An examination of the agenesis of third molar in hemifacial microsomia

Abstract

We previously reported that the prevalence of third molars is not related to antero-posterior dimensions of the mandible but to those of the maxilla. The purpose of this investigation was to clarify the correlation between the existence of third molar germs and sagittal maxillo-mandibular jaw dimensions. The existence of third molar germs in hemifacial microsomia (HFM) was examined to compare the presence of third molars on the affected side of the mandible and the normal side. The subjects were 69 HFM who had been treated at the Orthodontic Clinic of Hokkaido University Dental Hospital and who were less than 15 years old at the first examination. Panoramic radiographs that had been taken at the first examination and several years after the first examination were used as materials. A total of 391 patients who had been treated at the same hospital and who didn't have congenital deformities were used as a control group. The percentage of patients in the HFM group who did not have even one was significantly higher than that in the control group. There was no significant difference between prevalences of third molars on the affected side and normal side in the HFM group. These results suggest that agenesis of the third molar is related to the onset of HFM.