Repetitive forward placement of the tongue during swallowing, in between the teeth and against the lower lip, is known as tongue thrusting. It is more common in people with large tongues, who retain the pattern of infantile swallowing. The infantile type of swallow is normal during infancy as teeth are absent. The tongue forms the barrier between the lips to achieve a complete seal during infantile swallowing. The swallowing using the tongue to form a seal becomes pathological (habitual) as the teeth develop. It can be an adaptive behavior in absence of front teeth or grossly decayed front teeth.
While tongue thrusting may appear to be a minor issue, it can lead to significant complications particularly with the health of the teeth and gums.
Patients with tongue thrusting habit show a higher lip separation. They also usually exhibit a larger tongue size. The swallowing pattern in these individuals is jerky and inconsistent in nature. Tongue thrusting leads to several orthodontic problems such as malocclusion. The upper central incisors are proclined. The lower central incisors are tipped towards the tongue. Other orthodontic problems such as open bite or cross bite are commonly seen associated with tongue thrusting habit.
Tongue thrusting affects the speech. Patients exhibiting tongue thrusting habit usually have difficulty is pronunciations. The sounds including the alphabets ‘s’ ‘n’ ’t’ ‘d’ ‘l’ ‘th’ ‘z’ and ‘v’ are usually difficult to pronounce for these individuals. A person with the habit of tongue thrusting and undergoing orthodontic treatment tends to have a relapse of dental corrections due to the habit.
Tongue thrusting is caused by retained pattern of swallowing from infancy .The dental causes of retained infantile swallow includes early loss of front deciduous (milk teeth) or grossly destroyed front teeth. The teeth could be lost due to trauma as well. The failure to replace the decayed and missing front teeth leads to tongue thrusting habit.
The other causes of tongue thrusting habit include repeated upper respiratory tract infections and chronic tonsillitis. The enlarged tonsils promote more forward placement of tongue leading to tongue thrusting. Allergies are also associated with a tongue thrusting habit.
Condition such as a tongue tie; induce abnormal tongue movements which may lead to tongue thrust. Tongue thrusting is often associated with other oral habits such as thumb sucking and prolonged bottled feeding. To some extent, it can also be hereditary in nature, due the orofacial muscle structure and tongue size which is genetically determined.
Tongue thrusting habit is usually self correcting by 4 to 6 years of age. As the muscle structure improves and permanent incisors erupt, the habit ceases on its own. In cases where the habit fails to cease, dental intervention is necessary to prevent developing orthodontic problems.
- Developing malocclusion is treated with orthodontic therapy.
- Preventive and interceptive habit breaking orthodontic appliances are used. The commonly used appliances include Nance palatal arch, mouth guards and oral screen.
- The exercises comprises of whistling and swallowing practices as well.
- The patient must undergo speech therapy to overcome speech difficulties.
- Surgery is to be carried out in cases with tongue tie, followed by orthodontic therapy.