[The anthropomorphic proportions of the face: an evaluation of the response to orthodontic surgical treatment of Angle class III].

The purpose of this investigation was: to examine the anthropometric facial presurgical and postsurgical indices of patients having a dento-skeletal class III malocclusion and who were treated with the orthodontic-surgical procedure. To evaluate the postsurgical response of the soft tissues, according to the type of approach: mandibular surgery or maxillo-mandibular surgery. To recognize, if it is possible, what indices are to be considered more involved in the esthetic change. Ninety pre and postoperative frontal photographs of 45 subjects were studied. The subjects were 32 females and 15 males who had a dento-skeletal class III malocclusion and who had undergone the orthodontic-surgical treatment (21 had sagittal bilateral mandibular osteotomy, 24 had sagittal bilateral mandibular osteotomy + Le Fort I). The photographs were taken with lips in repose, relaxed soft tissue and centric occlusion. The mean age of the patients was 23 years (ranging 16-35). The post-treatment follow-up went from 1 to 3 years. 11 frontal landmarks: n = nasion, sn = subnasale, sto = stomion, sl = sublabiale, gn = gnathion, go = gonion (bilateral), zy = zygoma (bilateral), ch = cheilion (bilateral) were recognized and 3 horizontal and 5 vertical measurements were taken: zygomatic width (zy-zy), mouth width (ch-ch), gonial width (go-go); face height (n-gn), lower face height (sn-gn), upper face height (n-sto), height of lower third of the face (sto-gn), medial vertical chin height (sl-gn). 11 pre and post-treatment facial indices were obtained from the ratio per cent of the measurements previously mentioned using the method of Farkas: Facial (n-gn-zy-zy), Mandible-face width (go-go/zy-zy), Upper face (n-sto/zy-zy), Mandible width-face height (go-go/n-gn), Mandibular (sto-gn/go-go), Mouth face width (ch-ch/zy-zy), Lower face-face height (sn-gn/n-gn), Mandible face height (sto-gn/n-gn), Mandible-upper face height (sto-gn/n-sto), Mandible-lower face height (sto-gn/sn-gn), Chin-face height (sl-gn/sn-gn). In each patient the mean values, with their standard deviations, were calculated according to the sex for each index. A different group of average values was calculated according to the sex and to the type of surgical approach; 17 females and 4 males underwent a mandibular setback osteotomy and 15 females and 9 males underwent a sagittal bilateral mandibular osteotomy + Le Fort I osteotomy.(ABSTRACT TRUNCATED AT 400 WORDS)