射频磁控溅射法制备羟基磷灰石/β-磷酸三钙生物涂层

目的以粉末冶金烧成的羟基磷灰石(HA)/-β磷酸三钙(β-TCP)陶瓷为靶材,采用磁控溅射法在钛合金(Ti6Al4V)基体上制备HA/β-TCP生物涂层。方法利用XRD研究了复合涂层的晶化程度,讨论了涂层成分与生物降解性及相容性的关系。结果HA/β-TCP生物涂层为非晶态,经700℃,3h大气处理可显著提高涂层的晶化程度,当涂层成分为50wt%HA/50wt%β-TCP时其细胞相容性最好。结论在钛合金基体上制备HA/β-TCP生物涂层,通过HA与β-TCP的复合来控制材料的降解速度,使它的降解速度与周围骨组织的生长速度相匹配,使植入体具有良好的生物降解性、生物活性和力学性能。     

磁性多孔磷酸三钙陶瓷的生物相容性分析

一种新型骨移植替代材料,磁性多孔磷酸三钙陶瓷(MPTCP)可能为骨缺损的治疗开辟一条新途径.为检验其生物相容性及毒性,我们用40只大白鼠(雌雄各半)进行了以下实验:将平均重量为15.3mg的该材料颗粒植入大白鼠双侧股骨近端人工钻孔中,一半动物仅钻孔不植入材料作为对照组.术后30天作动物体重、器官重、器官/体重以及血液学、临床生化、X线拍片、普通切片、扫描电镜检查.结果表明,该材料生物相容性好,无异物及毒性反应,且材料周围骨细胞增生活跃,并向陶瓷孔隙中生长.故认为,MPTCP是一种很值得探讨的骨移植替代材料.     

不同比例羟基磷灰石/β-磷酸三钙涂层支架修复骨缺损

背景：羟基磷灰石/β-磷酸三钙双相磷酸钙陶瓷具有良好的生物相容性与骨传导能力,可以作为涂层材料联合用于超临界骨缺损修复,但羟基磷灰石/β-磷酸三钙涂层的最佳质量比目前尚无明确报道。目的：在兔桡骨超临界骨缺损部位植入不同比例羟基磷灰石/β-磷酸三钙涂层多孔生物陶瓷支架,评估其修复作用,以期获得最佳的涂层比例。方法：采用3D打印技术制备羟基磷灰石多孔生物陶瓷支架,并在其表面使用不同比例的羟基磷灰石与β-磷酸三钙(二者质量比分别为3∶7,5∶5,7∶3)进行涂层处理,然后对支架的细胞毒性、孔隙率、力学强度、涂层厚度等参数进行测试。在36只新西兰大白兔右前肢建立15.0 mm兔桡骨超临界骨缺损模型,随机分4组处理,每组9只：空白组不植入任何材料,3∶7涂层组、5∶5涂层组、7∶3涂层组分别植入对应质量比例涂层的羟基磷灰石多孔生物陶瓷支架,术后4,8,12周,分别进行X射线片及Micro-CT检查、Van-Gieson染色、苏木精-伊红染色及Ⅰ型胶原蛋白免疫组织化学分析。结果与结论：(1)3∶7、5∶5、7∶3涂层支架的细胞毒性均为0级,涂层厚度为(75.2±0.54)μm,孔隙率分别为(54....     

复合活性羟基磷灰石陶瓷的研制及其生物相容性研究

对自行研制出的复合活性羟基磷灰石陶瓷粉，经过体外实验、动物实验、并结合电镜观察，。表明该材料是一种无毒、无溶血性、对皮肤及肌肉无刺激作用、不含热原物质的生物医用材料，在动物体内不引起排异反应，在骨创面可诱导新骨形成。说明该材料具有良好的生?相容性，可应用于临床。     

纳米羟基磷灰石生物安全性评价与研究进展

国内外大多数研究显示羟基磷灰石具有良好的生物相容性和生物活性,医学领域的运用中,普通羟基磷灰石的缺点是脆性大,有很多研究显示纳米羟基磷灰石有更高的强度和韧性,纳米羟基磷灰石晶体在形态、尺寸、组成、结构和结晶度上与人骨羟基磷灰石晶体高度类似,因此纳米羟皋磷灰石在医学领域的应用也日益广泛。对纳米羟基磷灰石生物安全性的评价不断取得进展,大量研究认为纳米羟苯磷灰石具备生物安全性,但是作为一种新型生物材料,纳米羟基磷灰石在评价标准方面有一些问题。     

