Comparison of Chinese and white Bolton standards at age 13

To create a combined male-female Chinese Bolton standard for age 13 and to compare it to the combined Bolton standard for white 13 year olds.

Thirty-two Chinese and 32 white subjects (16 adolescent boys and 16 adolescent girls aged 13 years in each ethnic group) who fulfilled the selection criteria used to create the original Bolton standards were enrolled. Their cephalograms were traced and then averaged two at a time following the Bolton method. In addition to creating the template from the 32 subjects in each group, 43 linear and angular variables were measured and compared between the two ethnic groups and between the two sexes in each ethnic group using independent t-tests. A P value of .05 was used to assign statistical significance. The male-female combined templates for 13 year olds were also compared superimposing either in the Bolton relation or by soft tissue.

No sexual dimorphism was found in the white subjects, whereas the Chinese girls had decreased upper face height (Na-ANS), more protrusive incisors (SNA-U1), and shorter cranial base (Ba-Na) and posterior cranial base (S-Ba) compared with the Chinese boys. In terms of ethnic comparison, the Chinese subjects presented shorter sagittal facial dimensions, a clockwise rotated mandible with a more acute gonial angle, and a convex facial profile with a less prominent nose and chin. However, overall vertical dimensions were similar.

A 13-year-old combined male-female Chinese Bolton standard was created that demonstrated visually and with metric comparisons that Chinese and white clinically normal subjects have different craniofacial characteristics. These differences should be taken into consideration when an individualized orthodontic treatment plan is developed.