Dental Problems

Tongue Thrusting -Etiology and Diagnosis

TongueTongue thrusting is defined variously by different scientist. In this article, there is a brief discussion on the tongue thrusting -etiology and diagnosis. Read on to know more.

Tongue Thrusting – Etiology:

The cause of tongue thrust remains controversial. Several theories have been proposed based on clinical observation and existing research result.

  • Retained infantile swallow:

    There is a considerable amount of evidence which suggests that tongue thrust is merely a retention of the infantile suckling mechanism. With the eruption of the incisors at six months of age, the tongue does not drop back as it should and continues to thrust forward. Tongue posture during rest is also forward.

  • Upper respiratory tract infections:

    Upper respiratory tract infections such as mouth breathing, chronic tonsillitis, allergies, etc. promote a more forward tongue posture due to pain and decrease in the amount of space which brings about a tongue thrust swallow. It may also be present due to the physiological need to maintain an adequate airway.

  • Neurological disturbances:

    Hyposensitive palate, moderate motor disability, disruption of sensory control and coordination of swallowing can lead to tongue thrust.

  • Functional adaptability to transient change in anatomy:

    The tongue can protrude when the incisors are missing. Following the loss of deciduous teeth and prior to full eruption of the permanent incisors, there exists a natural opening for the tongue. The tip if the tongue may protrude into open area during swallowing. It has been observed that this protrusive activity will change with the full eruption of the permanent incisors.

  • Feeding practices and tongue thrusting:

    The development of improper swallowing habits has been attributed to bottle-feeding. However, there is a controversy as to whether bottle feeding is more contributory than breast-feeding to tongue thrust development. The consistency of the infant’s diet may also be a factor in the development of an adult swallow pattern.

  • Induced due to other oral habits:

    During these stages of development, thumb and finger sucking habits may still be prevalent in many children. When this habit has created a malocclusion such as an anterior open bite, the teeth is seen to protrude between the anterior during swallowing. With correction of the habit and with normalization in occlusion, a change in the protrusive tongue activity can take place.

  • Heredity:

    The type of maxillary structure that favors the development of tongue thrust may be hereditary. For example, inherited hyperactivity of orbicularis oris with specific anatomic configuration and neuromuscular activity.

  • Tongue size:

    Tongue size as well as tongue function is an important consideration. Conditions such as congenital aglossia and macroglossia can have an effect on the dentition.

  • Clinical manifestations:

    Clinical manifestations noted in patients with tongue thrust swallow will depend on variables such as the intensity, duration, frequency and the type of tongue thrust.

Extra oral findings:

  • Lip posture:

    Lip separation was greater in the tongue thrust group and this was a consistent finding both at rest and in function. This observation may suggest some lack of compensatory lip activity during swallowing in these subjects.

  • Mandibular movements:

    The mandibular movements during swallowing in the tongue thrust group were more erratic, and no correlations could be found between the movements of the tongue tip and of the mandible itself. In the tongue thrust group, the average path of mandible movement was upward and backward with the tongue moving forward.

  • Speech:

    Tongue thrust children are more likely to have various speech disorders such as sibilant distortions, lisping, problems in articulation of /s/, /n/, /t/, /d/, /I/ /th/, /z/, /v/ sounds.

  • Facial form:

    Increase in anterior face height.

Intraoral findings:

  • Tongue movements:

    The swallowing sequences are seen to be jerky and inconsistent in the tongue thrust group. The movements are also irregular from one swallow to another within the individuals. The chin point was found to be posterior in the tongue thrust group as compared to the normal position.

  • Tongue posture:

    The tongue tip at rest was lower in the tongue thrust group. This could be because of the anterior open bite present and also because of the longer period of time required for the tongue tip to move from rest to second stage of swallowing in the tongue group.

  • Malocclusion:

    Various malocclusions have been reported to be caused due to tongue thrust. These can further be subdivided as:

    a. Features pertaining to the maxilla:

    • Proclination of maxillary anterior resulting in an increase in over-jet.
    • Generalized spacing between the teeth.
    • Maxillary constriction.

    b. Features pertaining to the mandible:

    • Retroclination or proclination of mandibular teeth depending on the type of tongue thrust present.

    c. Intermaxillary relationships:

    • Anterior or posterior open bite based on the posture of the tongue.
    • Posterior teeth cross bite.

Tongue Thrusting – Diagnosis:

History:

History should include questions pertaining to the relevant details.

  • Determine the swallow pattern of siblings and parents to check for hereditary etiologic factor.
  • Determine whether or not remedial speech was ever provided.
  • Information regarding upper respiratory infections, sucking habits and neuromuscular problems.
  • Finally past and present information regarding the overall abilities, interests and motivation of the patient should be noted.

Examination:

The perverted swallowing habit should be detected and corrected early to facilitate normal development of the palate and dentitions.

  • Study the posture of the tongue while the mandible is on postural position. This cane be done if the lips rest apart. Tongue posture can also be noted in the lateral cephalogram of the mandibular posture.

Observe the tongue during various swallowing procedures, the unconscious swallow, the command swallow of saliva, and the command swallow of water, unconscious swallow during chewing. The complexity of the tongue thrust has to be observed carefully whether it is a simple tongue thrust, lateral tongue thrust or a complex tongue thrust. The following clinical features should be checked during swallowing.

Simple tongue thrust:

  • Normal tooth contact in posterior region
  • Anterior open bite
  • Contraction of the lips, mentalis muscle and mandibular elevators

Complex tongue thrust:

Generalized open bite with the absence of contraction of lip and muscle and teeth contact in occlusion.

Lateral tongue thrust:

Posterior open bite with tongue thrusting laterally

  • Observe the role of the tongue during mastication and speech.
  • Intrinsic and extrinsic muscle action of the tongue is to be checked.
  • Presence of grimace during swallowing is ascertained.
  • Function of the posterior pharyngeal wall, soft palate is noted.

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