-
Journal of the Mechanical Behavior of... Apr 2020of a mechanism of bone cutting has an important theoretical and practical significance for orthopaedic surgeries. In this study, the mechanism of material removal in...
of a mechanism of bone cutting has an important theoretical and practical significance for orthopaedic surgeries. In this study, the mechanism of material removal in orthogonal cutting of cortical bone is investigated. Chip morphology and crack propagation in cortical bone for various cutting directions and depth-of-cut (DOC) levels are analysed, with consideration of microstructural and sub-microstructural features and material anisotropy. Effects of different material properties of osteons, interstitial matrix and cement lines on chip morphology and crack propagation are elucidated for different cutting directions. This study revealed that differences in chip morphology for various DOCs were due to comparable sizes of the osteons, lamellae and DOC. Acquired force signals and recorded high-speed videos revealed the reasons of fluctuations of dynamic components in tests. Meanwhile, a frequency-domain analysis of force signals showed a frequency difference between formation of a bulk fractured chip and small debris for different cutting directions. In addition, SEM images of the top and side surfaces of the machined bone were obtained. Thus, the analysis of the cutting force and surface damage validated the character of chip formation and explained the material-removal mechanism. This study reveals the mechanism of chip formation in the orthogonal cutting of the cortical bone, demonstrating importance of the correlation between the chip morphologies, the depth of cut and the microstructure and sub-microstructure of the cortical bone. For the first time, it assessed the fluctuations of cutting forces, accompanying chip formation, in time and frequency domains. These findings provide fundamental information important for analysis of cutting-induced damage of the bone tissue, optimization of the cutting process and clinical applications of orthopaedic instruments.
Topics: Bone and Bones; Cortical Bone; Haversian System; Mechanical Phenomena; Orthopedic Procedures
PubMed: 31929098
DOI: 10.1016/j.jmbbm.2020.103618 -
Journal of the Mechanical Behavior of... Oct 2022This computational study addresses new biomimetic load-bearing implants designed to treat long bone critical-sized defects in a proximal diaphysis region. The design...
This computational study addresses new biomimetic load-bearing implants designed to treat long bone critical-sized defects in a proximal diaphysis region. The design encompasses two strategies: a Haversian bone-mimicking approach for cortical bone and lattices based on triply periodic minimal surfaces (TPMS) for trabecular bone. Compression tests are modeled computationally via a non-linear finite element analysis with Ti6Al4V alloy as a base material. Nine topologies resembling cortical bone are generated as hollow cylinders with different channel arrangements simulating Haversian (longitudinal) and Volkmann (transverse) canals to achieve properties like those of a human cortical bone (Strategy I). Then, the selected optimal structure from Strategy I is merged with the trabecular bone part represented by four types of TPMS-based lattices (Diamond, Primitive, Split-P, and Gyroid) with the same relative density to imitate the whole bone structure. The Strategy I resulted in finding a hollow cylinder including Haversian and Volkmann canals, optimized in canals number, shape, and orientation to achieve mechanical behavior close to human cortical bone. The surface area and volume created by such canals have the maximum values among all studied combinations of transverse and longitudinal channels. Strategy II reveals the effect of interior design on the load-bearing capacity of the whole component. Between four types of selected TPMS, Diamond-based lattice and Split-P have more uniform stress distribution, resulting in a superior load-bearing efficiency than Gyroid and Primitive-based design showing less uniformity. This work offers a new design of the bone-mimicking implant, with cortical and trabecular bone components, to repair long bone critical-sized defects.
Topics: Biomimetics; Diamond; Finite Element Analysis; Haversian System; Humans; Porosity; Prostheses and Implants
PubMed: 35872461
DOI: 10.1016/j.jmbbm.2022.105370 -
Brazilian Dental Journal 2021Aiming to evaluate cortical bone microarchitecture and osteonal morphology after irradiation, twelve male New Zealand rabbits were used. The animals were divided:...
