Composite Bone Cement Research Articles

Effect of different calcium sulfate aspect ratios and chitosan addition methods on the interface properties of calcium sulfate/chitosan composite bone cement

AbstractIt is a great challenge to improve the properties of pure calcium sulfate bone cement. Here, two calcium sulfate hemihydrate powders with different aspect ratios were prepared, and three chitosan addition methods were adopted to investigate the effect on the surface and interface properties of calcium sulfate/chitosan composite bone cement. The results showed that it lacked chemical bond between chitosan and calcium sulfate, and the short rod calcium sulfate displayed better interface adhesion with chitosan owing to its smaller size, so it possessed shorter setting time, better compressive strength and slower degradation than the long rod calcium sulfate, while the biocompatibility had no remarkable difference. Moreover, chitosan solution as liquid phase was a better solidification mode than citric acid, and calcium sulfate/chitosan composite as solid phase was the worst mode because of poor interface compatibility. Conclusively, it was a simple, low‐cost, and effective preparation process to choose short rod calcium sulfate powder as solid phase and 1 wt% chitosan solution as liquid phase, which could achieve calcium sulfate/chitosan composite bone cement with the best properties, including setting time, compressive strength, degradation rate, and biocompatibility, displaying a promising application in bone defect repair.

Insights into the Various Cellular Antimicrobial Responses, Biocompatibility, Osteogenesis, Wound Healing, and Angiogenesis of Copper-Doped Nano-Hydroxyapatite Composite Calcium Phosphate Bone Cement In Vitro

Calcium phosphate bone cement (CPC) is a popular material for bone remodeling, and nanohydroxyapatite (nHA) represents a breakthrough that has a wide range of clinical applications. During the early stages of bone repair, antibacterial and angiogenesis effects are essential to remodel new bone tissues. In this study, an antibacterial effect was achieved by incorporating Cu2+-doped nano-hydroxyapatite (Cu–nHA) synthesized through hydrothermal methods into CPC, and the impact of various amounts of Cu–nHA addition on the antibacterial and mechanical properties of CPC hybridization was evaluated. Moreover, the effects of Cu–nHA/CPC composites on the proliferation and mineralization of mouse progenitor osteoblastic cells (D1 cells) were characterized; the cell migration and angiogenesis ability of vascular endothelial cells (HUVECs) were also studied. Results indicated that incorporating 5 wt.% and 10 wt.% Cu–nHA into CPC led to a practical short-term antibacterial effect on S. aureus but not on E. coli. These Cu–nHA/CPC slurries remained injectable, anti-disintegrative, and non-toxic. Furthermore, compared with pure CPC, these Cu–nHA/CPC slurries demonstrated positive effects on D1 cells, resulting in better proliferation and mineralization. In addition, these Cu–nHA/CPC slurries were more effective in promoting the migration and angiogenesis of HUVECs. These findings indicate that 10 wt.% Cu–nHA/CPC has great application potential in bone regeneration.

Cerium as a crystalline phase stabilizer of α-TCP and its hydration and photothermal properties

Bone cement with photothermal properties can treat bone defects caused by bone tumors while killing residual tumor cells or preventing recurrence. In this study, trace amounts of cerium ions were introduced to enhance the crystal stability of α-TCP, thereby improving the hydration properties of α-TCP and obtaining excellent photothermal properties. The experimental results showed that the content of α-TCP in CON-TCP was 96.05 %, and the content of α-TCP in 1% Ce-TCP was 99.77 %, with an increase of 3.87 %; the compressive strength of 0.5% Ce-CPC hydrated for 5d increased from 16.6 MPa±2.18 MPa to 32.16 MPa±2.77 MPa, with an increase of 93.73 %. The temperature of 0.5% Ce-CPC can be raised to 50.9°C in two minutes under the irradiation of 808 nm laser, which is an increase of 31.5% compared with that of 38.7°C in the blank group. Therefore, trace cerium-doped calcium phosphate bone cement has excellent physicochemical and photothermal properties, and it is a promising composite bone cement material, and the results of the present study are expected to be used to treat bone defects in bone tumors.