冷冻干燥法制备的β-磷酸三钙多孔生物陶瓷支架

背景：影响冷冻干燥法制备生物陶瓷支架孔形貌和结构的因素有很多,如浆料的固含量,冷冻速率,烧结温度等。 目的：利用冷冻干燥技术结合陶瓷水基浆料,通过改变陶瓷浆料组成,制备不同形貌和孔隙率的β-磷酸三钙多孔生物陶瓷支架,并分析其影响因素。 方法：制备不同固含量和不同聚乙烯醇含量的β-磷酸三钙浆料,经冷冻、干燥及高温烧结得到多孔生物陶瓷支架。应用X射线衍射技术进行物相分析;扫描电镜观察支架截面的微观结构;阿基米德排水法测量支架材料的孔隙率。 结果与结论：X射线衍射图谱显示制备的支架材料各衍射峰强度与位置与β-磷酸三钙标准衍射谱吻合良好;浆料未添加聚乙烯醇时,多孔支架的孔径和孔隙率随着浆料固含量的增加而减小,支架由大的柱状孔和多孔的陶瓷壁组成;当浆料加入聚乙烯醇后,制备的支架由柱状孔转变为三维连通的网状孔,且随聚乙烯醇含量的增加材料的孔隙率升高。说明利用冷冻干燥法,通过控制陶瓷浆料的组成,可制备出形貌和孔隙率可控的生物陶瓷支架。     

自体骨髓富集间质干细胞与羟基磷灰石磷酸三钙材料复合在脊柱融合中的应用

BACKGROUND: The use of bone graft materials can promote bone fusion and enhance the stability of the spine during the spinal fusion. OBJECTIVE: To investigate the effect of autologous bone marrow mesenchymal stem cells with hydroxyapatite/ tricalcium phosphate in the spinal fusion. METHODS: A retrospective analysis of clinical data of 64 patients with spinal fusion was carried out, and these patients were divided into two groups (n=32 per group): control group undergoing autogenous iliac bone grafting and observation group undergoing autologous bone marrow mesenchymal stem cells combined with hydroxyapatite/tricalcium phosphate. All patients were followed up for 12 months, and their recovery conditions about low back pain, spinal fusion and vertebral reset were assessed. RESULTS AND CONCLUSION: The low-back outcome scale scores and excellent rate, Lenke grading and Cobb angle had insignificant differences between the two groups after treatment (P > 0.05). No infection, inflammation and skin irritation occurred in the two groups. The coagulation function, renal function and inflammatory factor levels were at normal levels in all the patients, and there was no difference between the two groups (P > 0.05). These findings indicate that autologous bone marrow mesenchymal stem cells combined with hydroxyapatite/tricalcium phosphate can achieve clinical outcomes equivalent to the autologous iliac bone grafting.      

生物玻璃-纳米羟基磷灰石梯度涂层的生物相容性研究

目的对生物玻璃-纳米羟基磷灰石(BG-nHA)梯度涂层的生物相容性作初步的评价。方法用低温烧结法在钛合金表面制备生物玻璃纳米羟基磷灰石梯度涂层,利用L929细胞检测梯度涂层材料的细胞毒性。取体外分离培养扩增的人骨髓基质干细胞(hBMSC),接种于涂层材料上,通过绿色荧光蛋白染色、扫描电镜和MTT法观察细胞的黏附和生长情况。结果生物玻璃-纳米羟基磷灰石梯度涂层的细胞毒性分级为1级,人骨髓基质干细胞可以在涂层材料表面黏附和生长。结论生物玻璃-纳米羟基磷灰石梯度涂层有良好的生物相容性,具有潜在的临床应用前景。     

生物玻璃-纳米羟基磷灰石梯度涂层的生物相容性研究

目的 对生物玻璃-纳米羟基磷灰石(BG-nHA)梯度涂层的生物相容性作初步的评价.方法 用低温烧结法在钛合金表面制备生物玻璃纳米羟基磷灰石梯度涂层,利用L929细胞检测梯度涂层材料的细胞毒性.取体外分离培养扩增的人骨髓基质干细胞(hBMSC),接种于涂层材料上,通过绿色荧光蛋白染色、扫描电镜和MTT法观察细胞的黏附和生长情况.结果 生物玻璃-纳米羟基磷灰石梯度涂层的细胞毒性分级为1级,人骨髓基质干细胞可以在涂层材料表面黏附和生长.结论 生物玻璃-纳米羟基磷灰石梯度涂层有良好的生物相容性,具有潜在的临床应用前景.     

