Cone-beam computed tomography (CBCT) is widely used in maxillofacial surgery. The CBCT image of the dental arches, however, is of insufficient quality to use in digital planning of orthognathic surgery. Several authors have described methods to integrate digital dental casts into CBCT scans, but all reported methods have drawbacks. The aim of this feasibility study is to present a new simplified method to integrate digital dental casts into CBCT scans. In a patient scheduled for orthognathic surgery, titanium markers were glued to the gingiva. Next, a CBCT scan and dental impressions were made. During the impression-taking procedure, the titanium markers were transferred to the impression. The impressions were scanned, and all CBCT datasets were exported in DICOM format. The two datasets were matched, and the dentition derived from the scanned impressions was transferred to the CBCT of the patient. After matching the two datasets, the average distance between the corresponding markers was 0.1？mm. This novel method allows for the integration of digital dental casts into CBCT scans, overcoming problems such as unwanted extra radiation exposure, distortion of soft tissues due to the use of bite jigs, and time-consuming digital data handling. 1. Introduction With the introduction of cone-beam computed tomography (CBCT), it became possible to obtain an accurate three-dimensional (3D) representation of the patient’s head with much lower radiation exposure than multislice computed tomography (MSCT) and a much higher information content compared to two-dimensional (2D) radiographs. This has proven to be a useful tool in diagnosis and treatment planning for certain problems in the maxillofacial region [1, 2]. When these 3D diagnostic methods are combined with 3D planning software, orthognathic surgery can be planned digitally and then transferred to the patient, which may reduce errors in terms of materials, construction of appliances, and hand skills [3]. Using software programs, 3D reconstructions can be modified, and simulation of the proposed surgery can be performed. Unfortunately, 3D virtual planning of orthognathic surgery still suffers from the disadvantages of CBCT imaging. For orthognathic surgery, a good representation of the dental surfaces and the occlusion is needed to properly position the dental arches. However, CBCT provides insufficient visualisation of the dental arches, since the teeth are not accurately rendered, and CBCT scans are subject to scattering from artefacts at the occlusal level [4–7]. Digital dental casts provide an accurate and
References
[1]
J. K. Mah, J. C. Huang, and H. Choo, “Practical applications of cone-beam computed tomography in orthodontics,” Journal of the American Dental Association, vol. 141, no. 10, pp. 7S–13S, 2010.
[2]
S. J. Merrett, N. A. Drage, and P. Durning, “Cone beam computed tomography: a useful tool in orthodontic diagnosis and treatment planning,” Journal of Orthodontics, vol. 36, no. 3, pp. 202–210, 2009.
[3]
J. Mah and A. Bumann, “Technology to create the three-dimensional patient record,” Seminars in Orthodontics, vol. 7, no. 4, pp. 251–257, 2001.
[4]
J. M. Plooij, T. J. J. Maal, P. Haers, W. A. Borstlap, A. M. Kuijpers-Jagtman, and S. J. Bergé, “Digital three-dimensional image fusion processes for planning and evaluating orthodontics and orthognathic surgery. A systematic review,” International Journal of Oral and Maxillofacial Surgery, vol. 40, no. 4, pp. 341–352, 2011.
[5]
J. Gateno, J. J. Xia, J. F. Teichgraeber et al., “Clinical feasibility of computer-aided surgical simulation (CASS) in the treatment of complex cranio-maxillofacial deformities,” Journal of Oral and Maxillofacial Surgery, vol. 65, no. 4, pp. 728–734, 2007.
[6]
J. Uechi, M. Okayama, T. Shibata et al., “A novel method for the 3-dimensional simulation of orthognathic surgery by using a multimodal image-fusion technique,” American Journal of Orthodontics and Dentofacial Orthopedics, vol. 130, no. 6, pp. 786–798, 2006.
[7]
H. Noh, W. Nabha, J. H. Cho, and H. S. Hwang, “Registration accuracy in the integration of laser-scanned dental images into maxillofacial cone-beam computed tomography images,” American Journal of Orthodontics and Dentofacial Orthopedics, vol. 140, no. 4, pp. 585–591, 2011.
[8]
P. S. Fleming, V. Marinho, and A. Johal, “Orthodontic measurements on digital study models compared with plaster models: a systematic review,” Orthodontics and Craniofacial Research, vol. 14, no. 1, pp. 1–16, 2011.
[9]
T. Komori, T. Takato, and K. Yokoyama, “Integration of dental models in a three-dimensional replica,” Journal of Oral and Maxillofacial Surgery, vol. 53, no. 5, pp. 621–624, 1995.
[10]
G. R. J. Swennen, W. Mollemans, C. De Clercq et al., “A cone-beam computed tomography triple scan procedure to obtain a three-dimensional augmented virtual skull model appropriate for orthognathic surgery planning,” Journal of Craniofacial Surgery, vol. 20, no. 2, pp. 297–307, 2009.
[11]
E. Nkenke, S. Zachow, M. Benz et al., “Fusion of computed tomography data and optical 3D images of the dentition for streak artefact correction in the simulation of orthognathic surgery,” Dentomaxillofacial Radiology, vol. 33, no. 4, pp. 226–232, 2004.
[12]
G. H. Golub and C. F. Van Loan, Matrix Computations, The Johns Hopkins University Press, Baltimore, Md, USA, 1996.
[13]
S. Inal, N. Yilmaz, C. Nisbet, and T. Güven？, “Biochemical and histopathological findings of N-Butyl-2-Cyanoacrylate in oral surgery: an experimental study,” Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology, vol. 102, no. 6, pp. e14–e17, 2006.
[14]
G. A. Greenhill and B. O'Regan, “Incidence of hypertrophic and keloid scars after N-butyl 2-cyanoacrylate tissue adhesive had been used to close parotidectomy wounds: a prospective study of 100 consecutive patients,” British Journal of Oral and Maxillofacial Surgery, vol. 47, no. 4, pp. 290–293, 2009.
[15]
T. J. J. Maal, J. M. Plooij, F. A. Rangel, W. Mollemans, F. A. C. Schutyser, and S. J. Bergé, “The accuracy of matching three-dimensional photographs with skin surfaces derived from cone-beam computed tomography,” International Journal of Oral and Maxillofacial Surgery, vol. 37, no. 7, pp. 641–646, 2008.
[16]
F. Maes, A. Collignon, D. Vandermeulen, G. Marchal, and P. Suetens, “Multimodality image registration by maximization of mutual information,” IEEE Transactions on Medical Imaging, vol. 16, no. 2, pp. 187–198, 1997.