A ternary calcium silicate bone cement with high mechanical properties and good operability

The treatment of vertebral compression fractures of the spinal necessitates the use of injectable bone repair materials with the adaptive modulus of elasticity. Currently, newly developed injectable self-curing materials for minimally invasive surgery are primarily categorized into calcium phosphate and calcium silicate systems, both of which exhibit excellent biocompatibility. However, calcium phosphate bone cement lacks adequate mechanical properties and the stress does not match between bone and material. Calcium silicate cement has a long curing time, low mechanical strength, and high alkalinity. These deficiencies render them inadequate for meeting clinical requirements. Therefore, we incorporated inorganic disodium phosphate, organic polyvinyl alcohol, and solid component cerium oxide into the matrix phase of tricalcium silicate bone cement to establish a ternary self-curing hydration reinforcement system and produced an organic-inorganic composite injectable bone cement. Even though the composite bone cement has a longer setting time, it exhibited high compressive strength (61.9Mpa) and fracture strain (7.88 %), demonstrating excellent mechanical properties. Furthermore, it also demonstrates good injectable properties (86 %), anti-collapse properties, good biological activity, and outstanding antibacterial properties. The composite bone cement has great potential to develop a new injectable self-curing material to replace PMMA bone cement in clinical vertebral compression fractures.

A Review of the Effect of Mechanical Vibrations on Bone Cement and Implants during Implantation in the Bone Cavity

This study of the literature looks at how mechanical vibrations affect the placement of implants and bone cement into bone cavities. The study investigates the many consequences of vibrations, from vibrational injury to potential advantages like enhanced osseointegration. Studies on the use of nanoparticles in bone cement to improve its mechanical characteristics and antibacterial resistance are presented, among other study findings. The paper also discusses the creation of innovative biomaterials that have better mechanical strength, anti-washout qualities, and biocompatibility, such composite bone cements and nanohybrids. The complicated interactions between mechanical vibrations, biomaterials, and orthopedic surgery are highlighted in this review of the literature, which also offers suggestions for improving implant stability and patient outcomes.

Mechanical Properties, Drug Release, Biocompatibility, and Antibacterial Activities of Modified Emulsified Gelatin Microsphere Loaded with Gentamicin Composite Calcium Phosphate Bone Cement In Vitro.

Bone defects are commonly addressed with bone graft substitutes; however, surgical procedures, particularly for open and complex fractures, may pose a risk of infection. As such, a course of antibiotics combined with a drug carrier is often administered to mitigate potential exacerbations. This study involved the preparation and modification of emulsified (Em) crosslinking-gelatin (gel) microspheres (m-Em) to reduce their toxicity. The antibiotic gentamicin was impregnated into gel microspheres (m-EmG), which were incorporated into calcium phosphate bone cement (CPC). The study investigated the effects of m-EmG@CPC on antibacterial activity, mechanical properties, biocompatibility, and proliferation and mineralization of mouse progenitor osteoblasts (D1 cells). The average size of the gel microspheres ranged from 22.5 to 16.1 μm, with no significant difference between the groups (p > 0.05). Most of the oil content within the microspheres was transferred through modification, resulting in reduced cytotoxicity. Furthermore, antibiotic-impregnated m-EmG did not compromise the intrinsic properties of the microspheres and exhibited remarkably antibacterial effects. After combining with CPC (m-EmG@CPC), the microspheres did not significantly hinder the CPC reaction and produced the main product, hydroxyapatite (HA). However, the compressive strength of the largest microsphere content of 0.5 wt.% m-EmG in CPC decreased significantly from 59.8 MPa of CPC alone to 38.7 MPa of 0.5m-EmG@CPC (p < 0.05). The 0.5m-EmG@CPC composite was effective against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in drug release and antibacterial tests. Compared with m-EmG alone, the 0.5m-EmG@CPC composite showed no toxicity to mouse fibroblast cells (L929). Additionally, the proliferation and mineralization of mouse osteoblastic osteoprogenitor cells (D1 cells) did not have a negative impact on the 0.5m-EmG@CPC composite over time in culture compared with CPC alone. Results suggest that the newly developed antibacterial 0.5m-EmG@CPC composite bone cement did not negatively affect the performance of osteoprogenitor cells and could be a new option for bone graft replacement in surgeries.

