The injection of bone cement is a promising surgical intervention for the treatment of osteoporosis.The aim of this study was to formulate a novel injectable bioactive bone cement to adress such medical problems.The b...The injection of bone cement is a promising surgical intervention for the treatment of osteoporosis.The aim of this study was to formulate a novel injectable bioactive bone cement to adress such medical problems.The bone cement primarily consists of tricalcium phosphate(β-TCP),konjac glucomannan(KGM),and hydroxyapatite whisker(HAw).An orthogonal experiment was designed to generate multiple sets of new composite calcium phosphate cement(NCPC)samples,and their setting times were measured.The in vitro compatibility of the new bone cement was assessed through relative cell proliferation rate(RGR)and in vitro cell growth experiments.Mechanical strength and porosity tests were conducted for each group of bone cement,and cross-sectional morphology was observed.The results demonstrate that the bone cement exhibits favorable properties such as self-curing,mechanical robustness,and resistance to collapse.The optimum formulation involves a doping ratio of 5/15(wt%)HAw and HA,an additional amount of 1.2wt%KGM,and a liquid citric acid concentration of 2wt%.Porosity tests confirmed that the material has high compressive strength and a favorable porosity of 27%,creating conducive conditions for cell growth,proliferation,and material degradation.Moreover,in vitro cell culture experiments revealed excellent biocompatibility of the material.Consequently,the developed NCPC emerges as a potential candidate material for applications of bone implantation.展开更多
BACKGROUND Percutaneous vertebroplasty(PVP)is an effective method for the treatment of neurologically intact Kümmell’s disease,but bone cement leakage during surgery is a problem that deserves attention.AIM To r...BACKGROUND Percutaneous vertebroplasty(PVP)is an effective method for the treatment of neurologically intact Kümmell’s disease,but bone cement leakage during surgery is a problem that deserves attention.AIM To reduce bone cement leakage and evaluate the effect of the sequential infusion of bone cement during PVP for the treatment of stage I or II Kümmell’s disease.METHODS Patients with Kümmell’s disease treated in our hospital from September 2015 to September 2018 were retrospectively analyzed.Patients meeting the inclusion and exclusion criteria were divided into two groups:Traditional single infusion and sequential infusion(SI).The visual analog scale(VAS)and Oswestry disability index(ODI)were evaluated and compared,and duration of operation,bone cement content and complications were recorded.RESULTS Forty-five patients were included in this study;there were 24 in the traditional single infusion group and 21 in the SI group.The VAS and ODI were significantly different for both groups when compared pre-and postoperatively,whereas the differences between 1 wk postoperatively and at the final follow-up were not statistically.When the VAS and ODI of the two groups were compared,there were no significant differences at any time point.The leakage rate of bone cement was significantly lower in the SI group(14.3%,3 of 21)than that in the traditional single infusion group(41.7%,10 of 24).CONCLUSION SI in unipedicular PVP is a safe and effective procedure for neurologically intact Kümmell’s disease,and this technique could decrease the incidence of bone cement leakage.展开更多
Poly methyl methacrylate(PMMA)bone cement is used in augmenting and stabilizing fractured vertebral bodies through percutaneous vertebroplasty(PVP)and percutaneous kyphoplasty(PKP).However,applications of PMMA bone ce...Poly methyl methacrylate(PMMA)bone cement is used in augmenting and stabilizing fractured vertebral bodies through percutaneous vertebroplasty(PVP)and percutaneous kyphoplasty(PKP).However,applications of PMMA bone cement are limited by the high elasticity modulus of PMMA,its low biodegradability,and its limited ability to regenerate bone.To improve PMMA bio activity and biodegradability and to modify its elasticity modulus,we mixed PMMA bone cement with oxidized hyaluronic acid and carboxymethyl chitosan in situ cross-linking hydrogel loaded with bone morphogenetic protein-2(BMP-2)to achieve novel hybrid cement.These fabric ated PMMA-hydrogel hybrid cements exhibited lower setting temperatures,a lower elasticity modulus,and better biodegradability and biocompatibility than that of pure PMMA cement,while retaining acceptable setting times,mechanical strength,and inj ectability.In addition,we detected release of BMP-2 from the PMMA-hydrogel hybrid cements,significantly enhancing in vitro osteogenesis of bone marrow mesenchymal stem cells by up-regulating the gene expression of Runx2,Coll,and OPN.Use of PMMA-hydrogel hybrid cements loaded with BMP-2 on rabbit femoral condyle bone-defect models revealed their biodegradability and enhanced bone formation.Our study demonstrated the favorable mechanical properties,biocompatibility,and biodegradability of fabricated PMMA-hydrogel hybrid cements loaded with BMP-2,as well as their ability to improve osteogenesis,making them a promising material for use in PKP and PVP.展开更多
Chitosan-hydroxyapatite （CS-HA） composite powders were synthesized via in situ co-precipitation method, through the reaction of Ca（NO3）2 and H3PO4 in the simulated body fluid （SBF） containing appropri- ate amoun...Chitosan-hydroxyapatite （CS-HA） composite powders were synthesized via in situ co-precipitation method, through the reaction of Ca（NO3）2 and H3PO4 in the simulated body fluid （SBF） containing appropri- ate amount of chitosan. The thermal evolution, microstructure and morphology were studied by TG-DTA （thermogravimetry-differential thermal analysis）, XRD （X-ray diffraction）, FTIR （Fourier transform infrared spectroscopy） and TEM （transmission electron microscopy）. The in vitro bioactivity test showed that the obtained CS-HA composites had higher capability of inducing calcium ions deposition. Effects of CS-HA com- posites on the bioactivity and compressive strength of bioglass bone cement were investigated. The results indicated that the bioactivity of bioglass bone cement could be improved further when CS-HA composite pow- ders were added into the cement, and appropriate amount of CS-HA additive was favorable for compressive strength improvement of bioglass bone cement.展开更多
