title: A cone-beam computed tomography triple scan procedure to obtain a three-dimensional augmented virtual skull model appropriate for orthognathic surgery planning.
abstract: The aim of this study was to present a new approach to acquire a three-dimensional virtual skull model appropriate for orthognathic surgery planning without the use of plaster dental models and without deformation of the facial soft-tissue mask. A "triple" cone-beam computed tomography (CBCT) scan procedure with triple voxel-based rigid registration was evaluated and validated on 10 orthognathic patients. First, the patient was scanned vertically with a wax bite wafer in place (CBCT scan No1). Second, a limited dose scan of the patient with a Triple Tray AlgiNot impression in place was carried out (CBCT scan No2). Finally, a high-resolution scan of the Triple Tray AlgiNot impression was done (CBCT scan No3). Sequential and semiautomatic triple voxel-based rigid registration (RNo1-RNo3) was performed to augment the patient's skull model with accurate occlusal and intercuspidation data (Maxilim, version 2.1.1., Medicim NV, Mechelen, Belgium). All registrations were based on the Maximisation of Mutual Information registration algorithm. Because the accuracy and stability of the voxel-based registration (RNo1) between the Triple Tray AlgiNot impression scan and the limited low-dose patient scan were not known, this particular registration step needed to be validated. The accuracy of registration was measured on a synthetic skull and showed to be highly accurate. A volume overlap of 98.1% was found for registered impression scan No1. The mean distance between registered impression scan No1 and registered impression scan No2 was 0.08 +/- 0.03 mm (range, 0.04-0.11 mm). As far as the stability of registration was concerned, successful registration with a stable optimal position was obtained with a maximum variability of less than 0.1 mm. The results of this study showed that semiautomatic sequential triple voxel-based rigid registration of the triple CBCT scans augmented the 3-D virtual skull model with detailed occlusal and intercuspidation data in a highly accurate and robust way. The method is therefore appropriate and valid for 3-D virtual orthognathic surgery planning in the clinical routine.
authors.affiliation: Division of Maxillo-Facial Surgery, Department of Surgery, General Hospital St-Jan Bruges, Ruddershove, Bruges, Belgium. gwen.swennen@azbrugge.be
authors.forename: Gwen R J
authors.initials: GR
authors.lastname: Swennen
authors.forename: Wouter
authors.initials: W
authors.lastname: Mollemans
authors.forename: Calix
authors.initials: C
authors.lastname: De Clercq
authors.forename: Johan
authors.initials: J
authors.lastname: Abeloos
authors.forename: Philippe
authors.initials: P
authors.lastname: Lamoral
authors.forename: Frank
authors.initials: F
authors.lastname: Lippens
authors.forename: Nathalie
authors.initials: N
authors.lastname: Neyt
authors.forename: Jan
authors.initials: J
authors.lastname: Casselman
authors.forename: Filip
authors.initials: F
authors.lastname: Schutyser
mesh_terms: D000465:Algorithms; D016302:Centric Relation; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003760:Dental Impression Materials; D003761:Dental Impression Technique / Q000295:instrumentation; D003766:Dental Occlusion; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007574:Jaw Relation Record / Q000295:instrumentation / Q000379:methods; D008953:Models, Anatomic; D056948:Orthognathic Surgical Procedures; D010347:Patient Care Planning; D010865:Pilot Projects; D012828:Silicones; D014584:User-Computer Interface; D014716:Vertical Dimension
chemical_list: D003760:Dental Impression Materials; D012828:Silicones