Advances in clinical applications of bioceramics in the new regenerative medicine era

In this editorial,we comment on the hard and soft tissue applications of different ceramic-based scaffolds prepared by different mechanisms such as 3D printing,sol-gel,and electrospinning.The new concept of regenerative medicine relies on biomaterials that can trigger in situ tissue regeneration and stem cell recruitment at the defect site.A large percentage of these biomaterials is ceramic-based as they provide the essential requirements of biomaterial principles such as tailored multisize porosity,antibacterial properties,and angiogenic properties.All these previously mentioned properties put bioceramics on top of the hierarchy of biomaterials utilized to stimulate tissue regeneration in soft and hard tissue wounds.Multiple clinical applications registered the use of these materials in triggering soft tissue regeneration in healthy and diabetic patients such as bioactive glass nanofibers.The results were promising and opened new frontiers for utilizing these materials on a larger scale.The same results were mentioned when using different forms and formulas of bioceramics in hard defect regeneration.Some bioceramics were used in combination with other polymers and biological scaffolds to improve their regenerative and mechanical properties.All this progress will enable a larger scale of patients to receive such services with ease and decrease the financial burden on the government.

RESEARCH AND DEVELOPMENT OF BIOCERAMICS(Ⅱ)

The article describes the performance,properties and application of bioceramics in the medicalclinic and reviews and discusses the advance in the researchinto several typical bioceramics,such as aluminium oxidebioceramics,carbons,bioactive glassceramics,calcium phos-phate bioceramics,bioceramic com posite materials etc,andcomes to that bioceramics is the most promising bioactive ma-terial in the modern medical clinic application.

MICROWAVE JOINING OF ALUMINA CERAMIC AND HYDROXYLAPATITE BIOCERAMIC

Microwave joining is a rapid developmental new technique in recent years. This paper introduces a new microwave joining equipment which was made by our lab,succeeds in alumina ceramic-hydroxylapatite bio-ceramic join in the equipment, and analyzes the join situation of join boundary by using scanning electron microscope (SEM). this paper analyzes the mechanism of microwave joining also.

Characteristics of a multi-component MgO-based bioceramic coating synthesized in-situ by plasma electrolytic oxidation

Plasma electrolytic oxidation(PEO)has held great potential for the advancement of biodegradable implants,as it helps in developing porous bioceramic coatings on the surface of magnesium alloys.In this research work,MgO-based bioceramic coatings containing the Si,P,Ca,Na,and F elements have been successfully fabricated on an AZ31 magnesium alloy plate utilizing the PEO method.The characteristic current-voltage behavior of the samples during the process was surveyed in an electrolyte containing Ca(H_(2)PO_(4))_(2),Na_(2)SiO_(3)·9H_(2)O,Na_(3)PO_(4)·12H_(2)O,NaF,and KOH with a pH of 12.5 and electrical conductivity of 20 mS/cm^(-1).The results revealed that applying a voltage of 350-400 V(that is 50-100 V higher than the breakdown limit)could greatly facilitate the synthesis of a PEO ceramic coating with fewer defects and more uniform morphology.The resulting coating was a compositionally graded bioceramic layer with a thickness in the range of 3.5±0.4 to 6.0±0.7µm,comprising the above-mentioned elements as promising bioactive agents.The synthesized ceramic features were investigated in terms of the elemental distribution of components through the thickness,which indicated a gradual rise in the Si and P contents and,conversely,a decline in the F content towards the outer surface.The growth mechanism of the PEO coating has been discussed accordingly.

Comparison of Apical Leakage in Root Canal Obturation Using Bioceramic and Polydimethylsiloxane Sealer (<i>In Vitro</i>)

