a—TCP／TTCP牙根管充填材料

a－TCP／TTCP骨水泥具有良好的水化硬化特性，符合临床需要的凝结时间和抗压强度，其水化产物主要为羟基磷灰石（HAP），以a－TCP／TTCP骨水泥作为牙根管充填材料，通过体外实验、动物实验，结合组织形态学及扫描电镜观察，检测a－TCP／TTCP牙根管充填材料的组织相容性，并动态观察根尖闭合情况及根尖周组织修复过程。结果表明，材料优良的生物相容性，在牙根管内可继续水化硬化，而且能引导根尖钙化组织沉积，封闭根尖孔，形成骨性结合，并促进根尖周组织愈合。     

磷酸钙骨水泥的生物相容性

磷酸钙（α-TCP/TTCP）复合骨水泥具有良好的水硬性能，与固化液按固液比为1.50g/mL拌和后，凝固时间可调，抗压强度达45．36MPa，其水化产物为羟基磷灰石（HAP）。通过体外模拟溶解实验表明，α-TCP/TTCP骨水泥具有一定的溶解性能，通过体外实验，动物实验，结合SEM和EPMA观察表明α-TCP/TTCP骨水泥不会产生全身或局部毒性反应，对肌肉无刺激，不致溶血，凝血，不引起炎症和排斥反应等，有利于骨组织长入并与骨组织紧密接触。α-TCP/TTCP骨水泥在动物体内可继续水化硬化，且随着植入时间的延长，材料与缩主骨完全融合在一起，α-TCP/TTCP骨水泥具有优良的生物相容性和生物活性，具有一定的降解性能和较好的成骨作用，适合于作为骨缺损的填充材料。     

α -TCP/TTCP牙根管充填材料

α TCP/TTCP骨水泥具有良好的水化硬化特性 ,符合临床需要的凝结时间和抗压强度 ,其水化产物主要为羟基磷灰石 (HAP)。以α TCP/TTCP骨水泥作为牙根管充填材料 ,通过体外实验、动物实验 ,结合组织形态学及扫描电镜观察 ,检测α TCP/TTCP牙根管充填材料的组织相容性 ,并动态观察根尖闭合情况及根尖周组织修复过程。结果表明 ,材料具有优良的生物相容性 ,在牙根管内可继续水化硬化 ,而且能引导根尖钙化组织沉积 ,封闭根尖孔 ,形成骨性结合 ,并促进根尖周组织愈合     

无生命材料参与有生命组织的过程

探讨细胞对可降解多孔磷酸三钙陶瓷(β-TCP)降解的影响及材料骨内植入后在体内超微结构的变化,研究了磷酸三钙陶瓷的生物降解、新骨生成过程及结构的变化,为可降解钙磷材料的生物降解和骨生成机制提供依据.研究结果表明,材料在体内超微结构的变化是影响材料降解的重要因素之一;钙磷材料通过溶解沉积参与新骨形成,以OCP,DOHA和HAP的形式存在于骨胶原纤维中,与其他有机质一起构成新骨.     

HAP／ZrO2纳米复相生物陶瓷的制备

采用化学反应法制备了纳米羟基磷灰石（HAP）粉体，并采用醇．水溶液加热法制备了纳米ZrO2粉体，通过对制备工艺的研究，同时结合TEM等分析测试手段对获得的纳米粉体进行了成分、颗粒尺度分布和微观形态分析。控制HAP和ZrO2的不同配比，分别选择40％和60％含量的HAP，采用热压烧结技术制备了HAP／ZrO2纳米复相生物陶瓷材料。分析了烧结温度、烧结时间及HAP含量等因素对HAP／ZrO2陶瓷材料的影响。确定了烧结工艺参数，即烧结温度1300℃，烧结压力30MPa及烧结时间1h，并对纳米生物陶瓷的微观组织和性能进行了分析测试，并采用模拟体液研究了该材料的体外生物相容性。结果表明：在短时烧结过程中HAP与ZrO2颗粒间没有反应发生，且该生物陶瓷材料具有无毒、无过敏等特点。     