人脐血间充质干细胞与β-磷酸三钙的生物相容性

背景：体内实验显示,β-磷酸三钙多孔陶瓷是较为理想的骨组织工程支架材料,但由于体内植入实验受多种因素的影响,不能很好反映细胞的生长、增殖和表型变化。 目的：观察体外人脐血间充质干细胞与β-磷酸三钙多孔陶瓷的生物相容性。 方法：将培养的第6代人脐血间充质干细胞悬液滴注入β-磷酸三钙内部进行复合,然后将干细胞-支架材料复合物置入含体积分数为10%胎牛血清的α-MEM培养体系中培养,于培养第4,8,12天电镜下观察人脐血间充质干细胞在材料表面及内部生长情况,采用MTT测试法绘制细胞生长曲线,并进行DNA含量、蛋白质含量测定。 结果与结论：人脐血间充质干细胞与β-磷酸三钙体外复合后能够在β-磷酸三钙支架材料表面及内部的孔隙内贴附,且生长良好,其DNA复制和蛋白合成功能不受β-磷酸三钙的影响。说明人脐血间充质干细胞和β-磷酸三钙支架材料生物相容性良好,二者可作为种子细胞和支架材料用于组织工程化骨与软骨的构建。     

3D打印技术制备β-磷酸三钙仿生骨支架在兔股骨髁部骨缺损修复中的应用

目的 探讨采用3D打印技术制备的β-磷酸三钙(β-TCP)仿生骨支架的形态结构特点及其相关生物性能,并观察其修复新西兰兔股骨髁部骨缺损的效果。方法 选取5～6月龄新西兰大白兔20只,随机分为支架组和空白组,每组10只;两组大白兔按造模术后采集标本的时间不同又分为两个亚组,每组5只。两组大白兔均于左侧股骨用环钻钻取直径约5 mm、长约10 mm的圆柱形松质骨块,建立股骨髁骨缺损模型。空白组截取的10个松质骨标本,使用微计算机断层扫描技术进行扫描,获得骨缺损标本的结构影像学数据,通过3D生物打印系统设计出相应的仿生骨支架模型,再以β-TCP作为打印材料,打印出20枚仿生骨支架。取10枚β-TCP支架测量高度、直径,电子显微镜下观察β-TCP支架孔道形态结构特点,测量大孔的直径和孔隙率,使用电子力学测试机测定β-TCP支架的弹性模量与抗压强度。空白组10只大白兔造模后不植入任何材料。支架组10只大白兔在造模后,将制备的10枚β-TCP支架植入骨缺损处。分别于术后第6、12周使用耳缘静脉推注空气方法处死空白组和支架组的各亚组大白兔,于骨缺损部位或植骨部位上下离断、截取长约10 mm骨段,制备切片,HE染色,观察骨组织生长情况;采用Lane-Sandhu组织学评分标准对骨组织修复情况进行评价。结果 使用3D生物打印技术制备的20枚圆柱体β-TCP支架,与松质骨标本结构形态相似。支架高度(9.97±0.08)mm、直径(5.09±0.07)mm,松质骨标本高度(9.96±0.39)mm、直径(5.01±0.22)mm,支架与松质骨标本比较差异均无统计学意义(P值均＞0.05)。扫描电镜观察到支架表面及内部呈均匀多孔状,孔径相互连通,大小相仿,孔隙分布较均匀,在大孔侧壁布满了微孔,外形多为近似圆形;其中大孔直径为(223.02±18.20)μm,孔隙率为74.02%±1.38%。松质骨标本大孔直径(227.02±31.20)μm,孔隙率为76.02%±3.29%,支架与松质骨标本比较差异均无统计学意义(P值均＞0.05)。使用电子力学测试机测定支架的抗压强度为(2.93±0.65)MPa,弹性模量为95～190 MPa。骨组织切片HE染色:术后第6周,支架组植骨处可见较成熟的骨组织,骨小梁和骨髓组织增多,新生骨正在逐渐覆盖植骨材料,周围可见少量成骨细胞,出现少量新生骨并向材料内长入;空白组的骨缺损处周围有少量类骨组织形成,大量成纤维细胞和脂肪组织生长,未见明显成骨细胞及骨小梁结构。术后12周,支架组植骨处出现成熟的骨小梁和骨髓组织,有编织骨形成,新生骨量较多,部分材料已被吸收降解,材料存留较少;空白组的骨缺损处见少量骨组织从缺损边缘向内长入,大部分被成纤维细胞和脂肪组织填充。Lane-Sandhu组织学评分,术后6周、12周支架组分别为(5.2±0.3)、(8.1±1.2)分,空白组分别为(1.3±0.5)、(4.5±0.6)分,支架组评分均大于空白组,差异有统计学意义(t=7.341、12.672, P值均＜0.05)。结论 3D生物打印技术制备的β-TCP仿生骨支架,与松质骨标本的骨组织解剖结构形态相似,且具有良好的生物力学性能,可以提供个体化的仿生骨支架,修复新西兰兔股骨髁部骨缺损的效果良好。     

