Agreement of Gonial Angle Measurements Between Cone-Beam Computed Tomography (CBCT)-Reconstructed Panoramic Radiographs and Conventional Panoramic Radiographs: A Cross-Sectional Study.

Introduction The gonial angle is an important cephalometric parameter used to assess mandibular morphology and vertical facial growth. Conventional lateral cephalograms (LCs) and orthopantomograms (OPGs) are routinely used for its evaluation; however, image distortion and superimposition may affect measurement accuracy. Cone-beam computed tomography (CBCT) enables 3D visualization and can generate reconstructed 2D cephalometric and panoramic images that may provide comparable measurements without requiring additional radiographic exposure when a CBCT scan is already available. Objective To evaluate the agreement between gonial angle measurements obtained from conventional LCs and OPGs and those derived from CBCT-reconstructed cephalograms and panoramic images in normodivergent individuals. Methods This cross-sectional study included 24 normodivergent orthodontic patients. Gonial angles were measured on conventional LCs, conventional OPGs, CBCT-reconstructed cephalograms, and CBCT-generated panoramic images using standardized digital imaging software. Mean measurements were compared using paired statistical analysis. Agreement between the imaging modalities was assessed using Bland-Altman analysis, while intra- and inter-examiner reliability were evaluated using intraclass correlation coefficients (ICCs) and weighted kappa statistics. Results No statistically significant differences were observed between gonial angle measurements obtained from conventional radiographs and those obtained from CBCT-reconstructed images (p > 0.05). Bland-Altman analysis demonstrated minimal systematic bias and acceptable limits of agreement between the imaging modalities. Both conventional and CBCT-derived measurements exhibited excellent intra- and inter-examiner reliability, supporting the reproducibility of the measurement techniques. Conclusions CBCT-reconstructed cephalograms and panoramic images demonstrated excellent agreement with conventional LCs and OPGs for gonial angle assessment in normodivergent individuals. When a CBCT scan has already been acquired for clinical indications, reconstructed images may provide reliable gonial angle measurements without the need for additional conventional radiographs, thereby reducing unnecessary radiation exposure.