ABSTRACT
To investigate the profile soft tissue changes, and associated dental and skeletal effects, in upper and lower incisors following 1[st] premolar extraction and incisor retraction in bimaxillary proclination orthodontic cases. Thirty-five patients [M:F ratio 18:17] with bimaxillary protrusion with age ranging from 14-17 years [mean calculated age 15.6 years] were treated with 1[st] premolar extractions followed by retraction of the upper and lower labial segments with fixed orthodontic appliances. Pre and post cephalometric values were recorded for each patient. The angular and linear soft tissue parameters measured were the naso-labial angle, labio-mental angle and the upper and lower lips distance to Ricketts esthetic plane to investigate the soft tissue changes compared with incisor retraction following treatment. The skeletal parameters measured were SNA, SNB, ANB, MMA, SN-MP and the facial height ratio, while the dental parameters measured were upper incisors to maxillary and SN plane, lower incisors to mandibular plane and the inter-incisal angle. Pre and post cephalometric values were calculated separately for each patient and the mean value was calculated. The upper lip prominence decreased by 3mm while the lower lip retracted by 5 mm following 1[st] premolar extraction space closure and retraction of the upper and lower labial segments. The naso-labial angle showed 4 degrees mean value change following upper incisor retraction, while the labio-mental angle demonstrated a mean value change of 2 degrees post-treatment. The facial soft tissue profile demonstrated both angular and linear changes post-treatment following 1st premolar extractions and incisor retraction in bi-maxillary proclination patients, followed by dental changes while skeletally the lower facial height dimension reduced post-treatment