Search

Bioactive ceramics have been used in bone tissue repair and regeneration. However, because of the complex in vivo osteogenesis process, long cycle, and difficulty of accurately tracking, the mechanism of interaction between materials and cells has yet to be fully understood, hindering its development. The ceramic microbridge microfluidic chip system may solve the problem and provide an in vitro method to simulate the microenvironment in vivo. Nevertheless, the complex microenvironment parameters of the chip system need to be studied in detail. Computer simulation bionics can provide clues for the setting of microenvironment parameters. This study used a computational bionic model to simulate the bone growth process in the presence of immune-related factors. The osteoblast differentiation of mesenchymal stem cells of calcium phosphate ceramics in a macrophage-dominated immune microenvironment was studied using a microfluidic chip system. The computational biomimetic model and microfluidic chip findings were basically consistent with the reported results of the animal experiments. These findings suggest that studying the osteogenic behavior of calcium phosphate ceramics using a microfluidic chip model is feasible. The method model provided in this study can be extended to other biomaterials, providing a viable path for their research and evaluation.

The synergistic piezoelectric and osteoconductive properties of barium titanate (BT) and hydroxyapatite (HA) could stir the development of a new generation of synthetic bone graft substitutes, with capability for rapid and safe osseointegration. The research focused on two concurrent approaches for coupling the BT and HA materials: (i) conventional sintering of BT-HA powder mixtures; and (ii) functionalization of pre-sintered BT with HA coatings using magnetron sputtering (MS). Irrespective of the BT/HA ratios ranging from 95/5 to 80/20 wt%, nanocrystalline or highly-crystallized nature of the powders, sub-micron- or micron-sized particle dimensions, and sintering temperature, it was observed that the BT-HA reactivity cannot be prevented above 800 °C. At higher temperatures in the range of 1000–1300 °C, HA undergoes decomposition and extensively reacts with BT, leading to the formation of several secondary phases such as CaTiO 3, Ba 2 Ca(PO 4) 2 , BaCa 6 (PO 4) 4 O, BaCa(PO 3) 4 , and β -Ca 2 P 2 O 7. As a consequence, the cytocompatibility assessed in fibroblast and osteoblast cell cultures, as well as the piezoelectric response, were significantly altered. Applying HA coatings by MS to the sintered BT ceramics successfully preserved their piezoelectric properties, while also providing an unaltered cytocompatible and osteogenic-prone surface. The HA coatings were fully crystallized at post-deposition annealing temperatures of 550 and 700 °C, achieving crystalline qualities comparable to HA powders sintered at 1100 and 1200 °C, respectively. No reactivity events between BT and HA were observed. Partial reactivity was only noticeable upon annealing at 1000 °C. Therefore, it is suggested that the HA coating of BT is effective in seamlessly coupling the piezoelectric and osteogenic properties of the two constituents without compromise. • BT-HA powder mixtures inevitably react at high-temperature to form secondary phases. • The HA osteogenic component can be lost at sintering temperatures above 1000 °C. • The secondary phases lead to a decay of the piezoelectric and biological responses. • HA-magnetron sputtered BT – a feasible solution to overcome inter-phases reactivity. • HA-coated BT yields uncompromised piezoelectric and in-vitro biologic performances. [ABSTRACT FROM AUTHOR]

In the biomedical field, the commonly used metal implant materials are prone to "stress shielding" because of their mechanical properties and elastic modulus are very different from human bone. The mechanical properties of metal materials are often difficult to maintain in corrosive media and release harmful ions. Nor can it reliably establish a sufficient combination with human bones, resulting in a service life that does not reach the desired goal. Researchers in this field propose to combine the superior mechanical properties of metals with bioactive materials, such as bioactive ceramics and the emerging ferrous glass, and achieve this through surface modification techniques. The laser cladding technique is of great interest for its low dilution rate, high bond strength and fine organisation. This review paper describes the development of common medical metal materials and the research progress of laser cladding surface modification technology. [ABSTRACT FROM AUTHOR]

Magnesium silicate ceramics are promising materials for bone tissue regeneration and can be prepared through 3D printing of magnesium oxide/silica (MgO/SiO2) cement pastes followed by calcination. Despite the growing interest in these formulations, additive manufacturing technology has only recently been explored for these cements, and the effects of admixtures and additives on such printing inks remain largely unexplored. In this study, we prepared various MgO/SiO2 cement formulations with differing amounts of sodium orthophosphate, a setting retarder, and cellulose ethers, used as rheo-modifiers. The samples' setting properties were investigated, and printing parameters were properly adjusted. The most promising formulations were then 3D printed and calcined to obtain forsterite bioceramics, which were further characterized using confocal Raman microscopy, scanning electron microscopy, atomic force microscopy, gas porosimetry, and compressive strength tests. Our results revealed that the cellulose derivatives influence the printability of the MgO/SiO2 formulations without affecting the hardening time, which can be adjusted by the addition of sodium phosphate. The use of fine-tuned formulations allowed for the preparation of 3D-printed forsterite bioceramics, potentially suitable for biological applications as cancellous bone scaffolds. [ABSTRACT FROM AUTHOR]

Bioactive ceramics, primarily consisting of bioactive glasses, glass–ceramics, calcium orthophosphate ceramics, calcium silicate ceramics and calcium carbonate ceramics, have received great attention in the past decades given their biocompatible nature and excellent bioactivity in stimulating cell proliferation, differentiation and tissue regeneration. Recent studies have tried to combine bioactive ceramics with bioactive ions, polymers, bioactive proteins and other chemicals to improve their mechanical and biological properties, thus rendering them more valid in tissue engineering scaffolds. This review presents the beneficial properties and potential applications of bioactive ceramic-based materials in dentistry, particularly in the repair and regeneration of dental hard tissue, pulp–dentin complex, periodontal tissue and bone tissue. Moreover, greater insights into the mechanisms of bioactive ceramics and the development of ceramic-based materials are provided. Article highlights Properties & characteristics of bioactive ceramics Properties and characteristics of bioactive glasses that are widely used in dental repair and regeneration. Properties and characteristics of glass-ceramics that are widely used in dental repair and regeneration. Properties and characteristics of calcium orthophosphate ceramics that are widely used in dental repair and regeneration. Properties and characteristics of calcium silicate ceramics that are widely used in dental repair and regeneration. Properties and characteristics of calcium carbonate ceramics that are widely used in dental repair and regeneration. Biomedical mechanisms & potential applications of bioactive ceramic-based materials in dental repair & regeneration Application and modification of bioactive ceramics for remineralization and regeneration of dental hard tissues. Application and modification of bioactive ceramics for pulp–dentin complex regeneration. Application and modification of bioactive ceramics for periodontal regeneration. Application and modification of bioactive ceramics for bone formation. Conclusion Due to the high bioactivity and biocompatibility, bioactive ceramics have been widely used in dental tissue repair. More recent attentions have focused on their modification to further enhance the bioactive behavior or further compositional changes that may introduce additional properties for dental hard tissue regeneration, pulp–dentin regeneration, periodontal regeneration and bone regeneration. Future perspective The bioactivity of ceramic-based materials is still to be further improved, such as nanosizing, surface modification, or combining or hybridizing with other bioactive substances to mimic the extracellular matrix environment as much as possible. These approaches may provide a key and effective direction to improve the application of bioactive ceramics in the field of oral tissue repair and regeneration. [ABSTRACT FROM AUTHOR]

ABSTRACTThe co-precipitation method is used in the lab to create a sample of the ferromagnetic 45CaO-30P2O5-15SiO2-10Fe2O3 (mol%). In simulated body fluid (SBF), the ability of the ferromagnetic sample to regenerate bone was examined, and XRD and FTIR graphs demonstrate that bone formation has taken place. The Vibration Sample Magnetometer has confirmed that the sample’s ferromagnetic behavior was brought on by the presence of iron (VSM). When an external magnetic field is present, the resulting sample may be utilized to treat bone cancer due to its ferromagnetic nature (hyperthermia). The sample’s drug release is therefore tested both with and without the help of an external magnetic field, and the findings reveal that when the magnetic field is present, the sample displays good drug release. BET analysis also supports the capacity of drugs to load and release. The sample’s ability to distribute drugs is tested using the antibiotic gentamicin. The prolonged release of the medication in SBF solution is investigated using a first-order kinetic equation. Being a drug-loaded ferromagnetic sample with high magnetic attraction, makes it simple to target any nearby spot. With a cytotoxicity rate of more than 90%, the produced sample is seen to interact amicably with the MG-63 human cell line. According to antimicrobial research, samples also guard against both gram-positive and gram-negative germs in the implant region. By lowering the cell’s oxidative stress, the sample’s antioxidant activity aids in cell proliferation, which increases the implanted site’s recuperation.

