The accuracy of photographic soft-tissue profile analysis to determine Class II and vertical skeletal relationships...

Lateral cephalometric analysis (LCA) is the reference standard for identifying common skeletal relationships in orthodontics, such as Cl II and hyperdivergent skeletal discrepancies, but it entails radiation exposure. Therefore, photographic soft-tissue profile analysis (PSPA) could be a useful alternative for these diagnoses, particularly for paediatric patients. This study aims to estimate the accuracy of PSPA for determining common skeletal discrepancies in children.

Cephalometric radiographs and profile photographs of a consecutive series of 100 children (8.0-17.6 years old) made on the same day were included. The validity of PSPA was verified against comparable LCA. First, by assessing the Pearson correlation and then estimating the sensitivity, specificity, receiver operating characteristic (ROC) curves and area under the curve (AUC) in sample A (n = 50). After external validation in a new sample B (n = 50), the ROC-AUC, diagnostic odds ratio, best cut-off points and discriminative validity were assessed in the total sample. Interrater reliability was estimated using the intraclass correlation coefficient, the standard error of measurement and Bland-Altman plots.

The measurement properties of the PSPA angles A'N'B', Gl'-Sn-Pog, N'-Sn-Pog', and N'-Tra-Me' were valid (ROC-AUC > 0.7) and reliable (ICCs > 0.92). The angles A'N'B', Gl'-Sn-Pog', and N'-Sn-Pog', with the respective cut-off points ≥7.7', ≥12.8', and ≤163.5', were accurate values for determining Cl II discrepancy. The N'-Tra-Me'-angle (≥63') was an accurate estimate for a hyperdivergent discrepancy.

These validated PSPA angles could be used in clinical settings as a minimally invasive diagnostic tool to screen children suspected of having skeletal Cl II and hyperdivergent discrepancies.