A novel strategy for calcium magnesium phosphate/carboxymethyl chitosan composite bone cements with enhanced physicochemical properties, excellent cytocompatibility and osteogenic differentiation

Artificial bone substitutes for bone repair and reconstruction still face enormous challenges. Previous studies have shown that calcium magnesium phosphate cements (CMPCs) possess an excellent bioactive surface, but its clinical application is restricted due to short setting time. This study aimed to develop new CMPC/carboxymethyl chitosan (CMCS) comg of mixed powders of active MgO, calcined MgO and calcium dihydrogen phosphate monohydrate. With this novel strategy, it can adjust the setting time and improve the compressive strength. The results confirmed that CMPC/CMCS composite bone cements were successfully developed with a controllable setting time (18–70 min) and high compressive strength (87 MPa). In addition, the composite bone cements could gradually degrade in PBS with weight loss up to 32% at 28 d. They also promoted the proliferation of pre-osteoblasts, and induced osteogenic differentiation. The findings indicate that CMPC/CMCS composite bone cements hold great promise as a new type of bone repair material in further and in-depth studies.

Effect of various admixtures on selected mechanical properties of medium viscosity bone cements: Part 2 – Hydroxyapatite

Poly methyl-methacrylate (PMMA) is one of the most widely used polymer composite materials in orthopaedic and trauma surgery. However, this material can change its mechanical properties when exposed to the highly aggressive environment of the human body, which may result in joint implant loosening and thus in a need for revision surgery. Therefore, in recent years, numerous researchers have investigated the effect of adding various particles to PMMA in order to obtain a composite bone cement with enhanced mechanical properties. In our study, we examined the effect of adding different grain sizes of hydroxyapatite (HA) to the commercially available PMMA (Palamed, Heraeus) on the mechanical properties of the fabricated PMMA/HA bone cement composite. Samples were subjected to compressive loading, as this type of load reflects typical conditions in the human body after joint prosthesis implantation. Hydroxyapatite of two different grain sizes was used: 5 µm (HA5) and 10 µm (HA10). Being a naturally occurring bone mineral, hydroxyapatite can improve the biocompatibility of bone cements, which would prolong the total joint replacement (TJR) survival rate. However, when added to PMMA, HA can affect its mechanical properties. In this study, the effects of adding HA was added in 0, 1, 2, 3, 5, 8, 10 % of dry mass were analysed. Obtained results demonstrated that only the addition of 2 % HA had a significant impact on the mechanical properties of PMMA. The other percentage concentrations had no effect on PMMA properties.

Effect of various admixtures on selected mechanical properties of medium viscosity bone cements: Part 1 – α/β tricalcium phosphate (TCP)

Every year millions of people around the world suffer from joint and bone diseases and require orthopaedic surgery. Owing to its unique properties such as biocompatibility and ability to bond bones with orthopaedic implants, poly methyl-methacrylate (PMMA) is among the most widely used polymer composites for bone cements in orthopaedic and trauma surgery. On the other hand, this material is characterized by low mechanical properties, which can lead to accelerated implant loosening in aggressive environments, such as the human body. Over the years, researchers have studied PMMA, especially its failure mechanism. Various additives to PMMA have been proposed to enhance the mechanical properties of this material. This study investigated the effect of mixing PMMA with α-TCP (PMMA/α-TCP bone cement composite) and β-TCP (PMMA/β-TCP bone cement composite) on its mechanical properties. The study was conducted on commercially available PMMA (Haraeus Palamed) mixed with α-TCP and β-TCP in different concentrations. TCP has bacteriostatic properties and, as a bone compatible material, it stimulates bone regeneration and bone ingrowth, which highly increases the survival rate of PMMA bonding. However, the addition of particles to PMMA can affect mechanical properties of bone cements. In this study, the effects of 0, 1, 2, 3, 5, 8 and 10% dry mass concentration of TCP in bone cement on the mechanical properties of PMMA were investigated. Samples were subjected to compressive loading. This loading mode is typical of the human body after joint prosthesis implantation. The analysis involved comparing selected mechanical parameters of samples prepared according to manufacturer’s instructions and of samples prepared with the addition of α-TCP and β-TCP. Results demonstrated that the addition of β-TCP, whose crystals are triangular, did not affect the mechanical properties of PMMA. On the other hand, the addition of more than 3% dry mass α-TCP, the inner structure of which is hexagonal, led to a slight yet significant decrease in the compressive strength of PMMA.

