Bassanite Research Articles

Evaluation of The Effectiveness of Using Calcium Sulfate Hemihydrate Graft for Socket Preservation after Teeth Extraction

Evaluation of The Effectiveness of Using Calcium Sulfate Hemihydrate Graft for Socket Preservation after Teeth Extraction

Strontium sintered calcium sulfate bone graft for enhancing osteogenesis in a rat femoral defect model

Strontium-containing calcium sulfate hemihydrate has been widely investigated in bone tissue engineering in recent years. The sensitive dose-dependent effect of strontium ions limits the clinical applications due to the uncontrollable release property of fabricated bone substitutes. The purpose of our study was to design a novel strontium sintered calcium sulfate anhydrate scaffold possessing a tailored released concentration and further in vivo bone regeneration. The in vitro biocompatibility, toxicity and differentiation of MC3T3E1 cells were evaluated by using different concentrations of SrCl2 and various weight ratios of strontium sintered calcium sulfate scaffolds. For the in vivo studies, we designed a critical-sized femoral defect model of rats transplanted with different weight ratios of strontium-substituted scaffolds to study new bone regeneration. In vitro data suggested that a Sr2+ concentration below 10−4 M had a positive effect on the osteogenic differentiation of MC3T3E1 cells. The enhanced cell viability, osteogenic profiles, bone mineralization and promising cellular proliferation were measured in 1% and 5% weight ratios of strontium-substituted scaffolds. Runt-related transcription factor 2 (RUNX2)-mediated osteogenesis was associated with the activation of extracellular signal-related kinase (ERK) signaling pathways in MC3T3E1 cells cultured in scaffold extracts. The in vivo experiments revealed that these sintered scaffolds showed acceptable biodegradability in X-ray and micro-CT images at the 12th week. Histological analysis showed intact surrounding bone regeneration, more osteoid formation, neovascularization and less fibrotic tissue in the 1% weight ratio of strontium sintered calcium sulfate scaffolds, suggesting that this sintered scaffolds weight ratio possesses potential for application in bone tissue engineering.

Evaluation of The Effectiveness of Using Calcium Sulfate Hemihydrate Graft for Socket Preservation after Teeth Extraction

Evaluation of The Effectiveness of Using Calcium Sulfate Hemihydrate Graft for Socket Preservation after Teeth Extraction

The effect of additives on the hydration of CaSO4·0.5H2O: A synchrotron X-ray diffraction study

To modulate the rate of hydration of calcium sulfate hemihydrate (HH) to calcium sulfate dihydrate for industrial applications, additives (both accelerants and retardants) are added to the HH. Here we explore in detail the kinetics and mechanism of HH hydration in the presence of the accelerators K2SO4 or ZnSO4, and also when a retardant (citric acid or tartaric acid) is added. Retardants tend to lower the maximum temperature of the reaction and increase the time needed to reach 50% hydration, yet the total conversion percentage is similar to that when an accelerant is added. The reaction process is found to involve heterogenous nucleation regardless of the nature of the additive. More soluble accelerants act mainly though increasing the rate of crystal growth, while less soluble species have a more significant effect on the rate of nucleation.

Physicochemical and biological properties of carboxymethyl chitosan zinc (CMCS-Zn)/α‑calcium sulfate hemihydrate (α-CSH) composites

To improve the osteoinductivity, antibacterial activity, and clinical application of calcium sulfate hemihydrate (CSH), carboxymethyl chitosan zinc (CMCS-Zn) and α-CSH were prepared using different mass ratios. The setting time and injectability of the CMCS-Zn/α-CSH composite were increased with increasing CMCS-Zn content. After adding different amounts of CMCS-Zn to α-CSH, the fine lamellar structure of CMCS-Zn was found by scanning electron microscopy (SEM), which is evenly distributed in the matrix of α-CSH. With the increase of CMCS-Zn, the pores on the surface gradually increased. After mixing CMCS-Zn and α-CSH, no new phase was measured by X-ray diffraction (XRD) and Fourier transform (FTIR) spectroscopy. The degradation rate of CMCS-Zn/α-CSH decreased with increasing CMCS-Zn content, and the pH was stable during the degradation process. The release of Zn2+ increased with increasing CMCS-Zn content, while the release of Ca2+ decreased. Extracts of CMCS-Zn/α-CSH composites up-regulated the osteoinduction and migration of rat bone marrow stem cells. The antibacterial ability of CMCS-Zn/α-CSH was evaluated as a function of CMCS-Zn content. In the rat bone defect model, 5% CMCS-Zn/α-CSH group revealed a higher volume and density of trabeculae by micro-CT 8 weeks after the operation. Therefore, CMCS-Zn/α-CSH was demonstrated to be an adjustable, degradable, substitute biomaterial (with osteogenesis-promoting effects) for use in bone defects, which also has antibacterial activity that can suppress bone infection.

Preparation and Characterization of Moldable Demineralized Bone Matrix/Calcium Sulfate Composite Bone Graft Materials.

Demineralized bone matrix (DBM) is a decalcified allo/xenograft retaining collagen and noncollagenous proteins, which has been extensively used because of its osteoconductive and osteoinductive properties. Calcium sulfate (CaSO4, CS) is a synthetic bone substitute used in bone healing with biocompatible, nontoxic, bioabsorbable, osteoconductive, and good mechanical characteristics. This study aims to prepare a DBM/CS composite bone graft material in a moldable putty form without compromising the peculiar properties of DBM and CS. For this purpose, firstly, porcine femur was defatted using chloroform/methanol and extracted by acid for demineralization, then freeze-dried and milled/sieved to obtain DBM powder. Secondly, the α-form and β-form of calcium sulfate hemihydrate (CaSO4·0.5H2O, CSH) were produced by heating gypsum (CaSO4·2H2O). The morphology and particle sizes of α- and β-CSH were obtained by SEM, and their chemical properties were confirmed by EDS, FTIR and XRD. Furthermore, the DBM-based graft was mixed with α- or β-CSH at a ratio of 9:1, and glycerol/4% HPMC was added as a carrier to produce a putty. DBM/CSH putty possesses a low washout rate, good mechanical strength and biocompatibility. In conclusion, we believe that the moldable DBM/CSH composite putty developed in this study could be a promising substitute for the currently available bone grafts, and might have practical application in the orthopedics field as a potential bone void filler.

Antimicrobial efficacy and activity perseverance in arthroplasty of calcium sulfate beads containing vancomycin prepared ahead of time and stored in ready-to-use formula

The use of local therapy with antibiotics in a suitable carrier is essential in the treatment and prevention of infections in orthopedic surgery and traumatology. In our orthopedic surgery department, a synthetic calcium sulfate hemihydrate (CaSO4·½H2O) is used as an antibiotic carrier, enabling the application of most types of intravenous antibiotics in the form of powder and liquid. This type of carrier with antibiotics is prepared in the theater during the procedure. During a surgical procedure, a small dead space is created (hand and foot area), which must be filled with an antibiotic carrier, and the situations arise where a large amount of the carrier is not used and thrown away. Therefore, we verified the efficacy of vancomycin in the pre-prepared carrier by an orientation microbiological method and by measuring the concentrations of the vancomycin released in active form and its two crystalline degradation products. Based on the agar diffusion test, we did not measure any difference in the effectiveness of the antibiotic in the carrier after its 12-day storage. Although vancomycin concentrations decreased by approximately 32% at the end of 12days of storage, the concentrations of the released active form of vancomycin are many times higher than the minimum inhibitory concentrations for resistant strains of Staphylococcus aureus. Thus, the calcium sulfate carrier with vancomycin can be prepared several days in advance before its application, certainly up to 12days.

The preparation and study on properties of calcium sulfate bone cement combined tuning silk fibroin nanofibers and vancomycin-loaded silk fibroin microspheres.

