
According to Proffit - Whenever there is an open bite due to thumb sucking habit, the tongue tries to close the open bite by wrong placement, which accentuates the deformity. Placing the tongue between anteriors to make an anterior lip seal is successfully achieved.
According to Equilibrium Theory - The pressure generated by the tongue is very less to affect the equilibrium, but if there is a forward resting posture of the tongue on anteriors for a long duration, then even if pressure exerting is very light then it could be a precipitating factor for a malocclusion.
Some thoughts about tongue thrust state that tongue thrust is seen in two circumstances:
1) In younger children with normal occlusion in whom, it represents a transitional stage during normal physiologic maturation.
2) In individuals of any age with displaced anteriors.
So, tongue thrusting habit or swallowing pattern can be considered as a result of displaced incisors and not the cause.
Effects of Tongue Thrust:
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Increased overjet will be there because of the forward positioning of the tongue.
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Increased overbite will be there because of faulty positioning of the tongue.
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In tongue thrusting, the tongue will not be positioned on the lingual cusps of posterior teeth, and so it eliminates interocclusal clearance.
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May be the cause for bruxism.
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The maxillary arch becomes narrow as the tongue is in a lower position in the mouth, which may be the cause of unilateral or bilateral crossbite.
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In horizontal growth patterns, tongue thrusting leads to bimaxillary protrusion.
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In vertical growth patterns, tongue thrusting leads to retroclination or lingual inclination of lower incisors.
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Diastema may be present.
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Deep bite in lateral tongue thrust.
How Is Tongue Thrust Diagnosed?
One has to keenly differentiate and diagnose among simple, complex, retained infantile swallowing patterns and faulty tongue posture. When we see the prognosis of tongue thrust, then it is good for simple tongue thrust, not very good for complex tongue thrust, and is poor for infantile swallowing patterns. Protracted tongue posture can be corrected when it is acquired. The method of examination of tongue dysfunction or posturing:
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Electronic recording.
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Electromyography examination.
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Intraoral recording of pressure exerted by the tongue.
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Roentgen cephalometric analysis.
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Cineradiography.
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Neurophysiologic examination.
What Is the Management of Tongue Thrust?
Simple Tongue Thrust -
It is when the teeth are in normal contact during swallowing. If there is excessive proclination of maxillary incisors, treatment of tongue thrust should be done after the retraction of incisors. The patient should be educated about swallowing exercises with sugarless mint and should be instructed to follow the instructions 40 times a day, and the patient is asked to maintain the record for the same. During the second appointment, there should be an improvement in the swallowing pattern, and the patient should swallow correctly at will.
Another way to fix this bad habit is with the use of orthodontic rubber bands. First, place the rubber band on the tip of the tongue, then press the tip of the tongue right behind the upper front teeth. After that, bite normally and avoid forward biting. Do not panic if the rubber band is accidentally swallowed, as it will pass through your system without any harm. Initially, this exercise may be a little difficult to do, but with practice, you will master this exercise, and soon you will be free of tongue thrusting. So, it is advised to do two sets of 30, once in the morning and once in the evening, for better results. After this, if the problem still continues, the soldered lingual archwire having short and sharp spurs is used.
Complex Tongue Thrust -
It is when the teeth are apart during swallowing. It can cause malocclusions, such as poor occlusal fit and generalized anterior open bite. An open bite may not be present if the tongue is seated evenly at the top.
The malocclusion is treated first. Muscle training should begin when treatment is in the retentive phase. The maxillary lingual arch appliance is necessary, and as the prognosis is not very good, the chances of relapse may be there.
Retained Infantile Swallow -
When the tongue thrust swallowing pattern is retained beyond age, it is defined as the retained infantile swallow. Individuals suffering from this swallow have occlusion only on one molar in each segment. They have difficulty in breathing and are sensitive to gag reflux.
A tongue crib can be used with 3 to 4 projections and should extend to the cingulum of lower incisors. The prognosis is poor.
Abnormal Tongue Posture -
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Endogenous Tongue Posture - It is an inherent tongue posture and is not a normal or ideal tongue posture. Here, the tip of the tongue lies between incisors. It results in a mild open bite. The prognosis is poor.
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Acquired Tongue Posture - Acquired tongue posture may be because of respiratory problems, chronic pharyngitis, or tonsillitis. In that case, one should consult an otolaryngologist. After the elimination of precipitating factors, the habit should be taken care of by lingual archwire with sharp spurs.
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Adaptive Tongue Posture - Here, narrow maxilla may be the cause. After treatment of the narrow maxillary arch with the help of rapid maxillary expansion, posterior intercuspation is corrected, and normal posture is achieved.
Conclusion:
As we all know, our tongue is a very powerful muscle and is strong enough to push our teeth out of their natural position, which causes a loss of equilibrium. An individual swallows around 2000 times a day. In tongue thrusting, there is improper swallowing. This improper swallowing becomes more apparent when it is persistent for a longer duration of time. It can also lead to open bite and malocclusion, in which only the back teeth touch together during swallowing, and anterior teeth will not touch.
