Bone Material Research Articles

Enhancing late postmortem interval prediction: a pilot study integrating proteomics and machine learning to distinguish human bone remains over 15 years

BackgroundDetermining the postmortem interval (PMI) accurately remains a significant challenge in forensic sciences, especially for intervals greater than 5 years (late PMI). Traditional methods often fail due to the extensive degradation of soft tissues, necessitating reliance on bone material examinations. The precision in estimating PMIs diminishes with time, particularly for intervals between 1 and 5 years, dropping to about 50% accuracy. This study aims to address this issue by identifying key protein biomarkers through proteomics and machine learning, ultimately enhancing the accuracy of PMI estimation for intervals exceeding 15 years.MethodsProteomic analysis was conducted using LC–MS/MS on skeletal remains, specifically focusing on the tibia and ribs. Protein identification was performed using two strategies: a tryptic-specific search and a semitryptic search, the latter being particularly beneficial in cases of natural protein degradation. The Random Forest algorithm was used to model protein abundance data, enabling the prediction of PMI. A thorough screening process, combining importance scores and SHAP values, was employed to identify the most informative proteins for model’s training and accuracy.ResultsA minimal set of three biomarkers—K1C13, PGS1, and CO3A1—was identified, significantly improving the prediction accuracy between PMIs of 15 and 20 years. The model, based on protein abundance data from semitryptic peptides in tibia samples, achieved sustained 100% accuracy across 100 iterations. In contrast, non-supervised methods like PCA and MCA did not yield comparable results. Additionally, the use of semitryptic peptides outperformed tryptic peptides, particularly in tibia proteomes, suggesting their potential reliability in late PMI prediction.ConclusionsDespite limitations such as sample size and PMI range, this study demonstrates the feasibility of combining proteomics and machine learning for accurate late PMI predictions. Future research should focus on broader PMI ranges and various bone types to further refine and standardize forensic proteomic methodologies for PMI estimation.

Numerical Investigation of Polymer-based Biomaterials for Artificial Hip Joint with Diverse Boundary Conditions

Background: Hip suffering is a serious concern for human health, which may be caused by arthritis, accidents, and childhood disorders; hence, man-made joints are the only option for restoring the function of natural hips and ensuring a comfortable life. To design an effective hip joint is a challenging task; there are myriads of novel designs continuously patented over the last two decades. Methods: The finite element approach was utilized in this extensive investigation to assess selfmated polymer-based biomaterials (PTFE, UHMWPE, and PEEK) with different boundary conditions. The numerical analysis was performed to find the stress intensity and deflection of the femoral head and the acetabular components; the evaluation was done critically with a 10-node quadratic tetrahedron element and different mesh intensities. Results: The detailed outcome showcases that the bare PEEK mated GO-PEEK has good load resistance and is affected by minimum stress and deflection, which is quantified at 20.89% less than the PTFE with GO-PEEK (M3) combination. This stress and deflection are quite higher than those of metal implants (Ti6Al4V) but comparatively more prominent materials for human cortical bone. Conclusion: This investigation proved the polymer-on-polymer combination effectively eliminates stress shielding and metal ion emission, reducing revision surgery and elevating implant longevity. Therefore, it was identified that PEEK-based polymer composites are the best-suited alternative substance for hip repair applications.

Prediction of bone ingrowth into a porous novel hip-stem: A finite element analysis integrated with mechanoregulatory algorithm.

