Depth of the Antegonial Notch Associated with Specific Diagnostic Features of Mandibular Vertical Development

Methods: Lateral cephalometric radiographs were traced and analyzed for 50 patients presenting various vertical facial lengths. Antegonial notch depth (mm) (AGN depth), sella nasion – mandibular plane angle (SN-MP), gonial angle (GoA), lower facial height (LFH). LFH was measured from menton (Me) to anterior nasal spine (ANS) and expressed as a percentage of total face height (TFH) measured from nasion to menton. Vertical incisor overbite (VOB) was measured to the nearest 0.1mm. Symphysis length (SL) was measured as the distance from incisor alveolar crest perpendicularly to the MP. The data was analyzed to determine whether any correlation between the AGN depth and the other measured parameters of vertical face height existed.

Results: Statistical analysis showed that there were no significant variables when predicting AGN depth and the other measured independent variables. However, there is a significant correlation between LFH and VOB (P<.07). SN-MP angle and GoA correlate significantly (P<.0001). Reproducibility of all measures was good with concordance correlation range of values from .92 to .96.

Conclusions: From this population of 50 subjects, one can conclude that a deeper AGN is not an indicator of greater vertical mandibular growth, nor is AGN depth correlated with any of the above vertical facial cephalometric measures. Furthermore the statistical correlation of the vertical skeletal cephalometric measures used in this study prove clinical reliability whereas the dental measures (OVB) are less reliable in predicting vertical development.