Background: One of the ideal properties of a root canal sealer is to have a good sealing ability, especially at the apical third of the root. Objective: To evaluate the comparison of the apical leakage between obturation using bioceramic sealer (BS) and polydimethylsiloxane sealer (PS). Materials and Methods: Thirty-six mandibular premolars were equally divided into two groups and were obturated with single cone technique. The sealers used for Group I and Group II were BS and PS respectively. After obturation, the samples were incubated (37&deg;C, 24 h), sealed with two coats of nail polish except for 2 mm from the apex, submerged in the Indian ink for 7 days, decalcified, dehydrated, and made transparent according to Robertson technique. Dye penetration was evaluated under stereomicroscope. Samples without dye penetration were given score 0, dye penetration ≤ 0.5 mm were given score 1, 0.51 - 1 mm were given score 2, and >1 mm were given score 3. Result: The largest proportion distribution in BS group was at the score 1 (55.6%), whereas in PS group was at the score 2 (44.4%). Conclusion: Bioceramic sealer showed similar apical leakage to polydimethylsiloxane sealer. Clinical Relevance: Based on this study, bioceramic sealer can be recommended to be used as sealer with low level of apical leakage as well as polydimethylsiloxane sealer.

RESEARCH ON AND DEVELOPMENT OF BIOCERAMICS(Ⅰ)

This article reviews and discusses the defi-nition,classification, performance, properties of the bioce-ramics which began to be researched on and developed inseventies and has been applied to the medical clinic sincethen, and the present situation of research on and develop-ment of the biological requirement put forward to bioce-ramic performance by the biont and comes to that the bioce-ramics is the most promising biological material in the mod-ern medical clinic application.

Evaluation of Bioactive Properties of α and β Wollastonite Bioceramics Soaked in a Simulated Body Fluid

Dense natural wollastonite bioceramics (CaSiO3) were prepared by a sintering method, varying the pressing load and sintering temperature, in order to obtain different phases of wollastonite, and different physical properties in the materials. The products were characterized by TGA-DTA, XRD, FT-IR, SEM-EDS, TEM and XPS techniques. The results indicate the presence of two polymorphic phases of wollastonite, the β-wollastonite and α-wollastonite with a transition temperature of the β phase to α phase at approximately 1250&#8451;. These materials were soaked in a simulated body fluid (SBF) during 1, 2 and 3 weeks, to study their solubility and bioactivity. The effect of different wollastonite phases on the solubility of Ca and Si, as well as the capacity of producing layers of “newly formed apatite” on the surfaces of these materials in SBF solution were analyzed.

Laser surface coating of RE bioceramic layer on TC4

A layer of premixed CaHPO 4·2H 2O CaCO 3 Y 2O 3 powders stuck on pretreated surface of Ti 6Al 4V alloy substrate was successfully transformed into a composite of rare earth bioceramic coating by laser synthesizing and cladding only once. The microstructure and properties of the coating material were introduced. The titanium alloy with bioceramic coating on one side were implanted into the femur bone and thigh muscles of adult Mongrel dogs for testing its biocompatibility. The results of implantation experiments show that the microstructure of the coating material is static, the bonding properties between coating and substrate are better. The bioceramic coating had not toxicity side effectiveness on the body and there is a better compatibility of osteoconducton. No effect of the coating material on the bio activity of osteoblast and osteoclast was found.

FHA BIOCERAMIC COMPOSITE MATERIALS ENHANCED BY ZrO_2

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Valorization of a Good Bioceramic from Moroccan Waste Fish Bone by a Heat Treatment Method

A tricalcium phosphate(TCP)material was produced from sardine and mackerel waste using a heat treatment method after a Soxhlet extraction to obtain the non-soluble portion of fish waste.The bones were annealed at temperatures between 400℃ and 1200℃.The thermal analysis(TG-DTA)was carried out to investigate the thermal stability of TCP and to confirm the removal of organic matter from the raw fish.The calcined bones were characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and field emission scanning electron microscopy(FESEM).The calcium to phosphorous weight ratio was determined by ICP-AES.FT-IR and XRD confirmed the similarities to syntheticβ-TCP(JCPDS-09-169),FE-SEM results revealed the formation of nanostructured TCP.These results suggest that varying the isolation temperature between 600-1200℃ has tremendous impact on the production of TCP from fish bone waste with the required properties.

Bioceramics utilization for the repair of internal resorption of the root:A case report

BACKGROUND The objective of this work is displaying a successful treatment for an internal resorption case under operating microscope using bioceramic material.CASE SUMMARY Periapical radiograph showed radiolucent lesion representing large internal resorption of the root.The respective defect was obturated using endoscquence bioceramic material follow up at the month 18 after treatment revealed no abnormal finings clinically and radiographically.CONCLUSION New generations bioceramics have many advantages that internal root resorption cases can benefit from.The use of operating microscope helps to apply obturating materials with precision.However,long term study on a large sample is required in future studies.