Bone defects that occur with fragment fractures lead to an increase in the number of postoperative complications. Therefore, to restore the structure and function of the bone, there is a need for bone replacement, in particular doped calcium-phosphate ceramics. The purpose of the work is the biochemical assessment of acute-phase and endothelial reactions and immune complex formation during bone replacement with germanium-doped calcium-phosphate ceramics of bone fragment fractures in dogs. Dogs with fragment fractures of long tubular bones and plate osteosynthesis were included in the study. In the experimental group (n = 10), bone defects were replaced with germanium-doped calcium-phosphate ceramics (HА/β-TCP/l-Gе-700), in the control group (n = 10) – unalloyed (HА/β-TCP-700). Blood samples were taken after the injury and on the 3rd, 7th, 14th, 30th, and 60th days after osteosynthesis. Partial recovery of limb function in the experimental group was faster by 1.3 times (P < 0.001) and full by 1.2 times (P < 0.01) compared to the control. On the 60th day, in experimental animals, the defect was filled with a regenerate of high X-ray density without a periosteal reaction, while in the control animals, the bone regenerate did not have sufficient density with a significant periosteal reaction. In both groups, total protein and albumin content varied within the normal range. The activity of protein C on the 3rd day in the experimental group was 1.3 times higher (Р ˂ 0.001), and on the 7th day, it was twice as high (P ˂ 0.001) compared to the control group with normalization by the 14th day. The concentration of ceruloplasmin from the 7th day in the control animals was 1.1 times higher (Р ˂ 0.001) than in the experimental animals, with normalization in the latter by the 60th day. The level of small molecular circulating immune complexes (CIC) after the injury increased by 1.1 times (Р ˂ 0.001) and reached a peak in the control and experimental groups on the 14th day, with an increase in indicators by 2.1 and 1.4 times (Р ˂ 0.001), respectively, with normalization in the experimental group on the 60th day. The level of nitric oxide (NO) in the control group increased from the 7th to the 60th day, with a peak on the 30th day, and in the experimental group – from the 3rd to the 30th, with a peak on the seventh day. Osteoreplacement of fragment fractures of long tubular bones in dogs with calcium-phosphate ceramics doped with germanium is accompanied by a moderate level of the acute phase reaction and immune complex formation, an increase in the endothelial reaction and the anticoagulant potential of the blood, which contributes to a decrease in the intensity of the inflammatory-resorptive stage of reparative osteogenesis and an increase in its proliferative phase, which, respectively, accelerates the consolidation of fractures.

The co-precipitation method is used in the lab to create a sample of the ferromagnetic 45CaO-30P2O5-15SiO2-10Fe2O3 (mol%). In simulated body fluid (SBF), the ability of the ferromagnetic sample to regenerate bone was examined, and XRD and FTIR graphs demonstrate that bone formation has taken place. The Vibration Sample Magnetometer has confirmed that the sample's ferromagnetic behavior was brought on by the presence of iron (VSM). When an external magnetic field is present, the resulting sample may be utilized to treat bone cancer due to its ferromagnetic nature (hyperthermia). The sample's drug release is therefore tested both with and without the help of an external magnetic field, and the findings reveal that when the magnetic field is present, the sample displays good drug release. BET analysis also supports the capacity of drugs to load and release. The sample's ability to distribute drugs is tested using the antibiotic gentamicin. The prolonged release of the medication in SBF solution is investigated using a first-order kinetic equation. Being a drug-loaded ferromagnetic sample with high magnetic attraction, makes it simple to target any nearby spot. With a cytotoxicity rate of more than 90%, the produced sample is seen to interact amicably with the MG-63 human cell line. According to antimicrobial research, samples also guard against both gram-positive and gram-negative germs in the implant region. By lowering the cell's oxidative stress, the sample's antioxidant activity aids in cell proliferation, which increases the implanted site's recuperation. [ABSTRACT FROM AUTHOR]

The spine is the most common site of bone metastases. Many cancer patients will ultimately develop spinal metastatic disease with symptomatic epidural spinal cord compression. At present, the main treatment for cervical spine tumors is surgical resection combined with postoperative radiotherapy. Implant materials for cervical spine anterior column reconstruction need to meet amounts of different properties, such as biocompatibility, bioactivity and the ability to maintain long‐term mechanical strength. The selection of different materials determines the surgical efficacy and prognosis of patients to a certain extent. This article provides an overview of a variety of implant materials used for anterior column reconstruction after cervical spine tumor resection, introduces and analyzes their properties, advantages, disadvantages, derivatives, and applications in clinical practice, and looks forward to the future development of implant materials.

Magnesium silicate ceramics are promising materials for bone tissue regeneration and can be prepared through 3D printing of magnesium oxide/silica (MgO/SiO2) cement pastes followed by calcination. Despite the growing interest in these formulations, additive manufacturing technology has only recently been explored for these cements, and the effects of admixtures and additives on such printing inks remain largely unexplored. In this study, we prepared various MgO/SiO2 cement formulations with differing amounts of sodium orthophosphate, a setting retarder, and cellulose ethers, used as rheo-modifiers. The samples’ setting properties were investigated, and printing parameters were properly adjusted. The most promising formulations were then 3D printed and calcined to obtain forsterite bioceramics, which were further characterized using confocal Raman microscopy, scanning electron microscopy, atomic force microscopy, gas porosimetry, and compressive strength tests. Our results revealed that the cellulose derivatives influence the printability of the MgO/SiO2 formulations without affecting the hardening time, which can be adjusted by the addition of sodium phosphate. The use of fine-tuned formulations allowed for the preparation of 3D-printed forsterite bioceramics, potentially suitable for biological applications as cancellous bone scaffolds.