Effect of interleukin-6 receptor （IL-6R） antibody on polymethyl methacrylate （PMMA） bone cement-mediated expression of osteoprotegerin （OPG） and ：receptor activator of nuclear fac- tor-kappaB ligand （RANKL） i...Effect of interleukin-6 receptor （IL-6R） antibody on polymethyl methacrylate （PMMA） bone cement-mediated expression of osteoprotegerin （OPG） and ：receptor activator of nuclear fac- tor-kappaB ligand （RANKL） in synovial fibroblasts was investigated. Synovial tissue obtained from to- tal knee arthroplasty was digested and cultured. Inverted microscope was employed to observe the synovial cells and immunocytochemistry （SABC method） staining was used to identify synovial fibro- blasts. This experiment was divided into three groups according to different culture media： PMMA group （75μg/mL PMMA bone cement particles）, IL-6R antibody group （10 ng/mL IL-6R antibody＋75 μg/mL PMMA bone cement particles）, and control group （no IL-6R antibody or PMMA bone cement particles）. Influence of IL-6R antibody and PMMA on proliferation of synovial fibroblasts was meas- ured by cell counting kit-8 （CCK-8）. ELISA method was used to measure OPG and RANKL levels in culture solution. Fluorescence quantitative real-time PCR （FQ-PCR） was used to detect the expression of OPG and RANKL mRNA. After three consecutive passages, more than 95% of the primary synovial cells became long spindle fibroblast-like cells. SABC staining results showed that the fibroblast-like cells were negative for anti-CD68 antibody and positive for anti-vimentin antibody, with brown madder stained. CCK-8 test demonstrated that the absorbance （A） value at 450 nm was significantly lower in IL-6R antibody group than in PMMA group and control group （P〈0.01）, but there was no statistically significant difference in A value at 450 nm between the control group and PMMA group （P〉0.05）. Re- suits of ELISA indicated that the expression of OPG was significantly higher in IL-6R antibody group than in PMMA group and control group （P〈0.01）. The expression of RANKL was inhibited （P〈0.05）, and the ratio of OPG/RANKL was significantly increased in IL-6R antibody group as compared with PMMA group and control group. There was no significant difference in the expression of OPG between control group and PMMA group （P〉0.05）, but the expression of RANKL was higher in PMMA group than in control group （P〈0.05）, and there was a significant difference in the ratio of OPG/RANKL be- tween them （P〈0.05）. Results of FQ-PCR revealed the expression of RANKL mRNA was significantly inhibited （P〈0.01） and the expression of OPG mRNA was significantly increased （P〈0.01） in IL-6R an- tibody group as compared with PMMA group and control group. The expression of RANKL mRNA was higher in PMMA group than in control group （P〈0.05）, but the expression of OPG mRNA had no sig- nificant difference between them （P〉0.05）. IL-6R antibody could significantly increase the expression of OPC~ but inhibit the expression of RANKL, which might provide a theoretical basis of molecular bi- ology for the prevention and treatment of aseptic loosening of prosthesis.展开更多
BACKGROUND Bone cement implantation syndrome(BCIS)is characterized by hypotension,arrhythmia,diffuse pulmonary microvascular embolism,shock,cardiac arrest,any combination of these factors,or even death following bone ...BACKGROUND Bone cement implantation syndrome(BCIS)is characterized by hypotension,arrhythmia,diffuse pulmonary microvascular embolism,shock,cardiac arrest,any combination of these factors,or even death following bone cement implantation.CASE SUMMARY An 80-year-old patient with pemphigus and Parkinson’s disease underwent total hip replacement under spinal subarachnoid block and developed acute pulmonary embolism after bone cement implantation.The patient received mask mechanical ventilation with a continuous intravenous infusion of adrenaline(2μg/mL)at a rate of 30 mL/h.Subsequently,the symptoms of BCIS were markedly alleviated,and the infusion rate of adrenaline was gradually reduced until the infusion was completely stopped 45 min later.The patient was then transferred to the Department of Orthopedics,and anticoagulation therapy began at 12 h postoperatively.No other complications were observed.CONCLUSION This is a rare case of BCIS in a high-risk patient with pemphigus and Parkinson’s disease.展开更多
Calcium phosphate cements(CPCs)are frequently used to repair bone defects.Since their discovery in the 1980s,extensive research has been conducted to improve their properties,and emerging evidence supports their incre...Calcium phosphate cements(CPCs)are frequently used to repair bone defects.Since their discovery in the 1980s,extensive research has been conducted to improve their properties,and emerging evidence supports their increased application in bone tissue engineering.Much effort has been made to enhance the biological performance of CPCs,including their biocompatibility,osteoconductivity,osteoinductivity,biodegradability,bioactivity,and interactions with cells.This review article focuses on the major recent developments in CPCs,including 3D printing,injectability,stem cell delivery,growth factor and drug delivery,and pre-vascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.展开更多
In view of the demographic changes and projected increase of arthroplasty procedures worldwide,the number of prosthetic joint infection cases will naturally grow.Therefore,in order to counteract this trend more rigid ...In view of the demographic changes and projected increase of arthroplasty procedures worldwide,the number of prosthetic joint infection cases will naturally grow.Therefore,in order to counteract this trend more rigid rules and a stricter implementation of effective preventive strategies is of highest importance.In the absence of a"miracle weapon"priorities should lie in evidence-based measures including preoperative optimization of patients at higher infection risks,the fulfilment of strict hygiene rules in the operating theatre and an effective antibiotic prophylaxis regimen.Instead of a"one size fits all"philosophy,it has been proposed to adjust the antibiotic prophylaxis protocol to major infection risks taking into account important patient-and procedure-related risk factors.A stronger focus on the local application mode via use of high dose dual antibioticloaded bone cement in such risk situations may have its advantages and is easy to apply in the theatre.The more potent antimicrobial growth inhibition in vitro and the strong reduction of the prosthetic joint infection rate in risk for infection patients with aid of dual antibiotic-loaded bone cement in clinical studies align with this hypothesis.展开更多
Prosthetic joint infection(PJI)is the most serious complication following total joint arthroplasty,this being because it is associated with,among other things,high morbidity and low quality of life,is difficult to pre...Prosthetic joint infection(PJI)is the most serious complication following total joint arthroplasty,this being because it is associated with,among other things,high morbidity and low quality of life,is difficult to prevent,and is very challenging to treat/manage.The many shortcomings of antibiotic-loaded poly(methyl methacrylate)(PMMA)bone cement(ALBC)as an agent for preventing and treating/managing PJI are well-known.One is that microorganisms responsible for most PJI cases,such as methicillin-resistant S.aureus,have developed or are developing resistance to gentamicin sulfate,which is the antibiotic in the vast majority of approved ALBC brands.This has led to many research efforts to develop cements that do not contain gentamicin(or,for that matter,any antibiotic)but demonstrate excellent antimicrobial efficacy.There is a sizeable body of literature on these socalled“antibiotic-free antimicrobial”PMMA bone cements(AFAMBCs).The present work is a comprehensive and critical review of this body.In addition to summaries of key trends in results of characterization studies of AFAMBCs,the attractive features and shortcomings of the literature are highlighted.Shortcomings provide motivation for future work,with some ideas being formulation of a new generation of AFAMBCs by,example,adding a nanostructured material and/or an extract from a natural product to the powder and/or liquid of the basis cement,respectively.展开更多
