Re-evaluation of the biocompatibility of bioinert ceramics in vivo.

The affinity of bone for bioinert ceramics and stainless steel was compared using calcified bone specimens. We implanted cylinders of alumina ceramics (Al2O3), zirconia ceramics (ZrO2) and SUS-316 L stainless steel into the distal femoral epiphyses of dogs and then made observations from 4 to 96 wk post-operatively. Irregularities in the histological specimens suggested the presence of artefacts due to the insertion technique. We subsequently used screws inserted into holes tapped with a tap that had a diameter identical to the screws, and observed these implants from 4 to 96 wk after insertion. There was no detectable difference in the affinity index for all three materials from 4 to 96 wk after implantation. The affinity index was calculated as the ratio of the new bone directly adjoining the implant without any intervening fibrous membrane or bone marrow to the total length of the bone-implant interface x 100%.     

饰瓷温度烧结对氧化锆陶瓷与树脂黏结剂剪切强度的影响

背景：研究已证实硅烷偶联剂和喷砂等表面处理方式,以及增加氧化锆陶瓷表面的微裂纹可提高氧化锆陶瓷与树脂黏结剂间的黏结强度,但有关多次反复烧结是否会对氧化锆陶瓷黏结剪切强度产生影响尚缺少相关研究。 目的：测试饰瓷温度烧结对牙科氧化锆陶瓷与树脂黏结剂黏结剪切强度的影响。 方法：从40片氧化锆瓷片随机选择20片,分成 5组,按照常规烧结程序分别烧结0(对照组),2,4,6,8次,热处理起始温度为500 ℃,最终温度1 000 ℃,升温速率55 ℃/min,抽真空时间7 min。每次烧结最终温度恒定不变。将各组分别用树脂黏结剂与剩余未烧结的陶瓷片对位黏结,用万能材料试验机测黏结界面的剪切强度;使用扫描电镜观察剪切后的试件断面形貌。 结果与结论：烧结4,6,8次组试件剪切强度高于对照组(P < 0.05);烧结2次组试件剪切强度稍高于对照组,但差异无显著性意义(P > 0.05);烧结8次组试件剪切强度高于烧结4,6次组(P < 0.05)。未烧结氧化锆陶瓷表面未见裂纹;经过2次烧结后表面可见细微裂纹;经过4次烧结后表面可见裂纹增多;经过6次烧结后表面已经开始有明显变化,裂纹增多并伴有细微空隙产生,少量黏结剂残留;经过8次烧结后表面可见裂纹与空隙明显增多并有黏结剂残留。表明经过4,6,8次烧结后的氧化锆陶瓷对树脂黏结剂有较好的黏结剪切强度,烧结8次后的黏结剪切强度最强。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

氧化锆与纳米羟基磷灰石陶瓷的剪切实验

BACKGROUND: Nano-hydroxyapatite as a surface modification material that is bonded to the surface of the zirconia ceramics upon sintering at high temperature can improve bone-inducing activity and bone bonding strength of the zirconia ceramics. Moreover, the sintering temperature is crucial for performance and bonding of the composite. OBJECTIVE: To detect the shear strength of nano-hydroxyapatite ceramics coating bonded to zirconia ceramics at different sintering temperatures. METHODS: Nano-hydroxyapatite slurry was prepared using sol/gel technology. Thereafter, 20 zirconium green bodies were coated with nano-hydroxyapatite slurry and randomly divided into four groups. Then, the specimens were put into non-pressure sintering furnace and sintered at 1 300, 1 400, 1 500, and 1 550 ℃, respectively. At last, we measured the shear strength of all the specimens after sintering by universal testing machine, and analyze the type of fractures. RESULTS AND CONCLUSION: With the rising of sintering temperature, the shear strength of the specimens was gradually increased, and there were significant differences between the four groups [(4.04±1.19), (6.60±0.95), (16.51±1.93), (80.47±19.31) MPa, P < 0.05]. Within the scope of 1 550 ℃, the sintering temperature was positively relative to the shear strength of specimens. These findings indicate that in the certain temperature range, the higher the sintering temperature, the greater the shear strength of the bonding interface between zirconia and nano-hydroxyapatite. When the sintering temperature is 1 550℃, the shear strength of the bonding interface is the highest.      

