Tongue Thrust and Tongue Rest Posture
Tongue Thrust or Tongue Thrust Swallow refers to the improper function of the tongue thrusting against or between the teeth during the act of swallowing. While a tongue thrust swallow can cause a misalignment or malocclusion of the teeth, it is the position of the tongue at rest that is of utmost importance. When the tongue does not rest up in the palate, it generally lies against or between the front teeth or it may lie covering the lower back and lower front teeth. These positions, referred to as Low or Forward Tongue Rest Postures, exert a light continuous pressure on the teeth causing a delay on the eruption pattern of the teeth, or it can move the teeth forward and/or apart. It only takes 15 gr/cm2 of continuous pressure from the tongue resting between the front teeth for hours per day, to inhibit the eruption of anterior teeth (Profitt, 1986). Anterior or Bilateral Open-bites are the most common indications of these disorders. There are many types of tongue thrust swallows and various degrees of severity. The tongue, which seems to have a mind of its own adapts or adjusts to the misaligned dentition during rest and function. An incorrect swallow or abnormal rest posture sometimes are not exhibited until after the teeth are more favorably aligned. Correcting or improving a tongue thrust swallow and proper tongue posture can be instrumental in restoring and facilitating the normal eruption patterns and alignment of orofacial growth and development.
Tongue Thrust and Speech
Research has revealed a high incidence of speech problems in those individuals who exhibit OMDs. Speech patterns may become distorted and speech sounds misarticulated due to improper tongue posture placement and toneness. The /s/ sound, more commonly known as a lisp or lazy tongue, is often associated with a forward tongue rest posture, tongue thrust swallow or a combination of OMDs. It is often difficult to correct the speech problem through traditional speech therapy alone (IAOM) when they are accompanied with other myofunctional disorders. Learning and habituating proper tongue placement along with exercises of the mouth, lips, and facial muscles can often assist in speech clarity. Other sounds that can benefit from these exercises are /t/, /d/, /n/, /l/, /z/, /sh/, /ch/, /j/, and /r/.