All-in-one strategy to develop a near-infrared triggered multifunctional bioactive magnesium phosphate bone cement for bone repair

Bone cement is widely used in clinical with optimistic filling and mechanical properties. However, the setting time of bone cement is difficult to accurately control, and the existing bone cements exhibit limited therapeutic functionalities. In response to these challenges, we designed and synthesized Nd-doped whitlockite (Nd-WH), endowing bone cement with photothermal-responsive and fluorescence imaging capabilities. The doping amount and photothermal properties of Nd-doped whitlockite were studied, and the composite bone cement was prepared. The results showed that the setting time of bone cement could be regulated by near infrared irradiation, and the multiple functions of promoting osteogenic differentiation, antibacterial and anti-tumor could be realized by adjusting the power and irradiation time of near infrared. By incorporating Nd-doped whitlockite and bone cement, we developed an all-in-one strategy to achieve setting time control, enhanced osteogenic ability, tumor cell clearance, bacterial clearance, and bone tissue regeneration. The optimized physical and mechanical properties of composite bone cement ensure adaptability and plasticity. In vitro and in vivo experiments validated the effectiveness of this bone cement platform for bone repair, tumor cell clearance and bacterial clearance. The universal methods to regulate the setting time and function of bone cement by photothermal effect has potential in orthopedic surgery and is expected to be a breakthrough in the field of bone defect repair. Further research and clinical validation are needed to ensure its safety, efficacy and sustainability. Statement of significanceBone cement is a valuable clinical material. However, the setting time of bone cement is difficult to control, and the therapeutic function of existing bone cement is limited. Various studies have shown that the bone repair capacity of bone cements can be enhanced by synergistic stimulatory effects in vivo and ex vivo. Unfortunately, most of the existing photothermal conversion materials are non-degradable and poorly biocompatible. This study provides a bone-like photothermal conversion material with photothermal response and fluorescence imaging properties, and constructed a platform for integrated regulation of the setting time of bone cement and diversification of its functions. Therefore, it helps to design multi-functional bone repair materials that are more convenient and effective in clinical operation.

Novel injectable calcium-magnesium phosphate cement-based composites with piezoelectric properties: advancements in bone regeneration applications

Designing a novel injectable bone cement is an important approach to the success of bone healing in minimally invasive surgeries. As natural bone has a piezoelectric property, which is crucial in bone regeneration, this study focused on the development of a novel injectable composite bone cement with piezoelectric properties. For the composite composition, calcium and zirconium doped barium titanate (BCZT) was used for its piezoelectric property, while calcium phosphate and magnesium phosphate cement (CMPC) were preferred for its bone-like properties. In this framework, first BCZT, CMPC, and their composites were prepared, and their phase structures, particle size distributions, and piezoelectric and dielectric properties were investigated. Then, the composite bone cements were prepared by mixing CMPC with BCZT in three different ratios (20%, 30%, and 40%). Next, polysorbate 80 solution was added to the cement mixtures to prepare the injectable pastes. Finally, injectability, setting time, and compressive strength of the composites were assessed. As a result, the composite bone cement containing 30% BCZT has the potential to be used as an injectable bone cement in invasive orthopedic surgery.

A Bioactive Degradable Composite Bone Cement Based on Calcium Sulfate and Magnesium Polyphosphate.

Calcium sulfate bone cement (CSC) is extensively used as a bone repair material due to its ability to self-solidify, degradability, and osteogenic ability. However, the fast degradation, low mechanical strength, and insufficient biological activity limit its application. This study used magnesium polyphosphate (MPP) and constructed a composite bone cement composed of calcium sulfate (CS), MPP, tricalcium silicate (C3S), and plasticizer hydroxypropyl methylcellulose (HPMC). The optimized CS/MPP/C3S composite bone cement has a suitable setting time of approximately 15.0 min, a compressive strength of 26.6 MPa, and an injectability of about 93%. The CS/MPP/C3S composite bone cement has excellent biocompatibility and osteogenic capabilities; our results showed that cell proliferation is up to 114% compared with the control after 5 days. After 14 days, the expression levels of osteogenic-related genes, including Runx2, BMP2, OCN, OPN, and COL-1, are about 1.8, 2.8, 2.5, 2.2, and 2.2 times higher than those of the control, respectively, while the alkaline phosphatase activity is about 1.7 times higher. Therefore, the CS/MPP/C3S composite bone cement overcomes the limitations of CSC and has more effective potential in bone repair.