The spine is the most common site of bone metastases. Many cancer patients will ultimately develop spinal metastatic disease with symptomatic epidural spinal cord compression. At present, the main treatment for cervical spine tumors is surgical resection combined with postoperative radiotherapy. Implant materials for cervical spine anterior column reconstruction need to meet amounts of different properties, such as biocompatibility, bioactivity and the ability to maintain long‐term mechanical strength. The selection of different materials determines the surgical efficacy and prognosis of patients to a certain extent. This article provides an overview of a variety of implant materials used for anterior column reconstruction after cervical spine tumor resection, introduces and analyzes their properties, advantages, disadvantages, derivatives, and applications in clinical practice, and looks forward to the future development of implant materials. [ABSTRACT FROM AUTHOR]

Bone defects that occur with fragment fractures lead to an increase in the number of postoperative complications. Therefore, to restore the structure and function of the bone, there is a need for bone replacement, in particular doped calcium-phosphate ceramics. The purpose of the work is the biochemical assessment of acute-phase and endothelial reactions and immune complex formation during bone replacement with germanium-doped calciumphosphate ceramics of bone fragment fractures in dogs. Dogs with fragment fractures of long tubular bones and plate osteosynthesis were included in the study. In the experimental group (n = 10), bone defects were replaced with germanium-doped calcium-phosphate ceramics (HA/ß-TCP/l-Ge-700), in the control group (n = 10) - unalloyed (HA/ß-TCP-700). Blood samples were taken after the injury and on the 3rd, 7th, 14th, 30th, and 60th days after osteosynthesis. Partial recovery of limb function in the experimental group was faster by 1.3 times (P < 0.001) and full by 1.2 times (P < 0.01) compared to the control. On the 60th day, in experimental animals, the defect was filled with a regenerate of high X-ray density without a periosteal reaction, while in the control animals, the bone regenerate did not have sufficient density with a significant periosteal reaction. In both groups, total protein and albumin content varied within the normal range. The activity of protein C on the 3rd day in the experimental group was 1.3 times higher (P < 0.001), and on the 7th day, it was twice as high (P < 0.001) compared to the control group with normalization by the 14th day. The concentration of ceruloplasmin from the 7th day in the control animals was 1.1 times higher (P < 0.001) than in the experimental animals, with normalization in the latter by the 60th day. The level of small molecular circulating immune complexes (CIC) after the injury increased by 1.1 times (P < 0.001) and reached a peak in the control and experimental groups on the 14th day, with an increase in indicators by 2.1 and 1.4 times (P < 0.001), respectively, with normalization in the experimental group on the 60th day. The level of nitric oxide (NO) in the control group increased from the 7th to the 60th day, with a peak on the 30th day, and in the experimental group - from the 3rd to the 30th, with a peak on the seventh day. Osteoreplacement of fragment fractures of long tubular bones in dogs with calcium-phosphate ceramics doped with germanium is accompanied by a moderate level of the acute phase reaction and immune complex formation, an increase in the endothelial reaction and the anticoagulant potential of the blood, which contributes to a decrease in the intensity of the inflammatory-resorptive stage of reparative osteogenesis and an increase in its proliferative phase, which, respectively, accelerates the consolidation of fractures. [ABSTRACT FROM AUTHOR]

Introduction: Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering. The current study explored an advanced bone tissue engineering approach combining an advanced 3D printing technique for bioactive resorbable ceramic scaffolds with a perfusion cell culture technique for pre-colonization with mesenchymal stem cells, and with an intrinsic angiogenesis technique for regenerating critical size, segmental discontinuity defects in vivo applying a rat model. To this end, the effect of differing Si-CAOP (silica containing calcium alkali orthophosphate) scaffold microarchitecture arising from 3D powder bed printing (RP) or the Schwarzwalder Somers (SSM) replica fabrication technique on vascularization and bone regeneration was analyzed in vivo. In 80 rats 6-mm segmental discontinuity defects were created in the left femur.Methods: Embryonic mesenchymal stem cells were cultured on RP and SSM scaffolds for 7d under perfusion to create Si-CAOP grafts with terminally differentiated osteoblasts and mineralizing bone matrix. These scaffolds were implanted into the segmental defects in combination with an arteriovenous bundle (AVB). Native scaffolds without cells or AVB served as controls. After 3 and 6 months, femurs were processed for angio-µCT or hard tissue histology, histomorphometric and immunohistochemical analysis of angiogenic and osteogenic marker expression.Results: At 3 and 6 months, defects reconstructed with RP scaffolds, cells and AVB displayed a statistically significant higher bone area fraction, blood vessel volume%, blood vessel surface/volume, blood vessel thickness, density and linear density than defects treated with the other scaffold configurations.Discussion: Taken together, this study demonstrated that the AVB technique is well suited for inducing adequate vascularization of the tissue engineered scaffold graft in segmental defects after 3 and 6 months, and that our tissue engineering approach employing 3D powder bed printed scaffolds facilitated segmental defect repair.

Bone defect disease causes damage to people's lives and property, and how to effectively promote bone regeneration is still a big clinical challenge. Most of the current repair methods focus on filling the defects, which has a poor effect on bone regeneration. Therefore, how to effectively promote bone regeneration while repairing the defects at the same time has become a challenge for clinicians and researchers. Strontium (Sr) is a trace element required by the human body, which mainly exists in human bones. Due to its unique dual properties of promoting the proliferation and differentiation of osteoblasts and inhibiting osteoclast activity, it has attracted extensive research on bone defect repair in recent years. With the deep development of research, the mechanisms of Sr in the process of bone regeneration in the human body have been clarified, and the effects of Sr on osteoblasts, osteoclasts, mesenchymal stem cells (MSCs), and the inflammatory microenvironment in the process of bone regeneration have been widely recognized. Based on the development of technology such as bioengineering, it is possible that Sr can be better loaded onto biomaterials. Even though the clinical application of Sr is currently limited and relevant clinical research still needs to be developed, Sr-composited bone tissue engineering biomaterials have achieved satisfactory results in vitro and in vivo studies. The Sr compound together with biomaterials to promote bone regeneration will be a development direction in the future. This review will present a brief overview of the relevant mechanisms of Sr in the process of bone regeneration and the related latest studies of Sr combined with biomaterials. The aim of this paper is to highlight the potential prospects of Sr functionalized in biomaterials. [ABSTRACT FROM AUTHOR]

Calcium phosphate bio-ceramics are osteo-conductive, but it remains a challenge to promote the induction of bone augmentation and capillary formation. The surface micro/nano-topography of materials can be recognized by cells and then the cell fate are mediated. Traditional regulation methods of carving surface structures on bio-ceramics employ mineral reagents and organic additives, which might introduce impurity phases and affect the biological results. In a previous study, a facile and novel method was utilized with ultrapure water as the unique reagent for hydrothermal treatment, and a uniform hydroxyapatite (HAp) surface layer was constructed on composite ceramics (β-TCP/CaSiO3) in situ. Further combined with 3D printing technology, biomimetic hierarchical structure scaffolds were fabricated with interconnected porous composite ceramic scaffolds as the architecture and micro/nano-rod hybrid HAp as the surface layer. The obtained HAp surface layer favoured cell adhesion, alleviated the cytotoxicity of precursor scaffolds, and upregulated the cellular differentiation of mBMSCs and gene expression of HUVECs in vitro. In vivo studies showed that capillary formation, bone augmentation and new bone matrix formation were upregulated after the HAp surface layer was obtained, and the results confirmed that the fabricated biomimetic hierarchical structure scaffold could be an effective candidate for bone regeneration.

This study aimed to evaluate the in vivo initial microbial adhesion of oral microorganisms on the biomaterial Biodentine compared to MTA and AH Plus. Cylindrical samples of the materials were prepared, and dentin slabs served as a control. An individual intraoral lower jaw splint served as a carrier for the samples and was worn by six volunteers. The specimens were worn for 120 min. Adherent bacteria were quantified by determining the colony-forming units (CFUs), while the visualization and quantification of total adherent microorganisms were facilitated by using DAPI and live/dead staining combined with fluorescence microscopy. Bovine dentin had a significantly higher number of aerobic CFUs compared to Biodentine (p = 0.017) and MTA (p = 0.013). The lowest amounts of DAPI-stained adherent microorganisms were quantified for Biodentine (15% ± 9%) and the control (18% ± 9%), while MTA showed the highest counts of initially adherent microorganisms (38% ± 10%). Significant differences were found for MTA and Biodentine (p = 0.004) as well as for MTA and the control (p = 0.021) and for AH Plus and the control (p = 0.025). Biodentine inhibited microbial adherence, thereby yielding an antimicrobial effectivity similar to that of MTA. [ABSTRACT FROM AUTHOR]

Various artificial bone graft substitutes based on ceramics have been developed over the last 20 years. Among them, calcium-silicate-based ceramics, which are osteoconductive and can attach directly to biological organs, have received great attention for bone tissue engineering applications. However, the degradation rate of calcium-silicate and bone formation is often out of balance, resulting in stress shielding (osteopenia). A new strategy to improve the drawbacks of these ceramics is incorporating trace elements such as Zn, Mg, and Zr into their lattice structures, enhancing their physical and biological properties. Recently, baghdadite (Ca3ZrSi2O9) ceramic, one of the most appealing calcium-silicate-based ceramics, has demonstrated high bioactivity, biocompatibility, biodegradability, and cell interaction. Because of its physical, mechanical, and biological properties and ability to be shaped using various fabrication techniques, baghdadite has found high potential in various biomedical applications such as coatings, fillers, cement, scaffolds, and drug delivery systems. Undoubtedly, there is a high potential for this newly developed ceramic to contribute significantly to therapies to provide a tremendous clinical outcome. This review paper aims to summarize and discuss the most relevant studies performed on baghdadite-based ceramics and composites by focusing on their behavior in vivo and in vitro.