Mimicking compositional and constructional features of the extracellular matrix(ECM)is an effective parameter in improving the biological response of biomaterials.In this regard,carbon nanotube(CNT)and gelatin were ad...Mimicking compositional and constructional features of the extracellular matrix(ECM)is an effective parameter in improving the biological response of biomaterials.In this regard,carbon nanotube(CNT)and gelatin were added to magnesium-calcium phosphate cement(CNG)to mimic fibrillar construction and organic composition of ECM,respectively,besides the CNG performance was compared with the plain and CNT-reinforced cement.Cementation behavior of the cements was investigated by evaluating their setting time,cement composition variation during setting,and viscosity fluctuation.Furthermore,compressive strength,degradation,and cell response of the cements were compared.Adding 5 wt.%gelatin reduced setting time about 60%,because of gel formation,not due to struvite precipitation.Moreover,the gelatin decreased compressive strength by about 20%.Although gelatin decreased compressive strength,the strength remained in the range attributed to trabecular bone.All the types of cement indicated shear thinning behavior that made their injectability feasible.Compared to other types of cement,CNG enhanced proliferation and differentiation of mesenchymal stem cells besides faster degradation,nontoxicity and suitable cell adhesion.Hence,mimicking features of CNG enhanced osteoconductivity and osteoinductivity of the cement compared to the plain one.展开更多
For the past several years,calcium phosphate cement was used in the biomedical applications.Outstanding biocompatibility,good bioactivity,self-setting qualities,minimum setting degree,appropriate toughness,and simple ...For the past several years,calcium phosphate cement was used in the biomedical applications.Outstanding biocompatibility,good bioactivity,self-setting qualities,minimum setting degree,appropriate toughness,and simple shape to accommodate any difficult geometry are among their most notable attributes.Calcium phosphate has some types and brushite is one of the most attractive mineral for bone repair application.Brushite is extensively employed in filling fractures and trauma treatments as a bone substituted material.This kind of material can potentially be used as a medicine delivery device.The replacement of metal,such as magnesium,zinc,and strontium ions,into the calcium phosphate structure is a major research topic these days.Brushite cement has low mechanical strength and quick setting rate.It is possible to produce biomaterials with higher mechanical characteristics.By adding metal that are great potential in controlling cellular density when included into biomaterials.As a result,it is a successful method to develop quite well regenerative medicine.This paper provides a detailed summary of the present achievements of metal-doped brushite cement for bone repair and healing process.The major purpose of this work is to give a simple but thorough analysis of current successes in brushite cement doped with Zn,Mg,Sr,and other ions as well as to highlight new advancements and prospects.The impact of metal replacement on cement physical and chemical properties,including microstructure,setting time,injectability,mechanical property,and ion release,is explored.The metal-doped cement has osteogenesis,angiogenesis,and antibacterial properties,as well as their prospective utility as drug carriers,also considered.展开更多
Biomaterial-associated infection(BAI)is a kind of serious post-operative complication in orthopaedic surgery.Antibiotic-loaded bone cement shines a light on BAI prevention for convenient manipulation and complex filli...Biomaterial-associated infection(BAI)is a kind of serious post-operative complication in orthopaedic surgery.Antibiotic-loaded bone cement shines a light on BAI prevention for convenient manipulation and complex filling.To this aim,we designed an antibacterial bone cement based on Nano-hydroxyapatite/Polyurethane(PUHA)loading with antibiotic Enoxacin(EN).The distinct shear-thinning behavior of the prepolymers was observed,indicating a good injectability.The PUHA bone cement possessed a suitable curing speed,and the addition of EN might slightly expedite the curing process and enhance the mechanical properties.The EN release profile indicated that the EN-loaded bone cement could reach the minimum inhibitory concentration in 2 h,and sustainedly released EN for almost 8 days,exhibiting an antibacterial delivery potential.Antibacterial test further confirmed the antibacterial ability of EN-loaded bone cement is in a dose-dependent manner.However,the osteogenic performance of drug-loaded bone cement with high dosage is not as good as antibacterial activity.When the EN concentration of antibacterial cement was lower than 32μg·mL^(-1),the proliferation and osteogenic differentiation of rat mesenchymal stem cells could be significantly promoted.Overall,this study verified the potential of the EN-loaded PUHA bone cement in anti-infection and osteogenesis for bone repairing.展开更多
To discuss the feasibility of bydroxyapatite bone cement （HAC） used as a drug delivery carrier and observe the bacteriostatic activity of HAC/ Norvancomycin（ HAC/ NVCM ） composite in vitro and its release charac...To discuss the feasibility of bydroxyapatite bone cement （HAC） used as a drug delivery carrier and observe the bacteriostatic activity of HAC/ Norvancomycin（ HAC/ NVCM ） composite in vitro and its release characteristics in vivo. Bacteriostatic zone and cycle of composite containing 1.5wt% of NVCM were measured in vitro studies. In vivo stndies , the composite was implanted into the top of rabbit＇ s tibia as the local medication group, HAC without NVCM being composed was also implanted and NVCM was injected into auricular vein as the systemic medication group. Cnncentrations of NVCM in blood and local bone were measured in both groups at different time points. The experimental results showed that HAC did not influence the bacteriostatic activity of NVCM otviously, and NVCM exist in the porosities of HAC in the pattern of amorphism. The blood coueemrations of NVCM in local medication group were always lower than those in systemic medication group at any time point, while the bone concentrations of NVCM in local medication group were much higher than those of systemic medication group,which remained to be 3.96μg/mg/mL after 2 weeks. And HAC has good release characteristics as a drug delivery earricr.展开更多
We introduced the hydrophilic groups to acrylic bone cement to improve compliance and achieve more interdigitation between the bone and the acrylic bone cement in order to create better substrates for immediate loadin...We introduced the hydrophilic groups to acrylic bone cement to improve compliance and achieve more interdigitation between the bone and the acrylic bone cement in order to create better substrates for immediate loading. FTIR-ATR, contact angle, and maximum breach torque were employed for measurement. The results reveal that the introduction of hydrophilic functional groups has increased PMMA＇s surface hydrophilicity after contact angle test. FTIR-ATR results suggest the hydrophilic groups participate in the polymerization reactions, and maximum breach torque of the hydrophilic acrylic bone cements is near 110 Ncm torque. Those effects make it possible for conventional acrylic bone cement application in immediate loading of dental implant.展开更多