ANALYSIS OF THE RESULTS OF PERCUTANEOUS VERTEBROPLASTY OF COMPRESSION FRACTURES OF BODIES OF CHEST AND LUMBAR VERTEBRAE ON THE BACKGROUND OF OSTEOPOROSIS

It is well known that the most frequent complication of osteoporosis is compression fractures of vertebral bodies. In addition to brittleness of the bones and mechanical stress, more and more evidence approving that compression fractures of vertebral bodies are related to many risk factors, such as aging, sex, concomitant morbidities of cardiovascular and cerebrovascular diseases and lifestyle (chronic smoking and alcohol consumption) are collected. Objective. Analyzing the condition of spines of the patients suffering from compression fractures of vertebral bodies on the background of osteoporosis after the performed Percutaneous vertebroplasty (PV). Methods. 553 patients who underwent hospital treatment at the spine pathology clinic of the Sytenko Institute of Spine and Joint Pathology (2005–2022) and underwent PV were examined. Results. The patients were divided into three groups depending on the number of damaged vertebrae. The 1st group included the patients with compression fractures of one vertebra (185 — 33.4 %); the 2nd group included the patients having 2 or 3 deformed vertebrae (216 — 39 %); and the 3rd group included the patients with 4–5 damaged vertebrae (152 — 27.4 %). Stages of compression of vertebral bodies during the X-ray morphometry was as follows before the surgery: I — 349 (24 %) vertebrae; II — 494 (34 %); III — 552 (38 %); and IV — 58 (4 %). We achieved the reduction of the level of compression of vertebral bodies as a result of PV in 20 % of cases (patients who noticed the manifestation of the pain syndrome within 2 weeks mostly suffered from these deformations). Conclusions. The results of analysis of PV of 553 patients with composite material and bone cement in the near and far future provide us an opportunity to state that this surgical treatment is an efficient and safe treatment method (despite the materials used). 40 (24 %) patients out of 165 patients of the group I, 52 (33 %) patients out of 157 patients of the group II and 54 (44 %) patients our of 133 patients of the group III were diagnosed with repeated compression fractures. Summarizing all the above, we should note that the more compression fractures the patient has, the higher the risk of further augmentation of other deformations of vertebral bodies is.

Investigating the in vitro antibacterial efficacy of composite bone cement incorporating natural product-based monomers and gentamicin

ObjectiveThe objective of this study is to investigate the impact of four natural product extracts, namely, aloe-emodin, quercetin, curcumin, and tannic acid, on the in vitro bacteriostatic properties and biocompatibility of gentamicin-loaded bone cement and to establish an experimental groundwork supporting the clinical utility of antibiotic-loaded bone cements (ALBC).MethodsBased on the components, the bone cement samples were categorized as follows: the gentamicin combined with aloe-emodin group, the gentamicin combined with quercetin group, the gentamicin combined with curcumin group, the gentamicin combined with tannic acid group, the gentamicin group, the aloe-emodin group, the quercetin group, the curcumin group, and the tannic acid group. Using the disk diffusion test, we investigated the antibacterial properties of the bone cement material against Staphylococcus aureus (n = 4). We tested cell toxicity and proliferation using the cell counting kit-8 (CCK-8) and examined the biocompatibility of bone cement materials.ResultsThe combination of gentamicin with the four natural product extracts resulted in significantly larger diameters of inhibition zones compared to gentamicin alone, and the difference was statistically significant (P < 0.05). Except for the groups containing tannic acid, cells in all other groups showed good proliferation across varying time intervals without displaying significant cytotoxicity (P < 0.05).ConclusionIn this study, aloe-emodin, quercetin, curcumin, and tannic acid were capable of enhancing the in vitro antibacterial performance of gentamicin-loaded bone cement against S. aureus. While the groups containing tannic acid displayed moderate cytotoxicity in in vitro cell culture, all other groups showed no discernible cytotoxic effects.