上釉技术对氧化钇稳定四方相氧化锆多晶陶瓷粘接及力学性能的影响

文题释义：氧化钇稳定四方相氧化锆多晶陶瓷：是以氧化钇为稳定剂、四方相为主要物相的氧化锆陶瓷，其具有较高的抗弯强度(900-1 200 MPa)和断裂韧性(9-10 MPa·m^1/2)。由于这些优异的机械性能，氧化钇稳定四方相氧化锆多晶陶瓷成为口腔冠桥修复中应用最广泛的陶瓷之一。 相变增韧机制：为氧化锆增韧的一种方法。稳定剂使四方相氧化锆在室温下可以处于亚稳态，但是在应力作用下亚稳态的四方相氧化锆易转化为单斜相氧化锆，同时伴有3%-5%的体积膨胀，这个过程能弥合微裂纹且消耗断裂能，提高氧化锆陶瓷的韧性。 背景：任何表面处理都应在不损害原有氧化钇稳定四方相氧化锆多晶陶瓷强度的前提下提高其粘接强度。目前缺乏上釉技术对氧化钇稳定四方相氧化锆多晶陶瓷粘接强度影响的资料，并且其对氧化钇稳定四方相氧化锆多晶陶瓷力学性能的影响尚不明确。 目的：评估上釉技术对氧化钇稳定四方相氧化锆多晶陶瓷力学行为及其与树脂水门汀粘接强度的影响。 方法：制作氧化钇稳定四方相氧化锆多晶陶瓷试件并随机分为4组：A组，表面不做任何处理；B组，110 μm氧化铝颗粒喷砂；C组，上釉+氢氟酸酸蚀；D组，上釉+氢氟酸酸蚀+硅烷化。检测每组试件的表面显微形貌、粗糙度、晶相结构、元素组成、剪切粘接强度和弯曲强度，并观察剪切粘接强度测试后所有断面的断裂模式。 结果与结论：①经表面处理后的试件粗糙度明显增大，降序排列依次为C组(0.62±0.01) μm、D组(0.55±0.02) μm、B组(0.11±0.02) μm、A组(0.05±0.01) μm，5组间粗糙度比较差异有显著性意义(P < 0.05)；②B组试件表面含有2.2%单斜相氧化锆，而其他组含量均为零；③除锆和氧2种元素外，B组还含有铝元素6.49%，C和D组分别含有硅元素18.67%和25.78%；④A、B、C、D组的剪切粘接强度分别为(3.11±0.40)，(4.23±0.45)，(6.62±0.60)，(10.46±0.83) MPa，组间两两比较差异均有显著性意义(P < 0.05)；⑤A、B、C和D组的三点弯曲强度分别为(961.07±75.53)，(1 234.73±114.09)，(1 024.28±120.51)，(1 036.09±80.10) MPa，其中A、C和D组两两比较差异无显著性意义(P > 0.05)，B组与A、C、D组比较差异有显著性意义(P < 0.05)；⑥结果表明，上釉技术未明显提升氧化钇稳定四方相氧化锆多晶陶瓷的弯曲强度，但上釉后经氢氟酸蚀刻并硅烷化处理可显著增强氧化钇稳定四方相氧化锆多晶陶瓷与树脂水门汀之间的粘接强度。 ORCID: 0000-0002-8066-2498(徐小敏) 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程     

Laminated and functionally graded hydroxyapatite/yttria stabilized tetragonal zirconia composites fabricated by spark plasma sintering

Hydroxyapatite (HA) ceramics have been conventionally strengthened and toughened in the form of composites and coatings. New microstructural designs and processing methodologies are still needed for the improvement of the mechanical properties of HA-based ceramics. This study was to prepare laminated and functionally graded HA/yttria stabilized tetragonal zirconia (Y-TZP) composites by the relatively new process of spark plasma sintering (SPS). The microstructure and the mechanical properties of the laminated and functionally graded composites were studied for possible orthopedic applications. It was found that the laminated and functionally graded HA/Y-TZP composites could be densified at 1200 degrees C within 5 min by the SPS process and the average HA grain size in the composite layers was reduced by half due to the well-dispersed Y-TZP second phase. The HA phase in the composite layers was stable up to 1200 degrees C and the Y-TZP second phase remained the tetragonal zirconia (t-ZrO(2)) phase after being processed at the highest temperature of 1250 degrees C. The laminated and functionally graded HA/Y-TZP composites exhibited much improved mechanical properties compared with the pure HA ceramics; the bending strength of the composites reached about 200 MPa, double the strength of the pure HA ceramics.     

