Department of Orthodontics, Kaohsiung Medical University Hospital, and Faculty of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
J Formos Med Assoc. 2011 May;110(5):342-6. doi: 10.1016/S0929-6646(11)60051-X.
Craniofacial skeletal dysplasia can lead to different skeletal malocclusions. Both environmental factors and heredity contribute to the formation of malocclusions. There are strong familial tendencies in the development of Angle's Class II and III malocclusions. Cases such as opposite-typed (Class II and III) malocclusions with skeletal and dentoalveolar discordance in siblings or dizygotic (DZ) twins have seldom been reported. We describe the rare case of a pair of opposite-sex DZ twins with completely different skeletal malocclusions, and discuss the clinical considerations for treatment. The patients were twins aged 13 years and 4 months. The girl had mandibular prognathism and a Class III dentoskeletal relationship, whereas the boy had skeletal Class II with mandibular retrusion. Several morphological traits have been implicated with hormonal effect. However, there was no evidence of whether the masculinization effect had any impact on jaw size in the female fetus or whether this effect lasted into adolescence. We suggest that, although DZ twins share the same growth environment, genetic or other unknown extrinsic factors can result in discordance of characteristics of the craniofacial skeleton, dentition, and occlusion.
颅面骨骼发育不良可导致不同的骨骼错颌畸形。环境因素和遗传因素都促成了错颌畸形的形成。Angle 类 II 和 III 错颌畸形的发展具有很强的家族倾向。在兄弟姐妹或异卵双生子（DZ）中，很少有报道相反类型（类 II 和 III）错颌畸形伴骨骼和牙颌不调的病例。我们描述了一对罕见的异性 DZ 双胞胎，他们患有完全不同的骨骼错颌畸形，并讨论了治疗的临床注意事项。患者为一对年龄分别为 13 岁 4 个月的双胞胎。女孩下颌前突，表现为 III 类牙颌骨骼关系，而男孩则表现为骨骼 II 类伴下颌后缩。已有多种形态特征与激素效应有关。然而，没有证据表明男性化效应是否对女胎的颌骨大小有任何影响，或者这种效应是否持续到青春期。我们认为，尽管 DZ 双胞胎共享相同的生长环境，但遗传或其他未知的外在因素可能导致颅面骨骼、牙齿和咬合特征的不协调。
