Bioinert Ceramics Research Articles

Advanced Bioceramics: Properties, Fabrication and Applications

Bioceramics are engineered materials that achieve their applications in the medical field. Bioceramics are promising inorganic materials to create scaffolds for bone regeneration due to their desirable properties, such as biocompatibility, osteoconduction, and their similarity with bone composition. Bioceramics can operate as tissue replacement and can be used for coating metal implants to increase their biocompatibility. Bioceramics are classified into three types: bioinert ceramics, bioactive bioceramics, and biodegradable ceramics. There are different methods for the fabrication of bioceramics, they can be prepared by conventional powder processing methods or by some new unconventional methods. Bioceramics can be fabricated by a sintering process, which takes place through the hardening of the green bodies at a relatively high temperature lower than their melting point. Nowadays, microwave sintering is excellent in both heating efficiency, saving energy and time, and the concomitant processing cost. There are other methods used to obtain bioceramics; such as sol-gel, gas-foaming, gel-casting, and freeze-casting techniques. Recently, the CAD/CAM technique (computer-aided design/manufacture) was used in the fabrication of bioceramics and is applied in the dentistry field. The application of bioceramics connects to the repair of the skeletal system, which consists of joints, bones, and teeth, as well as both soft and hard tissues. Bioceramics can be used to replace parts of the cardiovascular system, especially heart valves.

Bioinert ceramics scaffolds for bone tissue engineering by laser-based powder bed fusion: a preliminary review

The implementation of laser powder bed fusion (PBF-LB) on ceramics is far more demanding than their metallic and polymeric counterparts for bone tissue engineering (BTE). The review will shed light on bioinert ceramics-based biomaterials manufacturing through PBF-LB incorporating alumina and yttria-stabilized zirconia as oxide-based ceramics and nitride-based ceramics as non-oxide-based ceramics with particular prominence on their properties and requirements for biomedical devices and BTE. The review paper will also classify bioinert scaffolds processed through PBF-LB as a medium to manufacture drug delivery systems (DDS) and to ameliorate critical-sized bone defects based on the fracture site length of the bone with the various modes of functionalization through the incorporation of drugs, stem cells, and growth factors for personalized medicine.

Surface Activation of Calcium Zirconate-Calcium Stabilized Zirconia Eutectic Ceramics with Bioactive Wollastonite-Tricalcium Phosphate Coatings.

In this work, we have developed and characterized a ceramic composite based on a core of directionally solidified calcium zirconate-calcium stabilized zirconia (CZO-CSZ) eutectic composite coated with a bioactive glass-ceramic. The aim is to research new orthopedic implants as an alternative to conventional 3Y-TZP bioinert ceramics. The CZO-CSZ eutectic rods were grown from the melt of rods of CaO-ZrO2 in the eutectic composition using the laser floating zone technique (LFZ). The mechanical results indicated that directional eutectics prepared with this technique exhibited good mechanical strength and significant hardness and toughness. The LFZ technique was also used to melt the bioactive coating previously placed by dip coating on the CZO-CSZ rod surface. Depending on the thickness of the coating and the applied laser power, an alloying or coating process was achieved. In the first case, the coating was diluted with the surface of the eutectic cylinder, leading to the segregation of the calcium zirconate and zirconia phases and the formation of a bioactive phase embedding zirconia particles. In the second case, a layer of ceramic glass was formed, well attached to the eutectic cylinder. These layers were both studied from the microstructural and bioactivity points of view.

Review on vat photopolymerization additive manufacturing of bioactive ceramic bone scaffolds.

