RELIABILITY OF ORTHOPANTOMOGRAM INDETERMINATION OF GONIAL ANGLE

Abstract

The aim of this study was to assess the values of gonial angle on orthopantomogram (OPG) and correlate them with the respective values on lateral cephalogram in order to determine the diagnostic capability of OPG for vertical facial pattern.The study was conducted as a cross –sectional study at the Department of Orthodontics and Dentofacial Orthopedics, Khyber College of Dentistry by using 100 radiographs of the patients in the form of OPG and lateral head films. The sample included 35 male subjects with mean age of 18.00±5.167 years and 65 female subjects with mean age of 18.66±4.874 years. The gonial angle was determined by tracing a tangent to the lower border of the mandible and another tangent to the posterior ramus of the mandible both on OPG and lateral cephalogram manually and measured with the help of protractor.The mean value for gonial angle on right and left side of the mandible on OPG was 124.62±7.54ºand 124.31±8.37º respectively. The value was 124.65±7.99º on lateral cephalograms. The Pearson correlation showed statistically significant correlation between cephalometric and OPG gonial angle (p value <.01). One way ANOVA revealed no significant difference between the values.The results revealed a significant correlation between the cephalometric and panoramic values which concludes that panoramic radiography is as reliable as lateral cephalogram in predicting vertical facial pattern as determined by gonial angle. OPG can be used as an alternative to lateral cephalogram in determining gonial angle which shows its versatility as a diagnostic tool.