Mandibular retrognathia is a backward displacement of the mandible in relation to the base of the skull. The term mandibular retrognathia refers only to the description of the position of the mandible, but not its size. Also, mandibular retrognathia does not characterize the position of the maxilla and mandible in relation to each other.
What is mandibular retrognathia?
Mandibular retrognathia represents a genetically caused dysgnathia. This refers to maldevelopments of the jaw or teeth. In mandibular retrognathia, there is a shortened lower jaw that is overtopped by the upper jaw. The condition is manifested by a receding chin and a protruding upper lip, resulting in a negative lip step. In mandibular retrognathia, a so-called bird face appears in profile view. This is a consequence of the relative recession of the too small lower jaw. When the mouth is closed, the front teeth of the upper jaw protrude clearly in front of those of the lower jaw, which often bites into the palate.
Causes
The development of mandibular retrognathia can be due to diverse causes. In a majority of cases, the condition is hereditary. In this case, the disease exists from birth and becomes more pronounced in the course of childhood and pubertal growth phases. In addition, there are other causes that can be responsible for the formation of mandibular retrognathia that are not hereditary. For example, disorders related to the growth of the jaw, caused for example by an inflammation of the bone marrow (medical term osteomyelitis) can promote mandibular retrognathia. Fractures of the articular processes and ankyloses can also promote the development of the disease. In addition, inflammation in the growth plates of the jaw are possible causes of mandibular retrognathia.
Symptoms, complaints, and signs
Symptoms of mandibular retrognathia are usually prominent and characterize the appearance of affected individuals. Patients have a receding chin as well as a protruding upper lip. Usually, mandibular retrognathia occurs on both sides. In non-hereditary cases, it can also occur unilaterally. Mandibular retrognathia is characterized by a significant underdevelopment (medical term hypoplasia) of the mandible, which results in a receding chin. This results in a so-called distal bite or overbite. In individual cases, mandibular retrognathia can occur in combination with maxillary prognathism. This is a malocclusion of the teeth of the upper jaw. If mandibular retrognathia occurs in the presence of joint fractures and ankyloses, the affected individuals sometimes experience restrictions when opening their mouths. Often the incisors are elongated because they lacked natural resistance during the growth phase, for example in the form of the upper anterior teeth. In the final bite, the lower incisors touch the palatal mucosa. In the context of mandibular retrognathia, other syndromes occur in many cases, such as sleep apnea syndrome.
Diagnosis and course of the disease
For the diagnosis of mandibular retrognathia, various methods of examination are considered, which are applied depending on the manifestation of the disease in the individual case. In principle, the clinical symptoms in the form of receding chin and overbite are so characteristic that the suspicion of the presence of mandibular retrognathia arises very quickly. These suspicions must be verified by adequate specialist examinations in order to be able to make a reliable diagnosis and order appropriate therapeutic measures. In many cases, X-ray examinations are the method of choice for diagnosing mandibular retrognathia. These can be performed by an orthodontist, for example. The malposition of the upper and lower jaw can be clearly seen in the X-ray image. The individual degree of mandibular retrognathia can also be determined here. A specialist diagnosis is required in any case in order to be able to differentiate mandibular retrognathia from possible other diseases of the jaw.
Complications
As a rule, this disease results in a significantly altered appearance of the patient.For this reason, lowered self-esteem or even inferiority complexes can occur. Children can also suffer from bullying or teasing at a young age, leading to depression or other psychological upsets. Most sufferers also continue to suffer from overbite. It is not uncommon for the disease to cause discomfort when opening and closing the mouth, so that there are also restrictions on the intake of food and fluids. This can eventually lead to malnutrition or dehydration. Due to the reduced aesthetics, those affected also suffer from social difficulties and possibly exclusion. In most cases, the symptoms of this disease can be treated by surgical intervention. Complications do not occur. In some cases, however, several operations are necessary. Also, the life expectancy of the patient is not reduced or limited by this syndrome. Furthermore, the transplantation of bone may be necessary for the operation. However, no particular complications or discomfort occur.
When should you see a doctor?
