Cone-Beam Computed Tomography-Based Three-Dimensional McNamara Cephalometric Analysis

This article introduces a method that extends the McNamara cephalometric analysis to produce 3-dimensional (3D) measurement values from cone-beam computed tomography images. In the extended method, the cephalometric landmarks are represented by 3D points; the bilateral cephalometric landmarks are identified on both sides of the skull; the cephalometric lines, with the exception of the facial axis, are represented by 3D lines; the cephalometric planes, with the exception of the facial plane, are represented by planes; the effective mandibular length, the effective midfacial length, and the lower anterior facial height are measured as 3D point-to-point distances; the nasion perpendicular to point A, the pogonion to nasion perpendicular, the upper incisor to point A vertical, and the lower incisor to point A-pogonion line are measured each as components of a vector; the facial axis angle is measured as a line-to-plane angle; and the mandibular plane angle is measured as a plane-to-plane angle. As a result, the method provides real effective lengths of the maxilla and mandible on both sides of the skull; real height of the lower anterior face; directed distances from the point A to the nasion perpendicular, from the pogonion to the nasion perpendicular, from the left and right upper incisor to the point A vertical, and from the left and right lower incisor to the point A-pogonion line for both the lateral and posteroanterior views of the skull; and real angles of the facial axis and the mandibular plane. Additionality, the method enables the identification of craniofacial asymmetries. Address correspondence and reprint requests to José Mario De Martino, Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação, Av. Albert Einstein, 400, Cidade Universitária "Zeferino Vaz", Barão Geraldo, Campinas, São Paulo 13083-852, Brazil; E-mail: martino@fee.unicamp.br Received 9 May, 2017 Accepted 5 October, 2017 This work was supported by the Coordination for the Improvement of Higher Education Personnel (CAPES), a foundation within the Ministry of Education in Brazil. The authors report no conflicts of interest. © 2018 by Mutaz B. Habal, MD.

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