Classification of facial asymmetry by cluster analysis

Introduction: The purposes of this study were to classify patients with facial asymmetry by using the cluster analysis and to evaluate the characteristics of the resultant groups. Methods: One hundred consecutive orthodontic patients who had frontal cephalograms and photographs taken for the diagnosis of facial asymmetry were included in the sample. A cluster analysis was used to classify the subjects, with craniofacial measurements related to asymmetry obtained from the cephalograms and photographs. Results: The subjects were divided into 5 clusters based on only 3 variables from the frontal cephalograms: menton deviation, apical base midline discrepancy, and vertical difference of right and left antegonion. The results of the ANOVA test according to the variables showed statistically significant differences between the groups in all variables, indicating that each group can be easily identified with the variables. Conclusions: The results suggest that patients with facial asymmetry can be classified simply based on some variables on frontal cephalograms, and this classification can be helpful in proper diagnosis and treatment planning for these patients.