Invited Review Paper Orthognathic Surgery Digital three-dimensional image fusion processes for planning and evaluating orthodontics and orthognathic surgery. A systematic review Joanneke M. Plooij, Thomas J. J. Maal, Piet Haers, Wilfred A. Borstlap, Anne Marie Kuijpers-Jagtman, Stefaan J. Berge ´: Digital three-dimensional image fusion processes for planning and evaluating orthodontics and orthognathic surgery. A systematic review. Int. J. Oral Maxillofac. Surg. 2011; 40: 341–352. # 2010 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. Joanneke M. Plooij 1,2 , Thomas J. J. Maal 1,2 , Piet Haers 3 , Wilfred A. Borstlap 1,2 , Anne Marie Kuijpers-Jagtman 1,4 , Stefaan J. Berge ´ 1,2 1 3D Facial Imaging Research Group Nijmegen-Bruges, The Netherlands; 2 Department of Oral and Maxillofacial Surgery, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; 3 Department of Oral and Maxillofacial Surgery, Royal Surrey County Hospital Guildford, United Kingdom; 4 Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands Abstract. The three important tissue groups in orthognathic surgery (facial soft tissues, facial skeleton and dentition) can be referred to as a triad. This triad plays a decisive role in planning orthognathic surgery. Technological developments have led to the development of different three-dimensional (3D) technologies such as multiplanar CT and MRI scanning, 3D photography modalities and surface scanning. An objective method to predict surgical and orthodontic outcome should be established based on the integration of structural (soft tissue envelope, facial skeleton and dentition) and photographic 3D images. None of the craniofacial imaging techniques can capture the complete triad with optimal quality. This can only be achieved by ‘image fusion’ of different imaging techniques to create a 3D virtual head that can display all triad elements. A systematic search of current literature on image fusion in the craniofacial area was performed. 15 articles were found describing 3D digital image fusion models of two or more different imaging techniques for orthodontics and orthognathic surgery. From these articles it is concluded, that image fusion and especially the 3D virtual head are accurate and realistic tools for documentation, analysis, treatment planning and long term follow up. This may provide an accurate and realistic prediction model. Keywords: computer-assisted three-dimen- sional imaging; image fusion; orthodontics; maxillofacial surgery; surface-soft-tissue; facial skeleton; dentition; review. Accepted for publication 13 October 2010 Available online 20 November 2010 Facial soft tissue (skin, connective tissues, fat and muscles), facial skeleton (bone and cartilage) and dentition are the three important tissue groups in orthodontics and orthognathic surgery, which can be referred to as a triad 9 . Together with other structures such as the superficial muscu- loaponeurotic system, the skeleton and dentition support the facial soft tissue surfaces. The triad plays a decisive role in planning orthodontic therapy and orthognathic surgery. Patients with a dysgnathic deformity need careful assess- ment of the facial soft tissues surface, the underlying maxillofacial skeleton and the Int. J. Oral Maxillofac. Surg. 2011; 40: 341–352 doi:10.1016/j.ijom.2010.10.013, available online at http://www.sciencedirect.com 0901-5027/040341 + 012 $36.00/0 # 2010 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons.