Predicting the Degradability of Bioceramics through a DFT-based Descriptor

Bioceramics have attracted extensive attention for bone defect repair due to their excellent bioactivity and degradability.However,challenges remain in matching the rate between bioceramic degradation and new bone formation,necessitating a deeper understanding of their degradation properties.In this study,density functional theory(DFT)calculations was employed to explore the structural and electronic characteristics of silicate bioceramics.These findings reveal a linear correlation between the maximum isosurface value of the valence band maximum(VBM_(Fmax))and the degradability of silicate bioceramics.This correlation was subsequently validated through degradation experiments.Furthermore,the investigation on phosphate bioceramics demonstrates the potential of this descriptor in predicting the degradability of a broader range of bioceramics.This discovery offers valuable insights into the degradation mechanism of bioceramics and holds promise for accelerating the design and development of bioceramics with controllable degradation.

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 ON AND DEVELOPMENT OF BIOCERAMICS(Ⅰ)

This article reviews and discusses the definition, classification, performance, properties of the bioce-ramics which began to be researched on and developed in seventies and has been applied to the medical clinic since then, and the present situation of research on and development 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 modern medical clinic application.

RESEARCH AND DEVELOPMENT OF BIOCERAMICS(Ⅱ)

The article describes the performance, properties and application of bioceramics in the medical clinic and reviews and discusses the advance in the research into several typical bioceramics, such as aluminium oxide bioceramics, carbons, bioactive glassceramics, calcium phosphate bioceramics, bioceramic composite materials etc, and comes to that bioceramics is the most promising bioactive material in the modern medical clinic application.

Effect of Y_2O_3 Content on Microstructure of Gradient Bioceramic Composite Coating Produced by Wide-Band Laser Cladding

To eliminate thermal stress and cracks in the process of laser cladding, a kind of bioceramic coating with gradient compositional design was prepared on the surface of Ti alloy by using wide-band laser cladding. And effect of Y2O3 content on gradient bioceramic composite coating was studied. The experimental results indicate that adding rare earth can refine grain. Different rare earth contents affect formation of HA and β-TCP in bioceramic coating. When the content of rare earth ranges from 0.4% to 0.6%, the active extent of rare earth in synthesizing HA and β-TCP is the best, which indicates that “monosodium glutamate” effect of rare earth plays a dominant role. However, when rare earth content is up to 0.8%, the amount of synthesizing HA and β-TCP in coating conversely goes down, which demonstrates that rare earth gradually losts its catalysis in manufacturing HA and β-TCP.

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.

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 bioceramic 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. (Author abstract) 4 Refs.

The Bisphosphonate Clodronate Modifying Hydroxyapatite Bioceramics for Bone Scaffold

To investigate the efficiency of clodronate modifying HA bioceramics,and to evaluate the effect of clodronate modifying HA bioceramics on the cells in vitro,clodronate modified the porous HA bioceramics for bone scaffold by chelation .The outermost layer of the specimens was analyzd by XPS and FI-IR ,The depth profile was investigated by the argon-ion sputtering method.The cell culture test was conducted using MC3T3-E1 osteoblastic cells,The cells were inoculated and cultured on the scaffolds.Morphological observation of the cells,MTT test and ALP activity test evaluated the cell attachment ,proliferation and activity on the scaffolds.The cell culture test in cell quantity and morphology indicated active proliferation of the cells on the scaffolds.The ALP activity of the cells cultured for 3d and 7d on clodronate-HA bioceramics was slightly higher than that on HA bioceramics ,but the difference was not signifcant,This result indicated that clodronate-HA bioeramics had favorable cytocompatibility to be used as bone scaffold with potential ability to improve asteogensis.

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.

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

Experiments for investigating the problem to improve the mechanical properties of FHA [Ca(10) (PO4)6F(OH)] biomaterial have been presented in this paper. ZrO2 micro-particle, as strengthening phase, is added into FHA matrix material to make a composite biomaterial. Various mechanical properties were tested. Distribution be haviour of ZrO2 particle in sintered material and phase structure ' changes of material at elevated temperature were investigated by means of X-ray and SEM. Some biologic experiments were also carried out on animals to estimate the biological function of the corn posite material.

Dynamics of Gradient Bioceramic Composite Coating on Surface of Titanium Alloy by Wide-Band Laser Cladding

The gradient bioceramic coating was prepared on the surface of titanium alloy using wide-band laser cladding.The dynamics of gradient bioceramic composite coating containing hydroxyapatite(HA)prepared with mixture of CaHPO4·2H2O and CaCO3 under the condition of wide-band laser was studied theoretically.The corresponding mathematical model and its numerical solution were presented.The examination experiment showed that HA bioceramic composite coatings can be obtained by appropriately choosing wide-band laser cladding parameters.The microstructure and surface morphology of HA bioceramic coating were observed by SEM and X-ray diffraction.The experimental results showed that the bioceramic coating is composed of HA,β-TCP,CaO,CaTiO3 and TiO2.The surface of bioceramic coating takes coral-shaped structure or short-rod piled structure,which helps osteoblast grow into bioceramic and improves the biocompatibility.

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.

Contraceptive Efficacy and Local Effects of Bioceramic IUD in Rat

The contraceptive efficacy and local effects of bioceramw IUD in rat were studied. The experiment was divided into four groups ： bioceramic IUD group ; stainless steel IUD group ; operation control group ; normal control group. All IUD samples were put into uterus of rats, The experimental results show that the alumina bioceramic has a strong contraceptive effect for those rats. In bioceramic IUD group the endometrial inflammation reaction was as mild as that in stainless IUD group during the.early days （ 30 days ） and gradually abated with time during the late days （60 days ）. The experiments show that the alumina bioceramic has a good biocompatibility and contraceptive effects and hint at the alumina bioceramw IUD may become a more safety reproduction family planning IUD.

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.

Numerical Simulation of Mechanical Behaviors of Degradable Porous Bioceramics with Cracks

Hydroxyapatite bioceramics is simulated by using finite element method （FEM）. The influences of porosity, hole shape, angle of crack and other parameters on the ceramics are analyzed. The results show that with the increase of the angle between crack and horizontal direction, the stress intensity factor KⅠ decreases gradually, but stress intensity factor KⅡ increases at first and then it decreases. The value of KⅡ reaches maximum when the angle between crack and horizontal direction is 45°. KⅠ and KⅡ rise with the increase of porosity, and they are almost the same for the circular and hexagonal holes. For elliptical holes, KⅠ and KⅡ reach maximum when the long axis of ellipse is perpendicular to the loading direction and they reach minimum when the same axis is parallel to the loading direction. Moreover, with the increase of the angle between the long axis and loading direction, KⅠ and KⅡ increase gradually.

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.