Craniofacial structure and soft tissue profile in patients with severe hypodontia.

This study compares craniofacial structure and soft tissue profile in persons with mild hypodontia (group I: 2 to 5 congenitally missing teeth, n = 43), moderate hypodontia (group II: 6 to 9 congenitally missing teeth, n = 15) and severe hypodontia (group III: 10 or more congenitally missing teeth, n = 29) with the structure of persons without hypodontia and with normal occlusion (n = 50). The mean age was about 12 years. In group I, the lower second premolars were the most frequently missing teeth, followed by the upper second premolars and the upper lateral incisors. The relative prevalence of missing second premolars decreased with increasing severity of hypodontia. No consistent pattern could be observed when more than five teeth were missing, indicating a different genetic mechanism than for mild hypodontia. A significant retroclination of the incisors and an increased interincisal angle were observed with increasing severity of hypodontia. This was accompanied by a reduction of lip protrusion, being most evident for the upper lip. Increasing numbers of missing teeth resulted also in a decrease in the mandibular plane angle and a reduction in the anterior lower facial height. Few differences in the skeletal parameters were observed. It was concluded that the typical dentofacial structure in persons with advanced hypodontia may be due to dental and functional compensation rather than to a different growth pattern.