Maldevelopments of the human jaw should always be assessed and examined by a doctor. If the upper and lower jaws are not directly over each other, there is an impairment that must be clarified by a doctor. If there is discomfort when chewing or pain, a doctor is needed. If ingested food cannot be sufficiently ground by the possible chewing process, there is cause for concern. If body weight is low or weight loss occurs, a doctor’s visit is advised. If the affected person ingests only liquid or mostly mushy food due to the impairments, consultation with a doctor is recommended. Correction of the jaws is necessary, which is performed dentally. If an optical change of the facial appearance is recognizable due to the jaw positions, a visit to the doctor should be made. If the irregularities of the jaw positions increase within the growth process, a doctor should be consulted as soon as possible. In case of headaches or an impairment of the muscles in the neck as well as the neck, the affected person needs medical help and support. Sleep, concentration or attention disorders are further indications that should be investigated. If the mouth cannot be opened sufficiently, if there is reduced phonation or if comprehensive tooth cleaning is not possible, action is required. A visit to the doctor is necessary, because without treatment, serious complications may arise in the further course.
Treatment and therapy
Various methods are available for the treatment of mandibular retrognathia, which are adapted to the individual case. During the growth phase, the affected patient should undergo orthodontic treatment. If this therapy is successfully completed, in most cases a reconstruction of the chin or mandible is necessary. The therapeutic measures here are similar to those for maxillary retrognathia. Various other operations can be considered for the treatment of mandibular retrognathia in adults. Operations in the so-called ascending branches are possible. Here, the jaw is split and the lower jaw is moved forward, using a bite wrench as an aid. The individual fragments are stably fixed by means of lag screw osteosynthesis. If the malocclusion is not treated in time, damage to teeth and periodontium may result. This can result in the premature loss of teeth. Advancement of the mandible can only be achieved by lengthening the ascending branches on the mandibular bone. For this purpose, oral surgery requires either bone grafting or split bone fragments are gradually pulled apart (medical term callus distraction).
Outlook and prognosis
Mandibular retrognathia has a favorable prognosis if the affected person seeks medical care early. Otherwise, there is a risk of irreversible damage and sequelae during life. There may be a steady increase in health irregularities. In addition, the affected person must otherwise accept premature loss of teeth and damage to the jaw bones. In addition to pain, there are impairments of the ability to speak as well as eating disorders.There is a risk of deficiency symptoms and thus life-threatening developments may appear. In case of early cooperation with a doctor, maxillofacial surgical measures are initiated. In addition to the temporary wearing of braces, surgical interventions can be performed. Depending on the extent of the existing malocclusions, several operations are necessary in the course of life. Within the process of human growth, physical changes occur. This process can lead to the fact that further interventions are inevitable. Each operation is associated with risks. In a particularly severe case, blood poisoning can lead to a condition that is also life-threatening. Nevertheless, for some people, this medical care is the only way to achieve long-term relief from their symptoms. Moreover, these are routine procedures that in most cases proceed without incident. In rare cases, bone grafting must be performed as a last resort for improvement.
Prevention
Since mandibular retrognathia is mostly a hereditary disease of the jaw, there are no effective methods to prevent the disease. Affected patients can only counteract the malocclusion of the mandible by timely orthodontic therapy, and at the same time also prevent possible secondary damage of mandibular retrognathia.
Aftercare
The appearance of affected individuals usually changes as a result of the disease. There may be low self-esteem and inferiority complexes in affected individuals for this reason. Children often suffer bullying and teasing as a result. This can lead to severe depression and other mental illnesses. Advocating help from relatives is therefore indispensable to stabilize the recovery process permanently. It is important to involve the social environment in the process to avert tensions or misunderstandings. In many cases, however, repeated surgical interventions are necessary. The life expectancy of those affected is not affected by the disease. It happens that for the operations a transplantation of bones is necessary in affected persons. Permanent medical follow-up is therefore urgently needed to avoid further complications.
This is what you can do yourself
Patients with mandibular retrognathia often suffer from inferiority complexes as children due to their abnormal appearance. The condition usually represents a tremendous aesthetic stigma for those affected, affecting social relationships and influencing daily life in childcare settings and school. Therefore, psychotherapeutic treatment is often indicated to strengthen the child patients’ self-esteem and to support their psychological coping with the disease. Regarding the displaced or reduced lower jaw, orthodontic treatment is necessary for children. In this case, the parents take the responsibility for regular attendance of necessary medical appointments as well as daily wearing of braces. Such therapy improves the condition, but usually does not completely eliminate the external defect. To this end, further corrective measures are required in the course of surgery, usually involving several surgical procedures over a longer period of time. Particularly in the postoperative phase, patients strictly adhere to the instructions of the responsible physician as well as the clinic staff in order to avoid side effects and complications. Speech therapy supports the patients’ ability to speak and at the same time strengthens their self-confidence. For targeted strengthening of the jaw muscles, the affected person visits a physiotherapist, with whom he or she rehearses suitable exercises.
