- Contribution of Tissue Composition to Bone Material Properties
Melissa Kurtis Micou, Dawn Kilkenny in A Laboratory Course in Tissue Engineering, 2013
Cortical bone (also known as compact bone) lines the exterior surface of most bones. In cortical bone, the bone tissue is organized into cylindrical structures known as osteons that are composed of concentric lamellae, or plates of bone. Due to its low porosity, cortical bone tends to be stronger and heavier than trabecular bone (also called spongy or cancellous bone). Trabecular bone is found in vertebrae and at the ends of long bones, and is organized into trabecules (struts), which provide trabecular bone with its characteristic porous structure. The higher porosity makes it lighter and somewhat weaker than cortical bone, with a strong correlation between mechanical properties and the degree of porosity (Ethier and Simmons 2007). Consequently, the microarchitecture of bone plays an important role in determining its mechanical properties.
Bone Structure and Material Properties
Z. Yang in Finite Element Analysis for Biomedical Engineering Applications, 2019
Chapter 2 introduces bone structure, including its material properties. Bone is composed of both fluid and solid elements. In its solid part, apatite crystals are inserted into collagen to build a composite material that makes bone structure, with the Young's modulus between that of apatite and collagen. Bone structure also changes relevant to its stress-state. For perspective on the material properties of bone, bone is linear in a particular range of the strain and is very sensitive to the strain rate. Compared to cortical bone, cancellous bone is extremely anisotropic and nonhomogeneous. However, cortical bone is more than 40 times stiffer than cancellous bone, which makes cortical bone sustain greater stress, but less strain before failure.
Biomechanical Analysis of Long Bones Provides the Crucial Break in Decedent Identification
Heather M. Garvin, Natalie R. Langley in Case Studies in Forensic Anthropology, 2019
This chapter demonstrates how long bone biomechanical analysis was used to help identify the body of a woman discovered near a small Midwest town. It focuses on the periosteal, endosteal, and intracortical envelopes, which are prominent in the bone shaft. Tall and heavy individuals, for example, typically have relatively larger shaft diameters than shorter and lighter individuals to compensate for the greater forces experienced by the bone. Biomechanical analyses examine the size and shape of bones, especially long bones of the upper and lower limbs. Bone cells known as osteocytes detect strain, and bone responds by adding bone to specific locations to reduce future strain or by removing bone in areas where strain is low. According to the Mechanostat model, increased strain will result in the deposition of bone on the periosteal surface through modeling, retarded bone loss on the endosteal surface during modeling and remodeling, and decreased porosity of the cortical bone during remodeling.
Comparing the influence of crestal cortical bone and sinus floor cortical bone in posterior maxilla bi-cortical dental implantation: A three-dimensional finite element analysis
Published in Acta Odontologica Scandinavica, 2015
Xu Yan, Xinwen Zhang, Weichao Chi, Hongjun Ai, Lin Wu
Objective. This study aimed to compare the influence of alveolar ridge cortical bone and sinus floor cortical bone in sinus areabi-cortical dental implantation by means of 3D finite element analysis. Materials and methods. Three-dimensional finite element (FE) models in a posterior maxillary region with sinus membrane and the same height of alveolar ridge of 10 mm were generated according to the anatomical data of the sinus area. They were either with fixed thickness of crestal cortical bone and variable thickness of sinus floor cortical bone or vice versa. Ten models were assumed to be under immediate loading or conventional loading. The standard implant model based on the Nobel Biocare implant system was created via computer-aided design software. All materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied. Results. Von Mises stress mainly concentrated on the surface of crestal cortical bone around the implant neck. For all the models, both the axial and buccolingual resonance frequencies of conventional loading were higher than those of immediate loading; however, the difference is less than 5%. Conclusion. The results showed that bi-cortical implant in sinus area increased the stability of the implant, especially for immediately loading implantation. The thickness of both crestal cortical bone and sinus floor cortical bone influenced implant micromotion and stress distribution; however, crestal cortical bone may be more important than sinus floor cortical bone.
Finite element modelling of implant designs and cortical bone thickness on stress distribution in maxillary type IV bone
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2014
Chou I-Chiang, Lee Shyh-Yuan, Wu Ming-Chang, Chia-Wei Sun, Cho-Pei Jiang
The aims of this study were to examine the effect of implant neck design and cortical bone thickness using 3D finite element analysis and to analyse the stability of clinical evidence based on micromotion and principal stress. Four commercial dental implants for a type IV bone and maxillary segments were created. Various parameters were considered, including the osseointegration condition, loading direction and cortical bone thickness. Micromotion and principal stresses were used to evaluate the failure of osseointegration and bone overloading, respectively. It was found that the maximum stress of the peri-implant bone decreased as cortical bone thickness increased. The micromotion level in full osseointegration is less than that in non-osseointegration and it also decreases as cortical bone thickness increases. The cortical bone thickness should be measured before surgery to help select a proper implant. In the early stage of implantation, the horizontal loading component induces stress concentration in bone around the implant neck more easily than does the vertical loading component, and this may result in crestal bone loss.
Biochemical Studies Of Otosclerosis: Protein and Enzymes in Stapedes and Cortical Bone
Published in Acta Oto-Laryngologica, 1969
N. Soifer, F. Altmann, G. L. Endahl, C. E. Holdsworth, K. Weaver
Significant differences in the amounts of extracted protein and in lac-tate dehydrogenasc activity were found between normal cortical bone obtained from the inner end of the posterior metal wall and cortical bone from the same area in otosclerotic patients. The amount of protein extracted was 32% lower in cortical bone from otosclerotic patients. The activity of lactate dehydrogenase was 51 % lower on a per milliliter extract basis and 2(5% lower on a per microgram protein basis in cortical bone obtained from otosclerotic patients as compared to normal cortical bone. Since cortical bone is rarely affected by otosclerosis, these results could support the hypothesis, previously suggested, that the disease is a manifestation of a generalized metabolic disorder characterized by biochemical changes in the supporting tissues. Differences were also found in the biochemical composition of stapedes from non-otosclerotic individuals as compared to stapedes from otoscìerotic patients. The activity of lactate dehydrogenase was lower in otosclerotic stapedes on both a per milliliter extract basis (percentage decrease, 38%) and a per microgram protein basis (percentage decrease, 49%). The activity of malate dehydrogenase was also lower in otosclerotic stapedes though not to the same degree as lactate dehydrogenase. An eightfold increase in alkaline phosphatase activity was found in otosclerotic stapedes as compared with normal. These results suggest that otosclerosis is characterized by abnormal levels of enzyme activity, notably by decreases in lactate and malate dehydrogenase activities and by an increase in alkaline phosphatase activity.