PHBV微球／磷酸钙骨水泥复合材料研究

采用在磷酸钙骨水泥中添加一定量的PHBV微球来制备在初期有较高的抗压强度，而后随着PHBV微球的降解，在磷酸钙骨水泥基体中形成三维孔隙结构的PHBV微球／磷酸钙骨水泥复合材料。选用的骨水泥的固相成分以α-TCP为主，液相成分为NaH2PO4／Na2HPO4、KH2PO4/K2HPO4缓冲溶液，PHBV微球直径为100μm～300μm，主要研究不同的固化液，固液比以及PHBV微球添加量对PHBV／磷酸钙骨水泥复合材料抗压强度等性能的影响，制备出凝固时间在15min-30min，具备一定可注射性，抗压强度达到10MPa～30MPa的PHBV微球／磷酸钙骨水泥复合材料。最终制备的PHBV微球／磷酸钙骨水泥复合材料能够满足骨修复材料的要求。     

壳聚糖微球／磷酸钙骨水泥复合材料细胞亲和性研究

将成骨前体细胞株MC3T3-E1，分别接种于含10％壳聚糖微球的复合材料和磷酸钙骨水泥基体上进行培养，采用MTT法检测细胞在材料表面的增值情况，通过对碱性磷酸酶活性ALP的测定，表征前成骨细胞向成熟成骨细胞的分化状况，并利用环境扫描电镜（ESEM）观察了细胞在材料表面的粘附、增值和生长情况。结果表明，两种材料均具有良好的细胞相容性。细胞在含10％壳聚糖微球的复合材料表面增殖、分化能力更强，表现出了比磷酸钙骨水泥基体材料更好的细胞亲和性。     

钛表面种籽层水热沉积制备羟基磷灰石生物涂层

为了获得与基体结合强度高、生物活性好的羟基磷灰石(HAP)涂层,通过种籽层水热沉积方法在钛合金表面生长HAP,首先纳米尺寸的钙磷盐通过微弧氧化技术在钛金属表面形成,此种籽层在随后的水热沉积过程中促进了HAP的诱导沉积。讨论了络合剂和种籽层对HAP的形貌和结构的调控。采用此方法制备的生物活性梯度涂层无裂纹、涂层厚度分布均匀,与基体具有高的结合强度,HAP呈现良好的结晶性,并具有沿c轴的择优取向,此HAP涂层表现出优良的生物活性,有利于促进骨的生长。     

多孔磷酸钙骨水泥与钛合金支架材料修复兔颅骨骨缺损的比较研究

通过采用结构可控的多孔磷酸钙骨水泥(calcium acid phosphate cement, CPC)和钛合金支架材料修复兔颅骨骨缺损,比较了两种修复材料骨环境下的成骨性能。结果显示,与多孔钛合金材料相比,多孔CPC材料表现出了更好的成骨活性。CPC材料的新生骨量、成骨速率均高于钛合金材料。而且骨吸收重建过程也早于钛合金材料。同时,三维贯通的孔隙结构有利于骨组织的长入,能够在一定程度上克服钛合金材料的应力屏蔽缺陷, 使植入体在早期获得良好的固位, 从而使界面骨性结合得以顺利进行。     

壳聚糖微球/磷酸钙骨水泥复合材料动物体内植入实验研究

将壳聚糖微球/磷酸钙骨水泥复合材料植入兔股骨髁内,进行大体观察和X光片观察,并分别在植入兔股骨髁内8、16和24周,取出样本进行组织学观察和环境扫描电镜观察,研究植入材料与骨组织界面的结合状况和材料在动物体内的降解过程及新骨重建生成状况,探索材料在体内的降解机制和成骨机制.结果表明:壳聚糖微球/磷酸钙骨水泥在骨组织内具有良好的生物相容、组织相容性和和骨结合性,能够与自然骨组织形成紧密的骨性结合.材料在体内具有较快的降解速度,植入24周后,80%以上材料降解,被新生骨组织替代,该材料还具有良好的可塑性和临床操作性,是一种很有临床应用前景的骨修复材料.     

