Dyskinesia

Dyskinesias (ICD-10-GM G24.4: Idiopathic orofacial dystonia) are muscular dysfunctions in the stomatognathic (mouth and jaw) system. These are not conscious behaviors, but unconscious reflex processes. A distinction is made between primary – causative – and secondary – adaptive dyskinesias. While a primary dysfunction may lead to dentition abnormalities, pre-existing abnormalities of the teeth or jaws may cause a secondary dyskinesia. Classification of dyskinesias

  • Lip pressing, lip sucking and lip biting.
  • Sucking habit – thumb sucking (ICD-10-GM F98.4-: Stereotypic movement disorder).
  • Mentalishabit – hyperactivity (overactivity) of the chin muscle.
  • Mouth breathing (ICD-10-GM R06.5: Mouth breathing).
  • Sigmatism (ICD-10-GM F.80: Circumscribed developmental disorders of speech and language) – incorrect pronunciation of the S sounds, lisp.
  • Visceral swallowing – early childhood swallowing pattern.
  • Tongue depressor

Symptoms – complaints

Lip dyskinesia patients who suck their lips, this pulls the lower lip inward and put the upper incisors on it. In lip pressing, the upper and lower lips are pressed tightly together. This increases or causes a retrusion of the incisors (backward displacement of the incisors). Lip biting is usually clearly visible by the bite marks on the lower lip. Sucking Habit In thumb sucking, the thumb is lodged in the anterior portion of the maxilla and supported on the backs of the upper incisors. Mentalishabit If there is hyperactivity (overactivity) of the musculus mentalis (chin muscle), this causes the lower lip to be pulled up backwards and to rest against the upper incisors from behind. This habit often occurs in combination with lip sucking and also leads to an increase in existing malocclusions of the teeth and jaw. Mouth breathing Patients with habitual mouth breathing exhibit numerous symptoms and complaints. These include an increased risk of tooth decay as well as an increased risk of respiratory infections. The tongue, which should normally rest on the roof of the mouth, sinks downward and the following symptoms occur:

  • Narrow palate
  • Narrow jaw in the upper jaw
  • Pronounced dental crowding
  • Crossbite

In adulthood, patients have a characteristic appearance often referred to as facies adenoidea. The face is long and narrow, lip closure is compulsively difficult and the incisors protrude. Sigmatism There are several forms of sigmatism, the most common being:

  • Sigmatism interdentalis – interdental lisp – English “th” sound.
  • Sigmatism adentalis – pressing the tongue against the backs of the upper incisors – “sh” sound.
  • Sigmatism lateralis – attachment of the tongue to the lateral teeth – Raschel sound.
  • Sigmatism stridens

Common symptom of all forms of sigmatism is the mispronunciation of the S sound. Visceral swallowing In visceral swallowing, the tongue is positioned between the rows of teeth during the act of swallowing. However, its normal position should be in the oral cavity by the age of four at the latest, with the dentition closed. Tongue pressing During tongue pressing, the tongue is pressed firmly against the palate and the rows of teeth and may also become lodged between the rows of teeth.

Pathogenesis (disease development) – Etiology (causes)

Lip dyskinesias They often develop secondarily as a result of malocclusion of the teeth and jaws. Lip sucking is commonly seen in patients who already have mandibular posteriority, often the upper incisors are protruded (displaced forward) while the lower incisors tend to be retruded (displaced backward). Lip pressing is more common in patients with retruded (receding) anterior teeth, whereas lip biting is associated with a protruded (forward displaced) maxillary anterior. Thumb sucking Thumb sucking is considered physiological in infancy. At around three to five years of age, thumb sucking usually stops on its own. However, if it persists beyond the age of six, the cause is thought to be a mental problem in the child. Mentalishabit Mentalishabit is thought to be hereditary, among other causes. A familial accumulation has been observed.Mouth breathing Mouth breathing occurs either in the form of habitual (habituated) dysfunction or there is an organic cause – this is then referred to as constitutional mouth breathing. The cause is usually impaired nasal breathing due to adenoids or hyperplastic (enlarged) palatine tonsils. Visceral swallowing Normally, the infant’s visceral swallowing act (jaw open, tongue between the jaws) is replaced by another, the somatic swallowing act (jaw closed, tongue in the oral cavity) in the course of the eruption of the first dentition (milk teeth). By the age of four, the transition should have occurred. An incorrect swallowing pattern can lead to both tooth and jaw misalignment and speech problems. Tongue clenching Tongue clenching occurs either because of an existing tooth or jaw misalignment, or it is a primary clenching condition that can then cause tooth and jaw misalignment. Macroglossia (enlarged tongue) or hypoglossia (reduced tongue) as well as hyper- or hypotonic (too strong or too weak) tongue muscles can also lead to tongue pressing. Sometimes the tongue settles into the gap after milk tooth loss and maintains this position, even if the permanent teeth have already erupted. The tongue may also exacerbate existing abnormalities in open bite or protrusion of the incisors (advancement of the anterior teeth) of both jaws.

Consequential diseases

Dyskinesias can exacerbate existing dental and jaw abnormalities, making their treatment much more difficult. Lip dyskinesias can result in severely protrusive or retruded anterior teeth. Thumb sucking after the age of six results in pronounced forward growth of the maxilla, the upper incisors protrude and the lower incisors retrude, the bite is open and the growth of the jaws is severely affected. Mouth breathing increases the risk of tooth decay and respiratory infections and can lead to massive tooth and jaw misalignments, such as a severely pronounced narrow jaw, tooth crowding and crossbite. Tongue clenching causes the tongue to become lodged between the teeth, which can lead to an open bite in the anterior or posterior regions or exacerbate existing abnormalities. If a pronounced mentalishabit is present, the growth of the mandible in the saggital (forward) may be inhibited.

Diagnostics

Dyskinesias are diagnosed by the dentist or orthodontist based on symptoms characteristic of them. Often, simple observation of the child by the practitioner or even questioning of the parents is sufficient to detect dyskinesias. Based on the dental and jaw findings, the suspected diagnosis is confirmed as soon as typical findings are present. Subsequently, it must be determined whether primary or secondary dyskinesia is present. If stopping a habit – for example, with the help of an oral vestibular plate – also reduces the dental malocclusion, it can be assumed that a primary disorder was present.

Therapy

To treat dyskinesias appropriately, it must first be determined whether the dyskinesia is primary or secondary. Similarly, in the case of thumb sucking, for example, attention must also be paid to the psychological component of such habits. The following therapeutic areas may be used:

  • Speech therapy – speech therapy
  • Myofunctional therapy – muscle exercises for the mouth and facial area.
  • Orthodontics
  • Psychotherapy for psychological causes

Therapy of primary dyskinesia If there is a primary dyskinesia, it must be treated itself. Not infrequently, it then comes to the improvement of dental malocclusions, for example, to the conclusion of an open bite after weaning off thumb sucking. Dyskinesia is often treated within the framework of logopedic therapy. Treatment usually occurs in childhood and aims to break faulty functional patterns and replace them with correct muscular patterns. The use of an oral vestibular plate can also help to stop habits such as sucking or mouth breathing and thus help to normalize functional patterns. An ear, nose and throat specialist should always be consulted for mouth breathers to rule out obstructed nasal breathing as a cause. Therapy of secondary dyskinesia If, however, the dyskinesia is based on a dental or jaw malposition, orthodontic treatment is required. Depending on the malocclusion, the following removable or fixed appliances can be used, among others.This varies from individual to individual and must be decided after detailed analysis by the orthodontist.