In this study, a bioactive composite material based on calcium sulfate hemihydrate (CSH) bone cement was studied, which use calcium sulfate dihydrate (CSD) as coagulant and silk fibroin nanofibers (SFF) solution as the curing liquid, further loaded vancomycin silk fibroin microspheres (SFM/VCM). The drug release effect of bone cements caused by tuning weight content of SFM/VCM (0.5, 1, 2%) and the concentration of silk fibroin solution (SFS) (20, 60, 100 mg/mL) used for preparation of SFM was studied in this article. Scanning electron microscope (SEM) demonstrated that the average diameter of microspheres gradually increased and the setting time was prolonged with the concentration of SFS increasing. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) were used to analyze the composition of composite materials. The result of compressive strength revealed that the composites contained 0.5% SFM/VCM showed better mechanical performance independent on the concentration of microspheres and the cumulative drug release percentage of all composites were less than 55% after 4 weeks. The drug-loading bone cement possesses not only injectability but also sustained release capability which has a promising prospect in the field of bone substitute material.

Technology of Production of Binder Modifying Nanoadditives

The article deals with the issue concerning production of a dry nanoadditive. In order to achieve this goal, an aqueous solution of polyvinyl acetate dispersion (PVAD) and nanotubes, or lime slaking nanoparticles is used. As a result of the hydration process heat is released, the polyvinyl acetate emulsion forms particles with nanotubes in their composition. During the study performed an optimal ratio of all components was established: quicklime + PVAD-CNT – 71-73% and 0.01-0.018 CNT; “Megalith” – 21-25%; ammonium salt – 4-6%, as well as the optimal amount of the complex additive, which is in the range of 1-1.5% by weight of calcium sulfate hemihydrate. Later on the resulting nanoadditive can be used to modify binders or other materials

Pharmacokinetic and safety assessment of carboplatin-impregnated calcium sulfate hemihydrate beads in eight rats.

Evaluate local tissue toxicity and plasma platinum (Pt) in vivo after subcutaneous implantation of carboplatin-impregnated calcium sulfate hemihydrate (CI-CSH) beads. In vivo experimental study. Eight male Sprague-Dawley rats. CI-CSH beads were implanted subcutaneously (5mg carboplatin/rat; 13.5mg/kg carboplatin; 7.08 mg/kg Pt; 1.18 mg/m2 Pt) in eight rats (d0). Wound healing (daily), radiographic bead dissolution (weekly), systemic Pt uptake (plasma-Pt), local tissue Pt (d28), and histologic changes compared to nonincised and incised catheterization sites (d28) were assessed. Blood and tissue samples were analyzed by inductively coupled plasma mass spectrometry for Pt, and pharmacokinetic analysis was performed using noncompartmental methods. One rat died at d10, the remainder survived until d28. No wound complications were seen. The CI-CSH implantation site had higher histopathology scores than the other sites for necrosis (p=.013) and fibrosis (p=.013). Beads decreased in density radiographically (d0 to d28) (p=.062). Peak plasma-Pt concentration was 225.78 ng/ml at 12 h, and decreased over time, but Pt was still detectable on d28. The elimination half-life was 5.03 ± 1.13 days. Only 1.69% of implanted Pt remained in the beads at d28. CI-CSH beads incited microscopic mild inflammation but wound healing was not impaired. Pt was absorbed systemically and the release from the beads was near complete at d28. Piled CI-CSH bead implantation is well tolerated in rats with similar elution profile as previously described. Beads were radiographically visible at d28. Minimal Pt was detected systemically suggesting Pt release does not match bead dissolution.

Energy performance evaluation of heat storage of calcium sulfate hemihydrate composite with fine aggregate based on paraffinic phase change material

Calcium sulfate hemihydrate has been used as a building material because of its economical and non-combustible characteristics. By applying a heat storage material to a calcium sulfate hemihydrate composite (CSHC), the building energy consumption can be reduced. In this study, a CSHC with a high heat storage capacity was prepared using fine aggregates based on paraffinic shape-stabilized phase change materials (Fa-PSSPCMs) with exfoliated graphite nanoplatelets as stabilizing additives. The heat storage CSHC (Hs-CSHC) was prepared by mixing Fa-PSSPCM and calcium sulfate hemihydrate powder with water and then casting the mixture as boards using molds. For the Hs-CSHC containing 30 wt% Fa-PSSPCM, the latent heat capacities during heating and cooling were 46.39 and 44.28 J/g, respectively; its phase transition occurred at 20–35 °C. Based on analysis results, the Hs-CSHC exhibited acceptable chemical stability and high thermal performance, including a considerable latent heat capacity. The peak temperatures of Hs-CSHCs were approximately 1–2 °C lower than those of the plain CSHC. Moreover, compared with the plain CSHC, the Hs-CSHC with 30 wt% Fa-PSSPCM exhibited a time lag effect exceeding 720 min. In the energy simulation analysis, an 8.18% maximum cooling energy reduction was observed when the Hs-CSHC with 30 wt% Fa-PSSPCM was used. However, the effect of heating load reduction was insignificant due to the low outside temperature. Therefore, when a phase change material is utilized in a building, the phase change temperature and heat storage performance must be considered.