Bone ingrowth into a porous implant is necessary for its long-term fixation. Although attempts have been made to quantify the peri-implant bone growth using finite element (FE) analysis integrated with mechanoregulatory algorithms, bone ingrowth into a porous cellular hip stem has scarcely been investigated. Using a three-dimensional (3D) FE model and mechanobiology-based numerical framework, the objective of this study was to predict the spatial distribution of evolutionary bone ingrowth into an uncemented novel porous hip stem proposed earlier by the authors. A CT-based FE macromodel of the implant-bone structure was developed. The bone material properties were assigned based on CT grey value. Peak musculoskeletal loading conditions, corresponding to level walking and stair climbing, were applied. The geometry of the implant-bone macromodel was divided into multiple submodels. A suitable mapping framework was used to transfer maximum nodal displacements from the FE macromodel to the cut boundaries of the FE submodels. CT grey value-based bone materials properties were assigned to the submodels. Thereafter, the submodels were solved and simulations of bone ingrowth were carried out using mechanoregulatory principle. A gradual increase in the average Young's modulus, from 1200 to 1500 MPa, of the bone tissue layer was observed considering all the submodels. The distal submodel exhibited 82% of bone ingrowth, whereas the proximal submodel experienced 65% bone ingrowth. Equilibrium in the bone ingrowth process was achieved in 7 weeks postoperatively, with a notable amount of bone ingrowth that should lead to biological fixation of the novel hip stem.

Research on silk fibroin composite materials for wet environment applications

Silk fibroin material has good mechanical properties and excellent biocompatibility as a natural biomaterial with broad application prospects. However, by applying regenerated silk fibroin in biomaterials with high mechanical strength requirements, such as bone materials, there are problems, such as insufficient mechanical properties and a significant decline in mechanical properties in the wet state. In this report, a silk fibroin composite that maintains high strength in the wet state was prepared by adding nano-SiO2 as a nano-strengthening filler to the silk protein material and employing an epoxy-based silane coupling agent KH560 as an interfacial reinforcing agent. The results showed that the dry compressive strength of the composite material was substantially increased compared with that of the pure silk protein material; the wet compressive strength was significantly increased compared with that of the pure silk fibroin material, and the decrease of the mechanical properties in the wet state was low. The cytotoxicity test results of the composites showed that the materials were not cytotoxic. Rat bone marrow mesenchymal stem cells were cultured on the surface of the composites, and the results indicated that the composites could support the proliferation of bone marrow mesenchymal stem cells. The silk fibroin nanocomposites developed in this work can be applied as bone repair materials.

Total body irradiation is associated with long-term deficits in femoral bone structure but not mechanical properties in male rhesus macaques.

Exposure to ionizing radiation for oncological therapy increases the risk for late-onset fractures in survivors. However, the effects of total body irradiation (TBI) on adult bone are not well-characterized. The primary aim of this study was to quantify the long-term effects of TBI on bone microstructure, material composition, and mechanical behavior in skeletally mature rhesus macaque (Macaca mulatta) non-human primates. Femora were obtained post-mortem from animals exposed to an acute dose of TBI (6.0-6.75Gy) nearly a decade earlier, age-matched non-irradiated controls, and non-irradiated young animals. The microstructure of femoral trabecular and cortical bone was assessed via micro-computed tomography. Material composition was evaluated by measuring total fluorescent advanced glycation end products (fAGEs). Cortical bone mechanical behavior was quantified via four-point bending and cyclic reference point indentation (cRPI). Animals exposed to TBI had slightly worse cortical microstructure, including lower cortical thickness (-11%, p = 0.037) and cortical area (-24%, p = 0.049), but similar fAGE content and mechanical properties as age-matched controls. Aging did not influence cortical microstructure, fAGE content, or cRPI measures but diminished femoral cortical post-yield properties, including toughness to fracture (-32%, p = 0.032). Because TBI was administered after the acquisition of peak bone mass, these results suggest that the skeletons of long-term survivors of adulthood TBI may be resilient, retaining or recovering their mechanical integrity during the post-treatment period, despite radiation-induced architectural deficits. Further investigation is necessary to better understand radiation-induced skeletal fragility in mature and immature bone to improve care for radiation patients of all ages.