Aiming to evaluate cortical bone microarchitecture and osteonal morphology after irradiation, twelve male New Zealand rabbits were used. The animals were divided: control group (no radiation-NIr); and 3 irradiated groups, sacrificed after: 7 (Ir7d); 14 (Ir14d) and 21 (Ir21d) days. A single radiation dose of 30 Gy was used. Computed microtomography analyzed the cortical microarchitecture: cortical thickness (CtTh), bone volume (BV), total porosity (Ct.Po), intracortical porosity (CtPo-cl), channel/pore number (Po.N), fractal dimension (FD) and degree of anisotropy (Ct.DA). After scan, osteonal morphology was histologically assessed by means: area and perimeter of the osteons (O.Ar; O.p) and of the Haversian canals (C.Ar; C.p). Microtomographic analysis were performed by ANOVA, followed by Tukey and Dunnet tests. Osteon morphology analyses were performed by Kruskal-Wallis, and test Dunn's. Cortical thickness was significant difference (p<0.010) between the NIr and irradiated groups, with thicker cortex at Ir7d (1.15±0.09). The intracortical porosity revealed significant difference (p<0.001) between irradiated groups and NIr, with lower value for Ir7d (0.29±0.09). Bone volume was lower in Ir14d compared to control. Area and perimeter of the osteons were statistically different (p<0.0001) between NIr and Ir7d. Haversian canals also revealed lower values (p<0.0001) in Ir7d (80.57±9.3; 31.63±6.5) compared to NIr and irradiated groups. Cortical microarchitecture was affected by radiation, and the effects appear to be time-dependent, mostly regarding the osteons morphology at the initial days. Cortex structure in Ir21d revealed similarities to control suggesting that microarchitecture resembles normal condition after a period.
Topics: Animals; Bone and Bones; Cortical Bone; Fractals; Haversian System; Male; Porosity; Rabbits
PubMed: 33914008
DOI: 10.1590/0103-6440202103384 -
Bone Reports Jun 2021Diaphyseal long bone cortical tissue from 30 patients with lethal perinatal Sillence II and progressively deforming Sillence III osteogenesis imperfecta (OI) has been...
Histopathology of osteogenesis imperfecta bone. Supramolecular assessment of cells and matrices in the context of woven and lamellar bone formation using light, polarization and ultrastructural microscopy.
Diaphyseal long bone cortical tissue from 30 patients with lethal perinatal Sillence II and progressively deforming Sillence III osteogenesis imperfecta (OI) has been studied at multiple levels of structural resolution. Interpretation in the context of woven to lamellar bone formation by mesenchymal osteoblasts (MOBLs) and surface osteoblasts (SOBLs) respectively demonstrates lamellar on woven bone synthesis as an obligate self-assembly mechanism and bone synthesis following the normal developmental pattern but showing variable delay in maturation caused by structurally abnormal or insufficient amounts of collagen matrix. The more severe the variant of OI is, the greater the persistence of woven bone and the more immature the structural pattern; the pattern shifts to a structurally stronger lamellar arrangement once a threshold accumulation for an adequate scaffold of woven bone has been reached. Woven bone alone characterizes lethal perinatal variants; variable amounts of woven and lamellar bone occur in progressively deforming variants; and lamellar bone increasingly forms rudimentary and then partially compacted osteons not reaching full compaction. At differing levels of microscopic resolution: lamellar bone is characterized by short, obliquely oriented lamellae with a mosaic appearance in progressively deforming forms; polarization defines tissue conformations and localizes initiation of lamellar formation; ultrastructure of bone forming cells shows markedly dilated rough endoplasmic reticulum (RER) and prominent Golgi bodies with disorganized cisternae and swollen dispersed tubules and vesicles, structural indications of storage disorder/stress responses and mitochondrial swelling in cells with massively dilated RER indicating apoptosis; ultrastructural matrix assessments in woven bone show randomly oriented individual fibrils but also short pericellular bundles of parallel oriented fibrils positioned obliquely and oriented randomly to one another and in lamellar bone show unidirectional fibrils that deviate at slight angles to adjacent bundles and obliquely oriented fibril groups consistent with twisted plywood fibril organization. Histomorphometric indices, designed specifically to document woven and lamellar conformations in normal and OI bone, establish ratios for: i) indicating the percentage of an area occupied by cells (cellularity index) and ii) (pericellular matrix domains). Woven bone is more cellular than lamellar bone and OI bone is more cellular than normal bone, but these findings occur in a highly specific fashion with values (high to low) encompassing OI woven, normal woven, OI lamellar and normal lamellar conformations. Conversely, for the ratio, pericellular matrix accumulations in OI woven are smallest and normal lamellar largest. Since genotype-phenotype correlation is not definitive, interposing histologic/structural analysis allowing for a genotype-histopathologic-phenotype correlation will greatly enhance understanding and clinical management of OI.