BACKGROUND Percutaneous vertebroplasty(PVP)has been widely used in osteoporotic vertebral compression fracture(OVCF).Following surgery,the bone cement would be positioned permanently.However,in some cases of lumbar de...BACKGROUND Percutaneous vertebroplasty(PVP)has been widely used in osteoporotic vertebral compression fracture(OVCF).Following surgery,the bone cement would be positioned permanently.However,in some cases of lumbar degenerative disease,the cemented vertebrae needs to be fixed after decompression and fusion procedure.It is difficult to implant traditional pedicle screws into the cemented vertebrae because of the bone cement filling.At present,the main treatment strategy is to skip the cemented vertebra and conduct a long segment fixation.This article presents a cortical bone trajectory(CBT)fixation technique for cemented vertebrae.CASE SUMMARY PVP involving the L3 and L4 was performed in an 82-year-old man due to OVCF.During the surgery,bone cement leakage occurred,resulting in compression of the root of the right L3 nerve.We performed a partial facetectomy to retrieve the leaked bone cement and to relieve the patient’s neurological symptoms.After 3 mo,the patient developed lumbar disc herniation in L3/4,potentially due to instability caused by the previous surgery.Therefore,it was necessary to perform intervertebral fusion and fixation.It was difficult to implant traditional trajectory pedicle screws in L3 and L4 because of the bone cement filling.Hence,we implanted CBT screws in the L3 and L4 vertebrae.As a result,the patient’s symptoms resolved and he reported satisfaction with the surgery at follow-up after 8 mo.CONCLUSION It is feasible to utilize CBT in cemented vertebrae for the treatment of lumbar degenerative disease.展开更多
Natural diatomite （DT） is the ancient deposit of diatom skeleton with many regular pores of 50-200 nm and also an abundant source of biogenic silica. Although silica is considered biologically safe and there is an i...Natural diatomite （DT） is the ancient deposit of diatom skeleton with many regular pores of 50-200 nm and also an abundant source of biogenic silica. Although silica is considered biologically safe and there is an increasing interest of using natural diatomite for biomedical applications, the toxicity information about natural diatomite is still missing. Here, cytotoxicity of natural diatomite on osteoblasts and fibroblasts were compared to hydroxyapatite and the relationships between cytotoxicity and diatomite sizes, dose, geometry or impurity were systematically investigated. Cell adhesion and interaction with diatomite particles were also fluorescently observed, The results clearly suggested a size-, dose- and shape-dependent cytotoxicity of natural diatomite. Disk-shaped diatomite particles with average size of 30μm in diameter revealed the least toxicity, while the diatomite particles with irregular shapes and sizes less than 10 μm were remarkably toxic. Diatomite particles with proper sizes were then selected to investigate the reinforcing effect on injectable calcium phosphate bone cement. Results showed that diatomite significantly improved the compressive strength of bone cement but did not alter the injectability of the cement, This work provided important biocompatibility information of natural diatomite and demonstrated the feasibility of using selected diatomite as bone implant material.展开更多
Glass based bone cement (GBC) was synthesized by mixing CaO-SiO2-P2O5 based glass powder with ammonium phosphate liquid medium. Bone-like hydroxyapatite (HAP, Ca10(PO4)6(OH)2) was found to form after GBC was immersed ...Glass based bone cement (GBC) was synthesized by mixing CaO-SiO2-P2O5 based glass powder with ammonium phosphate liquid medium. Bone-like hydroxyapatite (HAP, Ca10(PO4)6(OH)2) was found to form after GBC was immersed in simulated body fluid (SBF). HAP crystal grew with an increasing time along c axle and reached about 200 nm in length after 30 days, however, the end plane granularity remained 30-50 nm. The chemical composition, crystal structure and morphology of HAP formed from GBC were proved to have great resemblance with living HAP. It is believed that GBC was a desirabie biomedicai material with high bioactivity. Furthermore, the high compressive strength guaranteed the possibility of GBC in clinical application.展开更多
tricalcium phosphate(α TCP)/tetracalcium phosphate(TTCP) composite bone cement had good hydration characteristic.In our system,α TCP/TTCP powder mixture was mixed with water at a powder/liquid (P/L) ratio of 1.50g...tricalcium phosphate(α TCP)/tetracalcium phosphate(TTCP) composite bone cement had good hydration characteristic.In our system,α TCP/TTCP powder mixture was mixed with water at a powder/liquid (P/L) ratio of 1.50g·mL -1 .The setting time could be adjusted,the maximum compressive strength was 45.36MPa,and the hydration product was hydroxyapatite (HAP).In vitro biological simulated experiments indicate that α TCP/TTCP bone cement has α certain dissolubility.The hardened product is mainly HAP after soaking in simulated body fluid (SBF) for 10 weeks.The results of in vitro test and animal experiments and SEM analyses show that no local or general toxicity response,no muscle stimulation,no haemolysis,no cruor,no inflammatory reaction and no exclusion response are caused by α TCP/TTCP cement, which can be contributed to bone tissue spreading and impinging.α TCP/TTCP cement hydrated and hardened continually in vivo.The materials fused with host bone together with implanting time prolonging.Therefore,it is believed that α TCP/TTCP composite bone cement has a high biocompatibility and bioactivity,a certain biodegradation and good osteogenesis as well.展开更多
Bioactive bone cements based on a paste-paste system for orthopaedic applications were developed consisting of hydroxyapatite （ HA ） filler panicles in a methacrylate matrix comprising urethane dimethacrylate （ UD...Bioactive bone cements based on a paste-paste system for orthopaedic applications were developed consisting of hydroxyapatite （ HA ） filler panicles in a methacrylate matrix comprising urethane dimethacrylate （ UDMA ） and triethylene glycol dimethacrylate （ TEGDMA ）. To improve the interface between inorganic filler and organic matrix the HA panicles were subjected to two different surface treatment methods, using polyacrylic acid （PAA） and γ-methacryloxy propyl trimethoxy silane （γMPS）. The aim of the present study was to determine the influence of surface treatment and the inclusion of multifunctional methacrylates on the mechanical properties, namely 3-point flexural strength （FS） and fracture toughness of the cements and the effect of ageing in simulated body fluid. Comparing the mechanical properties of the two cements, the γMPS- HA cement showed that the fracture toughness of the experimental bone cements were significantly greater （ p 〈 0.001） compared to that of the PMMA cement, whereas PAA-HA containing cement had strength vollues around 20% lower. Interestingly, PAA was found to be more effective in improving the interface as the PAA treated HA cement （ UTHAPPA ） maintained its strength on immersion in SBF, suggesting that PAA provided a coupling, which was less sensitive to moisture, a similar trend was also observed with the inclusion of the carboxyl containing multifunctional methacrylates.展开更多