Production of Bone Cement Composite from Polymethyl Methacrylate Produced in Laboratory Scale

Bone cement is an indispensable material in orthopedic medicine. In Indonesia, the fulfillment of bone cement needs still depends on imports from other countries. Polymethyl methacrylate (PMMA) is one of the main ingredients of bone cement which can be made from suspension polymerization of methyl methacrylate monomer (MMA). Therefore, this study aims to develop a technique for producing bone cement from PMMA. The production of bone cement consists of (1) the manufacture of PMMA, (2) the mixing of solid mixtures, (3) the mixing of solid mixtures and liquid mixtures, and (4) the molding of bone cement composites. The concentrations of barium sulfate (BaSO4) used were 7%, 9%, and 11% by weight. Composite products were analyzed by Scanning Electron Microscopy (SEM), Proton Nuclear Magnetic Resonance (H-NMR), and Compressive Strength. The increase of BaSO4 can trigger more smooth surface of bone cement composite. The tacticity from H-NMR shows that the bone cement dominantly consists of syndiotactic (58.83-59.91%) molecular arrangement. The highest compressive strength was 84.2 MPa which was obtained in 9% BaSO4 weight.

Effect of using nano-particles of magnesium oxide and titanium dioxide to enhance physical and mechanical properties of hip joint bone cement

In this work, the effect of adding Magnesium Oxide (MgO) and Titanium Dioxide (TiO2) nanoparticles to enhance the properties of the bone cement used for hip prosthesis fixation. Related to previous work on enhanced bone cement properties utilizing MgO and TiO2, samples of composite bone cement were made using three different ratios (0.5%:1%, 1.5%:1.5%, and 1%:0.5%) w/w of MgO and TiO2 to determine the optimal enhancement ratio. Hardness, compression, and bending tests were calculated to check the mechanical properties of pure and composite bone cement. The surface structure was studied using Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FE-SEM). Setting temperature, porosity, and degradation were calculated for each specimen ratio to check values matched with the standard range of bone cement. The results demonstrate a slight decrease in porosity up to 2.2% and degradation up to 0.17% with NP-containing composites, as well as acceptable variations in FTIR and setting temperature. The compression strength increased by 2.8% and hardness strength increased by 1.89% on adding 0.5%w/w of MgO and 1.5%w/w TiO2 NPs. Bending strength increases by 0.35% on adding 1.5% w/w of MgO and 0.5% w/w TiO2 NPs, however, SEM scan shows remarkable improvement for surface structure.

An Overview of Bone Cement Compositions used in Vertebroplasty and Their Viability in Clinical Settings

Vertebroplasty is a minimally invasive surgical procedure wherein a particular composition of bone cement is injected into a fractured vertebra in an attempt to restore joint mobility and reduce perceived pain. It is especially common in the treatment of osteoporotic vertebral compression fractures, most typically experienced by older women. The formulation of this bone cement takes on many forms, the most common being the group of cements known as polymethyl methacrylate acrylic bone cements. The different varieties of acrylic bone cements are investigated and compared, in addition to new potential rival materials being developed to rival the dominance of acrylic bone cements in the vertebroplasty bone cement industry. Factors such as biomechanical strength, handling, osteoconductivity/inductivity, biodegradability, additive delivery, and porosity are considered. While the main drawbacks of acrylic bone cements (significant biomechanical mismatch with vertebrae and lack of biodegradability and osteoconductivity) present opportunities for new solutions to enter the market to compete, the industry standard in vertebroplasty remains the most widely applicable, and thus wisest, cement choice for the procedure. Keywords: Vertebroplasty, Minimally Invasive Surgery, Biodegradability, Bone Cement

Comprehensive study through imaging techniques of the degradation of a resorbable calcium sulphate-based composite bone cement

The stabilization and treatment of vertebral compression fractures via vertebroplasty procedure foresees the injection of bone cements and recent research is focused on the use of degradable cements featuring an appropriate degradation kinetics. This study presents an investigation into the degradation behaviour of a resorbable ceramic composite cement based on calcium sulphate hemihydrate (CSH), supplemented with strontium-containing mesoporous bioactive glasses (Sr-MBG) and zirconia nanoparticles (ZrO2). The alterations in the material's microstructure resulting from the degradation process were thoroughly analysed using two image analysis techniques. Micro-computed tomography (Micro-CT) was employed for scanning, while CT-An software associated with the instrument and a Python-coded image analysis tool were utilised to assess porosity and pore size distribution over time. Comparative analysis of the obtained results demonstrated the efficacy of both techniques in comprehensively understanding the internal microstructural changes and volume variations during the degradation of the ceramic composite cement.

