Changes in facial form relative to progressive atrophy of the edentulous jaws.

The surgical and prosthodontic rehabilitation of the edentulous patient aims to restore oral function and facial form. Planning treatment requires an understanding of the effect of progressive jaw atrophy, and the concomitant effect on the soft tissues of the face. This study examined 179 Caucasians at different stages of jaw atrophy according to the Cawood and Howell classification; various standard anthropological measurements of the face, according to Farkas, were also taken. We have demonstrated that changes in the soft tissues are related to the degree of underlying jaw atrophy. This has important implications when planning surgical and prosthodontic rehabilitation of the edentulous patient. Early stages of jaw atrophy (Class II, III & IV) result in the collapse of the circumoral musculature causing a narrowing of the mouth, loss of lip support, inversion of the lips and contraction of the cheeks. Late changes of jaw atrophy (Class V & VI) result in changes in vertical facial proportion causing a decrease in lower facial height and an increase in chin prominence. These late skeletal changes accentuate the earlier soft tissue facial effects.