Development of a novel 3D-printed dynamic anthropomorphic thorax phantom for evaluation of four-dimensional computed tomography

Background and purposeIn radiotherapy, the image quality of four-dimensional computed tomography (4DCT) is often degraded by artifacts resulting from breathing irregularities. Quality assurance mostly employ simplistic phantoms, not fully representing complexities and dynamics in patients. 3D-printing allows for design of highly customized phantoms. This study aims to validate the proof-of-concept of a realistic dynamic thorax phantom and its 4DCT application. Materials and methodsUsing 3D-printing, a realistic thorax phantom was produced with tissue-equivalent materials for soft tissue, bone, and compressible lungs, including bronchi and tumors. Lung compression was facilitated by motors simulating customized breathing curves with an added platform for application of monitoring systems. The phantom contained three tumors which were assessed in terms of tumor motion amplitude. Three 4DCT sequences and repeated static images for different lung compression levels were acquired to evaluate the reproducibility. Moreover, more complex patient-specific breathing patterns with irregularities were simulated. ResultsThe phantom showed a reproducibility of ±0.2 mm and ±0.4 mm in all directions for static 3DCT images and 4DCT images, respectively. Furthermore, the tumor close to the diaphragm showed higher amplitudes in the inferior/superior direction (13.9 mm) than lesions higher in the lungs (8.1 mm) as observed in patients. The more complex breathing patterns demonstrated commonly seen 4DCT artifacts. ConclusionThis study developed a dynamic 3D-printed thorax phantom, which simulated customized breathing patterns. The phantom represented a realistic anatomy and 4DCT scanning of it could create realistic artifacts, making it beneficial for 4DCT quality assurance or protocol optimization.

Bone-seeking tumor cells alter bone material quality parameters on the nanoscale in mice

Bone metastases related to breast and prostate cancer present with multiple challenges and skeletal related events like fragility fractures impair the quality of life of the patients significantly. To determine local alterations in bone material quality with bone metastasis, we subjected murine tibial specimens, generated after intratibial injections of either RM-1 prostate cancer cells or EO771 breast cancer cells into male and female mice respectively, to high-resolution imaging modalities. Small and wide-angle X-ray scattering showed unaltered mineral characteristics in the more osteosclerotic prostate cancer model, while the quantification of calcium weight percentage via backscattered electron microscopy determined minor differences along the perilacunar bone matrix. Further analyses of mineral and collagen characteristics were performed using Raman spectroscopy and focused ion beam electron microscopy. Our study indicates that alterations in nanochannel properties occur due to the presence of bone seeking tumor cells with more prevalent nanopores in the perilacunar matrix.

Simultaneous co-assembly of collagen and glycosaminoglycans to build a biomimetic extracellular matrix for bone regeneration

Glycosaminoglycans (GAGs), also known as shape modules, are considered junctions that help define the shape of collagen matrix and further promote mineralization during osteogenesis. Many attempts have been made to immobilize GAGs on assembled collagen to modify the latter's surface state. However, it remains unclear how GAGs spontaneously identify collagen molecules during fibrillogenesis in vivo. Understanding the relationship between GAGs and collagen from both the bone physiology and materials science perspectives is of fundamental interest. Here, we introduced hyaluronic acid (HA, a main member of GAGs) during collagen self-assembly, in a process called modification cooperating with self-assembly (MCS). The molecular docking and morphological studies revealed that HA can help define collagen monomer deposition and thus promote fibrillogenesis through steric hindrance or by directly forming hydrogen bonds. Meanwhile, HA acts as a templating chaperone (TC) to increase the local mineral concentration within intrafibrillar channels but does not initiate nucleation, thus improving the crystallinity of formed apatite. The scaffolds synthesized through MCS model significantly improved the physicochemical stability and mechanical strength of collagen-based scaffolds. The optimized scaffolds promoted in-situ osteogenesis by stimulating the osteogenic differentiation of bone mesenchymal stem cells, either in an osteogenic medium, or after implantation into critical calvarial defects. This study provides novel insights towards evolving engineering scaffolds from inert supports to functional substitutes.