In Vivo Preliminary Study on Bone Neoformation Behavior of Three Types of Calcium Phosphate Bioceramics

Calcium phosphate microporous bioceramics and biphasic compositions of hydroxyapatite and β-calcium phosphate, in the form of microporous granular biomaterials, are research topics and present themselves as potential orthopedic and biomedical applications in rebuilding and repairing maxillofacial bones and tooth structure. This is associated with the characteristics of microstructure, biocompatibility, bioactivity and bone conductivity properties which these materials offer when applied in vivo or in a simulation environment. This study aimed to assess the behavior of bone neoformation of three types of calcium phosphate biomaterials in in vivo tests with sheep within 60 and 90 days, with the help of a scanning electron microscope. The biomaterials used were provided by the Group of Biomaterials at the Santa Catarina State University. The in vivo tests were carried out by generating, on sheep, tibial bone defects, three of which were filled with biomaterial (one different biomaterial for each bone defect generated), whilst the fourth received a bone fragment obtained during the generation of the defect in question, to serve as a control group. The scanning electron microscopy (SEM) technique was used for carrying out the preliminary characterization studies so as to observe new bone formation and osseointegration. The X-ray diffractometry (XRD) served as a support for the characterization of crystalline phases. The results obtained are encouraging and show that the biomaterials presented good performance in the process of bone formation, biomaterial osseointegration by a new tissue and bone mineralization.

Sol-gel bioceramic material from bentonite clay

Bioceramic material of the quaternary system;SiO2- CaO-Na2O-P2O5 that has composition similar to Bio- glass? 45S5 was prepared by the sol-gel method from locally obtained bentonite clay (BTC). The monolith obtained was sintered at 1000?C for 2 h to facilitate densification and phase transformation. X-ray diffraction (XRD) analysis revealed the presence of sodium calcium silicate, Na2Ca2Si3O9 as major crystal phase, and another secondary orthorhombic phase, NaCaPO4. Fourier transform infrared (FTIR) spectroscopic investigation confirmed the presence of Si-O-Si bonds and a crystalline phosphate in the glass network. Scanning electron microscopy (SEM) revealed a network of micropores and interconnected macropores. Overall, the material displays features amenable for possible utilization in tissue engineering scaffolds.

Behaviour of Composite Ca/P Bioceramics in Simulated Body Fluid

Behavior of Ca/P ceramics enhanced by MgAl2O4 in simulated body fluid(SBF) was studied.Results show that, biological apatite can precipitate on the sudece of Ca/P composite ceramics,however, dissolution of the surface of Ca/P composite ceramics also occurs due to a kind of amorphous material which is produced through reaction of MgAl2O4 with Ca/P ceramics at elevated temperature, therefore, the behavior of Ca/P composite ceramics in SBF mainly depends on those two processes. Analyses of joint influence of those two processes show that low content of MgAl2O4 favors the formation of biological apatite, therefore, brings about higher

Bioceramic scaffolds with two-step internal/external modification of copper-containing polydopamine enhance antibacterial and alveolar bone regeneration capability

Magnesium-doped calcium silicate(CS)bioceramic scaffolds have unique advantages in mandibular defect repair;however,they lack antibacterial properties to cope with the complex oral microbiome.Herein,for the first time,the CS scaffold was functionally modified with a novel copper-containing polydopamine(PDA(Cu^(2+)))rapid deposition method,to construct internally modified(*P),externally modified(@PDA),and dually modified(*P@PDA)scaffolds.The morphology,degradation behavior,and mechanical properties of the obtained scaffolds were evaluated in vitro.The results showed that the CS*P@PDA had a unique micro-/nano-structural surface and appreciable mechanical resistance.During the prolonged immersion stage,the release of copper ions from the CS*P@PDA scaffolds was rapid in the early stage and exhibited long-term sustained release.The in vitro evaluation revealed that the release behavior of copper ions ascribed an excellent antibacterial effect to the CS*P@PDA,while the scaffolds retained good cytocompatibility with improved osteogenesis and angiogenesis effects.Finally,the PDA(Cu^(2+))-modified scaffolds showed effective early bone regeneration in a critical-size rabbit mandibular defect model.Overall,it was indicated that considerable antibacterial property along with the enhancement of alveolar bone regeneration can be imparted to the scaffold by the two-step PDA(Cu^(2+))modification,and the convenience and wide applicability of this technique make it a promising strategy to avoid bacterial infections on implants.

