Now let us see what you mean by the term prognathism & something more about that. The word prognathism is derived from the Greek word pro, which means forward, & another word gnathos, which means jaw. This is a term which used to describe the positions of the mandible & maxilla & their relations to the skeletal base where either of the jaws is protruding out. In dentistry, this is assessed either clinically or radio-graphically in oral & maxillofacial surgery, & orthodontics.
Cephalometric analysis is the most accurate way of determining all the various types of prognathism as it includes the assessments of the skeletal base, the facial height, assessment of the soft tissue & the anterior dental angulations. In Maxillary prognathism it is the maxilla that protrudes, affecting the middle part of the face & is also a common feature seen in many people world over. Whereas in Mandibular prognathism, it is the mandible that protrudes which this affects the lower part of the face.
In Alveolar prognathism, the portion of the maxilla where the teeth are located is the part which protrudes, in the dental lining of the upper jaw. Prognathism can also be used to describe ways that the maxillary and mandibular dental arches can relate to one another. When there is either maxillary or alveolar prognathism or both, which causes an alignment of the maxillary incisors considerably front of the lower teeth, the condition is called an overbite, & when the reverse is the case, the condition is referred to as an under-bite.