3D打印技术制备新型HA/ZrO2梯度复合材料在犬股骨干骨缺损修复中的应用

目的 运用3D打印技术制备新型羟基磷灰石/二氧化锆(HA/ZrO₂)梯度复合材料,分析其性能,并观察其修复比格犬股骨干骨缺损的能力。方法 随机抽取6月龄雄性比格犬1只,截去右下肢股骨中段全层15 mm制成骨缺损模型后,放入动物专用Micro CT进行容积扫描,完成数据采集、转化及后期处理,将处理后的数据导入CeraFab 7500光固化3D打印机中。根据设定参数启动打印程序,形成复合光敏树脂初胚,并对其进一步脱脂烧结,然后采用浸涂法制备HA/ZrO₂梯度复合材料。运用扫描电镜、X射线衍射(XRD)和生物力学实验分析HA/ZrO₂梯度复合材料的性能。制备HA/ZrO₂梯度复合材料浸提液。培养小鼠成纤维细胞株L929,采用噻唑蓝(MTT)法检测HA/ZrO₂梯度复合材料对体外细胞增殖和毒性的影响。将16只比格犬随机分为4组,每组4只。A组:截取犬股骨中段15 mm后,不植入任何材料;B组、C组、D组分别截去股骨中段15、25、35 mm制成骨缺损模型,然后分别植入相应规格的HA/ZrO₂梯度复合材料。术后第2、4、8、12 周拍摄术肢股骨正侧位X片,观察植入材料与自身骨结合情况及周围骨痂生长情况。术后12 周处死实验动物,截取整段股骨,大体观察标本植入材料与周围骨生长状况;行Micro CT扫描,测定新生骨量,并对新生骨进行3D图像重建;对股骨标本进行极限抗压实验,测量极限抗压强度。结果 运用3D打印技术制备的HA/ZrO₂梯度复合材料扫描电镜显示表面光滑,结构均匀,断口表面层均匀过渡结合,没有明显界限,相互之间冶金结合,结构稳定。XRD分析显示HA及ZrO₂峰形明显、结晶程度较好、粉体纯度高。抗压试验显示极限抗压强度为(43.37±2.31) MPa。MTT试验显示HA/ZrO₂梯度复合材料无明显细胞毒性。实验动物术后X线片显示:A组术后形成骨不连;B组有连续性骨痂通过,人工假体与宿主骨之间的界线消失;C组术后第2、4、8周连续性骨痂及新生骨长入速度较B组缓慢,但人工假体与断端间隙逐渐被新生骨填充,有连续性骨痂通过;D组新骨生成缓慢,仅在断端周围出现新生骨。术后12周取材,Micro CT 3D重建及新生骨量检测,B、C、D组单位体积新生骨量分别为(238.55±19.11) mm³/cm³、(223.31±13.41) mm³/cm³、(110.83±6.48) mm³/cm³,3组间比较差异有统计学意义(F=156.824,P＜0.01),其中B、C组新生骨量明显多于D组,差异均有统计学意义(P值均＜0.05)。新生骨CT 3D重建显示:B组复合材料整体被新生骨包绕,无外露;C组复合材料少许外露,表面基本被新生骨填塞;D组复合材料大部外露,新生骨散在长入。B、C、D组股骨标本极限抗压强度分别为(49.72±2.33) MPa、(49.81±2.43) MPa、(46.92±3.61) MPa,3组间比较差异无统计学意义(F=1.119,P＞0.05)。结论 运用3D打印技术制备的纳米HA/ZrO₂梯度复合材料具有可靠的生物相容性及生物力学强度,可以实现临床个体化治疗原则,能很好地修复犬股骨干35 mm内骨缺损,是一种理想的骨组织替换材料。     

