The post-operative facial profile is critical for patients who undergo orthognathic surgery. The present study investigated the improvement in lip appearance (lateral and frontal aspects) following mandibular setback surgery.

Thirty-one patients with mandibular prognathism underwent mandibular setback surgery. Lateral and posteroanterior cephalograms were obtained before surgery (T0) and more than 1 year after surgery (T1). The landmarks (soft and hard tissues) and linear distances were compared by statistical analysis.

The lateral cheilion (Ch), point B (B), and pogonion (Pog) were significantly setbackin the horizontal plane: 5.59, 11.49, and 12.35 mm, respectively. In the vertical plane, B and Pog did not move significantly. The Ch moved significantly downward by 3.23 mm on average. The setback ratios of soft tissue/hard tissue, soft tissue of B/B, and soft tissue of Pog/Pog were 0.96. The Ch/Pog ratio was 0.45. The width of the frontal Ch was significantly reduced by 3.17 mm.

The relationship between the corresponding soft and hard tissues of the chin was approximately 1. The relationship between the lip corner and chin bone was nearly 50%. The width of the lip corner was also significantly reduced.