Tongue thrust, also known as an Orofacial Myofunctional Disorder (OMD), is a common condition characterized by the incorrect placement of the tongue during swallowing or at rest. A healthy mouth relies on proper tongue function, where the entire tongue is suctioned against the roof of the mouth, with the lips sealed and the teeth slightly apart. In tongue thrust, the tongue pushes forward or sideways against or between the teeth. This persistent, misplaced muscular force interferes with the normal development and function of the teeth, jaws, and facial structures.
Understanding the Mechanics of Tongue Thrust
A normal, mature swallow is a precise sequence where the tip of the tongue is placed on the alveolar ridge (the bump behind the upper front teeth) and moves food or liquid backward in a wave-like motion. A tongue thrust is a reverse swallow pattern where the tongue pushes forward between the teeth instead of lifting to the palate. Since a person swallows between 1,200 and 2,000 times every 24 hours, this creates a near-constant force.
During a typical swallow, the tongue can exert approximately four pounds of pressure. When this substantial, repetitive force is consistently directed against the teeth, it acts like a misplaced orthodontic appliance. The continuous pressure from the incorrect resting posture is often more influential on tooth position than the momentary pressure of swallowing. This constant, misdirected pressure gradually pushes the teeth out of alignment, leading to structural changes in the mouth and jaw.
Common Indicators of an Incorrect Swallowing Pattern
The physical consequences of a persistent tongue thrust manifest in several observable signs. One of the most common dental issues is an anterior open bite, where the front upper and lower teeth fail to meet when the back teeth are closed. The constant outward force can also cause the front teeth to protrude, or lead to gaps between the teeth.
Speech impediments are also a frequent indicator, particularly a lisp involving sounds like /s/ and /z/ because the tongue protrudes during articulation. Non-dental signs include chronic mouth breathing, which often leads to dry, chapped lips, and a strained appearance of the chin muscles when swallowing. Individuals may also exhibit messy eating habits or difficulty swallowing pills.
Primary Factors Contributing to Development
The development of a tongue thrust is often linked to the prolonged retention of an infantile swallowing pattern that should naturally mature by age six or seven. Several factors contribute to this condition:
- Persistent, non-nutritive sucking habits, such as prolonged thumb, finger, or pacifier use, prevent the tongue from resting correctly on the palate and encourage a low, forward resting posture.
- Chronic upper respiratory issues, including allergies, enlarged tonsils, or adenoids, cause habitual mouth breathing. When the mouth is open for breathing, the tongue must drop to the floor of the mouth to maintain an open airway.
- Ankyloglossia, or tongue-tie, restricts the tongue’s movement, limiting its ability to reach the palate for a correct rest and swallow.
- Genetic factors, which may include anatomical variations or low muscle tone, can also predispose an individual to developing this muscular imbalance.
Addressing and Correcting the Condition
The primary intervention for correcting a tongue thrust is Orofacial Myofunctional Therapy (OMT). This exercise-based treatment focuses on the neuromuscular re-education of the muscles of the mouth, face, and neck. A myofunctional therapist, often a speech-language pathologist, administers the therapy to retrain the muscles for proper swallowing and tongue rest posture. The therapy teaches a patient how to establish nasal breathing, achieve a lip seal, and position the tongue correctly against the palate at rest and during swallowing.
The active phase of OMT is typically short-term, often lasting around three to six months. Orthodontics, such as braces or specialized appliances, is frequently used in conjunction with OMT to correct the resulting dental misalignment. Addressing the underlying muscle pattern is necessary because a persistent tongue thrust can cause orthodontic relapse, where the teeth shift back to their original misaligned position after braces are removed.