Reliability of Panoramic Radiography for Vertical Facial Pattern Assessment Assessment

The orthopantomogram (OPG) is a common dental screening radiograph that has multiple implications. However, lateral cephalogram is the investigation of choice for the assessment of vertical facial pattern. Objective: The aim of the current study was to investigate the validity of an OPG parameter i.e. panoramic gonial angle (PGoA) for the assessment of the vertical facial pattern. Methods: A cross-sectional study was conducted on the pretreatment OPG and lateral cephalograms of 200 orthodontic patients aged 15-40 years. The PGoA was measured on both sides and an average was used for statistical analysis. The Pearson’s correlations of PGoA were measured with cephalometric gonial angle (CGoA), SN-GoGn, MMA, FMA, LAFH/TAFH% and PFH/TAFH%. The diagnostic test statistics were applied for PGoA against gold standard “definitive diagnosis (DD)” derived from SN GoGn and FMA. A p-value of <0.05 was taken as statistically significant. Results: The mean CGoA was 121.18o ± 5.16o which was significantly different (p <0.001) from the mean PGoA 117.14o ± 4.43o. PGoA was significantly correlated with SN-GoGn, MMA, FMA and CGoA. A standard of PGoA 116o±3o was used to classify subjects into low angle, normal angle and high angle groups. The validity of PGoA with DD showed a sensitivity of 90.32%, 82.72% and 77.78%; and specificity of 95.37%, 84.48% and 91.96% for low angle, normal angle and high angle cases, respectively. Conclusion: The current study identifies PGoA as a valid tool for the assessment of vertical facial pattern of orthodontic patients with its normal value 116o±3o in our sample.