Extraction treatment and soft tissue facial profile

A harmonious soft-tissue facial profile is an important consideration in orthodontic diagnosis and treatment planning. Extraction of premolar teeth sometimes is necessary to achieve the treatment goals. Facial soft tissue profile adaptation to incisors retraction is still controversial. This study was carried out to evaluate the response of soft tissue facial profile to maxillary and mandibular incisors retraction. Pre and post treatment lateral cephalograms of 30 patients, having bimaxillary dental protrusion, who required extraction of four first premolars, were traced, superimposed, and evaluated. All patients were treated with preadjusted straight wire appliances. All the subjects were females with a mean age of 16 years, 5 months to reduce variables caused by growth and sex differences. The Facial soft tissue profile was evaluated using a series of eight linear and angular measurements, and the effect of orthodontic correction was determined using paired t-tests, then Pearson r correlation analysis was done to calculate the correlation coefficient. The results demonstrated that the extraction of four premolars greatly reduces soft tissue procumbency seen in patients with bimaxillary protrusion that were indicated by the significant post treatment changes for all of the soft tissue profile variables studied. Pearson r correlation analysis indicated that: - The Nasolabial angle, Lower lip retraction and Upper lip retraction correlates well with upper incisors retraction. - Lower lip retraction correlates well with lower incisors retraction. - Upper lip retraction correlates well with the lower lip retraction. - Labiomental angle does not show good correlation with upper incisors retraction. - Lower lip thickness does not correlate with upper incisors retraction. - Upper lip thickness showed poor correlation with Upper incisors retraction.