Prediction of strength of cortical bone in vitro by microcomputed tomography

Wachter, N. J.; Augat, Peter; Krischak, Gert; Sarkar, Michael R.; Mentzel, M.; Kinzl, L.; Claes, Lutz

doi:10.1016/s0268-0033(00)00092-9

Cited by 47 publications

(44 citation statements)

References 25 publications

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“…It is known that the bone volume fraction in adult compact bone can reach values as high as 95%; often referred to as a porosity of 5% (Wachter et al 2001;Cooper et al 2004). In the condylar bone, where no significant increase with age was observed, the bone volume fraction was much less.…”

Section: Discussionmentioning

confidence: 99%

Architecture and mineralization of developing cortical and trabecular bone of the mandible

et al. 2005

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Ossification of the presumptive trabecular bone in the mandibular condyle and the presumptive cortical bone in the mandibular corpus of the pig mandible was investigated during development, using micro-computed tomography (microCT). Three-dimensional architecture and mineralization characteristics were assessed from ten pigs of different developmental ages. In the condyle, increases in trabecular thickness and separation and a decrease in the trabecular number, led to an unchanged bone volume fraction. A conversion from rod-like into plate-like trabeculae was observed. Bone volume and trabecular thickness were always higher in the corpus, where an increase in bone volume fraction was caused by an increase in the trabecular thickness and a decrease in separation. A transition from a plate-like structure into a more compact structure took place. The average degree of mineralization in the condyle and the corpus increased with age. In the corpus, the degrees of mineralization were higher than in the condyle. The differences between the condyle and corpus and the changes with age could be explained by differences in the distribution of mineralization within the trabecular elements. Generally, the degrees of mineralization increased from the surface toward the centers of the trabecular elements, indicating growth of the trabecular elements by the surface apposition of new mineral.

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Section: Discussionmentioning

confidence: 99%

Architecture and mineralization of developing cortical and trabecular bone of the mandible

et al. 2005

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“…The elastic modulus of bone can be approximated using its mineral density (Fig. 8) (Krischak et al, 1999;Lang et al, 1988;Lotz, Gerhart & Hayes, 1990;Wachter et al, 2001;Wachter et al, 2002).…”

Section: Bone Morphometry 3d Rendering and Solid Modelling For Feamentioning

confidence: 99%

Orthodontic mechanotransduction and the role of the P2X7 receptor

Viecilli

Katona

Chen

et al. 2009

American Journal of Orthodontics and Dentofacial Orthopedics

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DEDICATIONTo my parents, who have supported my education. iv ACKNOWLEDGMENTSOne of the most important things I have learned during my PhD is the necessity of the existence of a working network of people that can help you achieve your goals. The more effectively this network functions, the higher the chance you will achieve the goals quickly.I would first like to thank my parents, who have unconditionally supported my decision to abandon a profitable private practice in Orthodontics, and return to humble student conditions while aiming for a full time academic career.I also thank my girlfriend Laura Kruter who has (almost always) been ok with my, some might say, not very sane ideas. Sometimes they do turn out fine, though (like this "PhD" one).I can hardly think of anyone else that could have complemented my work and ideas during this Program as well as Dr. Thomas Katona. While I was passionately conditioned to an idea, he was always rational and careful. While I was sometimes furious with a shortcoming, he was always temperate and humorous. When I ran into his office with some news about a project, he would always listen and almost never seem too busy to see me. While I was working and something went wrong, he would listen and wonder with me about the "whys" and "hows", instead of telling me what to do or express disappointment. He was even subject to some of my home culinary experiments. I was extremely fortunate to find someone that thought about science the same way I did, and that actually helped me with my project instead of just telling me what to do. I felt like we worked as a team, and that helped to increase my motivation during my studies. The third part of this project tested the role of the P2X7 receptor in the dentoalveolar morphology of C57B/6 mice. P2X7R KO (knockout) mice were compared to C57B/6 WT to identify differences in a maxillary molar and bone. Tooth dimensions viii were measured and 3D bone morphometry was conducted. No statistically significant differences were found between the two mouse types. P2X7R does not have a major effect on alveolar bone or tooth morphology.The final part examines the role of the P2X7 receptor in a controlled biomechanical model. Orthodontic mechanotransduction was compared in wild-type (WT) and P2X7R knock-out (KO) mice. Using Finite Element Analysis, mouse mechanics were scaled to produce typical human stress levels. Relationships between the biological responses and the calculated stresses were statistically tested and compared.There were direct relationships between certain stress magnitudes and root resorption and bone formation. Hyalinization and root and bone resorption were different in WT and KO. Orthodontic responses are related to the principal stress patterns in the PDL and the P2X7 receptor plays a significant role in their mechanotransduction.

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“…However, studies have appeared in which the thickness of the subchondral bone plate is explained as the result of local adaptation to long-term pressure in the joint, such as in the cortical bone (Carter, 1987;Milz et al, 1997;Muller-Gerbl, 1998). Recent studies have used micro-CT scanners, well known for investigating the trabecular structure in osteoporosis studies, to evaluate the cortical structure in a nondestructive fashion (Buchman et al, 1998;Wachter et al, 2001;Cooper et al, 2003).…”

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confidence: 99%

Development of the subchondral bone layer of the medial coronoid process of the canine ulna

Wolschrijn

Weijs

2005

Anat. Rec.

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The medial coronoid process (MCP) of the ulna takes part in the weightbearing function of the elbow in quadrupedal animals. In this study, the timing of development of a solid subchondral bone layer (SBL) of the MCP in the dog is investigated, as this might be important in the pathogenesis of the fractured medial coronoid process, a common disease in young dogs of larger breeds. The SBL is considered to make an important contribution to the strength of the MCP. In this study, the SBL is visualized at the humeral articular side (H-side) and in the radial notch (RN) via three-dimensional reconstructions of micro-CT scans (34 m voxel size) in nine young golden retrievers. After micro-CT scanning, the area was investigated histologically. Gradually, the appearance of the SBL on the H-side changes from a trabecular aspect to an even surface with gaps and finally to a completely even surface. The surface in the RN is still rough at 24 weeks after birth, although some consolidation has occurred. Initially, the enchondral ossification activity, as observed in the histological sections, is high, but later, when the intertrabecular spaces are filled in with calcified cartilage and bone, activity is less evident. Some vessels penetrated the SBL, but it is unclear if they account for all the gaps in the surface seen in micro-CT. In addition, the formation of a cortical structure of the proximal ulnar shaft could be visualized. The bony cortex is already even at the mediocaudal side of the proximal ulna 4 weeks after birth, but remains trabecular at the dorsal side until 6 weeks later. We hypothesize that the observed differences in the formation of an even SBL or cortex can be explained by mechanical factors. A smooth cortical layer has an even thickness and will be stronger than a cortex with varying thickness. In the MCP, compressive forces exerted by the humerus may be responsible for the early smoothening on the H-side. In the proximal ulna, the resistance to bending in the sagittal plane will depend mainly on the caudal surface of the ulna (and dorsal surface of the radius), surfaces furthest away from the neutral axis. At least the caudal ulna smoothened first, thus providing stiffness against bending at an early age.

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Prediction of strength of cortical bone in vitro by microcomputed tomography

Cited by 47 publications

References 25 publications

Architecture and mineralization of developing cortical and trabecular bone of the mandible

Architecture and mineralization of developing cortical and trabecular bone of the mandible

Orthodontic mechanotransduction and the role of the P2X7 receptor

Development of the subchondral bone layer of the medial coronoid process of the canine ulna

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