Comparison of Gonial Angle Determination from Cephalograms and Orthopantomogram of Patients under Orthodontic Treatment

Abstract

Objective:To compare and find out the possible application of OPG for gonial angle and compare it with cephalogram in Orthodontic patients of a Public Sector Dental Institute. Materials and Methods:In this descriptive retrospective study lateral cephalograms and OPG of 103 patients, 27 males and 76 females were analyzed. The gonial angle was determined in panoramic radiographs by two tangents drawn from the condyle’s posterior borders and right and left ramus and inferior border of the mandible. Landmarks in the cephalogram were identified and spotted. Cephalometric protractor and calipers were used to mark and measure the angles. Angles and other parameters were rechecked to counter any missed measurement. Results: In lateral cephalograms the mean value of gonial angle was 121.77° and in panoramic radiographs 122.18°. In females, the difference among the mean gonial angle in both radiographs was 1.20 and in males 1.224 while difference among the two genders was 0.02°. As P > 0.05 for all the variables stated above, these differences were not significant. Conclusion: OPG may be considered to evaluate the gonial angle as correctly as a lateral cephalogram because in the values of gonial angles measured in both radiographs there was non- significant difference. The plus point in OPG is that it is more accurate in evaluating patient’s gonial angles without any overlaid images.