Validating the 3D and 2D Mandibular Plane to the Frankfort Plane for Craniofacial Measurement

Validating the 3D and 2D Mandibular Plane to the Frankfort Plane for Craniofacial Measurement

Purpose: This study evaluated whether the three-dimensional (3D) plane-to-plane mandibular plane angle measurement method could be applied in clinical analysis in a manner similar to the application of conventional two-dimensional (2D) cephalometric measurement, regardless of whether patients had symmetrical planes. Patients and methods: This retrospective study selected 30 patients who had undergone both lateral cephalometric radiography and cone-beam computed tomography (CBCT). The 2D measurement was manually traced from the lateral cephalometric radiographs for the Frankfort horizontal plane line and mandibular plane line (2D FMA). The 3D reconstructions for each patient in the CBCT were evaluated using 3D software and measured using two 3D measurement methods regarding the mandibular plane angle (3D FMA, 3D MP). The Kruskal-Wallis test was used to determine the differences among the three different methods. Dahlberg's formula was used to determine the intra-examiner reproducibility. Results: The mandibular plane angle acquired from two-dimensional measurements was larger than that obtained from 3D methods in the two asymmetry groups, and measurements revealed a greater difference in the horizontal asymmetry + vertical asymmetry group compared with the other two groups. However, no statistically significant difference was observed. Conclusion: The 3D plane-to-plane angle measurement method can be used for analysis in patients with symmetric and asymmetric planes.