Relationship between the heterogeneity in mechanical properties, bone density and composition parameters of cortical bone to design and develop bone scaffolds and implants: Analysis of bone microstructure

Bone is heterogeneous and anisotropic because its mechanical characteristics vary by anatomic location and loading direction. Previous research established a correlation between bone density, mineral, organic content, and porosity and mechanical qualities. Medical and bioengineering researchers can learn about bone heterogeneity and anisotropy by analysing bone density and later composition parameters across the bone diaphysis in both longitudinal and transverse orientations. This research examines bone density and composition parameters in bovine femoral cortical bone from higher, middle, and lower diaphysis regions and longitudinal and transverse orientations. At three homogeneous diaphysis sites, these properties did not alter in longitudinal or transverse orientations. At the upper and lower diaphysis locations, mineral and organic content were statistically different in both longitudinal and transverse orientations, contributing to anisotropy. At the middle location, all measured parameters were not statistically different. Transverse bone density and water heterogeneity were greater, while longitudinal values were higher for the other metrics. Upper and lower sites had increased bone variability due to %water, although mineral content was more homogenous. The longitudinal and transverse organic content and apparent density heterogeneity was greater at the middle position. At the later site, bone density and mineral content were more homogenous longitudinally and transversely. Lamellar bone microstructure with canalicular/vascular network, cavities, and holes contributed to bone materials' %water content. Collagen fibres contributed to bone material's organic composition, whereas intrafibrillar and extra fibrillar minerals contributed to its mineral content.

Fish species richness, resourse availability, and human selectivity reflected in the fish bone material from a medieval Franciscan friary in the Baltic Sea

Fish and fishing in the Baltic Sea during the Middle Ages is partly known through research on historical records and zooarchaeological materials, and combinations of them. Due to the uneven distribution of written records and research focus, much is known about the large-scale cod and herring fisheries in the southern parts of the Baltic Sea. However, in the northern parts of the Baltic Sea, both large-scale and small local fisheries are less researched. This article considers the species richness, resource availability, and human selection identifiable in these sources. Zooarchaeological material from the Franciscan friary on the island of Kökar in the Åland archipelago will be discussed in relation to zooarchaeological and written sources from the Castle of Kastelholm (Åland). Historical records identify the friary as having taxation rights to large-scale seasonal catches of cod in the outer archipelago; how the friary collected this toll is unclear. It has been assumed, based on the historical records, that cod was the most consumed fish at the site. This study revealed that the zooarchaeological assemblage does not support the interpretation of cod as the most important fish for consumption at the friary during the Medieval Period (AD 1450–1530).

Bone mechanical properties were altered in a mouse model of multiple myeloma bone disease

Multiple myeloma bone disease (MMBD) is characterized by the growth of malignant plasma cells in bone marrow, leading to an imbalance in bone (re)modeling favoring excessive resorption. Loss of bone mass and altered microstructure characterize MMBD in humans and preclinical animal models, although, no study to date has examined bone composition or material properties. We hypothesized that MMBD alters bone composition, mineral crystal properties and mechanical properties in the MOPC315.BM.Luc model after intra-tibial injection of myeloma cells and three weeks of daily in vivo tibial loading. Decreased cortical bone elastic modulus and hardness measured by nanoindentation of tibiae were observed in MM-injected mice compared to PBS-injected mice, whereas cortical bone composition, mineral crystal properties measured by Fourier-transform infrared imaging or small angle X-ray scattering, respectively remained unchanged. However, MM-injected mice had thinner cancellous bone mineral particles compared to PBS-injected mice. Mechanical loading did not lead to altered cortical bone composition, mineral structure, or mechanical properties in the context of MM. Unexpectedly, we observed the intra-tibial injection itself altered the material composition of bone, manifested by increased matrix mineralization and crystal size of the hydroxyapatite crystals in the bone matrix. In conclusion, our data suggest that mechanical stimuli can be used as an adjuvant bone anabolic therapy in patients with MMBD to rebuild bone with unaltered composition and mineral structure to reduce subsequent fracture risk.