PubMed: 33665234
DOI: 10.1016/j.bonr.2020.100734 -
Journal of Artificial Organs : the... Jun 2021In Japan, where allograft bone transplantation is not widespread, prospects for artificial bones are very high. Therefore, artificial bones with various compositions,... (Review)
Review
In Japan, where allograft bone transplantation is not widespread, prospects for artificial bones are very high. Therefore, artificial bones with various compositions, porous structures, and porosities have been developed and employed for clinical use. Both Affinos and Regenos (made of beta-tricalcium phosphate and hydroxyapatite, respectively) are artificial bones with a unique unidirectional porous structure, in which pores with a diameter suitable for tissue penetration (25-300 μm) are aligned in one direction. The unidirectional porous structure allows rapid penetration of blood deep into the materials by a capillary effect. In animal experiments, Affinos showed well-balanced resorption and was replaced with the host's own bone from an early stage after implantation and new bone formation and remodeling were observed in the cortical bone and medullary cavity. When implanted for clinical situation, resorption from an early stage and good replacement with the patient's own bone were also observed. Regenos has an internal osteon-like material and a vascular-like structure that is maintained within the pores even after long-term implantation, as noted in an animal experiment. When implanted for clinical situation, good osteoconductivity was observed from an early stage of implantation. In addition, the material was observed to be slowly absorbed over time in some cases. We have discussed the beneficial effects of combining teriparatide and platelet-rich plasma impregnation and the potential prospects of these artificial bones.
Topics: Animals; Biocompatible Materials; Bone Regeneration; Bone Substitutes; Bone Transplantation; Calcium Phosphates; Durapatite; Humans; Japan; Porosity; Prostheses and Implants
PubMed: 33893573
DOI: 10.1007/s10047-021-01270-8 -
American Journal of Physical... Aug 2019Histomorphometric studies show consistent links between physical activity patterns and the microstructure underlying the size and shape of bone. Here, we adopt a...
OBJECTIVES
Histomorphometric studies show consistent links between physical activity patterns and the microstructure underlying the size and shape of bone. Here, we adopt a combined bone approach to explore variation in microstructure of ribs and humeri related to physical activity and historical records of manual labor in skeletal samples of children (n = 175) from medieval England. The humerus reflects greater biomechanically induced microstructural variation than the rib which is used here as a control. Variation in microstructure is sought between regions in England (Canterbury, York, Newcastle), and between high- and low-status children from Canterbury.
MATERIALS AND METHODS
Thin-sections were prepared from the humerus or rib and features of bone remodeling were recorded using high-resolution microscopy and image analysis software.
RESULTS
The density and size of secondary osteons in the humerus differed significantly in children from Canterbury when compared to those from York and Newcastle. Among the older children, secondary osteon circularity and diameter differed significantly between higher and lower status children.
DISCUSSION
By applying bone remodeling principles to the histomorphometric data, we infer that medieval children in Canterbury engaged in less physically demanding activities than children from York or Newcastle. Within Canterbury, high-status and low-status children experienced similar biomechanical loading until around 7 years of age. After this age low-status children performed activities that resulted in more habitual loading on their arm bones than the high-status children. This inferred change in physical activity is consistent with historical textual evidence that describes children entering the work force at this age.