The bioactive α-Ca3（ PO4 ）2 bone cement was studied by XRD , SEM and isothermal calorimetric measurements. The results showed that a mixed pattern of TCP and hydroxylapatite were obtained after hydration and harden...The bioactive α-Ca3（ PO4 ）2 bone cement was studied by XRD , SEM and isothermal calorimetric measurements. The results showed that a mixed pattern of TCP and hydroxylapatite were obtained after hydration and hardening. The mechanism of hydration and hardening of the α-Ca3 （ PO4）2 was dissolution-precipitation, （ NH4 ） 112 PO4 was the best set accelerator to the α-Ca3 （ PO4）2 cement, and the HAP powers and the （ NH4）H2 PO4 concentration had a great effect on the hydration rate of a-Ca3（ PO4）2.展开更多
文摘The injection of bone cement is a promising surgical intervention for the treatment of osteoporosis.The aim of this study was to formulate a novel injectable bioactive bone cement to adress such medical problems.The bone cement primarily consists of tricalcium phosphate(β-TCP),konjac glucomannan(KGM),and hydroxyapatite whisker(HAw).An orthogonal experiment was designed to generate multiple sets of new composite calcium phosphate cement(NCPC)samples,and their setting times were measured.The in vitro compatibility of the new bone cement was assessed through relative cell proliferation rate(RGR)and in vitro cell growth experiments.Mechanical strength and porosity tests were conducted for each group of bone cement,and cross-sectional morphology was observed.The results demonstrate that the bone cement exhibits favorable properties such as self-curing,mechanical robustness,and resistance to collapse.The optimum formulation involves a doping ratio of 5/15(wt%)HAw and HA,an additional amount of 1.2wt%KGM,and a liquid citric acid concentration of 2wt%.Porosity tests confirmed that the material has high compressive strength and a favorable porosity of 27%,creating conducive conditions for cell growth,proliferation,and material degradation.Moreover,in vitro cell culture experiments revealed excellent biocompatibility of the material.Consequently,the developed NCPC emerges as a potential candidate material for applications of bone implantation.
文摘BACKGROUND Percutaneous vertebroplasty(PVP)is an effective method for the treatment of neurologically intact Kümmell’s disease,but bone cement leakage during surgery is a problem that deserves attention.AIM To reduce bone cement leakage and evaluate the effect of the sequential infusion of bone cement during PVP for the treatment of stage I or II Kümmell’s disease.METHODS Patients with Kümmell’s disease treated in our hospital from September 2015 to September 2018 were retrospectively analyzed.Patients meeting the inclusion and exclusion criteria were divided into two groups:Traditional single infusion and sequential infusion(SI).The visual analog scale(VAS)and Oswestry disability index(ODI)were evaluated and compared,and duration of operation,bone cement content and complications were recorded.RESULTS Forty-five patients were included in this study;there were 24 in the traditional single infusion group and 21 in the SI group.The VAS and ODI were significantly different for both groups when compared pre-and postoperatively,whereas the differences between 1 wk postoperatively and at the final follow-up were not statistically.When the VAS and ODI of the two groups were compared,there were no significant differences at any time point.The leakage rate of bone cement was significantly lower in the SI group(14.3%,3 of 21)than that in the traditional single infusion group(41.7%,10 of 24).CONCLUSION SI in unipedicular PVP is a safe and effective procedure for neurologically intact Kümmell’s disease,and this technique could decrease the incidence of bone cement leakage.
基金supported by the National Key R&D Program of China(No.2018YFA0703000)the National Natural Science Foundation of China(Nos.82071564,82072412,and 81772326)+1 种基金the Fundamental Research Program Funding of Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine(No.JYZZ070)Project of Shanghai Science and Technology Commission(No.19XD1434200/18431903700)。
文摘Poly methyl methacrylate(PMMA)bone cement is used in augmenting and stabilizing fractured vertebral bodies through percutaneous vertebroplasty(PVP)and percutaneous kyphoplasty(PKP).However,applications of PMMA bone cement are limited by the high elasticity modulus of PMMA,its low biodegradability,and its limited ability to regenerate bone.To improve PMMA bio activity and biodegradability and to modify its elasticity modulus,we mixed PMMA bone cement with oxidized hyaluronic acid and carboxymethyl chitosan in situ cross-linking hydrogel loaded with bone morphogenetic protein-2(BMP-2)to achieve novel hybrid cement.These fabric ated PMMA-hydrogel hybrid cements exhibited lower setting temperatures,a lower elasticity modulus,and better biodegradability and biocompatibility than that of pure PMMA cement,while retaining acceptable setting times,mechanical strength,and inj ectability.In addition,we detected release of BMP-2 from the PMMA-hydrogel hybrid cements,significantly enhancing in vitro osteogenesis of bone marrow mesenchymal stem cells by up-regulating the gene expression of Runx2,Coll,and OPN.Use of PMMA-hydrogel hybrid cements loaded with BMP-2 on rabbit femoral condyle bone-defect models revealed their biodegradability and enhanced bone formation.Our study demonstrated the favorable mechanical properties,biocompatibility,and biodegradability of fabricated PMMA-hydrogel hybrid cements loaded with BMP-2,as well as their ability to improve osteogenesis,making them a promising material for use in PKP and PVP.
基金supported by the Liaoning Province Doctoral Startup Foundation,China (No.20021054)the Liaoning Province Ministry Project of Education,China (No.202073425)
文摘Chitosan-hydroxyapatite （CS-HA） composite powders were synthesized via in situ co-precipitation method, through the reaction of Ca（NO3）2 and H3PO4 in the simulated body fluid （SBF） containing appropri- ate amount of chitosan. The thermal evolution, microstructure and morphology were studied by TG-DTA （thermogravimetry-differential thermal analysis）, XRD （X-ray diffraction）, FTIR （Fourier transform infrared spectroscopy） and TEM （transmission electron microscopy）. The in vitro bioactivity test showed that the obtained CS-HA composites had higher capability of inducing calcium ions deposition. Effects of CS-HA com- posites on the bioactivity and compressive strength of bioglass bone cement were investigated. The results indicated that the bioactivity of bioglass bone cement could be improved further when CS-HA composite pow- ders were added into the cement, and appropriate amount of CS-HA additive was favorable for compressive strength improvement of bioglass bone cement.