Influence of polysulfonates on the properties of β-calcium sulfate hemihydrate and its hydration

Surfactants have been used to modulate mechanical properties and hydration of calcium sulfate hemihydrates or other cement-like material, especially to improve the properties of cheap materials. In gypsum industry, β-Hemihydrate (β-H) costs less than the α-hemihydrate but presents lower mechanical strength after hydration. In this study, a group of polysulfonates was designed and synthesized to investigate their structure-performance relationship in hydration of β-H and properties of the gypsum plaster. It was found that the hydration of β-H can be modulated by changing the hydrophilic side chain of the polysulfonates, which endowed the gypsum with differential mechanical strength and water absorption. The sodium alkenyl methyl polyoxyethylene ether amide vinyl/ally sulfonate offered the β-H gypsum highest water absorption, retarded hydration and enhanced mechanical strengths by forming compacter rod crystals. The mechanical strength and water absorption of the gypsum were not in direct proportion to hydrophilicity of the polysulfonates and the molar fraction of sulfonic groups, but related to their McGowan’s HLB values. When the HLB values were below 15, the water absorption of β-H gypsum induced by the polymers increases with the increasing HLB values of the polymers.

Inhibition of calcium sulphate hemihydrate crystallization under simulated conditions of phosphoric acid evaporation

AbstractNucleation and crystal growth of CaSO4 ∙ 0.5H2O (calcium sulphate hemihydrate) was studied under conditions simulating scale formation in phosphoric acid production evaporators. Phosphoric acid, calcium hydrogen phosphate, and sulphuric acid were mixed at 88°C. The induction time was determined using a turbidimeter across a range of supersaturation from 1.3–3.5. Crystallization equations, taking as input the induction time and supersaturation, were used to calculate surface energy, nucleation rate, free energy, and the critical nucleus radius of CaSO4 ∙ 0.5H2O with and without the addition of 75 mg/L of various scale inhibitors: polyacrylic acid (PAA) 8000 g/mol, poly(diallyldimethylammonium chloride) (PDADMAC) <100 000 g/mol, or polyethyleneimine (PEI) 60 000 g/mol. The results suggest that PEI is capable of inhibiting crystal growth through the impediment of crystal nucleation.

A Novel One-Pot Synthesis and Characterization of Silk Fibroin/α-Calcium Sulfate Hemihydrate for Bone Regeneration

This study aims to fabricate silk fibroin/calcium sulfate (SF/CS) composites by one-pot synthesis for bone regeneration applications. The SF was harvested from degummed silkworm cocoons, dissolved in a solvent system comprising of calcium chloride:ethanol:water (1:2:8), and then mixed with a stoichiometric amount of sodium sulfate to prepare various SF/CS composites. The crystal pattern, glass transition temperature, and chemical composition of SF/CS samples were analyzed by XRD, DSC, and FTIR, respectively. These characterizations revealed the successful synthesis of pure calcium sulfate dihydrate (CSD) and calcium sulfate hemihydrate (CSH) when it was combined with SF. The thermal analysis through DSC indicated molecular-level interaction between the SF and CS. The FTIR deconvolution spectra demonstrated an increment in the β-sheet content by increasing CS content in the composites. The investigation into the morphology of the composites using SEM revealed the formation of plate-like dihydrate in the pure CS sample, while rod-like structures of α-CSH surrounded by SF in the composites were observed. The compressive strength of the hydrated 10 and 20% SF-incorporated CSH composites portrayed more than a twofold enhancement (statistically significant) in comparison to that of the pure CS samples. Reduced compressive strength was observed upon further increasing the SF content, possibly due to SF agglomeration that restricted its uniform distribution. Therefore, the one-pot synthesized SF/CS composites demonstrated suitable chemical, thermal, and morphological properties. However, additional biological analysis of its potential use as bone substitutes is required.