Lyophilized platelet rich fibrin and gelatin incorporated bioadhesive bone cement composite for repair of mandibular continuity defects

Mandibular continuity defects stem from conditions such as malignancies, trauma, cysts, osteomyelitis and osteoradionecrosis, presenting significant challenges. If mandibular reconstruction fails, it can result in facial collapse, causing significant aesthetic and functional concerns for the patient. In the present study we developed a bio-adhesive Bone Cement (BC) enriched with lyophilised PRF and gelatin to enhance bone repair and induce regeneration. The developed BC consisted of a mixture of Tetracalcium Phosphate (TTCP) and O-Phospho-l-serine (OPLS) in addition to lyophilised Platelet Rich Fibrin (PRF) for sustained growth factor release and gelatin (GE) for improved cement resorption. It is primarily designed for in-situ application, conforming to the shape and size of the defect for effective bone repair and regeneration. The study evaluated four groups: (i) BC (control), (ii) BC-GE (control), (iii) BC-PRF, and (iv) BC-GE-PRF. All the four groups were characterised using FTIR, SEM and XRD. The mechanical studies of the prepared beads exhibited a significant increase in the compressive strength of the PRF loaded bone cement composites. In vitro degradation study of the beads over a 60-day period revealed a significantly higher percentage of bone cement resorption in the gelatin-incorporated groups, BC-GE (44 ± 0.5 %), and BC-GE-PRF (45 ± 2 %). The assessment of growth factor release (TGF-β and VEGF) using ELISA revealed a prolonged and sustained release of both growth factors over a 28-day period. In vitro studies were performed on human Dental Follicle Stem Cells (DFSCs) to assess cell attachment, proliferation, mineralisation and osteogenic differentiation. These studies clearly depicted that BC-PRF and BC-GE-PRF showed significantly greater proliferation of DFSCs. Furthermore, BC-PRF and BC-GE-PRF samples exhibited notably elevated expression of Runx2 and OPN (osteogenic markers), as well as a higher intensity of alizarin red stain (mineralisation). Therefore, it was concluded that PRF incorporated bioadhesive bone cement composites greatly enhance the cell attachment, proliferation, mineralisation and osteogenic differentiation of the DFSCs. Thus, the PRF and gelatin incorporated bone cement composites is expected to facilitate effective and faster bone regeneration and healing in a wide range of dental and maxillofacial defects.

Design and Manufacture of Bone Cements Based on Calcium Sulfate Hemihydrate and Mg, Sr-Doped Bioactive Glass.

In the present study, a novel composite bone cement based on calcium sulfate hemihydrate (CSH) and Mg, Sr-containing bioactive glass (BG) as solid phase, and solution of chitosan as liquid phase were developed. The phase composition, morphology, setting time, injectability, viscosity, and cellular responses of the composites with various contents of BG (0, 10, 20, and 30 wt.%) were investigated. The pure calcium sulfate cement was set at approximately 180 min, whereas the setting time was drastically decreased to 6 min by replacing 30 wt.% glass powder for CSH in the cement solid phase. BG changed the microscopic morphology of the set cement and decreased the size and compaction of the precipitated gypsum phase. Replacing the CSH phase with BG increased injection force of the produced cement; however, all the cements were injected at a nearly constant force, lower than 20 N. The viscosity measurements in oscillatory mode determined the shear-thinning behavior of the pastes. Although the viscosity of the pastes increased with increasing BG content, it was influenced by the frequency extent. Pure calcium sulfate cement exhibited some transient cytotoxicity on human-derived bone mesenchymal stem cells and it was compensated by introducing BG phase. Moreover, BG improved the cell proliferation and mineralization of extracellular matrix as shown by calcein measurements. The results indicate the injectable composite cement comprising 70 wt.% CSH and 30 wt.% Mg, Sr-doped BG has better setting, mechanical and cellular behaviors and hence, is a potential candidate for bone repair, however more animal and human clinical evaluations are essential.