An entire human head obtained at autopsy was micro-CT scanned in a nano/micro-CT scanner in a 6-hour long session.
Despite the size of the head, it could still be scanned with a pixel size of 70 μm. The aim of this study was to obtain an
optimal quality 3D data-set to be used as baseline control in a larger study comparing the image quality of various cone
beam CT systems currently used in dentistry.
The image quality of the micro-CT scans was indeed better than the ones of the clinical imaging modalities, both with
regard to noise and streak artifacts due to metal dental implants. Bony features in the jaws, like the trabecular
architecture and the thin wall of the alveolar bone were clearly visible. Therefore, the 3D micro-CT data-set can be used
as the gold standard for linear, angular, and volumetric measurements of anatomical features in and around the oral
cavity when comparing clinical imaging modalities.
The root/periodontal ligament/bone (RPB) interface is important for a correct understanding of the load transfer mechanism of masticatory forces and orthodontic loads. It is the aim of this study to assess the three-dimensional structure of the RPB interface using high-resolution microtomography. A human posterior jaw segment, obtained at
autopsy from a 22-year old male donor was first scanned using a tomograph at the HASYLAB/DESY synchrotron facility (Hamburg, Germany) at 31μm resolution. Afterwards the first molar and its surrounding bone were removed with a 10mm hollow core drill. From this cylindrical sample smaller samples were drilled out in the buccolingual direction with a 1.5mm hollow core drill. These samples were scanned at 4μm resolution. The scans of the entire segment showed alveolar bone with a thin lamina dura, supported by an intricate trabecular network. Although featuring numerous openings between the PDL and the bone marrow on the other side to allow blood vessels to transverse, the lamina dura seems smooth at this resolution. First at high resolution, however, it becomes evident that it is irregular with bony spiculae and pitted surfaces. Therefore the stresses in the bone during physiological or orthodontic loading are much higher than expected from a smooth continuous alveolus.
In this study the structure of the adult human dentoalveolar process is examined using conventional and synchrotron
radiation-based microtomography (SRμCT). Mandibular and maxillary segments containing two to five adjacent teeth
were harvested at autopsy from 49 adult donors. These segments were embedded in blocks of methylmetacrylate and
scanned using a conventional table-top μCT-scanner at a pixel size and slice thickness of 35 μm. A few segments were
also scanned at a synchrotron facility at an initial pixel size of 16.4 μm, which was binned by a factor 2 to result in an
effective voxel size of almost 32.8 μm. The three-dimensional reconstructions revealed how intricately the teeth are
supported by the alveolar bone. Furthermore, this support is highly inhomogeneous with respect to the buccal, mesial,
lingual and distal quadrants. Reflecting their various degrees of mineralization, tissues like bone, dentine, enamel and
cementum, could well be identified, especially in the scans made with SRμCT. Despite comparable voxel sizes, the
reconstructed data-sets obtained with conventional μCT were less detailed and somewhat fuzzy in appearance compared
to the data-sets of SRμCT. However, for quantification of macroscopical features like the thickness of the alveolar wall
or the presence of dehiscences/fenestrations this seemed sufficient.
This study explores the application of conventional micro tomography (μCT) and synchrotron radiation (SR) based μCT to evaluate the bone around titanium dental implants. The SR experiment was performed at beamline W2 of HASYLAB at DESY using a monochromatic X-ray beam of 50 keV. The testing material consisted of undecalcified bone segments harvested from the upper jaw of a macaca fascicularis monkey each containing a titanium dental implant. The results from the two different techniques were qualitatively compared with conventional histological sections examined under light microscopy. The SR-based μCT produced images that, especially at the bone-implant interface, are less noisy and sharper than the ones obtained with conventional μCT. For the proper evaluation of the implant-bone interface, only the SR-based μCT technique is able to display the areas of bony contact and visualize the true 3D structure of bone around dental implants correctly. This investigation shows that both conventional and SR-based μCT scanning techniques are non-destructive methods, which provide detailed images of bone. However with SR-based μCT it is possible to obtain an improved image quality of the bone surrounding dental implants, which display a level of detail comparable to histological sections. Therefore, SR-based μCT scanning could represent a valid, unbiased three-dimensional alternative to evaluate osseointegration of dental implants.
Osteons are longitudinally arranged cylindrical structures, which form the structural units of cortical bone. Cortical bone remodeling is closely related to the osteonal organization as newly formed osteons continuously replace older ones. The degree of mineralization in these new osteons is initially lower than in the existing bone as it takes time before osteons mature. Synchrotron radiation-based computed microtomography (μCT) and scanning acoustic microscopy (SAM) are two techniques, which have both sufficient spatial resolution and sensitivity to detect local variations in bone
density. The aim of this study was therefore to compare both techniques for the analysis of osteonal mineralization. Eight human cortical bone samples were scanned with both techniques and the corresponding images were matched. Synchrotron-based μCT is not affected by beam hardening and the gray values in the reconstructed images are directly related to the local mineral density. For cortical bone this means that immature osteons appear darker than their surrounding. In SAM-images the gray values are a measure of the acoustic impedance, which is a function of the local stiffness and the density. Comparison of the μCT and the SAM images of the cortical samples shows a good correspondence in the gray values of the individual osteons.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.