Prognathism

Prognathism is a skeletal condition in which the jaw or jaws project forward beyond the normal craniofacial relationship. It can involve the maxilla (upper jaw), the mandible (lower jaw), or both. When the upper jaw protrudes, it is called maxillary prognathism; when the lower jaw protrudes, it is mandibular prognathism. A relative form can occur when one jaw is forward in relation to the other or to the cranial base, giving the impression of prognathism without a consistent forward displacement of all structures.

Causes and contributing factors include genetic predisposition and variation in normal facial development. Prognathism can be associated with certain craniofacial syndromes or developmental disorders, and in some cases with hormonal conditions such as acromegaly, which can stimulate jaw growth. Environmental and functional factors, such as bite patterns and early wear, may influence the expression of prognathic features, but the underlying skeletal direction is structural.

Diagnosis is based on clinical examination and radiographic assessment. A profile analysis may reveal forward-positioned jaws, and cephalometric radiographs are used to measure relationships among the maxilla, mandible, and cranial base (for example, through standard angular and linear measurements). Differentiation from retrognathism, where one or more jaws are positioned backward, is important for planning treatment.

Treatment depends on severity, age, and functional impact. Growing patients may benefit from orthodontic approaches that influence tooth movement and jaw development. In non-growing individuals or in more severe cases, orthognathic surgery is common, often combined with orthodontics. Procedures may include maxillary advancement or impaction (Le Fort I) and mandibular advancement (bilateral sagittal split osteotomy), with the goal of improving occlusion, facial aesthetics, and airway function. A multidisciplinary team typically manages these cases.