Prognathie

Prognathism is the forward projection of one or more jaw bones relative to the skull base. In medical and dental contexts it most often refers to mandibular prognathism (the lower jaw protrudes) or maxillary prognathism (the upper jaw protrudes). The term comes from Greek pro- “forward” and gnathos “jaw.”

Mandibular prognathism causes the mandible to extend in front of the maxilla, while maxillary prognathism involves forward growth of the maxilla. Each form can alter facial profile and occlusion and may occur alone or as part of a syndrome or developmental condition.

Causes include genetics and developmental factors; endocrine disorders such as acromegaly can enlarge jaw bones; trauma or disease affecting growth can also contribute.

Diagnosis relies on clinical examination and imaging. Lateral cephalometric radiographs or 3D imaging assess the relationship of the jaws to the cranial base, with measurements such as SNA and SNB used to quantify prognathism.

Treatment depends on severity and symptoms. Mild cases may be managed with orthodontic supervision; more pronounced prognathism often requires orthognathic surgery to reposition the jaws, typically in combination with orthodontics to restore function and aesthetics and, when relevant, address airway issues.

In anthropology, prognathism also describes the forward projection of the jaws in humans and other primates, a feature used in the study of craniofacial evolution.