Early weight bearing of porous HA/TCP (60/40) ceramics in vivo: a longitudinal study in a segmental bone defect model of rabbit

Porous interconnected hydroxyapatite (HA) and HA/tricalcium phosphate (TCP) (60/40) ceramics are promising materials for hard tissue repair. However, the mechanical properties of these materials have not been accurately determined under weight-bearing conditions. In this study, newly developed HA and HA/TCP (60/40) ceramics were used with intramedullary fixation in segmental bone defects of rabbits. Early radiological, histological, densitometric and biomechanical changes were evaluated. The mean radiological grade of healing and bonding to bone was higher in HA/TCP (60/40) ceramics than that of pure HA ceramics but the difference was not statistically significant. The densities of both implanted ceramics improved with time, supported by the histological evaluation of bone matrix ingrowth into ceramic pores, whereas the densities at the bone–ceramic interface decreased gradually. Flexural resonant frequencies and three-point bending strength increased, revealing an increase in mechanical stability during this early critical time interval where implant and/or bone–implant interface failures occur frequently. It can be concluded that both HA and HA/TCP (60/40) ceramics have a limited application in the treatment of load-bearing segmental bone defects but did not fail at the early stages of implantation.     

羟基磷灰石涂层改善骨内植物界面促进骨整合

BACKGROUND: We have designed and manufactured a novel artificial cervical vertebra and intervertebral complex (ACVC) which combines the cervical titanium cage with the artificial cervical disc, and also developed the ACVC with a hydroxyapatite biocoating (ACVC-HA). OBJECTIVE: To evaluate biomechanical properties of the joint system, and the role of HA coating in promoting osseointegration and long-term stability. METHODS: Twenty-four goats were randomly divided into three groups and underwent the anterior C _2/3 and C _3/4 discectomy, and C₃ subtotal corpectomy, followed by ACVC implantation (group 1) and ACVC-HA implantation (group 2), and given no intervention (black control group), respectively. group. At 12 weeks after surgery, C _1-5 samples were collected to undergo biomechanical tests and histological staining. RESULTS AND CONCLUSION: Prior to the fatigue test, compared with the blank control group, the range of motion and neural zone of groups 1 and 2 in the directions of flexion-extension and lateral bending showed no significant differences, but the above indicators were significantly increased in the direction of rotation (P < 0.05). Additionally, the stiffness in all three directions was significantly lower than that in the blank control group (P < 0.05). There were no significant differences in the range of motion and neural zone in all directions between groups 1 and 2. Similar results were found after the fatigue test. The histological staining showed that both two implants had good biocompatibility and abradability, but more new bone formed on the ACVC-HA. These results suggest that ACVC can effectively reconstruct the motor function of the cervical spine after decompression. Furthermore, HA coating can markedly improve bone-implant interface to promote osseointegration.     

Comparison of plasma-sprayed hydroxyapatite coatings and hydroxyapatite/tricalcium phosphate composite coatings: in vivo study

This study aimed to compare biological properties, including osteoconduction, osseointegration, and shear strength, between plasma-sprayed hydroxyapatite (HA) and HA/tricalcium phosphate (TCP) coatings, using a transcortical implant model in the femora of canines. After 3 and 12 weeks of implantation, the implants with surrounding bone were assessed histologically in undecalcified sections in backscattered electron images (BEIs) under a scanning electron microscope (SEM). After short-term (3 week) follow-up, both coatings conducted new bone formation and revealed direct bone-to-coating contact. The HA/TCP coating could not enhance early host-to-coating responses. At 12 weeks, serious dissolution of the HA/TCP coatings evidently occurred. By the new bone healing index (NBHI) and apposition index (AI), we found no significant difference between HA/TCP-coated implants and HA-coated implants throughout all implant periods. At 12 weeks of implantation, some particles dissociated from the HA/TCP coating were found within the remodeling canal. After push-out measurements, the shear strength and failure mode of HA/TCP-coated implants were similar to those of HA-coated implants, and no statistical differences were found between either coating. Consequently, this study indicates that HA/TCP coatings have excellent biological response and may be considered suitable bioactive ceramic coatings for short-term clinical use.     

