What is tongue thrust?
Tongue thrust refers to an “excessive anterior tongue movement during swallowing” or speech and the anterior placement of the tongue during rest (Bauman-Waengler, 2008). It is an orofacial muscular imbalance where the tongue contacts more than half the surface of either the upper or lower incisors or protrudes between them during swallowing, speech, and while the tongue is at rest. The lips maintain an open resting posture, or an open mouth posture, which facilitates the forward tongue movement (Harmon, 2004).
In the normal course of development, all infants use this pattern of swallowing because of the
reduced size of the oral cavity. By 6 years of age, however, most children automatically use the “normal” swallowing pattern. Some children do not — and that’s where the SLP comes in.
Other names :
Infantile swallow Reverse swallow Deviant swallow Visceral swallow
Some regard ‘tongue thrust’ as a misnomer because it implies volitional intent to force the tongue forward. However, such individuals do not seem to use more force than non-tongue thrusters. “Oral muscle pattern disorders” is suggested as a more accurate term.
Symptoms of tongue thrust include:
· Dental Malocclusion
· Poor facial development, facial hypotonia
· Open mouth posture or mouth breathing
· Periodontal problems
· Articulation disorders, Oral Apraxia, and/or Dysarthria
· Oral Habits: thumb-sucking, bruxism and/ or teeth clenching
· Limited tolerance to food textures, limited diet
· Limited jaw and chewing movement
· Inter-dental or lateral lisps
· Difficulty swallowing pills
· Facial Pain
· Recurring headaches of unknown etiology
· Undetermined conductive hearing loss
· Excessive belching, stomach discomfort and reflux
· Earaches of unknown etiology
· Difficulty wearing dentures
· Infants with feeding difficulties
· Oral Defensiveness
· High palatal arch
(Institute for Myofunctional Studies)
How does tongue thrust affect speech production?
Sibilant distortions occur more frequently in children with tongue thrust. Sometimes, tongue thrust is also associated with anterior placement for /sh/, /ch/, /dj/, /zh/, /t/, /d/, /l/, d /n/ . (Bernthal and Bankson, 1993)
How does tongue thrust affect the swallow?
Orofacial myofunctional differences may have a negative impact on the oral-preparatory or the oral phase of swallowing. These difficulties may manifest themselves in poor bolus formation, poor or uncoordinated posterior transfer of a bolus through the oral cavity, use of extraneous facial muscles for the process of initiating a swallow, and/or in the forward tongue movement during or immediately following the swallow.
Characteristics of the abnormal swallow:
4Lack of masseter contraction
4Anterior loss of the bolus
4Excessive or forced swallowing
4Poor bolus formation
4Inappropriate bite size
4Use of liquids to clear foods from the mouth
4Chewing with the mouth open
4Difficulty in isolating tongue to manipulate food
4Tongue at anterior and/or interdentalized position
According to recent literature, as many as 67 to 95 percent of the children 5 to 8 years old exhibit tongue thrust which may be associated with or contributing to an orthodontic or speech problem . However this declines to 25-35% at the age of nine years. (Rampp, 1983)
Types of tongue thrust:
Anterior open bite
This is the most common type of tongue thrust. In this case, the front lips do not close and the child often has his mouth open with the tongue protruding beyond the lips.
This occurs when the upper incisors are extremely protruded and the lower incisors are pulled in bythe lower lip. This particular type of thrust is generally accompanied by a strong mentalis.
Bite is characteristically open on one side of the mouth.
Anterior bite is closed, but posterior teeth from the first bicuspid to the back molars may be open on both sides. This is the most difficult thrust to correct.
Bilateral anterior open bite
The only teeth that make contact are the molars, with the bite completely open on both sides, including the anterior teeth. A large tongue is also noted.
Closed bite thrust
Typically shows a double protrusion such that both the upper and lower teeth are flared out and spread apart . (Wikipedia, 2009)
Causes of tongue thrust:
Although no one factor is to blame, several etiologies have been suggested:
Heredity: One study (Hanson & Barrett, 1988) showed family heredity involved in determining such factors as the size of a child's mouth, arrangement and number of teeth, and strength of lip, tongue, mouth, and facial muscles
Allergies: Children with allergies, for example, often breathe with their mouths open, and with the tongue lying flat on the bottom of their mouths. The resulting open mouth posture then causes the lip muscles to lose their strength and tone.
Structural features: Enlarged tonsils and adenoids may block the airway, resulting in an open-mouth breathing pattern which can persist even after successful medical clearing of the airway blockage.
Behavioral factors: Tongue thrust may also result from behaviors such as excessive finger sucking, lip and fingernail biting, excessive lip licking, and teeth clenching and bruxism (teeth grinding). Persistent thumb sucking, in particular, may change the shape of a child's upper and lower jaw and teeth, requiring speech, dental, and orthodontic intervention. .
Artificial nipples used in bottle feeding ,
Ankyloglossia (tongue tie)