Surgical Orthodontic Treatment in Case of Severe High Angle Skeletal Class II Malocclusion and Mandibular Retrusion

• Published in: Bulletin of Tokyo Dental College Vol. 61; no. 4; pp. 243 - 253
• Main Authors: Tachiki, Chie, Yamamoto, Masae, Takaki, Takashi, Nishii, Yasushi
• Format: Journal Article
• Language: English
• Published: Japan Tokyo Dental College, Japan 01.01.2020; Japan Science and Technology Agency
• Subjects: Adult; Case reports; Cephalometry; Counter-clockwise rotation; Dental occlusion; Dentistry; Esthetics, Dental; Female; High angle case; Humans; Jaw; Lip; Malocclusion, Angle Class II - surgery; Malocclusion, Angle Class III; Mandible; Mandible - surgery; Maxilla; Maxilla - surgery; Orthodontics; Osteotomy; Osteotomy, Le Fort; Patients; Retrognathia; Skeletal class II; Stability; Surgery; Surgical orthodontic treatment; Stability; High angle case; Skeletal class II; Counter-clockwise rotation; Surgical orthodontic treatment
• ISSN: 0040-8891
• DOI: 10.2209/tdcpublication.2020-0022

This report describes a patient with severe high angle class II malocclusion and mandibular retrusion in whom surgical orthodontic treatment to prevent an increase in ramus height resulted in a significant improvement in esthetics and long-term stability. The patient was a woman aged 30 years 5 months who presented with the chief complaint of maxillary protrusion. She had a convex facial type, a chin button on lip sealing, and a gummy smile. Cephalometric analysis revealed a normal maxilla anterior-posterior position, but significant mandibular retrusion with pronounced clockwise rotation. The anterior maxillary tooth axis was standard, but labially inclined in the mandible. Based on these findings, the diagnosis was skeletal class II high angle malocclusion and mandibular retrusion. The proposed treatment plan comprised 2-jaw surgery with premolar extraction. Le Fort I osteotomy, in particular, was planned in the maxilla to move the ANS upward by 3.0 mm and the PNS downward by 3.0 mm. Sagittal split ramus osteotomy (SSRO) was planned to adjust the mandible and move the mandible forward by 10.0 mm. To prevent postoperative relapse, the short lingual split method was used in performing the SSRO. The mandible was split to minimize stretching of the median pterygoid muscle. Postoperatively, the ANS, PNS, and pogonion showed movement of 2.0 mm upward, 3.0 mm downward, and 8.0 mm forward, respectively. Additionally, lip closure was now natural, and the gummy smile had markedly improved. At 6 years postoperatively, there has been no change skeletally or dentally. Follow-up is being continued to monitor further progress.