Carvable calcium phosphate bone substitute material

This study investigated the use of partially set hydroxyapatite forming calcium phosphate cement as a carvable and mechanically stable bone substitute material. Hydroxyapatite-forming cements were made of either mechanically activated alpha-tricalcium phosphate or a mixture of tetracalcium phosphate and dicalcium phosphate anhydrous and setting was arrested up to 4 h post setting. The study showed that these partially set rigid samples of defined geometry could be carved into a desired shape when the degree of reaction was 30-40% and the relative porosity between 40 and 50%; samples are then expected to set completely after implantation in the presence of water or serum, having the same compressive strength as a continuously set calcium phosphate cement (up to 36 MPa). The development of compressive strength, phase composition, and crystallinity when varying production parameters of these partially "preset" bone substitute materials are presented for both cement systems.     

颗粒状β-磷酸三钙复合骨形态发生蛋白2修复齿槽裂骨缺损

背景：齿槽裂的修复已成为唇腭裂序列治疗中的一个重要环节。以人工骨为载体进行优化组合制成具有高度骨诱导活性的复合人工骨,极大地提高了临床上骨缺损修复的治疗效果。 目的：观察β-磷酸三钙复合骨形态发生蛋白2修复齿槽裂的效果。 方法：选择连云港市第二人民医院口腔科收治的齿槽裂患者24例,随机分为实验组和对照组,实验组应用骨形态发生蛋白2/β-磷酸三钙复合物修复齿槽裂,对照组应用自体髂骨松质骨修复。 结果与结论：两组切口均一期愈合,无植入物排出。随访时间3~12个月,修复后3个月X射线可见局部骨性愈合,修复后1年实验组人工骨部分被自体骨取代,骨吸收不明显,而对照组骨吸收明显。Enemar等分级标准评估实验组Ⅰ级疗效率为84%,对照组Ⅰ级疗效率为17%,两组相比差异有显著性意义(P < 0.05)。提示颗粒状β-磷酸三钙复合骨形态发生蛋白2修复齿槽裂,具有恢复形态准确,修复创伤小的优点;植入物组织相容性好,具有骨引导性,可降解,能被自体骨完全取代,且无不良反应,是一种良好的齿槽裂修复方法。     

新型复合壳聚糖季铵盐纳米粒子抗感染骨水泥的生物学特性

BACKGROUND: Postoperative infection in patients underlying total knee arthroplasty is a long-standing puzzle. Current bone cement with antibiotics cannot effectively treat kidney function deficiency and bacterial resistance. OBJECTIVE: To develop a novel kind of bone cement prepared by quaternary ammonium salt chitosan nanoparticles. METHODS: There were three groups including QCSNP-15, Palacos R and Palacos R+G groups. Morphology of the bone cement in each group was observed using scanning electron microscope, the setting time of bone cement was measured, and the in vitro compression strength, cytotoxicity and antibacterial activity tests were performed. RESULTS AND CONCLUSION: Scanning electron microscope observed that QCSNP-15 was made of quaternary ammonium salt chitosan nanoparticles and methyl methacrylate copolymer, and these nanoparticles distributed onto the material surface. The setting time of QCSNP-15 was longer than that of the Palacos R+G bone cement. The compressive strength of QCSNP-15 was significantly lower than that of the Palacos R bone cement (P < 0.05), but was larger than 70 MPa stipulated by ISO 5833. Osteoblasts MC3T3-E1adhered well on the QCSNP-15, and pseudopodia fully expanded. Similar findings were observed on the Palacos R+G bone cement. The attachment rate of osteoblasts of the QCSNP-15 at 3 hours was significantly lower than that of the Palacos R+G bone cement (P < 0.05). The antibacterial activity did not significantly differ between QCSNP-15 and Palacos R+G bone cements, even after 2-week immersion in the PBS. These findings suggest that QCSNP-15 exhibits appropriate setting time, good biomechanical property and antibacterial activity in vitro with no obvious cytotoxicity.     

