An evaluation of relation between the relative parallelism of occlusal plane to ala-tragal line and variation in the angulation of Po-Na-ANS angle in dentulous subjects: A cephalometric study

AIMS The aim was to evaluate if any correlation exists between variation in angulation of Po-Na-ANS angle and relative parallelism of the occlusal plane to the different tragal levels of the ear in dentulous subjects. METHODOLOGY A total of 200 subjects were selected for the study. A custom made occlusal plane analyzer was used to determine the posterior point of the ala-tragal line. The lateral cephalogram was shot for each of the subjects. The points Porion, Nasion, and Anterior Nasal Spine were located and the angle formed between these points was measured. STATISTICAL ANALYSIS USED Fischer's exact test was used to find the correlation between Po-Na-ANS angle and relative parallelism of the occlusal plane to the ala-tragal line at different tragal levels. RESULTS Statistical analysis showed no significant correlation between Po-Na-ANS angle and relative parallelism of an occlusal plane at different tragal levels, and an inferior point on the tragus was the most common. CONCLUSION Irrespective of variations in the Po-Na-ANS angle, no correlation exists between the variation in the angulations of Po-Na-ANS angle and the relative parallelism of occlusal plane to the ala-tragal line at different tragal levels. Furthermore, in a large number of subjects (54%), the occlusal plane was found parallel to a line joining the inferior border of the ala of the nose and the inferior part of the tragus.