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BioMed Research International
Volume 2014 (2014), Article ID 276128, 6 pages
http://dx.doi.org/10.1155/2014/276128
Research Article

3D Assessment of Mandibular Growth Based on Image Registration: A Feasibility Study in a Rabbit Model

1Department of Oral Sciences, University of Otago, P.O. Box 647, Dunedin 9054, New Zealand
2Robotic System Laboratory (LSRO), Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
3Department of Oral Sciences, University of Naples Federico II, 80131 Naples, Italy

Received 14 September 2013; Revised 9 December 2013; Accepted 11 December 2013; Published 2 January 2014

Academic Editor: Daniel M. Laskin

Copyright © 2014 I. Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Our knowledge of mandibular growth mostly derives from cephalometric radiography, which has inherent limitations due to the two-dimensional (2D) nature of measurement. Objective. To assess 3D morphological changes occurring during growth in a rabbit mandible. Methods. Serial cone-beam computerised tomographic (CBCT) images were made of two New Zealand white rabbits, at baseline and eight weeks after surgical implantation of 1 mm diameter metallic spheres as fiducial markers. A third animal acted as an unoperated (no implant) control. CBCT images were segmented and registered in 3D (Implant Superimposition and Procrustes Method), and the remodelling pattern described used color maps. Registration accuracy was quantified by the maximal of the mean minimum distances and by the Hausdorff distance. Results. The mean error for image registration was 0.37 mm and never exceeded 1 mm. The implant-based superimposition showed most remodelling occurred at the mandibular ramus, with bone apposition posteriorly and vertical growth at the condyle. Conclusion. We propose a method to quantitatively describe bone remodelling in three dimensions, based on the use of bone implants as fiducial markers and CBCT as imaging modality. The method is feasible and represents a promising approach for experimental studies by comparing baseline growth patterns and testing the effects of growth-modification treatments.