Cephalometric norms for African Americans with normal occlusion in the Greater Philadelphia region : A retrospective observational study.

Abstract

Objectives: To establish cephalometric norms for African American adults with normal occlusion and balanced soft tissue profiles in the Greater Philadelphia region and compare these findings with existing African American norms.

Materials and methods: A total of 650 orthodontic records from adult African American subjects were reviewed. Normal occlusion was defined based on Angle's class I molar relationship, an overbite of 20-30% or greater than 0 mm and less than 3 mm, an overjet ranging from 1-3 mm, absence of crossbites, minor dental crowding, and gaps or rotations not exceeding 2 mm, along with a balanced facial profile. According to these criteria, 34 lateral cephalograms (25 females, 9 males; mean age 28.4 ± 12.7 years) were selected. These lateral cephalograms were digitally traced using Dolphin Imaging software (version 12.0, Chatsworth, CA, USA), and the obtained cephalometric measurements were compared with established African American norms from existing literature.

Results: Skeletally, African American subjects from the Greater Philadelphia region demonstrated smaller vertical measurements, characterized by reduced SN-GoGn, FMA, and Y‑axis angles compared to previously published norms for the African American population. The skeletal sagittal relationship indicated a more anteriorly positioned maxilla relative to established Caucasian norms. Dental evaluations revealed a slight increase in upper incisor inclination and a reduced interincisal angle, as evidenced by measurements such as the 1/to SN, 1/to FH, and 1/to NA angles when compared to existing African American norms. Additionally, subjects from the Greater Philadelphia region exhibited a more protrusive lower lip compared to previously reported norms for African Americans.

Conclusion: Our findings indicate that cephalometric norms vary by both ethnicity and geographic region, underscoring the necessity of establishing population-specific standards to ensure accurate diagnosis and effective treatment planning.