Wear properties of alumina/zirconia composite ceramics for joint prostheses measured with an end-face apparatus

While only alumina is applied to all-ceramic joint prostheses at present, a stronger ceramic is required to prevent fracture and chipping due to impingement and stress concentration. Zirconia could be a potential substitute for alumina because it has high strength and fracture toughness. However, the wear of zirconia/zirconia combination is too high for clinical use. Although some investigations on composite ceramics revealed that mixing of different ceramics was able to improve the mechanical properties of ceramics, there are few reports about wear properties of composite ceramics for joint prosthesis. Since acetabular cup and femoral head of artificial hip joint are finished precisely, they indicate high geometric conformity. Therefore, wear test under flat contact was carried out with an end-face wear testing apparatus for four kinds of ceramics: alumina monolith, zirconia monolith, alumina-based composite ceramic, and zirconia based composite ceramic. Mean contact pressure was 10 MPa and sliding velocity was 40 mm/s. The wear test continued for 72 hours and total sliding distance was 10 km. After the test, the wear factor was calculated. Worn surfaces were observed with a scanning electron micrograph (SEM). The results of this wear test show that the wear factors of the both composite ceramics are similarly low and their mechanical properties are much better than those of the alumina monolith and the zirconia monolith. According to these results, it is predicted that joint prostheses of the composite ceramics are safer against break down and have longer lifetime compared with alumina/alumina joint prostheses.     

Effects of bone morphogenetic protein-2 and hyaluronic acid on the osseointegration of hydroxyapatite-coated implants: an experimental study in sheep

Research efforts aim at enhancing early osseointegration of cementless implants to improve early fixation and, thus, reduce the risk of loosening. The aim of the present study was to investigate whether bone morphogenetic protein (BMP) 2 had a positive effect on the osseointegration of hydroxyapatite-coated implants. Hydroxyapatite (HA) implants (perforated hollow cylinders and solid rods) were coated with BMP-2 and hyaluronic acid (HY) as the carrier or with HY alone. Uncoated HA implants served as controls. The osseointegration of the implants was evaluated either by light microscopy or by pullout tests after 1, 2, and 4 weeks of unloaded implantation in the cancellous bone of 24 sheep. The BMP-2 coating significantly increased bone growth into the implant perforations compared with HA-coated implants at 2 and 4 weeks. Bone-implant contact and interface shear strength of BMP-2 implants were lower than HA implants at 2 weeks. At 4 weeks, there was no significant difference in bone-implant contact and shear strength between BMP-2 and HA-coated implants. The BMP-2 coating enhanced gap healing but had no positive or even an inhibitory effect (at 2 weeks) on bone-implant contact and interface shear strength. In the clinical situation, a perfect press-fit implantation cannot be achieved, and BMP-2 may be beneficial for enhancing bone growth into gaps around cementless implants.     

Mixed oxides prosthetic ceramic ball heads. Part 3: effect of the ZrO2 fraction on the wear of ceramic on ceramic hip joint prostheses. A long-term in vitro wear study

Using ceramic materials it is possible to obtain a number of beneficial mechanical properties such as considerable hardness, good chemical resistance, high tensile strength, and a good fracture toughness. The use of ceramic-on-ceramic as bearing surfaces for hip joint prostheses has been reported to produce a lower wear rate than other combinations (i.e. metal-on-polyethylene and ceramic-on-polyethylene) in total hip artroplasty. These advantages may increase the life expectancy of hip implants and improve the life of patients. Two new types of mixed-oxide ceramics (alumina and yttria-stabilised zirconia) femoral heads and acetabular cups containing different ratios of alumina and zirconia were compared with pure commercial alumina in terms of wear behaviour in a hip joint simulator. Hip joint wear simulator studies were carried out with a full-peak load of 2030 N and a frequency of 1 Hz in bovine calf serum. After 10 million cycles the measured weight loss of all specimens was very low. However, the experimental results did not show any significant difference between the new experimental mixed-oxide ceramics prototype and the commercial ceramic material couplings.     