PREPARATION OF CALCIUM SULFATE HEMIHYDRATE WHISKERS FROM COMPLEX JAROSITE WASTE

Complex jarosite waste was obtained from zinc metal hydrometallurgical process, which contained gypsum and ammonium jarosite (NH4Fe3(SO4)2(OH)6). The influence of impurity ions (Fe3+ and NH4+) on the calcium sulfate hemihydrate (HH) morphology was studied using pure gypsum as the raw material, respectively. HH crystals with a high aspect ratio were obtained without the impurity ions. The diameter increased and the aspect ratio of the HH decreased, while the addition of iron sulfate and ammonia sulfate increased. Ammonium iron (NH4+) can be removed by using calcium oxide to decompose the ammonium jarosite in the waste and then to wash the sediment with tap water. The sediment (calcified jarosite sediment) mainly contained CaSO4·2H2O and Fe(OH)3. The influence of cultivating time on HH crystals growth was researched by using the sediment as raw materials. The diameter of the whiskers increased, while the hydrothermal time increased. The whiskers were obtained, with high a aspect ratio (10–60), large diameter (1–4 µm) and smooth surface, after the sediment was treated at 140 °C for 6 h in pH = 5 solution.

Outcome of Using Medical Grade Calcium Sulfate Hemihydrate (DentoGen) in Unilateral Alveolar Cleft Repair

Objectives: The aim of this prospective study was to evaluate the efficacy of fast setting (DentoGen) bonesubstitute for secondary alveolar cleft repair.Materials and Methods: Ten patients with complete unilateral cleft lip and palate were included for alveolarcleft repair with fast setting (DentoGen) without autogenous bone graft in 2017 and 2018. Pre-operation and6 months post-operation CBCT were used for measurement of bone density and bone volume in cleft site.The data was analyzed by using Pearson’s correlation coefficient test and paired sample t-test via SPSSsoftware version 24.Results: The mean age of patients in this study was 10.4±2.657 years. The pre-operative mean alveolar cleftvolume was 0.8996±0.117cm3. Six months after grafting with fast setting (DentoGen) graft, satisfactorybone formation was observed in all patients except two patients. The mean bone density of cleft site was303±42.843 HU which was significantly lower than the non-cleft side, and the mean percentage of new boneformation was 64.74±10.290% compared with original cleft volume.Conclusion: Calcium sulfate hemihydrate (DentoGen) can represent a promising alternative to autogenousbone graft in repairing small unilateral alveolar cleft during mixed dentition.

Porous and self-strengthened poly(ε-caprolactone)/calcium sulfate hemihydrate composite fibers for bone regeneration

Porous polycaprolactone (PCL)/calcium sulfate hemihydrate (CSH) composite fibers with different compositions were fabricated via electrospinning by using chloroform/dimethyl sulfoxide (volume ratio = 8:2) as the co-solvent. It was found that the incorporation of fine CSH powders greatly improved the morphology of the PCL fibers and generated continuous, bead-free PCL/CSH composite fibers with the pore diameter varying from 0.2 to 1.1 μm when 20% CSH was added. As compared with the PCL fibers, the PCL/CSH composite fibers also exhibited enhanced thermal stability and hydrophilicity. The tensile strength and elastic modulus of the PCL/CSH fibrous membranes first increased and then decreased with the increase of the CSH content, while their ductility exhibited a sustained decrease. Moreover, after immersion in water, the PCL-20%CSH composite fibers presented a much higher tensile strength than the pristine ones probably due to the self-setting of the CSH powders through the porous structure. In addition, the PCL-20%CSH composite fibers displayed a strong ability to form bone-like apatite after immersion in simulated body fluid for 3 days, which suggests their potential applications in bone tissue regeneration as a novel type of substitute.