Enhanced bioactivity of a poly(propylene fumarate) bone graft substitute by augmentation with nano-hydroxyapatite

The bioactivity of a nano-hydroxyapatite-augmented, bioresorbable bone graft substitute made from the unsaturated polyester, poly(propylene fumarate), was analyzed by evaluating biocompatibility and osteointegration of implants placed into a rat tibial defect. Three groups of eight animals each were evaluated by grouting bone graft substitutes into 3-mm holes that were made into the anteromedial tibial metaphysis of rats. Thus, a total of 24 animals was included in this study. Two different formulations varying as to the type of hydroxyapatite were used: Group 1 - nano-hydroxyapatite, Group 2 - micron-hydroxyapatite, with a Group 3 control defect remaining unfilled. Animals of each of the three groups were sacrificed in groups of eight at postoperative week three. Histologic analysis revealed best superior biocompatibility and osteointegration of bone graft substitutes when nanohydroxyapatite was employed. At three weeks, there was more reactive new bone formation in this group when compared to the micron-hydroxyapatite group. The control group showed incomplete closure of the defect. This study suggested that nano-hydroxyapatite may improve upon the bioactivity of bone implant and repair materials. The model scaffold used in this study, poly(propylene fumarate), appeared to provide an osteoconductive pathway by which bone will grow in faster. Clinical implications of the use potential advantages of nano-hydroxyapatite on bone repair and orthopaedic implant design are discussed.     

Novel injectable calcium phosphate/chitosan composites for bone substitute materials

In this study, a novel injectable bone substitute material was developed which consists of chitosan, citric acid and glucose solution as the liquid phase, and tricalcium phosphate powder as the solid phase. This material was moldable because of its paste consistency after mixing. We used four groups of cement to investigate the mechanical properties and biocompatibility of the new biomaterial in vitro, which were named group A (10% citric acid), B (15% citric acid), C (20% citric acid) and D (25% citric acid). The setting times of the cements were 5-30 min. X-ray diffraction analysis showed that the products were hydroxyapatite (HA) and dicalcium phosphate anhydrous. When the concentration of citric acid was increased, the compressive strength of specimen increased. Through the simulated body fluid test, we observed the material was bioactive. Group D could induce Ca and P ions to deposit the surface group D quickly. These results indicated that the concentration of citric acid in the liquid component affected the mechanical properties and bioactivity of cements. The cell cultivation test showed that the cytocompatibility of the new biomaterial was good. The method for preparing the novel bone substitute material is simple. The starting material is more readily available and cheaper than HA, poly(methyl methacrylate), and so on. The cement could have good prospects for medical application.     

BMP-2 incorporated in a tricalcium phosphate bone substitute enhances bone remodeling in sheep

Bone morphogenetic protein-2 (BMP-2) is a well-known osteoinductive protein, which requires a carrier for local application. As an alternative to the previously described carriers, an in situ hardening, resorbable, and osteoconductive beta-tricalcium phosphate cement (TCP) is tested. Trepanation defects in the bovine distal femoral epiphysis are filled with a composite consisting of TCP and 200 microg rhBMP-2 per cm3 TCP, autologous bone graft, pure TCP, or left empty. A radiological follow-up is performed after 7 weeks and 3 months. The sheep are euthanized and bone samples are analyzed by microradiography, histology, and histomorphometry. Microradiography and histology show similar results for pure TCP and the composite. The defects are filled with trabecular bone and newly formed bone is in close contact with the remaining TCP-particles. The majority of the cement is resorbed, in the composite group the amount of remaining cement particles is reduced. Defects treated with autologous bone graft are filled completely, while untreated defects shows only a small amount of bone originating from the rim of the defect. Histomorphometry of the defects treated with pure TCP shows a significantly increased bone content in comparison to defects treated with the composite or autologous bone graft. Analysis of the remaining cement particles shows significantly less cement in the TCP/rhBMP-2 group in comparison to pure TCP. The sum of bone and cement content in the rhBMP-2 group shows amounts comparable to the calcified structures found following autologous bone grafting. The addition of rhBMP-2 to the TCP leads to faster remodeling of the defect comparable to autologous bone graft, while defects treated with pure TCP are not completely remodeled.     