RF-magnetron sputtering technique for producing hydroxyapatite coating film on various substrates

A sputtering technique is an effective method for surface modification of materials, but there are many complex process parameters to influence on the physical and chemical properties of the sputtered coating films. In this paper the process parameters were investigated when the hydroxyapatite (HA) was coated onto various substrates including titanium (Ti), alumina ceramic (Al(2)O(3)) and stainless steel (SUS) plates under various sputtering conditions, target type, Ar gas pressure, and discharge power. The deposition rate of HA was much higher in a solid plate target than in a powder lump target owing to the difference of apparent density 75%, 18%, respectively. Ar gas pressure little influenced on the deposition rate. The HA coating thickness increased in proportion with discharge power. After hydrothermal treatment the thickness of HA slightly decreased, on the other hands Ca/P ratio slightly raised. The surface of the HA coating was smooth, homogeneous and dense.     

矢状化小关节角度与退变性腰椎滑脱间关系的CT影像研究

目的 探讨矢状化小关节角度(FJA)与退变性腰椎滑脱(DLS)之间的关系。方法 回顾性研究。2010年1月—2018年5月首都医科大学宣武医院骨科单节段L_4/5 DLS住院患者89例纳入DLS组,按年龄分为A1、B1两亚组,A1组44例(男14例、女30例),年龄＜65岁;B1组45例(男17例、女28例),年龄≥65岁。对照组100例为同期骨科门诊腰腿痛患者,性别、年龄与DLS组相当,但未见腰椎滑脱者。按年龄分为A2、B2两亚组,A2组54例(男18例、女36例),年龄＜65岁;B2组46例(男15例、女31例),年龄≥65岁。在腰椎CT软组织窗测量各组L_4/5和L_3/4节段FJA,并应用SPSS 22.0统计学软件对患者FJA、小关节不对称(FT)程度和小关节退变分级之间的差异进行组间对比分析。结果 DLS组内,L_3/4节段A1组和B1组FJA分别为54.73°±7.26°和56.60°±6.94°,差异无统计学意义(P＞0.05);L_4/5节段A1组、B1组FJA分别为58.43°±10.41°和63.28°±6.56°,差异有统计学意义(P＜0.05)。对照组内,L_3/4节段A2和B2组FJA分别52.16°±10.07°和54.66°±8.66°,L_4/5节段A2组、B2组FJA分别为45.36°±7.78°和47.82°±9.65°,差异均无统计学意义(P值均＞0.05)。DLS组与对照组L_3/4、L_4/5节段FJA比较,差异均有统计学意义(P值均＜0.05)。两组内各亚组间FT比较,L_3/4与L_4/5节段差异均无统计学意义(P值均＞0.05);DLS组与对照组组间FT比较,在L_4/5节段差异有统计学意义(P＜0.05),在L_3/4节段差异无统计学意义(P＞0.05)。在L_4/5节段及L_3/4节段,小关节退变程度DLS组均高于对照组, DLS组内B1组均高于A1组,差异均有统计学意义(P值均＜0.01);而对照组内两亚组间比较差异均无统计学意义(P值均＞0.05)。结论 DLS患者具有更加矢状化的FJA,这可能是疾病发生发展过程中二次重塑的结果。     

Bond strength,compositional, and structural properties of hydroxyapatite coating on Ti,ZrO2-coated Ti,and TPS-coated Ti substrate

The effect of titanium plasma-sprayed (TPS) and zirconia (ZrO(2))-coated titanium (Ti) substrates on the adhesive, compositional, and structural properties of plasma-sprayed hydroxyapatite (HA) coatings were evaluated. X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, surface roughness, and adhesive strength were used to characterize the coatings. Apatite-type and alpha-tricalcium phosphate phases were observed for all HA coatings. A structural change due to the absence of a 960 cm(-1) peak during FTIR analysis was observed for all HA coatings. The coating surfaces appeared rough and melted, with surface roughness correlating to the size of the starting powder. No significant difference in the Ca/P ratio of HA on Ti and TPS-coated Ti substrates was observed. However, the Ca/P ratio of HA on ZrO(2)-coated Ti substrate was significantly increased. Interfaces between all coatings and substrates were observed to be dense and tightly bound, except for HA coatings on TPS-coated Ti substrate interface. However, an intermediate TPS or ZrO(2) layer between the HA and Ti substrate resulted in a lower adhesive strength as compared to HA on Ti substrate.     

