Introduction: Preoperative diagnosis and surgical planning are critical factors in determining the treatment outcome of orthognathic surgery. Especially in facial asymmetry, the pattern of asymmetry is so diverse that, diagnosis, surgical planning may sometimes be difficult and unexpected results sometimes occur. Accordingly, in our department we have designed TML-classification that may be useful in the diagnosis and prognosis prediction of facial asymmetry.

Objectives: The purpose of this study was to evaluate and report the surgical prognosis based on the TML-classification of facial asymmetry accompanying with mandibular prognathism.

Materials and methods: The sample consisted of 58 Korean patients with facial asymmetry and mandibular prognathism who were treated by Lefort l osteotomy and bilateral transoral vertical ramus osteotomy. PA cephalograms and facial photographs were taken within 2 months before surgery and at least 6 months after surgery. Soft and hard tissue asymmetry (chin, angle, maxillary cant, lip cant) were recorded and classified into TML-type, where ‘T’ is soft tissue transverse asymmetry, ‘M’ is maxillary cant and ‘L’ is lip cant. Postoperative result was analyzed according to preoperative TML-type.

Results:

• 1.

  There was significant correlation between soft tissue and hard tissue changes in chin deviation, maxillary cant, and lip cant.

• 2.

  There was no significant correlation between soft tissue and hard tissue changes in mandibular angle width.

• 3.

  Group T2 and T4 showed aggravation of transverse facial asymmetry postoperatively.

Conclusions: It would be necessary to differentiate the treatment planning according to the TML-type and consider additional surgical strategy in specific cases.

Conflict of interest: None declared.