Prediction of soft tissue profile changes following orthodontic retraction of incisors in Iranian girls.

AIM: To study the relationship between incisor retraction and soft tissue profile alterations and to identify and quantify the parameters that influence it.

METHODS

Pre- and posttreatment lateral cephalograms of 37 Class I and Class II Division 1 Iranian females in whom at least one maxillary premolar was bilaterally extracted were analyzed and compared.

RESULTS

Significant positive correlations were found between retraction of the maxillary and mandibular incisors and posterior movement of the upper lip (r=0.53, P<.001), the lower lip (r=0.63, P<.001), thickness increase of the upper (r=0.59, P<.001) and lower (r=0.69, P<.001) lip, increase of the soft tissue lower anterior face height (r=0.81, P<.001) and lower soft tissue component (r=0.49, P<.001), and an increase of the nasolabial angle (r=0.43, P<.01). The ratio of maxillary incisor to upper lip retraction was 2:1.

CONCLUSION

In Iranian girls, a strong correlation exists between anterior tooth retraction and the position and configuration of both lips.