新型梯度复合HA/ZrO2组织工程骨支架在猕猴颈椎融合中的应用

目的 构建新型梯度复合羟基磷灰石-二氧化锆(HA/ZrO₂)组织工程骨支架,并评估其在猕猴颈椎椎间融合中的效果。方法 通过离子交联法制备壳聚糖水凝胶作为骨形态发生蛋白2(BMP-2)的缓释载体,扫描电镜下观察其微观形态,检测其载药量、包封率及缓释速率;然后分离、培养猕猴源性骨髓间充质干细胞(BMSCs),并进行碱性磷酸酶、冯库萨染色等对其进行鉴定;最后将前期制备好的BMP-2明胶/壳聚糖凝水胶缓释系统和第3代猕猴BMSCs加载于HA/ZrO₂泡沫陶瓷,以构建新型组织工程骨,并观察其形态特征。将24只雄性猕猴按照随机数字表法分成4组,其中组织工程骨组(n=8)为植入梯度复合HA/ZrO₂泡沫陶瓷负载BMP-2明胶/壳聚糖水凝胶缓释系统和第3代猕猴BMSCs,泡沫陶瓷组(n=8)为植入梯度复合HA/ZrO₂泡沫陶瓷,自体髂骨组(n=4)为植入自体髂骨,假手术组(n=4)为只对相应部位的软组织进行切开、缝合,未破坏其椎间盘;观察术后颈椎X线(术后即刻、8周、16周)、组织形态学表现(术后8周、16周)及测试相应节段的生物力学(术后16周)。结果 扫描电镜下BMP-2明胶/壳聚糖水凝胶呈3D 网状结构,内见均匀分布的壳聚糖微球,其负载BMP-2后的包封率和载药率随时间逐渐降低:第1天分别为87.4%±0.9%和58.2%±0.5%、第15天分别为45.2%±0.6%和30.1%±0.4%,累积释放率第1天为12.6%±0.11%、第15天为55%±0.16%。显微镜下观察见BMSCs的形态呈多样性,以梭形及短棒形等较常见;第3代猕猴BMSCs成骨诱导后的碱性磷酸酶、冯库萨染色以及表面特异性抗原的检测结果显示,符合BMSCs的生物学特性。不同时点的X线及组织形态学观察显示材料内部新生骨量组织工程骨组较泡沫陶瓷组明显增多;生物力学测试结果显示,在最大载荷、抗压强度和能量吸收方面假手术组均低于其他3组(P值均＜0.05),在抗压强度上组织工程骨组与自体髂骨组差异无统计学意义(P＞0.05)。结论BMP-2明胶/壳聚糖水凝胶缓释系统复合猕猴第3代BMSCs种植于HA/ZrO₂泡沫陶瓷构建的新型组织工程骨支架,能有效促进猕猴颈椎椎间融合,在影像学及组织学表现和生物力学测试方面,可达到与自体骨相似的骨代替作用。     

Mechanical properties and short-term in-vivo evaluation of yttrium-oxide-partially-stabilized zirconia

Yttrium-oxide-partially-stabilized zirconia (YPSZ) belongs to a new class of ceramics exhibiting an improved toughness when compared to alumina. The toughening mechanism is related to a martensitic-like transformation of tetragonal metastable grains into a monoclinic state occurring at the crack tip. Specific tests showed that YPSZ exhibited a high bending strength (900-1200 MPa), a low Young's modulus (200 GPa), and a high toughness (KIC = 9-10 MN/m3/2). Its average grain size of 0.5 microns allows a surface roughness as low as 0.008 microns. Sterilization or aging in saline solution at room temperature for 100 days did not affect the toughness of this material. Cylindrical YPSZ samples, manufactured by cold isostatic pressing and sintering, were implanted in the paraspinal muscles in the rat up to 12 weeks. The tissue reaction was evaluated with reference to alumina (ISO requirements) by means of quantitative histomorphometry. No significant differences were found between YPSZ and alumina for both the membrane thickness and cell distributions surrounding the implants.     