ZnO晶须对TCP/HAP双相生物陶瓷烧结行为和性能的影响

在1000～1300 ℃温度范围内,就ZnO晶须(ZnO_w)对TCP/HAP双相生物陶瓷烧结行为和性能的影响进行研究,初步探讨其烧结机制,并制备出性能优良的ZnO_w增韧TCP/HAP双相生物陶瓷.采用XRD、SEM等分析手段对ZnO_w增韧TCP/HAP双相生物陶瓷的组织和性能进行了分析,并在37 ℃的模拟体液中考察了其降解性能.结果表明:ZnO_w的加入可以显著降低TCP/HAP陶瓷的烧结温度;在同一烧结温度下,随着ZnO_w添加量的增加,烧结试样的致密度增加,孔径增大,孔隙率减小;烧结后的试样主要由TCP与HAP两相组成,ZnO_w的加入未对其相组成产生明显的影响.在37 ℃的模拟体液中,ZnO_w增韧TCP/HAP双相生物陶瓷具有良好的生物降解性能.ZnO_w的加入在保证TCP/HAP双相生物陶瓷具有良好的生物降解性能的同时,使其性能接近人体松质骨,从而在骨缺损区提供一定的支撑作用.     

钛基底HAP涂层生体活性材料的改性研究

报道了不同先驱体制备ＨＡＰ－Ｔｉ材料的性能,并对不同工艺制备活体材料表面改性的效果进行了对比,采用溶胶－凝胶法（简称ＳＯＬ－ＧＥＬ）制备的ＨＡＰ－Ｔｉ复合种植体,其涂层与基底材料各组分相互混合达到分子水平的均匀,并在界面生成牢固的化学过渡层。     

Coating of hydroxyapatite films on metal substrates by seeded hydrothermal deposition

Hydroxyapatite (HAP) was successfully coated on various metal substrates by a novel seeded hydrothermal deposition method. A nanoscale HAP seed layer was first formed by a short electrochemical synthesis. The seed layer promotes HAP crystal growth onto the surface during a subsequent hydrothermal crystallization step. The surface morphology and microstructure of the HAP coatings can be regulated by varying the reaction temperature, solution pH, calcium-to-phosphorus molar ratio in the starting solution, and hydrothermal deposition time. The new method has advantages over many other reported HAP deposition techniques in that it produces highly crystalline, crack-free, adherent films of uniform thickness. In all the films, the HAP crystals are preferentially oriented with the c-axis normal to the substrate. The as-developed HAP coatings are attractive for applications in the area of bioactive surface modification of metallic implants where the microstructure of the film is advantageous for promoting bone growth.     

Characterization of Thermal-Sprayed HAP and HAP/TiO<Subscript>2</Subscript> Coatings for Biomedical Applications

In the present study, hydroxyapatite (HAP) coating along with HAP/TiO₂ coating has been deposited by high-velocity flame spray (HVFS) technique onto 316LSS. Titania was used as a bond coat and HAP as top coat in HAP/TiO₂ coating. The main aim of the study is to investigate the corrosion behavior of thermal spray coating of HAP and HAP/TiO₂ on steel. Electrochemical corrosion testing was carried out using potentiodynamic polarization test. The corrosion behavior of bare and as-sprayed specimens was analyzed in simulated body fluid known as Hank’s solution. As-sprayed specimens along with corroded specimens were further characterized by XRD, SEM/EDS, and x-ray mapping analysis. It was observed that the HAP/TiO₂ coating possessed higher microhardness (280 Hv) as compared to HAP coating (254 Hv). Surface roughness also got enhanced in case of HAP/TiO₂ coating (9.35 μm) as compared to pure HAP coating (7.37 μm). The porosity of the HAP coating was found to be higher than the bond coating. It was observed that the Ca/P ratio almost resembled that of the natural bone composition. The corrosion resistance of steel increased after the deposition of HAP and HAP/TiO₂ coatings. The maximum corrosion resistance was exhibited by HAP/TiO₂ coating.     

利用冷冻干燥原位构筑仿生型纳米羟基磷灰石、壳聚糖多孔支架材料

在目前仿生制备骨缺损修复材料研究的基础上,利用冷冻干燥技术结合原位复合方法在成分仿生的基础上进行结构仿生制备骨缺损修复材料.充分利用壳聚糖的溶解、沉析和羟基磷灰石形成特性,在室温下实现了纳米羟基磷灰石在多孔支架中的纳米分散.研究结果表明,利用冷冻干燥原位构筑的多孔支架材料拥有很好的相互贯穿多孔连通结构,孔径分布为100～136 μm,孔隙率达到96.1%.此外,原位形成的纳米羟基磷灰石(95 nm)对于多孔支架还起到了纳米增强作用,支架表现出良好的力学性能,可以根据不同缺损形状实现随意赋行.体外生物活性测试表明,该支架材料具有很好的生物活性,是一种优越的潜在骨缺损修复支架材料.     

