The aim of this study was to verify the reproducibility and accuracy of preoperative planning in maxilla repositioning surgery performed with the use of computer-aided design/manufacturing technologies and mixed reality surgical navigation, using new registration markers and the HoloLens headset. Eighteen patients with a mean age of 26.0 years were included. Postoperative evaluations were conducted by comparing the preoperative virtual operation three-dimensional image (Tv) with the 1-month postoperative computed tomography image (T1). The three-dimensional surface analysis errors ranged from 79.9% to 97.1%, with an average error of 90.3%. In the point-based analysis, the errors at each point on the XYZ axes were calculated for Tv and T1 in all cases. The median signed value deviation of all calculated points on the XYZ axes was -0.03mm (range -2.93mm to 3.93mm). The median absolute value deviation of all calculated points on the XYZ axes was 0.38mm (range 0mm to 3.93mm). There were no statistically significant differences between any of the points on any of the axes. These values indicate that the method used was able to reproduce the maxilla position with high accuracy.

Background: Free vascularized fibular flaps are commonly used in jaw reconstruction. CT scan images of the fibula are used in digital planning of jaw reconstruction. In order to fully describe the anatomy of the fibula, an imaging study of the fibula was undertaken. The purpose of the present study was to examine the anatomical structure of the fibula using patient CT images. Methods: The CT scan images of fibulae of 20 patients were used for the study. The results of the analysis showed that, of the widths, the anterior border of the fibula to the posterior surface was the largest dimension. The shape type analysis showed that the triangular type was most prominent near the head of the fibula, and the irregular type was most prominent towards the lateral malleolus. Results: The results of height and width related to the long axis of implant installation showed that the width of the central section was the largest. With respect to the length of available bone volume, the length near the lateral malleolus was larger than that near the head of the fibula. The results showed that there were significant differences in size between male and female fibulae. Conclusion: The present study provides a CT scan based analysis of the anatomy of the fibula. Important information for the optimal site of installation of osseointegrated implants in fibular free flap reconstructions is also provided.

The purpose of this study was to reveal the structural properties that need to be considered in dental implant treatment by investigating differences between dentulous and edentulous maxillae in the three-dimensional (3D) microstructure of the incisive canals (ICs) and their surrounding bone. A total of 40 maxillary bones comprising 20 dentulous maxillae and 20 edentulous maxillae were imaged by micro-CT for 3D observation and measurement of the IC and alveolar bone in the anterior region of the IC. The Y-morphology canal was most frequently observed at 60% in dentulous maxilla and 55% in edentulous maxilla. There was a significant difference between dentulous and edentulous maxillae in IC diameter and volume, but no significant difference between the two in the major axis of the ICs. The anatomic structure surrounding the IC has limited area for implant placement. Therefore, where esthetic and long-term maintenance requirements are taken into account, careful attention is needed when setting the placement position. Also, due to the resorption of bone, edentulous maxillae have a different IC morphology from dentulous maxillae, and therefore, a cautious approach is required.

"Syringomyelia and hydrocephalus in a dog" published on 01 Sep 1996 by American Veterinary Medical Association.

The aim of this study was to clarify the influence of shear modulus on the analytical accuracy in peri-implant jaw bone simulation. A 3D finite element (FE) model was prepared based on micro-CT data obtained from images of a jawbone containing implants. A precise model that closely reproduced the trabecular architecture, and equivalent models that gave shear modulus values taking the trabecular architecture into account, were prepared. Displacement norms during loading were calculated, and the displacement error was evaluated. The model that gave shear modulus values taking the trabecular architecture into account showed an analytical error of around 10-20% in the cancellous bone region, while in the model that used incorrect shear modulus, the analytical error exceeded 40% in certain regions. The shear modulus should be evaluated precisely in addition to the Young modulus when considering the mechanics of peri-implant trabecular bone structure.