Self-joining of zirconia/hydroxyapatite composites using plastic deformation process

A plastic deformation process was demonstrated to self-join 3 mol.% yttria partially stabilized zirconia (3Y-TZP)/hydroxyapatite (HA) composites. The 3Y-TZP/40 vol.% HA composites were fabricated by conventional ceramic processing by cold pressing premixed 3Y-TZP and HA powders into pellets. Densification (≈90%) of composites was achieved by sintering composite powder compacts at 1450 °C for 5 h. Optimum self-joining of 3Y-TZP/40 vol.% HA composites was obtained at 1300 °C for a strain rate of 5 × 10⁻⁵/s. The flow stress during joining was 40 MPa. Microstructural and mechanical characterizations of the joint interface demonstrated that there were no discernible differences between the joint and the composite material away from the interface.     

自体血液回输对成人心脏瓣膜置换术患者血液携氧功能的影响

目的 探讨自体血回输对体外循环下心瓣膜置换术患者血液携氧功能的影响。方法抽选河南省胸科医院心外科2014年4月—2016 年1月收治的90例首次接受心脏手术的心脏瓣膜病患者作为研究对象,随机分为观察组和对照组。观察组45例采用自体血液回收技术;对照组45例不采用自体血液回收技术,直接使用库血。检测并比较两组术前(T₁)、术毕(T₂)、术后24 h(T₃)、术后第7天(T₄)的动脉血液携氧功能指标,包括RBC、Hb、红细胞比容(Hct)、氧合指数、红细胞内2,3-二磷酸甘油酸浓度(2,3-DPG) 、红细胞变形指数(RCD)。结果 观察组与对照组在T₂时点的RBC分别为(3.59±0.37)×10¹²/L和(3.64±0.44)×10¹²/L,Hb分别为(101.26±19.54)g/L和(102.38±20.05)g/L,Hct分别为(0.35±0.12)和(0.34±0.13),较组内T₁降低,差异均有统计学意义(P值均＜0.05);但T₃和T₄与组内T₁时点比较,差异均无统计学意义(P值均>0.05),且组间各时点比较差异均无统计学意义(P值均>0.05)。观察组在T₁~T₄的氧合指数分别为(415.14±51.24)、(348.33±39.45)、(317.59±33.36)和(377.16±45.44) mmHg(1 mmHg=0.133 kPa),对照组则分别为(418.16±52.18)、(344.44±42.20)、(320.65±35.11)和(375.24±43.94) mmHg,组间各时点比较差异均无统计学意义(P值均>0.05),但组内术后各时点与术前比较差异均有统计学意义(P值均＜0.01)。两组间及组内术前术后红细胞2,3-DPG比较差异均无统计学意义(P值均>0.05)。两组RCD术后较术前的有明显增高(P值均＜0.01),而组间比较差异均无统计学意义(P值均>0.05)。结论 应用自体血液回输对成人心脏瓣膜置换术中血液携氧功能无明显损伤,可减少库血的使用,具有较高的临床意义。     

Aging test and dynamic fatigue test of apatite-wollastonite-containing glass ceramics and dense hydroxyapatite

The purpose of this study is to examine the changes in mechanical strength of two bioactive ceramics in living tissue. An aging test and dynamic fatigue test were performed using apatite-wollastonite-containing glass ceramics (A X W-GC) and dense hydroxyapatite (HA). Specimens (5 mm X 5 mm X 25 mm, abraded with No. 2000 Al2O3 powder) were implanted into subcutaneous tissue of rats for varying periods of time. The bending strength of aged samples was measured by the three-point loading method. The bending strength of A X W-GC was greater than that of HA (P less than 0.001). There was no reduction in bending strength for both A X W-GC and HA in living tissue. The n value of both A X W-GC and HA did not decrease significantly after implantation as assessed by the results of the dynamic fatigue test according to analysis of covariance. SEM-EPMA showed that Si and Mg contents decreased, Ca content did not change, while P content increased in the surface of A X W-GC. The area where x-ray intensity changed increased moderately after implantation. There were no changes in Ca and P at the interface between HA and soft tissue. In macroscopic and microscopic observations, specimens were found to be encapsulated with a thin layer of connective tissue. Foreign body giant cells, osteoblasts, or osteoclasts were not observed in the soft tissue. There was no bonding between ceramics and soft tissue.