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

Abstract

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

Materials and methods: 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.

Results: 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.

Conclusions: 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.