Correlation of Antegonial Notch Depth with Craniofacial Morphology - a Cephalometric and Electro Myographic Study

Abstract

Treatment planning in orthodontics other than the biomechanical considerations requires a thorough understanding of the craniofacial musculature and its association with the growth and development of the dentofacial complex. There is still much controversy regarding the influence of the mandibular muscles on normal growth and development, and on orthodontic treatment and stability. The purpose of this study was to investigate the relationship between antegonial notch depth, masseter muscle activity and the vertical craniofacial morphology. 90 adult individuals (52 females and 38 males) with normal occlusion, no history of - orthodontic treatment, craniomandibular disorder, trauma to face .or jaws and muscular disorder, no facial asymmetry, pain or tenderness in TMJ or muscles of mastication, no missing teeth except 3rd molars. A lateral cephalogram was taken of each subject with teeth in occlusion, and the subjects were divided according to the depth of antegonial notch into 3 groups - shallow (1 mm), moderate (1-2.5 mm) and deep (2.5 mm). Cephalometric readings studied for each individual comprised of 8 angular and 8 linear measurements. Masseter muscle activity at rest and at maximum clenching volume was also recorded for each individual. The results suggest that there is an increased masseter muscle activity in subjects with deep antigonial notch thus indicating a positive correlation between masseter muscle activity and the depth of the antegonial notch. No statistically significant correlation was seen between the vertical craniofacial morphology and the depth of the antigonial notch.