This study aimed to evaluate the in vivo initial microbial adhesion of oral microorganisms on the biomaterial Biodentine compared to MTA and AH Plus. Cylindrical samples of the materials were prepared, and dentin slabs served as a control. An individual intraoral lower jaw splint served as a carrier for the samples and was worn by six volunteers. The specimens were worn for 120 min. Adherent bacteria were quantified by determining the colony-forming units (CFUs), while the visualization and quantification of total adherent microorganisms were facilitated by using DAPI and live/dead staining combined with fluorescence microscopy. Bovine dentin had a significantly higher number of aerobic CFUs compared to Biodentine (p = 0.017) and MTA (p = 0.013). The lowest amounts of DAPI-stained adherent microorganisms were quantified for Biodentine (15% ± 9%) and the control (18% ± 9%), while MTA showed the highest counts of initially adherent microorganisms (38% ± 10%). Significant differences were found for MTA and Biodentine (p = 0.004) as well as for MTA and the control (p = 0.021) and for AH Plus and the control (p = 0.025). Biodentine inhibited microbial adherence, thereby yielding an antimicrobial effectivity similar to that of MTA.

Poly(methyl methacrylate) (PMMA)‐based bone cements (BCs) can be defined as a family of materials that consist of powder and liquid phases which after mixing form a plastic paste that can self‐set once implanted in the human body. PMMA‐based BCs are easily molded and adapted to complex bone cavities or used in orthodontic applications to restore dental damage. The main advantages of the use of cement are the excellent primary fixation between bone and implant and, therefore, the faster recovery of the patient. Despite the initial success rate of implant fixation with BCs, they have some disadvantages such as local tissue damage due to exothermic polymerization reactions, mechanical mismatch between native bone and cement, lack of bone regeneration and bioactivity and poor mechanical properties which may cause the failure of the BCs. BCs are still considered as a top option for bone repair. Due to the disadvantages highlighted, research has focused on alternative materials used with PMMA‐based BCs. This review aims to critically review the BCs and emerging materials used in combination with PMMA‐based BCs. These materials include titania, apatite–wollastonite (A‐W), glass ceramic (GC) and hydroxyapatite (HA). The review discusses the properties of these materials and their pathway to clinical study. Among the various kinds of reinforcement, HA has been extensively used. So, in this review, we compare the effects of HA as reinforcement in PMMA‐based BCs. Upcoming study of PMMA‐based BCs should concentrate on trialing combinations of these reinforcing agents as this might improve beneficial characteristics. © 2020 Society of Industrial Chemistry [ABSTRACT FROM AUTHOR]

Stem cells are the central element of regenerative medicine (RM). However, in many clinical applications, the use of scaffolds fabricated with biomaterials is required. In this sense, mesoporous bioactive glasses (MBGs) are going to play an important role in bone regeneration because of their striking textural properties, quick bioactive response, and biocompatibility. As other bioactive glasses, MBGs are mainly formed by silicon, calcium, and phosphorus oxides whose ions play an important role in cell proliferation as well as in homeostasis and bone remodeling process. A common improvement of bioactive glasses for RM is by adding small amounts of oxides of elements that confer them additional biological capacities, including osteogenic, angiogenic, antibacterial, anti-inflammatory, hemostatic, or anticancer properties. Moreover, MBGs are versatile in terms of the different ways in which they can be processed, such as scaffolds, fibers, coatings, or nanoparticles. MBGs are unique because their textural properties are so high that they still exhibit outstanding bioactive responses even after adding extra inorganic ions or being processed as scaffolds or nanoparticles. Moreover, they can be further improved by loading with biomolecules, drugs, and stem cells. This article reviews the state of the art and future perspectives of MBGs in the field of RM of hard tissues.

Introduction. Many researchers are currently searching for new, safe, and effective methods of maxillofacial reconstruction in cancer patients.In this case, special attention should be paid to ceramic implants.Objective: to develop a personalized approach to the maxillofacial reconstruction using bioactive ceramic implants.Materials and methods. We performed virtual planning of the implants for the reconstruction of the maxillofacial region basing on the preoperative spiral computed tomography scans of the facial skeleton.Results. We have developed a new method of preoperative planning and creation of individualized implants made of bioactive ceramics for reconstructing the maxillofacial region. This method is demanded in reconstructive surgery and can be applied in routine clinical practice.Conclusion. Reconstructive surgeries with the implants made of bioactive ceramics allow achieving good functional and aesthetic results in patients with large postoperative defects in the maxillofacial region, thus, improving their quality of life.

[Display omitted] • The innovative uses of bioactive ceramics in restorative dentistry is pointed out. • Theycan be combined with GIC and RMGIC cements for repairing teeth lesions. • They can be associated with laser therapy for treating dentin hypersensitivity. • Restorative dentistry can be progressively replaced by regenerative approaches in the future. Restorative dentistry comprises approaches to repair the tooth structure or manage conditions like dentin hypersensitivity, which all require biomaterials. Restorative clinical approaches are primarily based on bioactive materials, such as glass-ionomer cement (GIC) and resin-modified glass-ionomer cement (RMGIC). Although these cements show in vivo bioactivity, it is possible to increase their bioactive behavior, fastening and increasing the establishment of chemical bonds between the tooth and the cement, decreasing the risk of failure. Here, we reported how bioactive ceramics have been used to treat dentin hypersensitivity, either by being directly applied to the dentin, modifying GIC and RMGIC, or combined with other therapeutic approaches like laser therapy. Overall, bioactive ceramics have improved the bonding of composites to mineralized tooth structures, which is desired in restorative dentistry, and in some cases, they are likely to replace restorative with regenerative approaches. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Ideal artificial bone grafts aim for multiscale porosity, high mechanical strength and ensure rapid vascularization for bone ingrowth. In this work modular ceramic arteriovenous loops (AV-loops) with a hierarchical porosity approach were designed and manufactured to meet these criteria and to exceed the poor mechanical strength of monolithic scaffolds. Bioactive building blocks (β-TCP, HAp, BCP) with dimensions of 1.5–3.0 mm were prepared by injection molding and assembled to complex AV-loop scaffolds using a customized automated assembly technology (pick and place). The building blocks were bonded with a biocompatible adhesive. Single building blocks are characterized by a compressive strength of 112.4–134.5 MPa with a residual sintering porosity of 32.2–41.5%, matching the strength of cortical bone of 100–230 MPa. The compressive strength of the modular assemblies varied between 22.3 and 47.6 MPa primary depending on the building block arrangement. The achieved compressive strengths are superior to current monolithic AV-scaffolds and sufficient for the implantation as non-load-bearing AV-loop scaffolds in isolation chambers. The modular AV-loop scaffolds provide a hierarchical interconnected pore network (P = 58.8%) combining small macropores of 4.1–4.3 µm size for possible enhanced protein absorption and large gradient macropores of 200–1700 µm size for optimum vascularization and complete bone ingrowth. The modular building block approach allows to design patient individualized scaffolds with complex hierarchical pore networks. The pore volume, size and geometry as well as the biological response can effectively be tuned by changing the dimensions, shape and placing gap of the bioactive building blocks. Statement of Significance Gold standard of bone replacement in case of surgery or cancer is still own bone material usually taken from the hip/arm or leg in second surgery with poor mechanical properties and limited amount. To avoid a second surgery and provide mechanical strong scaffold structures for fast patient regeneration a novel modular building block approach is used. This allows complex scaffold geometry with a hierarchical interconnection porosity for blood vessel ingrowth. The pore volume, size and geometry as well as the biological response can effectively be tuned by changing the dimensions, shape and placing gap of the bioactive building blocks. [ABSTRACT FROM AUTHOR]