Bone defects frequently occur in clinical settings due to trauma, disease, tumors, and other causes. The clinical use of autologous bones and allograft bone, however, has several limitations, such as limited sources, donor site morbidity, and immunological rejection. Nevertheless, there is newfound hope for regenerating and repairing bone defects through the development and integration of bone tissue engineering scaffold and additive manufacturing (AM) technology, also known as 3D printing. In particular, vat photopolymerization (VPP)-AM of bioactive ceramic bone scaffolds has garnered significant interest from interdisciplinary researchers in recent years. On the one hand, VPP-AM demonstrates clear advantages in printing accuracy and speed compared to other AM and non-AM technologies. On the other hand, bioactive ceramic materials exhibit superior bioactivity, biodegradability, and mechanical properties compared to metals, polymers, and bioinert ceramics, making them one of the most promising biomaterials for developing bone scaffolds. This paper reviews the research progress of VPP-AM of bioactive ceramic bone scaffolds, covering the process principles of various VPP-AM technologies, the performance requirements and preparation process of VPP ceramic slurry, the VPP process of bioactive ceramic bone scaffolds, and the research progress on different material types of VPP bioactive ceramic scaffolds. Firstly, we provide a brief introduction to the process principles and medical applications of various VPP technologies. Secondly, we explore the composition of the VPP ceramic slurry system, discussing the function of various components and their effects on printing quality. Thirdly, we delve into the performance requirements of bone scaffolds and summarize the research progress of VPP bioactive ceramic bone scaffolds of various material types including hydroxyapatite (HA), tricalcium phosphate (TCP), bioglass (BG), etc.; Finally, we discuss the challenges currently faced by VPP-AM bioactive ceramic bone scaffolds and propose possible development directions for the future.

Invitro and invivo examination for bioceramic degradation

 Even after a century of regulated clinical usage, there is still a great deal we do not understand about the deteriorating mechanisms of ceramics. Crack propagation mechanisms in bioinert ceramics used in orthopaedics, such as zirconia and alumina, are well-known; however, their interactions with other degradation mechanisms (dissolution, wear, shocks, low-temperature degradation, etc.) and the in vivo environment must be thoroughly established. Dissolution–precipitation mechanisms in bioactive ceramics, such as bioactive glasses and calcium phosphates, have a substantial effect on both implant degradation and biological efficacy. Both bioactive and inert ceramic implants can degrade and interact with one another and their surroundings, and the purpose of this article is to offer an overview of these processes.

3D Printing of Bioinert Oxide Ceramics for Medical Applications.

Three-dimensionally printed metals and polymers have been widely used and studied in medical applications, yet ceramics also require attention. Ceramics are versatile materials thanks to their excellent properties including high mechanical properties and hardness, good thermal and chemical behavior, and appropriate, electrical, and magnetic properties, as well as good biocompatibility. Manufacturing complex ceramic structures employing conventional methods, such as ceramic injection molding, die pressing or machining is extremely challenging. Thus, 3D printing breaks in as an appropriate solution for complex shapes. Amongst the different ceramics, bioinert ceramics appear to be promising because of their physical properties, which, for example, are similar to those of a replaced tissue, with minimal toxic response. In this way, this review focuses on the different medical applications that can be achieved by 3D printing of bioinert ceramics, as well as on the latest advances in the 3D printing of bioinert ceramics. Moreover, an in-depth comparison of the different AM technologies used in ceramics is presented to help choose the appropriate methods depending on the part geometry.

Influence of Bioactive and Bio Inert Ceramic Powders on Tribology Properties of PMMA Composite Denture Base

Polymer matrix composites are suitable materials for medical applications, such as denture base resin polymethyl methacrylate (PMMA). This includes light weight and high strength. This paper describes the effect of selected weight fractions (1, 2, 3, 4 & 5) % wt of nano(Alumina AL2O3, Zirconia ZrO2, Hydroxyapatite HA and Halloysite nanoClay) reinforcements on the biopolymer matrix (PMMA). Some tribology tests were used to evaluate the prepared system (impact strength, hardness surface, and wear rate) tests. The samples were fabricated by (Hand Lay-Up) with different particle reinforcement percentages. All tests were accomplished at room temperature, and samples were developed according to the ASTM standard. The weight fraction of (4% for AL2O3, 4% for ZrO2, 3% for HA and 5% for Clay) nanoparticles are the best results that appeared in the work.

Recent advances in the extrusion methods for ceramics

In recent years, extrusion 3D printing processes have undergone an important development. They allow obtaining complex shapes in an easy way and relatively low cost. Different plastic materials can be 3D printed with the fused filament fabrication (FFF) technology. Bioinert ceramics such as alumina or zirconia have excellent physical and mechanical properties (high melting point, high strength…) that make them appropriate in different fields: medicine, electronics, etc. However, 3D printing of ceramics is by far less developed than 3D printing of plastics or metals. A possible application for 3D printing of ceramics is the manufacture of prostheses, which usually have complex shapes with porous structures. Ceramic prostheses have several advantages over the use of other materials: they generate low debris, they are hard and they are inert and corrosion-resistant. In the present work the recent advances about extrusion 3D printing of ceramic materials are presented, with a special focus on the manufacture of prostheses.