基金supported by grants from the Research and Development Projects of Shenzhen of P.R.China(No.JCYJ20130402114702130)the Healthcare and Medical Research Fund of Shenzhen of P.R.China(No.201302064)
文摘Effect of interleukin-6 receptor （IL-6R） antibody on polymethyl methacrylate （PMMA） bone cement-mediated expression of osteoprotegerin （OPG） and ：receptor activator of nuclear fac- tor-kappaB ligand （RANKL） in synovial fibroblasts was investigated. Synovial tissue obtained from to- tal knee arthroplasty was digested and cultured. Inverted microscope was employed to observe the synovial cells and immunocytochemistry （SABC method） staining was used to identify synovial fibro- blasts. This experiment was divided into three groups according to different culture media： PMMA group （75μg/mL PMMA bone cement particles）, IL-6R antibody group （10 ng/mL IL-6R antibody＋75 μg/mL PMMA bone cement particles）, and control group （no IL-6R antibody or PMMA bone cement particles）. Influence of IL-6R antibody and PMMA on proliferation of synovial fibroblasts was meas- ured by cell counting kit-8 （CCK-8）. ELISA method was used to measure OPG and RANKL levels in culture solution. Fluorescence quantitative real-time PCR （FQ-PCR） was used to detect the expression of OPG and RANKL mRNA. After three consecutive passages, more than 95% of the primary synovial cells became long spindle fibroblast-like cells. SABC staining results showed that the fibroblast-like cells were negative for anti-CD68 antibody and positive for anti-vimentin antibody, with brown madder stained. CCK-8 test demonstrated that the absorbance （A） value at 450 nm was significantly lower in IL-6R antibody group than in PMMA group and control group （P〈0.01）, but there was no statistically significant difference in A value at 450 nm between the control group and PMMA group （P〉0.05）. Re- suits of ELISA indicated that the expression of OPG was significantly higher in IL-6R antibody group than in PMMA group and control group （P〈0.01）. The expression of RANKL was inhibited （P〈0.05）, and the ratio of OPG/RANKL was significantly increased in IL-6R antibody group as compared with PMMA group and control group. There was no significant difference in the expression of OPG between control group and PMMA group （P〉0.05）, but the expression of RANKL was higher in PMMA group than in control group （P〈0.05）, and there was a significant difference in the ratio of OPG/RANKL be- tween them （P〈0.05）. Results of FQ-PCR revealed the expression of RANKL mRNA was significantly inhibited （P〈0.01） and the expression of OPG mRNA was significantly increased （P〈0.01） in IL-6R an- tibody group as compared with PMMA group and control group. The expression of RANKL mRNA was higher in PMMA group than in control group （P〈0.05）, but the expression of OPG mRNA had no sig- nificant difference between them （P〉0.05）. IL-6R antibody could significantly increase the expression of OPC~ but inhibit the expression of RANKL, which might provide a theoretical basis of molecular bi- ology for the prevention and treatment of aseptic loosening of prosthesis.
文摘BACKGROUND Bone cement implantation syndrome(BCIS)is characterized by hypotension,arrhythmia,diffuse pulmonary microvascular embolism,shock,cardiac arrest,any combination of these factors,or even death following bone cement implantation.CASE SUMMARY An 80-year-old patient with pemphigus and Parkinson’s disease underwent total hip replacement under spinal subarachnoid block and developed acute pulmonary embolism after bone cement implantation.The patient received mask mechanical ventilation with a continuous intravenous infusion of adrenaline(2μg/mL)at a rate of 30 mL/h.Subsequently,the symptoms of BCIS were markedly alleviated,and the infusion rate of adrenaline was gradually reduced until the infusion was completely stopped 45 min later.The patient was then transferred to the Department of Orthopedics,and anticoagulation therapy began at 12 h postoperatively.No other complications were observed.CONCLUSION This is a rare case of BCIS in a high-risk patient with pemphigus and Parkinson’s disease.
基金supported by NIH R01 DE14190 and R21 DE22625(HX)the National Science Foundation of China 81401794(PW)and 81400487(LW)+2 种基金the Youth Fund of Science and Technology of Jilin Province 20150520043JH(LW)the China Postdoctoral Science Foundation 2015M581405(LW)the University of Maryland School of Dentistry bridge fund(HX)
文摘Calcium phosphate cements(CPCs)are frequently used to repair bone defects.Since their discovery in the 1980s,extensive research has been conducted to improve their properties,and emerging evidence supports their increased application in bone tissue engineering.Much effort has been made to enhance the biological performance of CPCs,including their biocompatibility,osteoconductivity,osteoinductivity,biodegradability,bioactivity,and interactions with cells.This review article focuses on the major recent developments in CPCs,including 3D printing,injectability,stem cell delivery,growth factor and drug delivery,and pre-vascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.
文摘In view of the demographic changes and projected increase of arthroplasty procedures worldwide,the number of prosthetic joint infection cases will naturally grow.Therefore,in order to counteract this trend more rigid rules and a stricter implementation of effective preventive strategies is of highest importance.In the absence of a"miracle weapon"priorities should lie in evidence-based measures including preoperative optimization of patients at higher infection risks,the fulfilment of strict hygiene rules in the operating theatre and an effective antibiotic prophylaxis regimen.Instead of a"one size fits all"philosophy,it has been proposed to adjust the antibiotic prophylaxis protocol to major infection risks taking into account important patient-and procedure-related risk factors.A stronger focus on the local application mode via use of high dose dual antibioticloaded bone cement in such risk situations may have its advantages and is easy to apply in the theatre.The more potent antimicrobial growth inhibition in vitro and the strong reduction of the prosthetic joint infection rate in risk for infection patients with aid of dual antibiotic-loaded bone cement in clinical studies align with this hypothesis.
文摘Prosthetic joint infection(PJI)is the most serious complication following total joint arthroplasty,this being because it is associated with,among other things,high morbidity and low quality of life,is difficult to prevent,and is very challenging to treat/manage.The many shortcomings of antibiotic-loaded poly(methyl methacrylate)(PMMA)bone cement(ALBC)as an agent for preventing and treating/managing PJI are well-known.One is that microorganisms responsible for most PJI cases,such as methicillin-resistant S.aureus,have developed or are developing resistance to gentamicin sulfate,which is the antibiotic in the vast majority of approved ALBC brands.This has led to many research efforts to develop cements that do not contain gentamicin(or,for that matter,any antibiotic)but demonstrate excellent antimicrobial efficacy.There is a sizeable body of literature on these socalled“antibiotic-free antimicrobial”PMMA bone cements(AFAMBCs).The present work is a comprehensive and critical review of this body.In addition to summaries of key trends in results of characterization studies of AFAMBCs,the attractive features and shortcomings of the literature are highlighted.Shortcomings provide motivation for future work,with some ideas being formulation of a new generation of AFAMBCs by,example,adding a nanostructured material and/or an extract from a natural product to the powder and/or liquid of the basis cement,respectively.