Topics: Adolescent; Anthropology, Physical; Bone Remodeling; Child; Child, Preschool; England; Exercise; Haversian System; History, Medieval; Humans; Humerus; Microscopy; Ribs; Social Class
PubMed: 31087660
DOI: 10.1002/ajpa.23853 -
Annals of Anatomy = Anatomischer... Apr 2023There is a genetic component to the minimum effective strain (MES)-a threshold which determines when bone will adapt to function-which suggests ancestry should play a...
BACKGROUND
There is a genetic component to the minimum effective strain (MES)-a threshold which determines when bone will adapt to function-which suggests ancestry should play a role in bone (re)modelling. Further elucidating this is difficult in living human populations because of the high global genetic admixture. We examined femora from an anthropological skeletal assemblage (Mán Bạc, Vietnam) representing distinct ancestral groups. We tested whether femur morphological and histological markers of modelling and remodelling differed between ancestries despite their similar lifestyles.
METHODS
Static histomorphometry data collected from subperiosteal cortical bone of the femoral midshaft, and gross morphometric measures of femur robusticity, were studied in 17 individuals from the Mán Bạc collection dated to 1906-1523 cal. BC. This assemblage represents agricultural migrants with affinity to East Asian groups, who integrated with the local hunter-gatherers with affinity to Australo-Papuan groups during the mid-Holocene. Femur robusticity and histology data were compared between groups of 'Migrant' (n = 8), 'Admixed' (n = 4), and 'Local' (n = 5).
RESULTS
Local individuals had more robust femoral diaphyses with greater secondary osteon densities, and relatively large secondary osteon and Haversian canal parameters than the migrants. The Migrant group showed gracile femoral shafts with the least dense bone made up of small secondary osteons and Haversian canals. The Admixed individuals fell between the Migrant and Local categories in terms of their femoral data. However, we also found that measures of how densely bone is remodelled per unit area were in a tight range across all three ancestries.
CONCLUSIONS
Bone modelling and remodelling markers varied with ancestral histories in our sample. This suggests that there is an ancestry related predisposition to bone optimising its metabolic expenditure likely in relation to the MES. Our results stress the need to incorporate population genetic history into hierarchical bone analyses. Understanding ancestry effects on bone morphology has implications for interpreting biomechanical loading history in past and modern human populations.
Topics: Humans; Vietnam; Femur; Lower Extremity; Haversian System; Histological Techniques
PubMed: 36696927
DOI: 10.1016/j.aanat.2023.152054 -
Bulletin of Experimental Biology and... Jul 2021We studied immunolocalization of CD29, CD44, osteocalcin, and TGF-β1 in the bone tissue of the mandible of miniature pigs with extra-bone fixation of a free gingival...
We studied immunolocalization of CD29, CD44, osteocalcin, and TGF-β1 in the bone tissue of the mandible of miniature pigs with extra-bone fixation of a free gingival graft. Three months after surgery, neoosteogenesis foci with high expression of the studied markers were found in the contact area of the free gingival graft with the alveolar bone. The markers were localized in the layer of external circumferential lamellae, on the surface of concentric lamellae of the growing osteons, and in the connective tissue of the Haversian canals. TGF-β1-immunopositive cells predominated in the connective tissue of the Haversian and Volkmann canals and in the adventitia and inner lining of the vascular wall. The established morphochemical patterns of osteogenous cells indicate significant reparative capabilities of a free gingival graft and allows considering it as an effective osteoinductive factor.
Topics: Alveolar Bone Grafting; Animals; Biomarkers; Bone Nails; Gene Expression; Gingiva; Hyaluronan Receptors; Integrin beta1; Male; Mandible; Osteocalcin; Osteogenesis; Regeneration; Surgical Fixation Devices; Swine; Swine, Miniature; Transforming Growth Factor beta1; Transplants
PubMed: 34292444
DOI: 10.1007/s10517-021-05237-w -
Biomaterials Advances Feb 2023Despite advances in bone tissue engineering, fabricating a scaffold which can be used as an implant for large bone defects remains challenge. One of the great importance...
