RESUMO
The purpose of this investigation was to determine changes in soft tissue profile of African-Americans following orthodontic treatment involving extraction of four premolars. The sample consisted of pretreatment and postreatment lateral cephalometric radiographs of 30 males and 30 females of African-American descent exhibiting bimaxillary protrusion. The age of the patients ranged between 10 years 4 months and 17 years 6 months at the start of treatment. Average time between pretreatment and postreatment radiographs was 2 years 11 months in the male group and 3 years 3 months in the female group. Changes in the dentofacial complex and facial soft tissue as a result of treatment and growth were evaluated with cephalometric analysis. Student's t-tests were performed to compare differences. Nasolabial angle increased 9.1 degrees in males and 7.1 degrees in females. Upper lip procumbency relative to SnPg' decreased 1.5 mm in males and 1.7 mm in females. Lower lip retraction relative to SnPg' was 2.7 mm in males and 2.5 mm in females.