Structural characteristic and formation mechanism of hemihydrate calcium sulfate whiskers prepared using FGD gypsum

Hemihydrate calcium sulfate whiskers (HH-CSWs) were hydrothermally synthesized in a sulfuric acid solution at 120°C for different holding times (20, 40, and 60min). The phase structures and morphologies were characterized by XRD and SEM, respectively. The XRD pattern of the sample under 60min was refined via the Rietveld fitting method. The structure models of the HH-CSW sample under a 60-min holding time was established based on Rietveld fitting results. No difference in the positions of diffraction peaks was determined. The as-prepared holding time increased the intensity and aspect ratio of the diffraction peaks of both samples. In the prepared HH-CSW structure, Ca–O polyhedron is a 12-sided polyhedron similar to that in the gypsum structure; the Ca atom is located in two positions in the one-unit cell; the H2O channel along the c-axis similar is O-shaped and bigger than that in hexagonal and monoclinic CaSO4·0.5H2O structures. Therefore, although the prepared HH-CSW crystals’ structure are similar to that of the reported hexagonal and monoclinic CaSO4·0.5H2O structures, they are not the same. The formation mechanism of HH-CSW from flue gas desulfurization (FGD) gypsum is discussed based on the analysis of gypsum structure.

Sintering of degradable bone substitutes at room temperature

The possibility of preparing bone substitutes in clinic is demonstrated in this study. With the addition of a small amount of water, the relative density of the calcium sulfate specimen prepared at room temperature became higher than 92%. This value is close to the density of the specimen prepared through conventional sintering at 1100 °C for 1 h. The biaxial strength of the specimen disc can reach 120 MPa. Densification is assisted by the hydration of calcium sulfate hemihydrate to dihydrate wherein coarse hemihydrate particles transformed to fine dihydrate dendrites. Strength is conferred by the entanglement of dendrites and microstructure refinement. The densified calcium sulfate disc remains degradable; its degradation rate in a phosphate buffer saline solution is ~1.6 wt%/day, and the rate remains steady for 28 days.

Tetracalcium Phosphate/Monetite/Calcium Sulfate Hemihdrate Biocement Powder Mixtures Prepared by the One-Step Synthesis for Preparation of Nanocrystalline Hydroxyapatite Biocement-Properties and In Vitro Evaluation.

A modified one-step process was used to prepare tetracalcium phosphate/monetite/calcium sulfate hemihydrate powder cement mixtures (CAS). The procedure allowed the formation of monetite and calcium sulfate hemihydrate (CSH) in the form of nanoparticles. It was hypothesized that the presence of nanoCSH in small amounts enhances the in vitro bioactivity of CAS cement in relation to osteogenic gene markers in mesenchymal stem cells (MSCs). The CAS powder mixtures with 15 and 5 wt.% CSH were prepared by milling powder tetracalcium phosphate in an ethanolic solution of both orthophosphoric and sulfuric acids. The CAS cements had short setting times (around 5 min). The fast setting of the cement samples after the addition of the liquid component (water solution of NaH2PO4) was due to the partial formation of calcium sulfate dihydrate and hydroxyapatite before soaking in SBF with a small change in the original phase composition in cement powder samples after milling. Nanocrystalline hydroxyapatite biocement was produced by soaking of cement samples after setting in simulated body fluid (SBF). The fast release of calcium ions from CAS5 cement, as well as a small rise in the pH of SBF during soaking, were demonstrated. After soaking in SBF for 7 days, the final product of the cement transformation was nanocrystalline hydroxyapatite. The compressive strength of the cement samples (up to 30 MPa) after soaking in simulated body fluid (SBF) was comparable to that of bone. Real time polymerase chain reaction (RT-PCR) analysis revealed statistically significant higher gene expressions of alkaline phosphatase (ALP), osteonectin (ON) and osteopontin (OP) in cells cultured for 14 days in CAS5 extract compared to CSH-free cement. The addition of a small amount of nanoCSH (5 wt.%) to the tetracalcium phosphate (TTCP)/monetite cement mixture significantly promoted the over expression of osteogenic markers in MSCs. The prepared CAS powder mixture with its enhanced bioactivity can be used for bone defect treatment and has good potential for bone healing.