The cytotoxicity of monticellite based bioactive ceramic powder, which was synthesized from boron derivative waste has been determined by in vitro assays of MTT, NRU, and JC-1 staining. The toxicity of powder on different mammalian cell lines (3T3-L1, HUVEC, CRL-2120) was evaluated at the concentrations of 10, 100, 200, 400 and 800 µg/mL to justify its potential for biomedical applications. The obtained results showed that monticellite based bioactive ceramic powder possesses not only bioactive feature but also biocompatible characteristic at the concentration range of 10–200 µg/mL. Hence, monticellite based bioactive ceramics have high potential as a bone graft substitute for bone void filling and coating applications. [ABSTRACT FROM AUTHOR]

Monticellite bioactive ceramics have a high usage potential as bone graft substitutes due to their superior mechanical properties compared to hydroxyapatite and excellent bioactivity. Turkey has almost 72% of the global boron reserves and the fairly high amount of emerged boron derivative waste causes storage problems and environmental pollutions. The aim of this study was the solid state synthesis of monticellite based ceramic powders from boron derivative waste and the evaluation of bioactivity characteristic of produced powders. The monticellite based ceramic powders were synthesized at low temperature (800 °C). The powders were incubated in Simulated Body Fluid and their surfaces were examined using a scanning electron microscope. The surfaces of synthesized powders were bioactive and allowed formation of bone-like apatite layer within 15 days. Results of the study confirmed that cost-effective and eco-friendly monticellite based bioactive ceramic powders can be synthesized from boron derivative waste. [ABSTRACT FROM AUTHOR]

Biomaterials have a profound effect on tissue engineering and regenerative medicine, but few studies have reported the role of extracts from bioceramics in the regulation of stem cell pluripotency. The present study investigated the effects of bioceramics extracts, including silicate bredigite (Ca7MgSi4O16) and conventional β-tricalcium phosphate (β-TCP), on the pluripotency and the multilineage differentiation potential of human dental pulp cells (hDPCs). Basic fibroblast growth factor (bFGF), which is a known regulator of hDPCs pluripotency, was used as a reference. Bredigite extracts significantly promoted cell growth, proliferation, TERT expression and maintained hDPCs in a presenescent state. The extracts of bredigite significantly up-regulated the expression of pluripotency-related genes such as Stro1, Oct4 and Sox2, and further promoted the multilineage differentiation of hDPCs after odontogenic/adipogenic induction. The stimulation of bredigite extracts on hDPCs pluripotency was comparable to that of bFGF, whereas β-TCP extracts lacked these properties. Our results suggested for the first time that bredigite extracts enhance the pluripotency of dental-derived stem cells, paving the way for extended applications in regenerative medicine. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3465-3474, 2017. [ABSTRACT FROM AUTHOR]

The high brittleness and low strength of bioactive ceramics have severely restricted their application in bone repair despite the fact that they have been regarded as one of the most promising biomaterials. In the last few years, low-dimensional nanomaterials (LDNs), including carbon nanotubes, graphene and boron nitride nanotubes, have gained increasing attention owing to their favorable biocompatibility, large surface specific area and super mechanical properties. These qualities make LDNs potential nanofillers in reinforcing bioactive ceramics. In this review, the types, characteristics and applications of the commonly used LDNs in ceramic composites are summarized. In addition, the fabrication methods for LDNs/ceramic composites, such as hot pressing, spark plasma sintering and selective laser sintering, are systematically reviewed and compared. Emphases are placed on how to obtain the uniform dispersion of LDNs in a ceramic matrix and maintain the structural stability of LDNs during the high-temperature fabrication process of ceramics. The reinforcing mechanisms of LDNs in ceramic composites are then discussed in-depth. The in vitro and in vivo studies of LDNs/ceramic in bone repair are also summarized and discussed. Finally, new developments and potential applications of LDNs/ceramic composites are further discussed with reference to experimental and theoretical studies. Statement of Significance Despite bioactive ceramics having been regarded as promising biomaterials, their high brittleness and low strength severely restrict their application in bone scaffolds. In recent years, low-dimensional nanomaterials (LDNs), including carbon nanotubes, graphene and boron nitride nanotubes, have shown great potential in reinforcing bioactive ceramics owing to their unique structures and properties. However, so far it has been difficult to maintain the structural stability of LDNs during fabrication of LDNs/ceramic composites, due to the lengthy, high-temperature process involved. This review presents a comprehensive overview of the developments and applications of LDNs in bioactive ceramics. The newly-developed fabrication methods for LDNs/ceramic composites, the reinforcing mechanisms and the in vitro and in vivo performance of LDNs are also summarized and discussed in detail. [ABSTRACT FROM AUTHOR]

This study examines the effect of a hyaluronic acid (HyAc) containing tricalcium phosphate putty scaffold material (TCP-P) and of a particulate tricalcium phosphate (TCP-G) graft on bone formation, volume stability and osteogenic marker expression in biopsies sampled 6 months after bilateral sinus floor augmentation (SFA) in 7 patients applying a split-mouth design. 10% autogenous bone chips were added to the grafting material during surgery. The grain size of the TCP granules was 700 to 1400 μm for TCP-G and 125 to 250 μm and 500 to 700 μm (ratio 1:1) for TCP-P. Biopsies were processed for immunohistochemical analysis of resin-embedded sections. Sections were stained for collagen type I (Col I), alkaline phosphatase (ALP), osteocalcin (OC) and bone sialoprotein (BSP). Furthermore, the bone area and biomaterial area fraction were determined histomorphometrically. Cone-beam CT data recorded after SFA and 6 months later were used for calculating the graft volume at these two time points. TCP-P displayed more advantageous surgical handling properties and a significantly greater bone area fraction and smaller biomaterial area fraction. This was accompanied by significantly greater expression of Col I and BSP and in osteoblasts and osteoid and a less pronounced reduction in grafting volume with TCP-P. SFA using both types of materials resulted in formation of sufficient bone volume for facilitating stable dental implant placement with all dental implants having been in function without any complications for 6 years. Since TCP-P displayed superior surgical handling properties and greater bone formation than TCP-G, without the HyAc hydrogel matrix having any adverse effect on bone formation or graft volume stability, TCP-P can be regarded as excellent grafting material for SFA in a clinical setting. The greater bone formation observed with TCP-P may be related to the difference in grain size of the TCP granules and/or the addition of the HyAc. [ABSTRACT FROM AUTHOR]

