The dental arch dimensions in Vietnamese children at 7 years of age, and their variation by gender and ethnicity

Purpose Dental arch dimensions are important not only in dentistry (e.g. orthodontists and prosthodontists, and forensic odontology), but also other medical fields, biology, biometrics, painting or sculpture. This study aimed to determine these dimensions in Vietnamese children and compare these measurements across four ethnic groups and genders. Methods A cross-sectional study was conducted on 3204 Vietnamese children at 7 years of age from four major ethnic groups in Vietnam (Kinh, Tay, Thai and Muong). Results The means variables in study subjects were 33.72 ± 2.16 mm for upper inter-canine width (UCW); 52.74 ± 2.55 mm for upper inter-molar width (UMW); 8.69 ± 1.79 mm for upper anterior length (UAL); 29.59 ± 1.97 mm for upper posterior length (UPL); 26.94 ± 2.49 mm for lower inter-canine width (LCW); 45.89 ± 2.59 mm for lower inter-molar width (LMW); 5.04 ± 1.53 mm for lower anterior length (LAL); and 26.22 ± 2.07 mm for lower posterior length (LPL). The UCM, UMW, and LMW of Muong were significantly wider in males, but narrower in females compared with other ethnic groups. The Kinh, Tay and Thai groups had no significant differences between genders in all dimensions, but these sizes were significantly larger in males than females of Muong group. Conclusions This study presents the means of dental arch dimensions in 7 year-old Vietnamese children, and there is no statistical differences in these dimensions between genders of almost studied groups, except Muong group. Ethnic differences are observed only in UCW, UMW and LMW of Muong vs other groups. Furthermore, Vietnamese children have dental arch width similar to the African and Caucasian.