Surgical-orthodontic treatment of a severe skeletal class III malocclussion**

Resumen

25-year-old female patient attended the Orthodontics clinic of the Division of Post-Graduate Studies and Research of the Faculty of Dentistry, UNAM. The chief complaint was that she wanted to change her facial appearance. The facial clinical examination showed an increased lower third; a long oval-shaped face, a dolichofacial biotype, asymmetrical facial planes and disproportionate fi fths. The smile arch was non-consonant; the smile was positive with a tooth exposure of 100% of the clinical crowns; the facial midline did not match the dental. The lateral and oblique view showed a concave profi le, hypoplasia of the facial middle third, good anteroposterior chin projection, open nasolabial angle and a negative lip step. Intraorally, the frontal photograph revealed a slight deviation of the dental midlines, lingual position of the lower teeth, anterior crossbite and unilateral right posterior crossbite. The molar and canine class was III. The upper arch form was ovoid with crowding and lack of space of less than 6 mm. The lower arch was ovoid and showed mild rotations. Overjet was less than 6 mm and the overbite was minus 2 mm. Orthodontic treatment was performed in three phases: presurgical, surgical and postsurgical. In the presurgical phase dental decompensation was achieved and the patient was prepared for surgery. During the surgical phase, a high Le Fort maxillary advancement surgery with bilateral sagittal osteotomy and advancement genioplasty was made. In the postsurgical phase ideal occlusal relationships, in terms of canine and molar class, overjet, overbite and coincident dental midlines were obtained as well as a more harmonious profile.