Bone, a highly dynamic connective tissue, consist of a bioorganic phase comprising osteogenic cells and proteins which lies over an inorganic phase predominantly made of CaPO 4 (biological apatite). Injury to bone can be due to mechanical, metabolic or inflammatory agents also owing pathological conditions like fractures, osteomyelitis, osteolysis or cysts may arise in enameloid, chondroid, cementum, or chondroid bone which forms the intermediate tissues of the body. Bone tissue engineering (BTE) applies bioactive scaffolds, host cells and osteogenic signals for restoring damaged or diseased tissues. Various bioceramics used in BTE can be bioactive (like glass ceramics and hydroxyapatite bioactive glass), bioresorbable (like tricalcium phosphates) or bioinert (like zirconia and alumina). Limiting the size of these materials to nano-scale has resulted in a higher surface area to volume ratio thereby improving multi-functionality, solubility, surface catalytic activity, high heat and electrical conductivity. Nanoceramics have been found to induce osteoconduction, osteointegration, osteogenesis and osteoinduction. The present review aims at summarizing the interactions of nanoceramics and osteoblast/stem cells for promoting the proliferation and differentiation of the osteoblast cells by nanoceramics as superior bone substitutes in bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA)/β-tricalcium phosphate (β-TCP) composites attract attentions as bone implant materials. As one of the fabrication method of HA/β-TCP is mixing of HA and β-TCP powder in advance of sintering. This method enables to control the ratio of content of β-TCP easier. However, it is difficult to obtain dense composites. In this study, we focused on pulse electric current sintering (PECS) to obtain dense HA/β-TCP composites. The sinterability is evaluated with relative density and grain size measurements. Composition of sintered body was also characterized by X-ray diffraction. In comparison with pressureless sintering, PECS increased relative density of the composites without grain growth. In HA/β-TCP sintered by PECS, the phase transformation from β-TCP to α-TCP was promoted. This is due to higher thermal energy by spark discharge during PECS. On the other hand, sintering additives (MgO) inhibited phase transformation. It was suggested that sinterability of HA/β-TCP composites was improved by PECS. [ABSTRACT FROM PUBLISHER]

Recently new coating technologies have been developed based on the so-called Pulsed Laser Deposition (PLD) method, which consists in the laser ablation of a target material, and as a consequence of the matter-radiation interaction, the transport of ablated species from the target to the substrate is originated. PLD is quite versatile technique, and allows the incorporation of a reactive atmosphere and electric discharges in the process so that the properties of the coatings can be modified. In this work, these new technologies were applied in the processing of bioactive ceramic thin films of hydroxyapatite and bioactive glass. The influence of processing parameters, such as temperature, voltage applied of the radiofrequency discharge and reactive atmosphere, on the coating properties have been studied. It was found that in the case of hydroxyapatite coatings, the water vapour atmosphere coupled with the radiofrequency discharge enhances the deposition rate and cristallinity of the coatings. Nevertheless, the optimum properties for bioactive glass coatings were obtained in vacuum and absence of electrical discharge conditions.En la actualidad existen nuevas tecnologías de procesamiento de recubrimientos basados en la técnica denominada depósito por láser pulsado (PLD), la cual consiste en la ablación de un blanco mediante un haz láser y como consecuencia de la interacción radiación – materia se origina el transporte del material hasta el sustrato a recubrir. Esta técnica es muy versátil ya que permite la incorporación de atmósferas reactivas en el proceso y de descargas eléctricas en la pluma de ablación las cuales pueden inducir modificaciones en las propiedades de los recubrimientos. En este trabajo se aplican estas nuevas tecnologías a la obtención de capas cerámicas bioactivas de hidroxiapatita y de vidrio bioactivo. Se ha estudiado la influencia de parámetros de proceso como temperatura, diferencia de potencial de la descarga de radiofrecuencia aplicada y atmósfera reactiva, desde el punto de vista de la composición y estructura de los recubrimientos. En el caso de la hidroxiapatita, la presencia de una atmósfera de vapor de agua y de una descarga de radiofrecuencia favorece el ritmo de depósito y la cristalinidad de los recubrimientos. Sin embargo, los recubrimientos óptimos de vidrio bioactivo se obtienen en condiciones de vacío y ausencia de descargas eléctricas.

This study examines the effect of a hyaluronic acid (HyAc) containing tricalcium phosphate putty scaffold material (TCP-P) and of a particulate tricalcium phosphate (TCP-G) graft on bone formation, volume stability and osteogenic marker expression in biopsies sampled 6 months after bilateral sinus floor augmentation (SFA) in 7 patients applying a split-mouth design. 10% autogenous bone chips were added to the grafting material during surgery. The grain size of the TCP granules was 700 to 1400 µm for TCP-G and 125 to 250 µm and 500 to 700 µm (ratio 1:1) for TCP-P. Biopsies were processed for immunohistochemical analysis of resin-embedded sections. Sections were stained for collagen type I (Col I), alkaline phosphatase (ALP), osteocalcin (OC) and bone sialoprotein (BSP). Furthermore, the bone area and biomaterial area fraction were determined histomorphometrically. Cone-beam CT data recorded after SFA and 6 months later were used for calculating the graft volume at these two time points. TCP-P displayed more advantageous surgical handling properties and a significantly greater bone area fraction and smaller biomaterial area fraction. This was accompanied by significantly greater expression of Col I and BSP and in osteoblasts and osteoid and a less pronounced reduction in grafting volume with TCP-P. SFA using both types of materials resulted in formation of sufficient bone volume for facilitating stable dental implant placement with all dental implants having been in function without any complications for 6 years. Since TCP-P displayed superior surgical handling properties and greater bone formation than TCP-G, without the HyAc hydrogel matrix having any adverse effect on bone formation or graft volume stability, TCP-P can be regarded as excellent grafting material for SFA in a clinical setting. The greater bone formation observed with TCP-P may be related to the difference in grain size of the TCP granules and/or the addition of the HyAc.

The consolidation of highly porous nanostructured wollastonite powders was conducted via Spark Plasma Sintering (SPS) technique, and porous composite materials of high mechanical strength were obtained (Young׳s modulus over 60 MPa). Peculiarities of structural parameters variation of studied materials under SPS conditions within the temperature interval 800–1000 °С are described. The procedure of porous structure control of CaSiO 3 composites, allows obtaining of hierarchically porous silica framework from nano- to microsized pores through a poreforming agent (carbonaceous template), is suggested. Obtained silicate composites are classified as bioactive ceramic materials, which are prospective for application in medical practice. [ABSTRACT FROM AUTHOR]

Synthetic biopolymers are commonly used for the repair and regeneration of damaged tissues. Specifically targeting bone, the composite approach of utilizing inorganic components is considered promising in terms of improving mechanical and biological properties. We developed gelatin-apatite co-precipitates which mimic the native bone matrix composition within poly(lactide-co-caprolactone) (PLCL). Ionic reaction of calcium and phosphate with gelatin molecules enabled the co-precipitate formation of gelatin-apatite nanocrystals at varying ratios. The gelatin-apatite precipitates formed were carbonated apatite in nature, and were homogeneously distributed within the gelatin matrix. The incorporation of gelatin-apatite significantly improved the mechanical properties, including tensile strength, elastic modulus and elongation at break, and the improvement was more pronounced as the apatite content increased. Of note, the tensile strength increased to as high as 45 MPa (a four-fold increase vs. PLCL), the elastic modulus was increased up to 1500 MPa (a five-fold increase vs. PLCL), and the elongation rate was ∼240% (twice vs. PLCL). These results support the strengthening role of the gelatin-apatite precipitates within PLCL. The gelatin-apatite addition considerably enhanced the water affinity and the acellular mineral-forming ability in vitro in simulated body fluid; moreover, it stimulated cell proliferation and osteogenic differentiation. Taken together, the GAp-PLCL nanocomposite composition is considered to have excellent mechanical and biological properties, which hold great potential for use as bone regenerative matrices. [ABSTRACT FROM PUBLISHER]

