A comparison of craniofacial morphology in patients with and without facial asymmetry--a three-dimensional analysis with computed tomography

This study intended to evaluate the morphological characteristics of the cranial base and maxillomandibular structures of facial asymmetry in adult patients, so as to determine whether mandibular asymmetry is a result of primary mandibular deformity or if it is influenced by cranial base deformity. Forty-two adult patients with dentofacial deformity were placed into two groups according to the deviation of the chin: Asymmetry group (n = 24) and Non-asymmetry group (n = 18). They were compared with three-dimensional (3D) CT reformatted images using a 3D visualization and analyzing program. The differences between the two groups, the correlation between the cranial base and maxillomandibular asymmetry were evaluated statistically. The degree of cranial base asymmetry in the Asymmetry group was not statistically different from the Non-asymmetry group. The asymmetric condyle position was found to be associated with skull base characteristics. The 3D position of the condyle and cranial base, however, was not closely related with mandibular asymmetry. The results showed that the cranial measurement variables were not the dominant factors that determined the degree of facial asymmetry. It seems that the mandibular skeletal factors itself, functional or intrinsic asymmetric growth potential, compensate or aggravate the influence of cranial asymmetry during the growth period.