YIJOM-3762; No of Pages 8 Please cite this article in press as: Santos RMG, et al. Cone beam computed tomography-based cephalometric norms for Brazilian adults, Int J Oral Maxillofac Surg (2017), http://dx.doi.org/10.1016/j.ijom.2017.06.030 Clinical Paper Orthognathic Surgery Cone beam computed tomography-based cephalometric norms for Brazilian adults R. M. G. Santos, J. M. De Martino, F. Haiter Neto, L. A. Passeri: Cone beam computed tomography-based cephalometric norms for Brazilian adults. Int. J. Oral Maxillofac. Surg. 2017; xxx: xxx–xxx. ã 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. R. M. G. Santos 1 , J. M. De Martino 1 , F. Haiter Neto 2 , L. A. Passeri 3 1 Department of Computer Engineering and Industrial Automation, School of Electrical and Computer Engineering, University of Campinas, Campinas, SP, Brazil; 2 Department of Oral Diagnosis, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil; 3 Department of Surgery, School of Medical Sciences, University of Campinas, Campinas, SP, Brazil Abstract. This study established cone beam computed tomography (CBCT)-based cephalometric norms for Brazilian adults, including the assessment of sexual dimorphism. An observer performed McNamara’s cephalometric analysis twice on 60 CBCT datasets acquired from patients with a normal dental occlusion, divided equally into two groups by sex. Welch’s t-test was applied to assess differences between the sexes in hard tissue cephalometric measurements, and Dahlberg’s formula was used to calculate measurement error introduced by the observer. The cephalometric measurements of effective mandibular length, effective midfacial length, maxillomandibular differential, and lower anterior facial height presented sexual dimorphism. Linear measurements had error 0.78 mm, and angular measurements had error 1.24  . The results show that (1) the CBCT-based cephalometric norms established in this study are reliable for use by researchers and clinicians, and (2) Brazilian adult males and females have similar craniofacial morphology, with males possessing larger jaws than females. Key words: orthodontics; cephalometry; three-dimensional imaging; dental occlusion; reference values. Accepted for publication 6 June 2017 Since its introduction by Broadbent in 1931, cephalometric radiography has been the standard craniofacial imaging tech- nique used by clinicians for evaluating and planning the treatment of orthodontic and orthognathic surgery patients 1 . How- ever, its position has been increasingly challenged by cone beam computed to- mography (CBCT), the state-of-the-art imaging technique in the field of oral and maxillofacial surgery, introduced by Mozzo et al. in 1998 2 . CBCT has been gaining acceptance over radiography, since the latter produces undesirable effects inherently related to perspective projection, such as size and shape distor- tion, superimposition, and misrepresenta- tion of anatomical structures, which can jeopardize cephalometric analysis 3 . These effects affect cephalometric measurement outcomes, mainly because they amplify values and distort the correct location of cephalometric landmarks 4,5 . Besides over- coming these problems, CBCT provides an accurate and reliable three-dimensional (3D) image of the patient’s skull 5–7 . Among other advantages, CBCT allows clinicians to virtually orient the head after the image acquisition process, obtain the 3D position of cephalometric landmarks Int. J. Oral Maxillofac. Surg. 2017; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2017.06.030, available online at http://www.sciencedirect.com 0901-5027/000001+08 ã 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.