Morphological differences in the craniofacial structure between Japanese and Caucasian girls with Class II division 1 malocclusions

Abstract

The craniofacial features of 49 Japanese and 75 British Caucasian girls with Class II division 1 malocclusions were evaluated from lateral cephalometric radiographs, and the morphological differences between both races were examined. The subjects' ages ranged from 11 years 1 month to 12 years 11 months. The mean values of 13 linear and 13 angular cephalometric parameters were compared. The Japanese Class II division 1 sample had a significantly shorter anterior cranial base length (S-N; P < 0.001) and a more obtuse articular angle (S-Ar-Go; P < 0.001). Analysis of the dentoalveolar components in Japanese subjects showed more proclined lower incisors (L1/Go-Me; P < 0.05) and a steeper occlusal plane (Occ.P/S-N; P < 0.01) relative to those of Caucasians. The short anterior cranial base length and excessive vertical development in the Japanese population might be common racial morphological features, but the main reason for the Class II division 1 skeletal disharmony in both races was different; it was caused by the anteriorly positioned maxilla in Caucasians and the backward rotated mandible in the Japanese.

Growth hormone receptor gene variant and three-dimensional mandibular morphology

“…16 In comparison with European Americans and whites, mandibular size tends to be slightly smaller in the Japanese population. 35,36 This suggests the need for investigation of the relationship between craniofacial morphology and GHR gene variants in other populations.…”

Perioral age-related changes in smile dynamics along the vertical plane

“…[7][8][9][11][12][13] Dental and skeletal changes lead to loss of skeletal volume and reduced vertical dimension.…”

Recent Advances in the Genetics of Orthodontics

“…A haplotype-based study based on HapMap data is required to assess the differences among Asian populations, and a larger-scale study with the ethnicities kept distinct is required to obtain a conclusive result (Roeder et al, 2006;Ambrosius et al, 2004;Schork et al, 2002;Longmate et al, 2001). Our work emphasizes the importance of close matching of ethnic groups, especially when measuring craniofacial morphology, which is known to vary by ethnicity (Miyajima et al, 1996;Ishii et al, 2001;Ishii et al, 2002;Ioi et al, 2007). Growth hormone insensitivity syndrome of genetic origin has been linked to many different mutations of GHR, and is associated with a wide range of severities of clinical and biochemical phenotypes.…”

“…These differences might imply the need for independent studies on the association of GHR with craniofacial morphology in each ethnic group. The mandibular size of Japanese people appears to be slightly smaller than that of European-Americans (Miyajima et al, 1996) or Caucasians (Ishii et al, 2001;Ishii et al, 2002;Ishizuka et al, 1989 Table 7. Allele distribution of 5 SNPs in exon10 of the GHR On average, the allele frequencies for populations from different continents differ by 16-19%, and for populations within a continent, such as Koreans and Japanese, they differ by 5-10% (Miller et al, 2005).…”