The goal of periodontal tissue engineering is to regenerate alveolar bone, root cementum and periodontal ligament. To achieve this goal, bioactive scaffolds play an important role in inducing in vitro osteogenic/cementogenic gene expression of periodontal ligament cells (PDLCs) and in vivo bone/cementum formation. Diopside (DIOP: CaMgSi2O6) ceramics have shown excellent in vitro bioactivity for potential bone repair application. However, there is no study about DIOP porous scaffolds for periodontal tissue engineering. The aim of this study is to prepare DIOP scaffolds and investigate their in vitro and in vivo osteogenesis/cementogenesis for periodontal regeneration application. DIOP scaffolds with highly porous architecture were prepared and β-tricalcium phosphate (β-TCP) scaffolds were used for the control. The interaction of DIOP scaffolds with PDLCs was studied by investigating cell attachment, proliferation and ostegenic/cementogenic differentiation of PDLCs. DIOP scaffolds were implanted into the periodontal defects of beagle dogs to evaluate their in vivo osteogenesis/cementogenesis by hematoxylin and eosin (H&E), tartrate-resistant acid phosphatase staining, and immunohistochemistry (type I collagen: Col I; cementum attachment protein) analyses. The results have shown that DIOP scaffolds supported the attachment and proliferation of PDLCs. DIOP scaffolds significantly enhanced osteogenesis/cementogenesis-related gene expression (Col 1, Runx2, transforming growth factor beta 1, and bone morphogenetic protein 2) of PDLCs, compared to β-TCP scaffolds. The in vivo study showed that DIOP scaffolds induced new bone and cementum regeneration of periodontal tissue defects. The rate of new bone and cementum in DIOP scaffolds is comparable to that in conventional β-TCP scaffolds. Our results indicated that silicate-based DIOP ceramics could not only be used for bone tissue engineering, but also for periodontal tissue engineering due to their excellent in vitro and in vivo osteogeneis/cementogenesis. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 105-116, 2014. [ABSTRACT FROM AUTHOR]

Abstract: As-cast samples of a cobalt base alloy (ASTM F-75) were heat treated in contact with different bioactive materials: (a) powder mixtures of β-tricalcium phosphate (TCP)–bioactive glass (BG) in different proportions (TCP–BG: 60–40, 70–30 and 80–20wt%) and (b) mineral and synthetic wollastonite. Samples were packed with each bioactive material and heat treated for 1h at 1220°C. To characterize the in vitro bioactivity, heat treated samples were immersed in a simulated body fluid. After immersion, a ceramic layer containing Ca and P was formed on all samples. The thicker and more homogeneous layers, identified as apatite, were formed more rapidly on the heat treated samples in contact with 80TCP–20BG and synthetic wollastonite. The more bioactive coatings were selected for MC3T3 cell adhesion, proliferation and differentiation assays. Cell proliferation and alkaline phosphatase activity were not affected by the different coatings. Additionally, samples packed with 80TCP–20BG presented a higher cell adhesion than those packed with synthetic wollastonite. On the samples previously packed with synthetic wollastonite, a denser homogeneous Ca- and P-rich layer was formed 21 days after cell seeding and incubation in differentiative conditions. [Copyright &y& Elsevier]

Abstract: Angiogenesis is critical for bone tissue engineering. Stimulating proangiogenesis in an engineered bone construct using bioglass or bioceramic is now attracting much attention. However, the specific ion that plays important roles in the stimulation of proangiogenesis has not yet been elucidated. In this study, calcium silicate (CS), an osteogenic bioceramic containing only Ca and Si ions, significantly stimulated proangiogenesis of human umbilical vein endothelial cells (HUVECs). The determination of the ionic dissolution product indicates that Si ion concentrations of the CS extracts were significantly higher than that of the calcium phosphate ceramic extracts and control medium. However, the concentrations of Ca and P ions of both ceramic extracts and normal medium were at the same level. With the specific Si ion and its effective concentrations, CS extracts stimulated the proliferation of HUVECs, up-regulated the expression of vascular endothelial growth factor, basic fibroblast growth factor and their receptors, and finally stimulated the proangiogenesis. As the Si ion played an important role in osteogenesis stimulated by Si-containing bioceramics, confirmation of the Si ion’s specific role and its effective ion concentrations in CS-induced angiogenesis may be extremely useful in designing osteogenic and angiogenic bioactive materials for bone tissue engineering. [Copyright &y& Elsevier]

Abstract: Two different oxide-based bioactive materials, namely tricalcium phosphate (TCP) and K2O–CaO–P2O5–SiO2 bioactive glass (“Bio-K”), were processed by the High Velocity Suspension Flame Spraying (HVSFS) technique. Single splats were deposited onto polished cold glass plates using a custom-built experimental set up. In addition, complete coatings were deposited onto pre-heated Ti plates. Deposited splats and coatings were examined by scanning and transmission electron microscope (SEM, TEM) techniques and their phase composition was investigated by micro-Raman spectroscopy. The 3-D profiles of single splats were also reconstructed through atomic force microscopy (AFM). Based on the experimental results, explanations of the deposition mechanisms were put forward, discussing the different heating and melting behaviour of particles and agglomerates. The critical particle sizes needed to obtain deposition of molten splats at impact, and their solidification behaviour onto cold vs. hot surfaces were studied as well. Most importantly, the splats can only be formed by molten droplets comprised within a given size range (“sprayability window”). Smaller droplets possess insufficient thermal and mechanical inertia to overcome the stagnation flow in front of the substrate; larger ones are mostly unmelted. This “sprayability window” depends on the deposition process itself and on the physical properties of sprayed materials. [Copyright &y& Elsevier]

New tissue-engineering tool for bone regeneration is described to facilitate homogeneous cell seeding and effective osteogenic development. Calcium phosphate (CaP) scaffolds with macrochanneled and well-defined pore structure was developed, however, a large portion of the cells seeded directly within the scaffold easily penetrates without good adhesion to the scaffold surface. To overcome this, a method was exploited to dispense cells evenly throughout the CaP scaffold using collagen hydrogel. Rat bone marrow-derived mesenchymal stem cells (MSCs) were mixed within a neutralized collagen solution, which was then infiltrated into the macrochanneled pore space and gelled to result in macrochanneled bioceramic scaffold combined with MSCs-hydrogel. MSCs contained within the hydrogel-CaP scaffolds were highly viable, with similar growth pattern to those in the collagen hydrogel. Cells seeded by this approach were initially almost double in number compared with those seeded directly onto the CaP scaffold and had an active proliferation more than 14 days. Assessments of the MSCs showed significantly higher alkaline phosphatase levels in the combined scaffold, which was accompanied by enhanced osteogenesis including the expression of genes [collagen type I, bone sialoprotein, and osteopontin (OPN)] and proteins (OPN and osteocalcin). Extracellular calcium was also elevated significantly in the combined scaffold compared to the CaP scaffold. In addition, mechanical strength of the constructs was improved significantly in the combined scaffold compared to the CaP scaffold. Based on these, the cell culturing and tissue engineering strategy within the macrochanneled bioactive ceramic scaffolds could be improved greatly by the combinatory approach of using collagen hydrogel. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A: 2431-2440, 2012. [ABSTRACT FROM AUTHOR]

