Abstract: Objective　 To explore the characteristics of soft tissue changes in different facial areas after maxillofacial surgery in patients with skeletal Class III malocclusion. Methods　 Eighteen cases of skeletal Class III malocclusion in our hospital from 2017 to 2019,9 cases of male and female. Using 3dMD photogrammetry system, the facial images of the patients were taken on any day of the week before and 6 months after the surgery. The facial images before and after the operation were reconstructed and matched by Geomagic Qualify. Then the changes of soft tissue in each area of the face were obtained. Results　 The changes of soft tissue after operation were -0.17 mm in temporal region (R1), -0.42 mm in zygomatic arch area (R4), -0.81 mm in under the mouth next district (R11)and -3.08 mm in lower lip and chin area (M3). Negative changes happened in the above regions (P<0.05); The soft tissue changes were 0.29 mm in infraorbital region (R2), 1.58 mm in paranasal area, 1.08 mm in on the mouth next district (R8), 0.59 mm in nasal region (M1),and 2.05 mm in superior labial region (M2) . Positive changes happened in the above regions (P<0.05). Soft tissue changes in both sides of the same facial area were not significantly different (P>0.05); and the differences between men and women in soft tissue changes of the same region had no statistical significance (P>0.05). Conclusions　 The soft tissue of patients with skeletal Class III malocclusion in temporal region, zygomatic arch area, under the mouth next district, lower lip and chin area became depressed after bimaxillary surgery, while the soft tissue in infraorbital region, paranasal area, on the mouth next district, nasal area and superior labial region became protruding. There was no difference in soft tissue changes in the same facial area on the left and right sides, and gender had no effect on the changes of soft tissue in each area of the face after surgery.

Key words: skeletal Class III malocclusion, bimaxillary surgery, 3dMD, facial soft tissue