Orthognathic surgery norms for American black patients

Upon analyzing the literature, it becomes apparent that the hard- and soft-tissue norms of blacks differ from those of whites. However, these established black norms are not complete when evaluating potential surgical cases. Therefore, the intent of this study was to establish black norms that will be valuable aids for diagnosis in such cases. Lateral cephalometric radiographs were taken of 50 white adults (25 male, 25 female) and 50 black North American adults (25 male, 25 female). All subjects met the following criteria: 18 to 50 years of age; a normal Class I skeletal and dental relationship without any severe anteroposterior, vertical, or transverse discrepancies; and a balanced profile. The tracings involved 24 measurements that were analyzed with a digitizer. Sexual differentiation was included within each measurement. Significant differences between white and black subjects were found in the following areas: hard tissue (SNA, ANB, mandibular length, and the Wits analysis); dental (anterior dental height [ADH], amount of tooth exposure at rest, upper incisor-palatal plane [UI-PP], and lower incisor-mandibular plane [LI-MP]); and soft tissue (nasolabial angle [NLA], upper lip length [ULL], lower lip length [LLL], throat length [TL], and the lip-chin-throat angle [LCTA]). From a practical point of view, this study can be used by orthodontists and oral surgeons to aid in the diagnosis of black patients contemplating orthognathic surgery.