低强度脉冲超声波对β－磷酸三钙与兔骨髓基质干细胞相容性的影响

目的研究低强度脉冲超声波(LIPUS)对-磷酸三钙(-TCP)与兔骨髓基质干细胞(BMSCs)相容性的影响。方法抽取新西兰白兔的骨髓,分离纯化获取BMSCs,加入条件培养基和-TCP体外混合培养并随机分为两组,一组应用LIPUS对BMSCs每天作用20分钟,另一组作为对照未予作用。通过倒置相差显微镜观察细胞增殖分化情况,分别于1周、2周、3周后停止LIPUS作用,在扫描电镜下观察细胞生长情况,评估TCP与BMSCs的相容性。结果BMSCs在两组-TCP表面生长繁殖良好。混合培养1周、2周时,实验组TCP表面BMSCs数目较对照组明显增多,并具有统计学意义(<0.05)。混合培养3周时,实验组TCP表面BMSCs数目与对照组相比无统计学差异(﹥0.05)。结论LIPUS可以提高培养早期-TCP和BMSCs的生物相容性,而对于培养晚期TCP和BMSCs的生物相容性无明显影响。     

The effects of microporosity on osteoinduction of calcium phosphate bone graft substitute biomaterials

The effect of increasing strut porosity on the osteoinductive ability of silicate substituted calcium phosphate (SiCaP) biomaterials was investigated in an ectopic ovine model. Implants with strut porosities of 22.5%, 32.0% and 46.0% were inserted into the parapsinalis muscle. At 8, 12 and 24 weeks histological sections were prepared. Sections were examined using backscattered scanning electron microscopy and un-decalcified histology. Bone area, implant area and bone-implant contact were quantified. At 8 weeks there was no significant difference between the groups in terms of bone area and implant area. However at 12 weeks, the amount of bone formation observed was significantly greater in SiCaP-46 (6.17 ± 1.51%) when compared with SiCaP-22.5 (1.33 ± 0.84%) p=0.035. Results also showed significantly increased amounts of bone-implant contact to the SiCaP-46 scaffold (3.30 ± 1.17%) compared with SiCaP-22.5 (0.67 ± 0.52%, p=0.043) at 8 weeks and 12 weeks; (SiCaP-46 (21.82 ± 5.59%) vs SiCaP-22.5 (3.06 ± 1.89%), p=0.012). At 24 weeks, bone formation and graft resorption had significantly increased in all groups so that the level of bone formation in the SiCaP-46 group had increased 75-fold to 30.05 ± 8.38%. Bone formation was observed in pores <10 μm. Results suggest that bone graft substitute materials with greater strut porosity are more osteoinductive.     

Development of calcium phosphate cement using chitosan and citric acid for bone substitute materials.

We developed a calcium phosphate cement that could be molded into any desired shape due to its chewing-gum-like consistency after mixing. The powder component of the cement consists of alpha-tricalcium phosphate and tetracalcium phosphate, which were made by decomposition of hydroxyapatite ceramic blocks. The liquid component consists of citric acid, chitosan and glucose solution. In this study, we used 20% citric acid (group 20) and 45% citric acid (group 45). The mechanical properties and biocompatibility of this new cement were investigated. The setting times of cements were 5.5 min, in group 20 and 6.4 min, in group 45. When incubated in physiological saline, the cements were transformed to hydroxyapatite at 3, and 6 weeks, the compressive strengths were 15.6 and 20.7 MPa, in group 45 and group 20, respectively. The inflammatory response around the cement implanted on the bone and in the subcutaneous tissue in rats was more prominent in group 45 than in group 20 at 1 week after surgery. After 4 weeks, the inflammation disappeared and the cement had bound to bone in both groups. These results indicate that this new calcium phosphate cement is a suitable bone substitute material and that the concentration of citric acid in the liquid component affects its mechanical properties and biocompatibility.