A Novel Process for Production of High Purity Zirconium Oxy Chloride from Zircon Sand for Bio-Inert Ceramics

A Novel Process for Production of High Purity Zirconium Oxy Chloride from Zircon Sand for Bio-Inert Ceramics

Strengthening bioceramic through an approach of powder processing

Bioactive ceramics, such as calcium phosphate and calcium sulfate, have gained attention with the increase of aged population. Contrast to bio-inert ceramics, such as alumina and zirconia, the strength of bioactive ceramics is much lower. The strength of calcium sulfate (CaSO4) is the lowest among all. In the present study, two approaches, involving the refinement of microstructure and the addition of nano-particles, are combined to enhance the strength. Various powder-processing treatments are adopted to facilitate these approaches. A pre-grinding treatment is applied first to reduce the matrix CaSO4 grain size. The nano-silica (SiO2) particles are then fixed onto the CaSO4 particles through an attrition milling process. The strength of CaSO4 is enhanced by 60% by adding only 1 mass% nano-SiO2 particles. The strength of the SiO2-CaSO4 composites follows the Orowan-Petch relationship, indicating that their strength is dominated by the flaws. The addition of nano-particles refines the matrix grain size, consequently, the flaw size.

Thermal Sprayed Composite Coatings for Biomedical Implants: A Brief Review

The implant materials used currently in field of cardiovascular and orthopedics surgery dearth in osteoconductivity. Different surface modification techniques are used, developed and investigated over the years to enhance the osteoconductivity of biomaterials like metals, polymer and ceramics. Although implants made up of metals are strong mechanically but have low bonding ability due to bio-inert nature.To overcome the limitations and to accomplish the desired purpose, composite coatings consisting of bioactive are developed on the metallic biomaterials. In general bio-inert ceramics like yttria stabilized zirconia (ysz), titania, and alumina may be incorporated into hydroxyapatite (HA) matrix to develop composite coatings with improved mechanical properties over the years. The composite coatings developed by thermal spraying have shown promising approach to have good mechanical and biological properties in comparison with single-component and/or monolayer coatings. The strategy to use composite coatings is adopted widely by the professionals/scientists in the area of biomaterials for development and production of materials in order to repair and regeneration of the human tissue. In this article, commercially used thermal spraying techniques used for deposition of composite coatings for biomedical implants are discussed.

Coatings Based on Organic/Non-Organic Composites on Bioinert Ceramics by Using Biomimetic Co-Precipitation

Bioinert ceramics have been commonly used in the field of orthopedic and dentistry due to their excellent mechanical properties, esthetic look, good biocompatibility and chemical inertness. However, an activation of its bioinert surface could bring additional advantages for better implant-integration in vivo. Therefore, we introduce an innovative biomimetic co-precipitation technique by using modified simulated body fluid (SBF) to obtain a composite coating made of organic/non-organic components. The zirconia samples were soaked in SBF containing different concentrations of protein (0.01, 0.1, 1, 10 and 100 g/l). Bovine serum albumin (BSA) was applied as a standard protein. During the soaking time, a precipitation of calcium phosphate took place on the substrate surfaces. The proteins were incorporated into the coating during precipitation. Morphology changes of precipitated hydroxyapatite (HAp) due to the presence of proteins were observed on SEM-images. The presence of proteins within the coating was proven by using SEM/energy dispersive X-ray spectroscopy (EDX) and immunohistochemical analysis. We conclude that it is possible to co-precipitate the organic/non-organic composite on inert ceramic by using the wet-chemistry method. In future studies, BSA could be replaced by targeted proteins appropriate to the application area. This method could create new biomaterials, the surfaces of which could be tailored according to the desires and requirements of their use.