Abstract: Carbonate hydroxyapatite (CHAp) was synthesized by a wet precipitation method. In the synthesis, calcium oxide, H3PO4 and (NH4)2HPO4 were applied as reactants. NH4HCO3 in the amount of 0.05–0.20mol per 0.3mol of H3PO4 or (NH4)2HPO4 was used as the source of CO3 2− groups. Sintering was carried out using powders and uniaxially pressed samples of carbonate and non-carbonate hydroxyapatites. The influence of synthesis conditions as well as sintering atmosphere on sinterability and phase composition of the final ceramic materials was evaluated. It was found that using properly synthesized CHAp powders and CO2 atmosphere during heat-treatment it was possible to obtain dense CHAp ceramics with 1% of CaCO3 as the secondary phase at the temperature 300–350°C lower than that required for non-carbonate hydroxyapatite. Chemical stability and bioactive potential of CHAp–CaCO3 ceramics were confirmed by in vitro tests. [Copyright &y& Elsevier]

Abstract: Biodegradable polymer–ceramic composite scaffolds have gained importance in recent years in the field of orthopedic biomaterials and tissue engineering scaffolds for improving the rate of degradation and limited mechanical properties of bioactive ceramics. This study sought to create composites using the electrospinning process to achieve fibrous scaffolds with uniform fiber morphologies and uniform ceramic dispersions. Composites consisting of 20% hydroxyapatite/80% β-tricalcium phosphate (20/80 HA/TCP) and poly (ε-caprolactone) (PCL) were fabricated. The 20/80 HA/TCP composition was chosen as the ceramic component because of previous reports of greater bone tissue formation in comparison with HA or TCP alone. For electrospinning, PCL was dissolved in either methylene chloride (Composite–MC) or a combination of methylene chloride (80%) and dimethylformamide (20%) (Composite–MC+DMF). Composite–MC mats contained a bimodal distribution of fiber diameters with nanofibers between larger, micron-sized fibers with an average pore size of 79.6±67μm, whereas Composite–MC+DMF fibers had uniform fiber diameters with an average pore size of 7.0±4.2μm. Elemental mapping determined that the ceramic was distributed throughout the mat and inside the fiber for both composites. However, physical characterization using differential scanning calorimetry (DSC) and mechanical testing revealed that the ceramic in the mats produced with MC+DMF were more uniformly dispersed than the ceramic in the mats produced with MC alone. Maximum tensile stress and strain were significantly higher for Composite–MC+DMF mats compared with Composite–MC mats and were comparable with the mechanical properties of mats of PCL alone. For both composites, there was molecular interaction between the PCL and the ceramic, as demonstrated by a maximum increase of ∼10°C in the glass transition values with the addition of the ceramic, as confirmed by Fourier transform infrared analysis. In addition, the crystallization behavior of the composites suggested that the ceramic was acting as a nucleating agent. Cell viability studies using human mesenchymal stem cells (MSC) showed that both composite scaffolds supported cell growth. However, cell numbers at early time points in culture were significantly higher on mats produced from MC+DMF compared with mats prepared with MC alone. Further examination revealed that cells were able to infiltrate the pores of the Composite–MC mats, but remained on the outer surface of the Composite–MC+DMF and unfilled PCL mats during the culture period. The results of this study demonstrate that the solvent or solvent combination used in preparing the electrospun composite mats plays a critical role in determining its properties, which may, in turn, affect cell behavior. [Copyright &y& Elsevier]

Abstract: Microparticulates are useful for directly filling defective tissues as well as for delivering cells and bioactive molecules in regenerative medicine. This paper reports on the production of bioactive ceramic microspheres with an interconnected macropore structure. The sol–gel derived calcium silicate powder was homogenized with an oligomeric Camphene melt, which was used as a novel porogen, and spherical-shaped microparticulates were obtained by an oil-in-water emulsion method. A porous structure was generated through the sublimation of Camphene within the calcium silicate–Camphene solidified blend under ambient conditions. The microspheres retained the crystalline phase of apatite and wollastonite during heat treatment and induced calcium phosphate precipitation under a body-simulating medium, showing the characteristics of bone-bioactive materials. Osteoblastic cells were observed to anchor to and spread well over the surface of the porous microspheres, and further to proliferate actively with culturing time. The bioactive and porous microspheres developed are considered potentially useful in the regeneration of hard tissues as a matrix for tissue engineering as well as a direct filling material. [Copyright &y& Elsevier]

Abstract: CaO–SiO2 based ceramics have been regarded as potential candidates for artificial bone due to their excellent bone bioactivity and biocompatibility. However, they cannot be used as implants under a heavy load because of their poor mechanical properties, in particular low fracture toughness. Plasma spraying CaO–SiO2 based ceramic coatings onto titanium alloys can expand their application to the hard tissue replacement under a heavy load. Plasma sprayed wollastonite, dicalcium silicate and diopside coatings have excellent bone bioactivity and high bonding strength to titanium alloys. It is possible that these plasma sprayed CaO–SiO2 based ceramic coatings will be applied in clinic after they are widely and systematically researched. [Copyright &y& Elsevier]

Abstract: Hydroxyapatite is a bioactive ceramic material that mimics the mineral composition of natural bone. This material does not possess acceptable mechanical properties for use as a bulk biomaterial; however, it does demonstrate significant potential for use as a coating on metallic orthopaedic and dental prostheses. This paper reviews recent developments involving pulsed laser deposition of hydroxyapatite thin films for medical and dental applications. The structural, mechanical, and biological properties of hydroxyapatite thin films are described. In addition, future directions in pulsed laser deposition of hydroxyapatite thin films are discussed. [Copyright &y& Elsevier]

Abstract: Diamondlike carbon (DLC) is an amorphous form of carbon that may contain a high fraction of sp3-hybridized carbon atoms. DLC thin films possess high hardness values, low coefficient of friction values, chemical inertness, and compatibility with human cells. The cardiovascular, orthopedic, ophthalmic, biosensor, and microelectromechanical system (MEMS) device applications for diamondlike carbon thin films are reviewed. Finally, processing of nanostructured diamondlike carbon thin films for medical applications is presented. [Copyright &y& Elsevier]

This study aimed to investigate the long-term clinical results of the apatite wollastonite-containing glass ceramic (AWGC) iliac spacer and to discuss its efficacy in reconstruction of the bone graft donor site at the iliac crest. Thirty-one patients were studied for more than 10 years. All patients underwent anterior spinal fusion using autogenous tricortical iliac bone graft. After harvest of tricortical iliac bone graft, an AWGC iliac spacer ranging from 15 mm to 70 mm in length was press-fitted into the gap. Long-term clinical results were obtained from radiological and blood examinations. Thirty patients (97%) were satisfied with the spacer. There was new bone formation around the spacer on the radiograph. There was no abnormal silicon concentration in blood examinations. AWGC iliac spacer appears to be useful in the reconstruction of harvested iliac crest. New bone formation occurs, reducing the defect size. [ABSTRACT FROM AUTHOR]

Bioactive ceramics developed during the past few decades have interesting properties from the biological standpoint, but their effects on cellular events remain partially unknown. In the current work, we investigated cellular viability, proliferation, morphology changes and metabolic activity of rat primary culture osteoblasts in contact with the ionic products from the dissolution of a bioactive glass with 60% of silica (BG60S) and a biphasic calcium phosphate (BCP). We observed that although osteoblasts cultured with BG60S showed vacuole formation, cell viability was increased when compared to BCP and control. The vacuole formation was not due to the presence of high calcium concentration in the ionic products from the dissolution of BG60S and was not related to nitric oxide production from the osteoblasts. We did find that high silicon concentration could induce cellular vacuole formation. Additionally, energy dispersive spectroscopy analysis indicated that vacuole contained 75% more silicon than other regions in the cell outside the vacuole. We further found that collagen production was higher in osteoblast cultured in the presence of BG60S compared to BCP and control, while alkaline phosphatase production was similar among cells incubated with BG60S, BCP and control. Together, our results indicate that osteoblast vacuole formation was due to high silicon contents in the dissolution of BG60S and we can suggest that despite the vacuole formation, there is no significant alteration in the bioceramic cell interaction. [Copyright &y& Elsevier]