文摘Mimicking compositional and constructional features of the extracellular matrix(ECM)is an effective parameter in improving the biological response of biomaterials.In this regard,carbon nanotube(CNT)and gelatin were added to magnesium-calcium phosphate cement(CNG)to mimic fibrillar construction and organic composition of ECM,respectively,besides the CNG performance was compared with the plain and CNT-reinforced cement.Cementation behavior of the cements was investigated by evaluating their setting time,cement composition variation during setting,and viscosity fluctuation.Furthermore,compressive strength,degradation,and cell response of the cements were compared.Adding 5 wt.%gelatin reduced setting time about 60%,because of gel formation,not due to struvite precipitation.Moreover,the gelatin decreased compressive strength by about 20%.Although gelatin decreased compressive strength,the strength remained in the range attributed to trabecular bone.All the types of cement indicated shear thinning behavior that made their injectability feasible.Compared to other types of cement,CNG enhanced proliferation and differentiation of mesenchymal stem cells besides faster degradation,nontoxicity and suitable cell adhesion.Hence,mimicking features of CNG enhanced osteoconductivity and osteoinductivity of the cement compared to the plain one.
基金The authors are grateful to the University of Engineering and Technology,Lahore,Pakistan(ORIC/99 ASRB-614)for funding this research.
文摘For the past several years,calcium phosphate cement was used in the biomedical applications.Outstanding biocompatibility,good bioactivity,self-setting qualities,minimum setting degree,appropriate toughness,and simple shape to accommodate any difficult geometry are among their most notable attributes.Calcium phosphate has some types and brushite is one of the most attractive mineral for bone repair application.Brushite is extensively employed in filling fractures and trauma treatments as a bone substituted material.This kind of material can potentially be used as a medicine delivery device.The replacement of metal,such as magnesium,zinc,and strontium ions,into the calcium phosphate structure is a major research topic these days.Brushite cement has low mechanical strength and quick setting rate.It is possible to produce biomaterials with higher mechanical characteristics.By adding metal that are great potential in controlling cellular density when included into biomaterials.As a result,it is a successful method to develop quite well regenerative medicine.This paper provides a detailed summary of the present achievements of metal-doped brushite cement for bone repair and healing process.The major purpose of this work is to give a simple but thorough analysis of current successes in brushite cement doped with Zn,Mg,Sr,and other ions as well as to highlight new advancements and prospects.The impact of metal replacement on cement physical and chemical properties,including microstructure,setting time,injectability,mechanical property,and ion release,is explored.The metal-doped cement has osteogenesis,angiogenesis,and antibacterial properties,as well as their prospective utility as drug carriers,also considered.
基金funded by the Sichuan International Science and Technology Innovation Cooperation Project[Grant Numbers2021YFH0122]the Fundamental Research Funds for the Central Universities。
文摘Biomaterial-associated infection(BAI)is a kind of serious post-operative complication in orthopaedic surgery.Antibiotic-loaded bone cement shines a light on BAI prevention for convenient manipulation and complex filling.To this aim,we designed an antibacterial bone cement based on Nano-hydroxyapatite/Polyurethane(PUHA)loading with antibiotic Enoxacin(EN).The distinct shear-thinning behavior of the prepolymers was observed,indicating a good injectability.The PUHA bone cement possessed a suitable curing speed,and the addition of EN might slightly expedite the curing process and enhance the mechanical properties.The EN release profile indicated that the EN-loaded bone cement could reach the minimum inhibitory concentration in 2 h,and sustainedly released EN for almost 8 days,exhibiting an antibacterial delivery potential.Antibacterial test further confirmed the antibacterial ability of EN-loaded bone cement is in a dose-dependent manner.However,the osteogenic performance of drug-loaded bone cement with high dosage is not as good as antibacterial activity.When the EN concentration of antibacterial cement was lower than 32μg·mL^(-1),the proliferation and osteogenic differentiation of rat mesenchymal stem cells could be significantly promoted.Overall,this study verified the potential of the EN-loaded PUHA bone cement in anti-infection and osteogenesis for bone repairing.
文摘To discuss the feasibility of bydroxyapatite bone cement （HAC） used as a drug delivery carrier and observe the bacteriostatic activity of HAC/ Norvancomycin（ HAC/ NVCM ） composite in vitro and its release characteristics in vivo. Bacteriostatic zone and cycle of composite containing 1.5wt% of NVCM were measured in vitro studies. In vivo stndies , the composite was implanted into the top of rabbit＇ s tibia as the local medication group, HAC without NVCM being composed was also implanted and NVCM was injected into auricular vein as the systemic medication group. Cnncentrations of NVCM in blood and local bone were measured in both groups at different time points. The experimental results showed that HAC did not influence the bacteriostatic activity of NVCM otviously, and NVCM exist in the porosities of HAC in the pattern of amorphism. The blood coueemrations of NVCM in local medication group were always lower than those in systemic medication group at any time point, while the bone concentrations of NVCM in local medication group were much higher than those of systemic medication group,which remained to be 3.96μg/mg/mL after 2 weeks. And HAC has good release characteristics as a drug delivery earricr.
文摘We introduced the hydrophilic groups to acrylic bone cement to improve compliance and achieve more interdigitation between the bone and the acrylic bone cement in order to create better substrates for immediate loading. FTIR-ATR, contact angle, and maximum breach torque were employed for measurement. The results reveal that the introduction of hydrophilic functional groups has increased PMMA＇s surface hydrophilicity after contact angle test. FTIR-ATR results suggest the hydrophilic groups participate in the polymerization reactions, and maximum breach torque of the hydrophilic acrylic bone cements is near 110 Ncm torque. Those effects make it possible for conventional acrylic bone cement application in immediate loading of dental implant.