Despite advances in bone tissue engineering, fabricating a scaffold which can be used as an implant for large bone defects remains challenge. One of the great importance in fabricating a biomimetic bone implant is considering the possibility of the integration of the structure and function of implants with hierarchical structure of bone. Herein, we propose a method to mimic the structural unit of compact bone, osteon, with spatial pattern of human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (hMSCs) in the adjacent layers that mimic Haversian canal and lamella, respectively. To this end, coaxial extrusion-based bioprinting technique via a customized quadruple-layer core-shell nozzle was employed. 3D implant scaffold-cell construct was fabricated by using polyethylene glycol as a hollowing agent in the first layer, gelatin methacryloyl (GelMA) and alginate blended hydrogel encapsulating HUVEC cells with vascular endothelial growth factor nanoparticles in the second layer (vasculogenic layer) to mimic vascular vessel, and GelMA and alginate blended hydrogel containing hMSCs cells in the outer osteogenic layer to imitate lamella. Two types of bone minerals, whitlockite and hydroxyapatite, were incorporated in osteogenic layer to induce osteoblastic differentiation and enhance mechanical properties (the young's modules of nanocomposite increased from 35 kPa to 80 kPa). In-vitro evaluations demonstrated high cell viability (94 % within 10 days) and proliferation. Furthermore, ALP enzyme activity increased considerably within 2 weeks and mineralized extra cellular matrix considerably produced within 3 weeks. Also, a significant increase in osteogenic markers was observed indicating the presence of differentiated osteoblast cells. Therefore, the work indicates the potential of single step 3D bioprinting process to fabricate biomimetic osteons to use as bone grafts for regeneration.
Topics: Humans; Alginates; Bioprinting; Haversian System; Human Umbilical Vein Endothelial Cells; Hydrogels; Nanogels; Tissue Scaffolds; Vascular Endothelial Growth Factor A; Printing, Three-Dimensional
PubMed: 36584583
DOI: 10.1016/j.bioadv.2022.213254 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Apr 2023This study aimed to investigate the effect of new biomimetic micro/nano surfaces on the osteoclastic differentiation of RAW264.7 macrophages by simulating natural...
OBJECTIVES
This study aimed to investigate the effect of new biomimetic micro/nano surfaces on the osteoclastic differentiation of RAW264.7 macrophages by simulating natural osteons for the design of concentric circular structures and modifying graphene oxide (GO).
METHODS
The groups were divided into smooth titanium surface group (SS), concentric microgrooved titanium surface group (CMS), and microgroove modified with GO group (GO-CMS). The physicochemical properties of the material surfaces were studied using scanning electron microscopy (SEM), contact-angle measurement, atomic force microscopy, X-ray photoelectron spectroscopy analysis, and Raman spectroscopy. The effect of the modified material surface on the cell biological behavior of RAW264.7 was investigated by cell-activity assay, SEM, and laser confocal microscopy. The effect on the osteoclastic differentiation of macrophages was investiga-ted by tartrate-resistant acid phosphatase (TRAP) immunofluorescence staining and quantitative real-time polymerase chain reaction (qRT-PCR) experiments.
RESULTS
Macrophages were arranged in concentric circles along the microgrooves, and after modification with GO, the oxygen-containing groups on the surface of the material increased and hydrophilicity increased. Osteoclasts in the GO-CMS group were small in size and number and had the lowest TRAP expression. Although it promoted the proliferation of macrophages in the GO-CMS group, the expression of osteoclastic differentiation-related genes was lower than that in the SS group, and the difference was statistically significant (<0.05).
CONCLUSIONS
Concentric circular microgrooves restricted the fusion of osteoclasts and the formation of sealing zones. Osteomimetic concentric microgrooves modified with GO inhibited the osteoclastic differentiation of RAW 264.7 macrophages.
Topics: Graphite; Titanium; Haversian System; Macrophages; Cell Differentiation; Oxides; Surface Properties
PubMed: 37056182
DOI: 10.7518/hxkq.2023.2022354