McNamara analysis comparison between Indigenous and Chinese ethnic with skeletal class I malocclusion in Medan

To compare lateral cephalometric variables based on McNamara analysis between Indigenous and Chinese-Indonesian ethnic patients with skeletal class I malocclusion from Medan city.

Simple random sampling of retrospective data from pre-treatment lateral cephalograms of orthodontic adult patients of three successive generations of the Mongoloid race in Medan from 2015 to 2023. Thus, the unpaired t-test and Mann-Whitney test were conducted after the normality test to compare the cephalometric analysis between Indigenous and Chinese-Indonesian ethnicities.

This cross-sectional study analyzed 32 Indigenous and 34 Chinese ethnic lateral cephalograms. There were significant differences (P < 0.05) between Indigenous and Chinese ethnic in the lower pharynx, nasolabial angle, A to N perpendicular, maxillomandibular differential, and Pog to N Perpendicular variables for skeletal parameters. There were also significant differences (P < 0.05) in nasolabial angle for the soft tissue parameter and lower pharynx for the airway parameter. Conversely, there were no significant differences (P > 0.05) between these groups in the Co-A, Co-gnathion, lower anterior facial height (LAFH), facial axis angle, and mandibular plane angle for skeletal parameters. There were also no significant differences (P > 0.05) in upper incisor to A and lower incisor to A-Pog for dental parameters. Furthermore, there were also no significant differences (P > 0.05) in cant of the upper lip for soft tissue parameters and upper pharynx for airway.

It is advisable to consider certain landmarks and reference lines based on McNamara cephalometry parameters that showed a significant difference between Indigenous and Chinese ethnic groups with skeletal class I malocclusion when determining diagnosis and formulating individualized orthodontic treatment plans for multiethnic subpopulation patients in Medan.