Arab and German Phenotypic Variations of Skeletal Class II Malocclusion

Background Skeletal Class II malocclusion is one of the common orthodontic problems and can affect the person’s physical and psychosocial health. Misdiagnosis and inaccurate treatment process can happen due to many reasons. One of these reasons is the fact that the patients’ from different ethnic groups can vary in the diagnosis and treatment values. Therefore, the main aim of this study is to introduce a novel information about the variations between Arab and German skeletal class II malocclusion patients. Methods In this study we assessed the lateral cephalometric parameters of Arab and German skeletal class II patients. The study consisted of the coded records of 680 Arab and German patients diagnosed as skeletal Class II malocclusion, according to the individualized ANB as defined by Panagiotidis and Witt. In this study, we compared the different subgroups of age and gender between the two populations, using Mann Whitney test. In addition, we applied machine learning models to classify the origin of the patients based on their cephalometric profile, and finally, we performed hierarchical clustering analysis to distinguish unique clusters. Results The results revealed that among different subgroups, there were significant variations between the two populations. NL/ML angle results revealed the severe divergence of the jaw bases among Arab patients. Besides, the results showed different growth patterns, as shown in the PFH/AFH, and gonial angle. Our results demonstrated the ability of the random forest model to accurately classify the patient’s origin with 97% accuracy based on the cephalometric profile. Besides, the accuracy remained the same even when selecting one feature from six clusters. Finally, our results revealed that the data can be analyzed into 7 unique clusters. The Arab patients were clustered mainly in clusters 1,2, and 4, whereas the German patients were mainly clustered in clusters 3,5,6 and 7. The clustering results demonstrated a unique growth pattern, and variated severity of skeletal class II. Conclusion This study was the first study to examine the differences between Arab and German populations. The results emphasize the need to take the ethnic characteristics when diagnosing and planning the treatment for skeletal class II patients.