Research Article Oral Health and Care Oral Health Care, 2017 doi: 10.15761/OHC.1000116 Volume 2(2): 1-5 ISSN: 2399-9640 TORONTO facial tetrahedron 3D analysis: efcient cephalometric application for surgical mandibular asymmetry, genioplasty, and predictive response to functional dentofacial orthopedic appliances John Voudouris 1 *, Sunjay Suri 2 , Bryan Tompson 3 , James Poulos 4 and Christos Schismenos 5 1 Clinical Researcher and Associate in Orthodontics, University of Toronto, Discipline of Orthodontics, Toronto, Canada 2 Chairman and Director, University of Toronto, Faculty of Dentistry, Discipline of Orthodontics, Toronto, Canada 3 University of Toronto, Faculty of Dentistry, Discipline of Orthodontics, and Director Craniofacial Clinic, Hospital for Sick Children, Toronto, Canada 4 College of Dentistry, Ohio State University in Columbus, Ohio, USA 5 College of Dentistry, Department of Orthodontics, Private practice, Agrinio, Greece Correspondence to: John Voudouris, Clinical Researcher and Associate in Orthodontics, University of Toronto, Discipline of Orthodontics, Toronto, Canada; E-mail: jvoud@pathcom.com Received: April 04, 2017; Accepted: April 18, 2017; Published: April 21, 2017 Simple, accurate, and highly efcient are the words and factors a contemporary orthodontic practice looks for in a cephalometric analysis today. A four-sided Tetrahedron is presented for the orthodontic team to trace easily and allow an active orthodontic clinician to assess, at a glance, a patient’s facial pattern and condition. Te tetrahedron is suggested as an advancement to the prior Tweed triangle [1]. Te reason is a tetrahedron is more representative of the four-sides of the maxilla and mandible. It uses the position of the upper incisor with upper lip, and lower incisor with sof tissue chin as references, simultaneously similar as to how a clinician would apply them chairside. One problem with dentofacial orthopedic treatment is that fxed functional appliances are ofen placed indiscriminately in patients with Class II skeletal dysplasia and at all ages. However, a set of cephalometric guidelines or directions, is indicated for proper patient selection to prevent failures [2]. Namely the tetrahedron adds the simple key measurement of CoGnMe shown to provide greater predictability toward more successful orthodontic outcomes with specifc types of orthodontic appliances. Tis not only includes fxed and removable functional appliances, but additionally headgear, and Class II elastics used in skeletal Class II treatment. A second related problem in the orthodontic profession is a large proportion of orthodontic clinicians (approximately 60%) report growingly [3] they do not trace cephalometric radiographs for diagnosis and treatment planning [4,5]. Tis is ofen because it is too time-consuming or complex for the orthodontic team, or they feel it is unnecessary. However, this causes several types of diagnostic, prognostic, and other possible medicolegal complications in dentofacial orthopedic treatment. Te purpose of the tetrahedron in the tracing is to be, quick to draw, user-friendly and accurate for the orthodontic staf in order to preserve and attempt to revive the high value of cephalometric measurements under attack, and declining in the orthodontic specialty (Figure 1). Tetrahedron four walls Te method used in the Tetrahedron analysis to evaluate the important sof tissue chin position must be, once again, similar to a clinician’s technique at chairside, using the natural head position (NHP) at the patient’s frst consultation appointment. In fact, NHP has been shown to be reproducible long-term [6-11]. By having the patient stand, or sit upright in the orthodontic chair most clinicians draw mentally a perpendicular line to NHP horizontal, through sof tissue subnasale to evaluate the nasolabial angle and sof tissue pogonion. Similarly, the position of the important sof tissue upper lip is evaluated using the same vertical line. Since dentofacial orthopedics combines sof and hard tissue evaluations, the Tetrahedron analysis includes distinctly Figure 1. TORONTO Tetrahedron