Physical, chemical, and biological property of silk reinforced polycaprolactone composites for bone tissue engineering

To develop a biodegradable implantable bone material with compatible mechanics with the bone tissue, providing a new biomaterial for clinical bone repair and regeneration. Silk reinforced polycaprolactone composites (SPC) containing 20%, 40%, and 60% silk were prepared by layer-by-layer assembly and hot-pressing technology. Macroscopic morphology was observed and microstructure were observed by scanning electron microscopy, compressive mechanical properties were detected by compression test, surface wettability was detected by surface contact angle test, degradation of materials was observed after soaking in PBS for 180 days, and proliferation of MC3T3-E1 cells was detected by cell counting kit 8 assay. Six Sprague Dawley rats were subcutaneously implanted with polycaprolactone (PCL) and 20%-SPC, respectively. Masson staining was used to analyze the in vivo degradation behavior and vascularization effect within 180 days. The pore defects of the three SPC sections were relatively few. In the range of 20% to 60%, as the silk content increased and the PCL content decreased, the interlayer spacing of silk fabric decreased, and the fibers almost covered the entire cross-section. The compressive modulus and compressive strength of SPC showed an increasing trend, and the compressive modulus of 60%-SPC was slightly lower than that of 40%-SPC. There were significant differences in compressive modulus and compressive strength between the materials ( P<0.05). In vitro simulated fluid degradation experiments showed that the mass loss of the three types of SPC after 180 days of degradation was within 5%, with the highest mass loss observed in 60%-SPC. The differences in mass loss between the materials were significant ( P<0.05). As the silk content increased, the static water contact angle of each material gradually decreased, and all could promote the proliferation of MC3T3-E1 cells. The subcutaneous degradation experiment in rats showed that 20%-SPC began to degrade at 30 days after implantation, and material degradation and vascularization were significant at 180 days, which was in sharp contrast to PCL. SPC has the mechanical and hydrophilic properties that are compatible with bone tissue. It maintains its mechanical strength for a long time in a simulated body fluid environment in vitro, and achieves dynamic synchronization of material degradation, tissue regeneration, and vascularization through the body's immune regulation mechanism in vivo. It is expected to provide a new type of implant material for clinical bone repair.

A critical assessment of the diatom test of rib bone marrow as a supporting procedure in the case of drowning

Diatoms (Bacillariophyta), being single-celled photosynthetic organisms, are widely distributed in aquatic ecosystems around the globe. Their exoskeletons are resistant to most environmental factors as well as chemical reagents in laboratory settings. Moreover, the ornamentation featured on exoskeletons can be used to identify individual diatomaceous species. As a result, the detection of diatoms in the internal organs, and especially rib marrow, of corpses found in water can serve as an important tool for diagnosing drowning as the cause of death as long as passive postmortem penetration of diatoms into those organs is excluded. In the environmental experiments described in this paper, diatoms were detected in rib marrow only when contamination resulted from a mechanical breach of bone integrity and structure, irrespective of the residence time of bone material in the aquatic environment. Our research suggests that the presence of diatom in the rib marrow may be the gold standard in the diagnosis of drowning in the future. Our animal model research dispels one of the doubts, such as the possibility of passive penetration of diatoms into the bone marrow, which is still under discussion in the forensic medicine community.

Assessment of artificial bone materials with different structural pore sizes obtained from 3D printed polycaprolactone/β-tricalcium phosphate (3D PCL/β-TCP)

Artificial bone is the alternative candidate for the bone defect treatment under the circumstance that there exits enormous challenge to remedy the bone defect caused by attributes like trauma and tumors. However, the impact of pore size discrepancy for regulating new bone generation is still ambiguous. Using direct 3D printing technology, customized 3D polycaprolactone/β-tricalcium phosphate (PCL/β-TCP) artificial bones with different structural pore sizes (1.8, 2.0, 2.3, 2.5, and 2.8 mm) were successfully prepared, abbreviated as the 3D PCL/β-TCP. 3D PCL/β-TCP exhibited a 3D porous structure morphology similar to natural bone and possessed outstanding mechanical properties. Computational fluid dynamics analysis indicated that as the structural pore size increased from 1.8 to 2.8 mm, both velocity difference (from 4.64 × 10-5to 7.23 × 10-6m s-1) and depressurization (from 7.17 × 10-2to 2.25 × 10-2Pa) decreased as the medium passed through.In vitrobiomimetic mineralization experiments confirmed that 3D PCL/β-TCP artificial bones could induce calcium-phosphate complex generation within 4 weeks. Moreover, CCK-8 and Calcein AM live cell staining experiments demonstrated that 3D PCL/β-TCP artificial bones with different structural pore sizes exhibited advantageous cell compatibility, promoting MC3T3-E1 cell proliferation and adhesion.In vivoexperiments in rats further indicated that 3D PCL/β-TCP artificial bones with different structural pore sizes promoted new bone formation, with the 2.5 mm group showing the most significant effect. In conclusion, 3D PCL/β-TCP artificial bone with different structural pore sizes could promote new bone formation and 2.5 mm group was the recommended for the bone defect repair.

