Ethnic differences in craniofacial and upper spine morphology between European and Asian children with skeletal Class III malocclusion

The aims of this study were to analyze differences in craniofacial and upper cervical spine morphology, including posterior cranial fossa and growth prediction signs between European and Asian skeletal Class III children, and to analyze associations between morphologic deviations in the upper cervical spine and craniofacial characteristics.

A total of 60 skeletal Class III children, 19 Danes and 41 Koreans, were included. Upper spine morphology, Atlas dimensions, and craniofacial morphology, including posterior cranial fossa and growth prediction signs, were assessed on lateral cephalograms. Differences and associations were analyzed by multiple linear and logistic regression analyses adjusted for age and gender.

In the craniofacial morphology, the inclination of the maxilla (NSL/NL, P <0.05) and the shape of the posterior cranial fossa (s-d, d-p, p-iop; P <0.01 and P <0.0001, respectively) were significantly different between the 2 groups. There was no significant difference in upper cervical spine morphology and Atlas dimensions between the groups. Fusion was significantly associated with the sagittal jaw relationship (P <0.05), and the total upper spine deviations were significantly associated with some growth prediction signs (P <0.05, P <0.01). Atlas dimensions were significantly associated with the prognathia of the mandible (P <0.05), posterior cranial fossa (P <0.01, P <0.0001), and some growth prediction signs (P <0.05, P <0.01).

Upper spine morphology and Atlas dimensions may provide valuable information for predicting jaw growth and craniofacial morphology in Class III malocclusion.