Fig. 1

Schematic diagram of different protrusive facial deformities. a Normal maxilla and mandible with upper and lower incisors proclination, small nasolabial angle, and prominent lips. b–d Retruded mandibular and normal maxilla relative to the cranial base, which is the main type of facial protrusive deformities in Chinese population. This type can be divided into horizontal growth pattern (b), average growth pattern (c), and vertical growth pattern (d). e Bimaxillary protrusive deformities with mentalis strain on lip closure. f Maxillary protrusion and mandibular retrusion, accompanied by compensatory lingual inclination of upper incisors and proclination of lower incisors. g Insufficient maxilla with severe mandibular retrusion and proclined upper and lower incisors. h Protruded maxilla and normal mandible, accompanied by lingually inclined upper incisors and proclination of lower incisors