Material Homogenization of Human Femur Bone Material Using a New Weighted Approach

Abstract The design of efficient and safe biocompatible artificial implants for bone replacement and reconstructions requires a thorough understanding of natural bone material. A new homogenization approach is therefore used to predict effective material properties of the human femur bone. The bone structure is idealized as a functionally graded composite made of different quantities of a collagen protein matrix reinforced by hydroxyapatite mineral acting as the filler. Two distinct composite models were investigated, one where the mineral reinforcements were assumed to be randomly dispersed inclusions in a matrix of collagen, and a second model wherein the minerals were assumed to be unidirectional fibers. Predicted results for longitudinal and transverse elastic modulus from the models compare very well with range of values from published experimental data. It is also compared to those predicted using classical homogenization models. These material properties are then used to obtain the structural response of a bone plate section under transverse load.

Horizontal Ridge Augmentation Using Sticky Bone with Platelet-Rich Fibrin (PRF) in Anterior Maxilla Clinical and Histologic Evidence: A Case Report

Alveolar ridge deficiency is an unavoidable sequela of tooth extraction and poses major clinical challenges when reconstruction is anticipated. Various surgical approaches have been proposed to address horizontal defects, with autogenous bone grafting considered the current benchmark. However, alternative methods, utilizing tissue engineering principles and bone substitutes, offer reduced patient morbidity. This report presents an alternative case of severe horizontal bone defect augmentation in the anterior maxilla using sticky bone in conjunction with platelet-rich fibrin (PRF), and a Ti-reinforced membrane. Histologic evidence of sticky, deproteinized bovine bone material (DBBM) mixed with PRF without the use of autogenous bone is reported.

Research on Dual-Phase Composite Forming Process and Platform Construction of Radial Gradient Long Bone Scaffold.

The structure and composition of natural bone show gradient changes. Most bone scaffolds prepared by bone tissue engineering with single materials and structures present difficulties in meeting the needs of bone defect repair. Based on the structure and composition of natural long bones, this study proposed a new bone scaffold preparation technology, the dual-phase composite forming process. Based on the composite use of multiple biomaterials, a bionic natural long bone structure bone scaffold model with bone scaffold pore structure gradient and material concentration gradient changes along the radial direction was designed. Different from the traditional method of using multiple nozzles to achieve material concentration gradient in the scaffold, the dual-phase composite forming process in this study achieved continuous 3D printing preparation of bone scaffolds with gradual material concentration gradient by controlling the speed of extruding materials from two feed barrels into a closed mixing chamber with one nozzle. Through morphological characterization and mechanical property analysis, the results showed that BS-G (radial gradient long bone scaffolds prepared by the dual-phase composite forming process) had obvious pore structure gradient changes and material concentration gradient changes, while BS-T (radial gradient long bone scaffolds prepared by printing three concentrations of material in separate regions) had a discontinuous gradient with obvious boundaries between the parts. The compressive strength of BS-G was 1.00 ± 0.19 MPa, which was higher than the compressive strength of BS-T, and the compressive strength of BS-G also met the needs of bone defect repair. The results of in vitro cell culture tests showed that BS-G had no cytotoxicity. In a Sprague-Dawley rat experimental model, blood tests and key organ sections showed no significant difference between the experimental group and the control group. The prepared BS-G was verified to have good biocompatibility and lays a foundation for the subsequent study of the bone repair effect of radial gradient long bone scaffolds in large animals.