Li-Mg-Si bioceramics provide a dynamic immuno-modulatory and repair-supportive microenvironment for peripheral nerve regeneration

Biomaterials can modulate the local immune and repair-supportive microenvironments to promote peripheral nerve regeneration. Inorganic bioceramics have been widely used for regulating tissue regeneration and local immune response. However, little is known on whether inorganic bioceramics can have potential for enhancing peripheral nerve regeneration and what are the mechanisms underlying their actions. Here, the inorganic lithium-magnesium-silicon (Li-Mg-Si, LMS) bioceramics containing scaffolds are fabricated and characterized. The LMS-containing scaffolds had no cytotoxicity against rat Schwann cells (SCs), but promoted their migration and differentiation towards a remyelination state by up-regulating the expression of neurotrophic factors in a β-catenin-dependent manner. Furthermore, using single cell-sequencing, we showed that LMS-containing scaffolds promoted macrophage polarization towards the pro-regenerative M2-like cells, which subsequently facilitated the migration and differentiation of SCs. Moreover, implantation with the LMS-containing nerve guidance conduits (NGCs) increased the frequency of M2-like macrophage infiltration and enhanced nerve regeneration and motor functional recovery in a rat model of sciatic nerve injury. Collectively, these findings indicated that the inorganic LMS bioceramics offered a potential strategy for enhancing peripheral nerve regeneration by modulating the immune microenvironment and promoting SCs remyelination.

Bioceramic scaffolds with triply periodic minimal surface architectures guide early-stage bone regeneration

The pore architecture of porous scaffolds is a critical factor in osteogenesis,but it is a challenge to precisely configure strut-based scaffolds because of the inevitable filament corner and pore geometry deformation.This study provides a pore architecture tailoring strategy in which a series of Mg-doped wollastonite scaffolds with fully interconnected pore networks and curved pore architectures called triply periodic minimal surfaces(TPMS),which are similar to cancellous bone,are fabricated by a digital light processing technique.The sheet-TPMS pore geometries(s-Diamond,s-Gyroid)contribute to a 3‒4-fold higher initial compressive strength and 20%-40%faster Mg-ion-release rate compared to the other-TPMS scaffolds,including Diamond,Gyroid,and the Schoen’s I-graph-Wrapped Package(IWP)in vitro.However,we found that Gyroid and Diamond pore scaffolds can significantly induce osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs).Analyses of rabbit experiments in vivo show that the regeneration of bone tissue in the sheet-TPMS pore geometry is delayed;on the other hand,Diamond and Gyroid pore scaffolds show notable neo-bone tissue in the center pore regions during the early stages(3-5 weeks)and the bone tissue uniformly fills the whole porous network after 7 weeks.Collectively,the design methods in this study provide an important perspective for optimizing the pore architecture design of bioceramic scaffolds to accelerate the rate of osteogenesis and promote the clinical translation of bioceramic scaffolds in the repair of bone defects.

Additive manufacturing of hydroxyapatite bioceramic scaffolds: Dispersion, digital light processing, sintering, mechanical properties, and biocompatibility

Hydroxyapatite(HA)bioceramic scaffolds were fabricated by using digital light processing(DLP)based additive manufacturing.Key issues on the HA bioceramic scaffolds,including dispersion,DLP fabrication,sintering,mechanical properties,and biocompatibility were discussed in detail.Firstly,the ffects of dispersant dosage,solid loading,and sintering temperature were studied.The optimal dispersant dosage,solid loading,and sintering temperature were 2wt%,50vol%,and 1250℃,respectively.Then,the mechanical properties and biocompatibility of the HA bioceramic scaffolds were investigated.The DLP-prepared porous HA bioceramic scaffold was found to exhibit excellent mechanical properties and degradation behavior.From this study,DLP technique shows good potential for manufacturing HA bioceramic scaffolds.