A Study The Bio Inert Ceramic Coated by Electrophoretic Deposition on Corrosion behavior of SS316L Alloy Used for Surgical Implant Applications

Biocompatibility for the alloys which are used in the human body such as biomaterials depending on corrosion behavior. This study aim at research was to study the corrosion action and the biocompatibility of the samples of SS316L alloy uncoated and coated and compare the effect of coatings on corrosion behavior. Partially Stabilized Zirconia (PSZ) coating was do it by (EPD) technique on SS316L alloy . Structural investigation by using techniques including XRD , microstructure and crystalline of the coatings investigation in this study. Electrochemical measurement when effort the exams has been done in simulated body solution (Ringer and artificial saliva) in order to know the limitation and comparison the corrosion behavior of the gilder samples and clumsily samples as an evi- dence biocompatibility. Corrosion behavior for these coated specimens was more nobler than for the uncoated specimens.

Bioceramics for Osteochondral Tissue Engineering and Regeneration.

Considerable advances in tissue engineering and regeneration have been accomplished over the last decade. Bioceramics have been developed to repair, reconstruct, and substitute diseased parts of the body and to promote tissue healing as an alternative to metallic implants. Applications embrace hip, knee, and ligament repair and replacement, maxillofacial reconstruction and augmentation, spinal fusion, bone filler, and repair of periodontal diseases. Bioceramics are well-known for their superior wear resistance, high stiffness, resistance to oxidation, and low coefficient of friction. These specially designed biomaterials are grouped in natural bioceramics (e.g., coral-derived apatites), and synthetic bioceramics, namely bioinert ceramics (e.g., alumina and zirconia), bioactive glasses and glass ceramics, and bioresorbable calcium phosphates-based materials. Physicochemical, mechanical, and biological properties, as well as bioceramics applications in diverse fields of tissue engineering are presented herein. Ongoing clinical trials using bioceramics in osteochondral tissue are also considered. Based on the stringent requirements for clinical applications, prospects for the development of advanced functional bioceramics for tissue engineering are highlighted for the future.

Mechanical properties and microstructures of bio-inert layers of chrome oxide coatings deposited by the APS process

Plasma spray Cr2O3 ceramic layers are used as a separate coating or as a supplement to bio-reactive organic composite ceramics Ca10(PO4)6(OH)2-Al2O3-ZrO2-Cr2O3 and other bio-inert ceramics in composites of the types Al2O3-ZrO2-SrO-Cr2O3-Y2O3, ZrO2-TiO2-Cr2O3 and TiO2-Cr2O3 to increase the mechanical properties and resistance components of artificial joints on sliding abrasion and corrosion. This paper analyzes the influence of the plasma gun distance from the substrate on the mechanical properties and the microstructure of Cr2O3 layers deposited with the current of 40kW. The aim was to deposit layers with optimal characteristics that will enable the effective implementation of Cr2O3 layers on substrates of steel implants exposed to dry friction without lubrication and to corrosion of living tissues. The mechanical properties were tested by examining microhardness layers using the HV0.3 method and the strength was tested by tensile testing. The surface of powder particles was examined by SEM. The microstructures of layers were analyzed with the use of an optical microscope (OM) and a scanning electron microscope (SEM). The test results confirmed a possibility of effective application of bio-inert layers of Cr2O3 with other ceramics intended for the production of functional implants.

Bioinert Ceramics: State-of-the-Art

Bioinert ceramics in use today are the result of more than 60 years of continuous development. Early studies were concentrated on alumina that in the late 1960s was the most advanced ceramic, and on pyrolytic carbon. After tests in orthopedic bearings, pyrolytic carbon found clinical applications in artificial heart valves, where it is in clinical use so far. After 1970 zirconia-toughened ceramics (YTZP, ZTA, ATZ) were investigated in view of their use as biomaterials in orthopedics. Especially the introduction of YTZP in clinics in the 1990s gave a new momentum to the use of inert bioceramics. So far, zirconia-toughened ceramics are replacing alumina because of their outstanding mechanical properties leading to high reliability in ceramic components. The behavior of ZTAs and ATZs are exploited in several innovative devices. Especially metal-free devices are of interest, because of the increasing number of patients sensitized to metals. Using zirconia-toughened ceramics were achieved remarkable development in ceramic knee replacements, a field pioneered by Japanese researchers, because the behavior of these materials allow the production of devices similar in size to the metallic ones. In dentistry, a number of manufacturers are marketing metal-free dental implants, as well as machinable zirconia blanks for the production of crowns, bridges, copings by CAD/CAM. Besides oxides, that in todays’ orthopedics and dentistry are the state-of-the-art bioinert ceramics, silicon nitride has found application in spinal surgery, and investigations in view of its use in joint replacement bearings are in progress.