文摘BACKGROUND Percutaneous vertebroplasty(PVP)has been widely used in osteoporotic vertebral compression fracture(OVCF).Following surgery,the bone cement would be positioned permanently.However,in some cases of lumbar degenerative disease,the cemented vertebrae needs to be fixed after decompression and fusion procedure.It is difficult to implant traditional pedicle screws into the cemented vertebrae because of the bone cement filling.At present,the main treatment strategy is to skip the cemented vertebra and conduct a long segment fixation.This article presents a cortical bone trajectory(CBT)fixation technique for cemented vertebrae.CASE SUMMARY PVP involving the L3 and L4 was performed in an 82-year-old man due to OVCF.During the surgery,bone cement leakage occurred,resulting in compression of the root of the right L3 nerve.We performed a partial facetectomy to retrieve the leaked bone cement and to relieve the patient’s neurological symptoms.After 3 mo,the patient developed lumbar disc herniation in L3/4,potentially due to instability caused by the previous surgery.Therefore,it was necessary to perform intervertebral fusion and fixation.It was difficult to implant traditional trajectory pedicle screws in L3 and L4 because of the bone cement filling.Hence,we implanted CBT screws in the L3 and L4 vertebrae.As a result,the patient’s symptoms resolved and he reported satisfaction with the surgery at follow-up after 8 mo.CONCLUSION It is feasible to utilize CBT in cemented vertebrae for the treatment of lumbar degenerative disease.
基金financially supported by the National Natural Science Foundation of China(Nos.81622032,51672184,51525101and 51472279)the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD)+2 种基金the Jiangsu Innovation and Entrepreneurship Program,the National Basic Research Program of China(973 Program,No.2014CB748600)the Jiangsu Provincial Special Program of Medical Science(No.BL2012004)the Jiangsu Six Peak of Talents Program(No.2013-WSW-056)
文摘Natural diatomite （DT） is the ancient deposit of diatom skeleton with many regular pores of 50-200 nm and also an abundant source of biogenic silica. Although silica is considered biologically safe and there is an increasing interest of using natural diatomite for biomedical applications, the toxicity information about natural diatomite is still missing. Here, cytotoxicity of natural diatomite on osteoblasts and fibroblasts were compared to hydroxyapatite and the relationships between cytotoxicity and diatomite sizes, dose, geometry or impurity were systematically investigated. Cell adhesion and interaction with diatomite particles were also fluorescently observed, The results clearly suggested a size-, dose- and shape-dependent cytotoxicity of natural diatomite. Disk-shaped diatomite particles with average size of 30μm in diameter revealed the least toxicity, while the diatomite particles with irregular shapes and sizes less than 10 μm were remarkably toxic. Diatomite particles with proper sizes were then selected to investigate the reinforcing effect on injectable calcium phosphate bone cement. Results showed that diatomite significantly improved the compressive strength of bone cement but did not alter the injectability of the cement, This work provided important biocompatibility information of natural diatomite and demonstrated the feasibility of using selected diatomite as bone implant material.
基金This work was partially supported by the National Natural Science Foundation of China(grant number 50272041)the Nanotechnology Special Foundation of Shanghai Science and Technology Committee(grant number 0144NM064).
文摘Glass based bone cement (GBC) was synthesized by mixing CaO-SiO2-P2O5 based glass powder with ammonium phosphate liquid medium. Bone-like hydroxyapatite (HAP, Ca10(PO4)6(OH)2) was found to form after GBC was immersed in simulated body fluid (SBF). HAP crystal grew with an increasing time along c axle and reached about 200 nm in length after 30 days, however, the end plane granularity remained 30-50 nm. The chemical composition, crystal structure and morphology of HAP formed from GBC were proved to have great resemblance with living HAP. It is believed that GBC was a desirabie biomedicai material with high bioactivity. Furthermore, the high compressive strength guaranteed the possibility of GBC in clinical application.
文摘tricalcium phosphate(α TCP)/tetracalcium phosphate(TTCP) composite bone cement had good hydration characteristic.In our system,α TCP/TTCP powder mixture was mixed with water at a powder/liquid (P/L) ratio of 1.50g·mL -1 .The setting time could be adjusted,the maximum compressive strength was 45.36MPa,and the hydration product was hydroxyapatite (HAP).In vitro biological simulated experiments indicate that α TCP/TTCP bone cement has α certain dissolubility.The hardened product is mainly HAP after soaking in simulated body fluid (SBF) for 10 weeks.The results of in vitro test and animal experiments and SEM analyses show that no local or general toxicity response,no muscle stimulation,no haemolysis,no cruor,no inflammatory reaction and no exclusion response are caused by α TCP/TTCP cement, which can be contributed to bone tissue spreading and impinging.α TCP/TTCP cement hydrated and hardened continually in vivo.The materials fused with host bone together with implanting time prolonging.Therefore,it is believed that α TCP/TTCP composite bone cement has a high biocompatibility and bioactivity,a certain biodegradation and good osteogenesis as well.
文摘Bioactive bone cements based on a paste-paste system for orthopaedic applications were developed consisting of hydroxyapatite （ HA ） filler panicles in a methacrylate matrix comprising urethane dimethacrylate （ UDMA ） and triethylene glycol dimethacrylate （ TEGDMA ）. To improve the interface between inorganic filler and organic matrix the HA panicles were subjected to two different surface treatment methods, using polyacrylic acid （PAA） and γ-methacryloxy propyl trimethoxy silane （γMPS）. The aim of the present study was to determine the influence of surface treatment and the inclusion of multifunctional methacrylates on the mechanical properties, namely 3-point flexural strength （FS） and fracture toughness of the cements and the effect of ageing in simulated body fluid. Comparing the mechanical properties of the two cements, the γMPS- HA cement showed that the fracture toughness of the experimental bone cements were significantly greater （ p 〈 0.001） compared to that of the PMMA cement, whereas PAA-HA containing cement had strength vollues around 20% lower. Interestingly, PAA was found to be more effective in improving the interface as the PAA treated HA cement （ UTHAPPA ） maintained its strength on immersion in SBF, suggesting that PAA provided a coupling, which was less sensitive to moisture, a similar trend was also observed with the inclusion of the carboxyl containing multifunctional methacrylates.
文摘The bioactive α-Ca3（ PO4 ）2 bone cement was studied by XRD , SEM and isothermal calorimetric measurements. The results showed that a mixed pattern of TCP and hydroxylapatite were obtained after hydration and hardening. The mechanism of hydration and hardening of the α-Ca3 （ PO4）2 was dissolution-precipitation, （ NH4 ） 112 PO4 was the best set accelerator to the α-Ca3 （ PO4）2 cement, and the HAP powers and the （ NH4）H2 PO4 concentration had a great effect on the hydration rate of a-Ca3（ PO4）2.
