The upward curving of the inferior border of the mandible anterior to the mandibular angle is known as the antegonial notch. Previous studies suggest that antegonial notch development is dependent on the growth of the mandibular condyle and the mandibular ramus, and the mandibular angle’s attachment to the superficial layer of masseter muscle and medial pterygiod muscle.
The functions of the muscle group of the upper hyoid bone for opening movement are known to influence maxillofacial growth which is also affected by the position of the hyoid bone group and the mandibular shape. We assume that antegonial notch variables relate to the variance in the position of the hyoid bone. The aim of this paper is to determine possible associations between the antegonial notch’s depth and maxillofacial morphology which includes the mandible and the position of the hyoid bone.
This study was based on 31 adult female subjects with a mean age of 23 years and 5 months (S. D., 1 year,2 months). Lateral roentgenocephalograms were taken to study the depth of the antegonial notch, facial shape, and the position of the hyoid bone. Simple correlation analysis was used to assess the cephalometric variables.
In subjects with a deep antegonial notch, point B was significantly positioned to the posterior position (p<0.05), the ramus height was shorter (p<0.05), the mandibular plane angle was larger (p<0.05), the lower facial height was longer (p<0.01), and the angle between the mandibular plane and the hyoid bone was larger (p<0.01).
This suggests that the depth of the antegonial notch was affected not only by mandibular shape and size but also by the position of the hyoid bone.
