Tongue thrust (also called "reverse" or "immature" swallow) is the common name given to orofacial muscular imbalance, a human behavioral pattern in which the tongue protrudes through the anterior incisors during swallowing, speech, and while the tongue is at rest (ASHA, 2011). When the atypical swallow is observed in older children and adults, it is often associated with prolonged breastfeeding, short frenulum, hypertrophic adenoids and tonsils, oral breathing, allergic rhinitis, and abnormal head lower jaw, and tongue posture.
Dentists and orthodontists are concerned with the effects of the tongue and facial muscles on the occlusion (how teeth fit together) of teeth. The evidence proving that too much tongue pressure against the teeth on the inside and an unequal amount of facial muscle pressure from the outside (which is the case with a tongue thrust swallow and/or incorrect tongue resting posture) may result in malocclusion or misalignment of the teeth. The resting posture of the tongue and facial muscles play a vital role. When the tongue is constantly resting against the front teeth and the upper lip in short or flaccid (weak and flabby), the front teeth will be pushed forward.
1. Prevent Orthodontic Relapse
A person diagnosed with a tongue thrust has a difficult orthodontic road ahead. If their tongue thrust goes untreated, relapse of the orthodontic correction is almost guaranteed. In terms of malocclusion, tongue thrust has been correlated with a posterior crossbite, open bite, and excess overjet. It has been demonstrated that protrusive tongue activity (tongue thrust) during swallowing might result in a labial inclination of incisors, open bite, and spacing problems in some cases. A swallow in which the tongue is placed on or through the teeth also causes an anterior open bite. Speech sounds such as a lisp can place additional pressure against the teeth during a conversation.
Respiration and swallowing, both essential to our very existence are carried on via a common passageway, the pharynx. Both the body and root of the tongue, which has important functions in swallowing, must avoid the restriction of this airway. Bosma (1963) agrees with Hoffman et al (1965) who advances the theory that the tongue may protrude at certain times to provide adequate pharyngeal airway space (which is essential to life) when the oral cavity is not yet large enough to accommodate the tongue and at the same time maintain an airway for essential respiration.
Deglutition or Swallowing is the most constant activity of the tongue (approximately 3,000 times per· 24 hour day). Because of the major part it plays in activity and communication, it has been thought of as perhaps the primary cause of tongue-thrust (Weiss, 1969). Swallow patterns include the following clinical characteristics (Fletcher et al., 1961): (1) extreme tension in the mouth closing musculature, (2) diminution or absence of palpable contraction in the muscles of mastication during the swallowing act, and (3) forward thrust of the tongue causing it to protrude between the incisors.
The imbalance of a TMD patient's facial, chewing and neck muscles can cause difficulty swallowing. This is called dysphagia. Because of the instability of the jaw, head, and neck, cervical problems are common. This can lead to occipital headaches located at the back of the head. The three muscles concerned in this swallowing act appear to be the masseter and temporalis (of the masticatory group) and mentalis (of the facial expression group). You can experience difficulty swallowing because the muscles of your head, jaw, and neck are too tight. When they're too tight, they don't function properly, which can make chewing and even swallowing difficult.
5. Improve speech and voice
The position of the teeth and the occlusion can influence the quality of speech production. The neuromuscular and respiratory systems also play a key role in the quality and coordination needed for functional speech. They influence the accuracy of movement of the oral musculature and the coordination of respiration and phonation to achieve adequate control of the air stream during articulation.
Myofunctional therapy and speech therapy are done for the treatment of tongue thrust. The goal of myofunctional therapy is to develop a normal oral resting position where the lips and teeth are closed, and the tongue tip rests against the ridge behind the upper front teeth. Exercises are also done to obtain proper tongue movement during swallowing. Respiratory muscular training for the upper airway is also involved as the muscles of swallowing are also the same muscles for respiration. Myofunctional therapy is often done in coordination with orthodontic treatment to move the teeth into proper alignment. Some orthodontic appliances can also be used to help train the child to keep the tongue in the right position. Speech therapy is often needed to correct the abnormal tongue position resulting in a frontal production of specific speech sounds.