Objective: To find the mean gonial angle values among different facial divergent cases.
Study design: Cross-sectional descriptive study.
Place and duration of study: Karachi Medical and Dental College from October 2018 to December 2019.
Methodology: Panoramic radiographs (OPG) and lateral cephalograms of 91 patients, 33 males and 58 females, were obtained. Sella-Nasion-Mandibular Plane (SNMP) angle was measured on lateral cephalogram and gonial angles were measured on panoramic radiograph. Subjects were divided into three groups as per SNMP angle as hypodivergent, normodivergent and hyperdivergent. A p-value of less than 0.05 was considered statistically significant.
Results: The mean value of the gonial angle in OPG among all the patients was 125.05° with a standard deviation 7.24°. The average gonial angle in males was 124.10° ±5.67° and in females was 125.59° ±7.99°. Out of 91 patients, 14 were hypodivergent, 28 were normodivergent and 49 were hyperdivergent. The mean values of gonial angle among these three groups were 119.77° ±6.05°, 123.66° ±5.50° and 127.36° ±7.52°. One-way ANOVA demonstrated highly significant differences in the values of gonial angles among three facial divergences (p=0.001). Post-Hoc Tukey analysis showed that there was a significant difference between gonial angle of hyperdivergent and hypodivergent cases (p=0.001).
Conclusion: Gonial angle on panoramic radiographs (OPG) may provide useful knowledge about the facial divergence of the orthodontic patients. Key Words: Gonial angle, Facial divergence, Lateral cephalogram, Panoramic radiograph, Orthodontic diagnosis.