Cephalometric evaluation of soft tissue changes after extraction of upper first premolars in class ΙΙ div 1 patients.

Introduction: Tooth extraction to provide sufficient space, or camouflage of underlying skeletal problems is quite common in orthodontics. The present study evaluated soft tissue changes after upper first premolars extraction in class ΙΙ div 1 patients. Material and Methods: 20 cases (15 females, 5 males), with a mean age of 17.8±2.9 years with class ΙΙ div1 malocclusion and normal vertical height, who needed upper first premolars extraction were selected. Pre- and post-treatment lateral cephalometric radiographs were digitized. Image analysis was conducted by View Box 3.1.1 software. Paired t-test was used for comparison of pre- and post-treatment results. Results: The relationship of upper and lower lip to E-line and B-line had significant reduction. Dental variables of U1-NA(mm), U1-NA(°), overjet and overbite showed statistically significant reduction. Interincisal angle had significant increase. There were no significant difference in lower incisor variables and skeletal variables like SN-GoGn and FMA. Conclusions: Extraction of upper first premolars in patients with class ΙΙ div 1 malocclusion resulted in normal position of lips as presented by Holdaway, Legan and Ricketts which play a role in aesthetic profile. However, the amount of lip retraction was different from patient to patient. Key words:Soft tissue, fixed orthodontic treatment, class ΙΙ div 1, upper first premolar extraction.