Prognathism is characterized by an extension of the part of the mandible (lower part of the jaw). This formation anomaly appears when the teeth are not aligned correctly as a result of a specific shape of the bones of the face.

This disease can be defined by a malocclusion (misalignment of the occlusal surface of the upper and lower teeth). This can make the subject appear angry and mean. This characteristic can also be part of symptoms in other syndromes. (1)

During the normal aging process of an individual, the mandible loses its vertical height and anterior projection. This causes an alteration in the normal balance of the face. In this sense, a bone atrophy (decrease in tissue) of the lateral part of the mandible is observable. Located between the chin and the jowls, this situation causes the formation of caesura in the cheeks and an irregular delineation of the mandible. These atypical features are accentuated as the subject ages and gives him the appearance of a puppet face.

The clinical manifestations associated with the disease are directly related to the deformation of the mandible. Or, abnormalities affecting the patient’s face from the cheek to the chin.

Symptoms are therefore linked to prognathism, such as: (4)

– difficulties in chewing;

– swallowing difficulties;

– pain in the cheek or jaw joints;

– headaches;

– excessive wear of the dentition;

– the presence of a space between the teeth of the upper part of the jaw and those of the lower part of the jaw when the mouth is closed;

– an asymmetry of the face from the front and from the side;

– abnormalities in the face;

– a bald chin and jaw;

– the presence of a protruding jaw;

– an inability to connect the lips without forcing;

– breathing preferentially through the mouth;

– sleep apnea (breathing abnormalities during sleep).

Prognathism is a pathology that develops when an individual is born. This disease results from abnormalities during the embryonic and / or fetal development of the child.

Prognathism can also result from genetic abnormalities passed on to offspring.

In addition, there are some underlying illnesses that can be the root cause of the disease to develop. This is particularly the case: (4)

– acromegaly, a disease which is the consequence of an excess of growth hormone causing abnormal enlargement of the tissues. The jaw thus ends up protruding by force of widening it;

– basal cell nevomatosis, a rare hereditary pathology leading to abnormalities in facial features: wide nose, wide eyes, prominent forehead, etc. ;

– acrodysostosis: rare disease which generally develops at birth. This can cause shortening of the arms and legs, cause hearing loss, shortening of the nose, and even mental retardation.

The disease can develop during childhood or even in adulthood in the context of gigantism oracromgaly. (1)

The risk factors for developing the disease are related to underlying diseases, such as: acromegaly, basal cell nevomatosis or acrodysostosis.

Genetic factors may also pose an additional risk to those affected.

The diagnosis of the disease is usually differential, given the characteristic facial deformities.

Associated treatments include:

– dental care: thanks to orthodontic procedures, the doctor can correct the jaw by orthognathic surgery. These treatments also make it possible to correct misaligned dentition, generally for aesthetic reasons;

– medical care: through the treatment of potential underlying pathologies responsible for deformities of the jaw. In this sense, acromegaly is treated by surgery when removing the tumor responsible for the abnormally high production of growth hormones. The use of radiotherapy and / or chemotherapy may be useful without the treatment of this pathology. In the case of basal cell nevomatosis, treatment depends on the location affected. Finally, the treatment of acrodysostosis relates to specialized education in the context of mental retardation and orthopedic care in the treatment of bone abnormalities.

Diet often follows surgery. Complete recovery is often estimated between 9 and 12 months.