Characterization of Trabecular Bone Microarchitecture and Mechanical Properties Using Bone Surface Curvature Distributions.

Understanding bone surface curvatures is crucial for the advancement of bone material design, as these curvatures play a significant role in the mechanical behavior and functionality of bone structures. Previous studies have demonstrated that bone surface curvature distributions could be used to characterize bone geometry and have been proposed as key parameters for biomimetic microstructure design and optimization. However, understanding of how bone surface curvature distributions correlate with bone microstructure and mechanical properties remains limited. This study hypothesized that bone surface curvature distributions could be used to predict the microstructure as well as mechanical properties of trabecular bone. To test the hypothesis, a convolutional neural network (CNN) model was trained and validated to predict the histomorphometric parameters (e.g., BV/TV, BS, Tb.Th, DA, Conn.D, and SMI), geometric parameters (e.g., plate area PA, plate thickness PT, rod length RL, rod diameter RD, plate-to-plate nearest neighbor distance NNDPP, rod-to-rod nearest neighbor distance NNDRR, plate number PN, and rod number RN), as well as the apparent stiffness tensor of trabecular bone using various bone surface curvature distributions, including maximum principal curvature distribution, minimum principal curvature distribution, Gaussian curvature distribution, and mean curvature distribution. The results showed that the surface curvature distribution-based deep learning model achieved high fidelity in predicting the major histomorphometric parameters and geometric parameters as well as the stiffness tenor of trabecular bone, thus supporting the hypothesis of this study. The findings of this study underscore the importance of incorporating bone surface curvature analysis in the design of synthetic bone materials and implants.

The Story, Properties and Applications of Bioactive Glass “1d”: From Concept to Early Clinical Trials

Bioactive glasses in the CaO–MgO–Na2O–P2O5–SiO2–CaF2 system are highly promising materials for bone and dental restorative applications. Furthermore, if thermally treated, they can crystallize into diopside–fluorapatite–wollastonite glass-ceramics (GCs), which exhibit appealing properties in terms of mechanical behaviour and overall bone-regenerative potential. In this review, we describe and critically discuss the genesis, development, properties and applications of bioactive glass “1d” and its relevant GC derivative products, which can be considered a good example of success cases in this class of SiO2/CaO-based biocompatible materials. Bioactive glass 1d can be produced by melt-quenching in the form of powder or monolithic pieces, and was also used to prepare injectable pastes and three-dimensional porous scaffolds. Over the past 15 years, it was investigated by the authors of this article in a number of in vitro, in vivo (with animals) and clinical studies, proving to be a great option for hard tissue engineering applications.

Assessment of cranial reconstruction utilizing various implant materials: finite element study

The human head can sometimes experience impact loads that result in skull fractures or other injuries, leading to the need for a craniectomy. Cranioplasty is a procedure that involves replacing the removed portion with either autologous bone or alloplastic material. While titanium has traditionally been the preferred material for cranial implants due to its excellent properties and biocompatibility, its limitations have prompted the search for alternative materials. This research aimed to explore alternative materials to titanium for cranial implants in order to address the limitations of titanium implants and improve the performance of the cranioplasty process. A 3D model of a defective skull was reconstructed with a cranial implant, and the implant was simulated using various stiff and soft materials (such as alumina, zirconia, hydroxyapatite, zirconia-reinforced PMMA, and PMMA) as alternatives to titanium under 2000N impact forces. Alumina and zirconia implants were found to reduce stresses and strains on the skull and brain compared to titanium implants. However, PMMA implants showed potential for causing skull damage under current loading conditions. Additionally, PMMA and hydroxyapatite implants were prone to fracture. Despite these findings, none of the implants exceeded the limits for tensile and compressive stresses and strains on the brain. Zirconia-reinforced PMMA implants were also shown to reduce stresses and strains on the skull and brain compared to PMMA implants. Alumina and zirconia show promise as alternatives to titanium for the production of cranial implants. The use of alternative implant materials to titanium has the potential to enhance the success of cranial reconstruction by overcoming the limitations associated with titanium implants.Graphical