Femtosecond laser multi-patterning of zirconia for screening of cell-surface interactions

Yttria-stabilised tetragonal zirconia polycrystals (3Y-TZP) bioinert ceramics combine excellent strength and toughness, good aesthetics, high resistance to corrosion and absence of allergic reaction. However, improved osseointegration is needed as higher marginal bone loss was sometimes reported. In the present work, 3Y-TZP multi-patterned samples for rapid screening of cell-surface interactions were fabricated by femtosecond laser micromachining. Pits with well-defined edges and micrometric precision in pit diameter, depth and spacing were produced, as determined by white light interferometry. Pits showed a nanometric granular texture on the sidewalls and ripples at pit bottom, as attested by scanning electron microscopy. Focused ion beam analyses indicated limited laser-induced damage. Micropatterns impacted human mesenchymal stem cell (hMSC) size and morphology. Cell area and aspect ratio were mainly influenced by pit diameter, while solidity and circularity were affected by both pit diameter and depth. The pattern 30μm diameter/10μm depth induced the strongest osteoblastic hMSC commitment.

Nitride, Zirconia, Alumina, and Carbide Coatings on Ti6Al4V Femoral Heads: Effect of Deposition Techniques on Mechanical and Tribological Properties

Ti6Al4V has been extensively studied in orthopedic applications because of its biocompatibility, desirable mechanical strength, and fatigue resistance. A wide range of bioinert ceramics have been investigated to further develop the tribological and mechanical properties of Ti6Al4V for the production of potential femoral heads. However, an analysis of the literature indicates that the performance of the coatings produced has been inconsistent. In this review, for the first‐time deposition techniques of the most widely studied bioinert ceramics namely nitrides, carbides, zirconia, and alumina on Ti6Al4V substrates and their relevant mechanical and tribological performance have been analyzed. Finally, graphene has also been suggested for use together with bioinert ceramics due to its excellent mechanical and physical properties for coating Ti6Al4V femoral heads.

Direct silanization of zirconia for increased biointegration.

The use of zirconia-based ceramics in biomedical devices is broad and well accepted, especially in dental implants. However, they do not bond naturally to bone, therefore to ensure fixation surgeons typically rely on roughness at different scales, or on cements. Alternatively in this work we present a new perspective of surface modification through chemistry to enhance the interaction between surface and biological environment, without the downsides of roughness. This surface treatment is proposed for zirconia, which allowed a direct silanization of its surface and a higher cell attachment. The results of this research may open the possibility for the next generation of bioinert ceramic implants with more advanced tailored surfaces for increased osseointegration.

Enhanced cell adhesion on bioinert ceramics mediated by the osteogenic cell membrane enzyme alkaline phosphatase

Functional bone and dental implant materials are required to guide cell response, offering cues that provide specific instructions to cells at the implant/tissue interface while maintaining full biocompatibility as well as the desired structural requirements and functions. In this work we investigate the influence of covalently immobilized alkaline phosphatase (ALP), an enzyme involved in bone mineralization, on the first contact and initial cell adhesion. To this end, ALP is covalently immobilized by carbodiimide-mediated chemoligation on two highly bioinert ceramics, alpha-alumina (Al2O3) and yttria-stabilized zirconia (Y-TZP) that are well-established for load-bearing applications. The physicochemical surface properties are evaluated by profilometry, zeta potential and water contact angle measurements. The initial cell adhesion of human osteoblasts (HOBs), human osteoblast-like cells (MG-63) and mesenchymal stromal cells (hMSCs) was investigated. Cell adhesion was assessed at serum free condition via quantification of percentage of adherent cells, adhesion area and staining of the focal adhesion protein vinculin. Our findings show that after ALP immobilization, the Al2O3 and Y-TZP surfaces gained a negative charge and their hydrophilicity was increased. In the presence of surface-immobilized ALP, a higher cell adhesion, more pronounced cell spreading and a higher number of focal contact points were found. Thereby, this work gives evidence that surface functionalization with ALP can be utilized to modify inert materials for biological conversion and faster bone regeneration on inert and potentially load-bearing implant materials.