Electronic microscopy analysis of HAP single crystals prepared by hydrothermal method

Hydroxyapatite(HAP,Ca10(PO4)6(OH)2in one of the quite important bone implant materials.The hydroxyapatite crystals were synthesized under hydrothermal condition.The specimen was verified to be HAP crystal by the X-ray powder diffractometry(XRD).Then the specimen was distinguished single crystal from polycrystal by the use of the transmission electron microscope(TEM).The diffraction pattern of the specimen is neatly affanged diffraction spots,that verified the crystals were single crystals.The interplanar distance d calculated from diffraction spot is coincided with that of HAP‘s JCPD card.Moreover,crystal face angles calculated from crystal face index are coincided with the values by measuring on the pattern.The HAP crystals are needle-like in shape with about 3μm in diameter and 180μm in length.Most of the crystals are whiskers.Their length/diameter ratio ranges from 40 to 100.The average ratio is about 60.     

磷酸镁生物骨胶的制备与性能表征

研究了液固比和氧化镁煅烧温度对磷酸镁生物骨胶固化时间的影响,并分析了生物骨胶的相组成、微观结构。结果表明：降低液固比或提高氧化镁煅烧温度,生物骨胶的固化时间有所增加;生物骨胶主要由未参与反应的氧化镁和水化产物构成,内部含有大量微裂纹,分析认为很可能是由于固化过程中释放的热应力及固化过程中体积发生膨胀引起的。     

Fabrication and Characterizations of Metallic Mg Containing PMMA-Based Partially Degradable Composite Bone Cements

Inadequate strength at the bone/cement interface is one of the main drawbacks of poly(methylmethacrylate)(PMMA)bone cement in the current orthopedic surgeries.In the present work,a partially degradable PMMA/Mg composite bone cement(PMC)was developed for enhancing the bone/cement interfacial strength,which is proposed to be accomplished by increasing the osteo-conductivity of PMMA and enhancing the mechanical interlocking between bone tissue and the porous PMMA surface formed by the degradation of Mg on the surface of the cement.PMCs were prepared with various concentrations of Mg particles with different sizes and alloy compositions.The effects of Mg particle size,composition and content on the injectability,mechanical and degradation properties,and biocompatibility of PMCs were evaluated.The results show that these parameters affected the properties of the PMCs simultaneously.The good injectability and compressive strengths of PMMA were preserved,while the compatibility to osteoblasts was enhanced when adding Mg particles in a proper manner.The PMCs degraded at the surface with time and formed porous surface structures in the physiological environment,while maintaining the original compressive strengths.This preliminary study shows that the PMC is promising for minimally invasive orthopedic surgery;however,it still requires to be optimized and evaluated in the future.     

Study on the subsonic speed flame spraying coating of hydroxyapatite

A new method of preparation of biomaterial composite coating by the technique of subsonic thermal spraying was discussed in this paper. Ti6Al4V and pure Ti were chosen as substrate and sublayer material respectively and the working layer was sprayed with biomaterial hydroxyapatite (HAP), forming the composite coating. The experiments of heat shock and tensile strength showed that the bonding strength between coating and substrate is almost as same as that of specimen in which Ni/Al powder was adopted as sublayer. The phases of TiN, TiO2, and Ti2O3 were formed in the sublayer, which are free of toxic and have no side effects. The powder of working layer HAP was decomposed partly during spraying, but it can be solved by later treatment.     

Inhibition mechanism of aspartic acid on crystal growth of hydroxyapatite

The effects of aspartic acid on the crystal growth, morphology of hydroxyapatite（HAP） crystal were investigated, and the inhibition mechanism of aspartic acid on the crystal growth of hydroxyapatite was studied. The results show that the crystal growth rate of HAP decreases with the increase of the aspartic acid concentration, and the HAP crystal is thinner significantly compared with that without amino acid, which is mainly due to the （10^-10） surface of HAP crystal being inhibited by the aspartic acids. The calculation analysis indicates that the crystal growth mechanism of HAP, following surface diffusion controlled mechanism, is not changed due to the presence of aspartic acid. AFM result shows that the front of terrace on vicinal growth hillocks is pinned, which suggests that the aspartic acid is adsorbed onto the （10^-10） surface of HAP and interacts with the Ca^2＋ ions of HAP surface, so as to block the growth active sites and result in retarding of the growth of HAP crystal.