目的制备海藻酸钙-纳米羟磷灰石复合材料,探讨其作为骨修复材料的可行性。方法应用化学交联及冷冻干燥技术制备海藻酸钙-纳米羟磷灰石复合材料,通过扫描电镜(SEM)和X光衍射(XRD)对材料性能进行表征,液体置换法测定孔隙率。将第5代骨髓基质干细胞(BMSCs)接种至材料上,倒置显微镜及SEM观察细胞生长情况。材料浸提液与BMSCs共培养,甲基噻唑基四唑(MTT)法检测接种后1、3、5 d的相对增殖率(RGR),并评估毒性分级。新鲜犬血加入材料浸提液进行溶血试验,分光光度计测定光密度值并计算溶血率。结果制备的海藻酸钙-纳米羟磷灰石复合材料具有多孔性,孔隙率达(88.6±4.5)%。倒置显微镜及SEM观察可见,细胞在材料周围及表面伸展充分、生长旺盛。材料浸提液培养的细胞具有较好的活力,其毒性分级为1级。溶血试验结果表明复合材料的溶血率为1.28%,满足医用生物材料的要求。结论本研究制备的复合材料具有较高的孔隙率和良好的生物相容性。

Objective To prepare sodium alginate-nanohydroxyapatite composite material and to explore its feasibility as a bone repair material. Methods Sodium alginate-nanohydroxyapatite composite material was prepared using chemical cross-linking and freeze-drying technology. The composite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and its porosity was measured by liquid displacement method. The fifth passage of bone marrow stromal stem cells (BMSCs) were incubated on the composite material and then growth was observed by inverted micros-cope and SEM. BMSCs were cultured with liquid extracts of the material, methyl thiazolyl tetrazolium (MTT) assay was used to calculate the relative growth rate (RGR) on 1, 3, 5 d and to evaluate the cytotoxicity. Fresh dog blood was added into the liquid extracts to conduct hemolysis test, the spectrophotometer was used to determine the optical density (OD) and to calculate the hemolysis rate. Results Sodium alginate-nano

釉质表面的溶解(脱矿)和重建(再矿化)是一个持续的过程,再矿化已经成为治疗早期龋损的重要研究趋势之一。添加成分不同,产生的羟磷灰石晶体的形貌、性质等也不相同。良好的矿物生长可以为临床上预防和治疗早期釉质脱矿提供有力的实验依据。本文就添加成分对釉质体外再矿化影响的研究作一综述。

The enamel surface dissolution(demineralization) and reconstruction(remineralization) is a continuous process. Remineralization treatment of early caries has become an important research trend. Adding the different components, the morphology and properties of hydroxyapatite crystal are different. Good growth of minerals for cli-nical prevention and treatment of early enamel demineralization provide powerful experimental basis. This paper was reviewed the research of the effects of adding composition on enamel remineralization in vitro.

目的 制备一种新型的人工软骨材料并对其进行表征及性能评价.方法 将聚甲基丙烯酸羟乙酯(PHEMA)与0.5％二氧化硅(SiO2)及1％～5％羟基磷灰石(HA)复合制备成复合材料,用红外光谱仪和扫描电镜表征了材料的结构,测试材料的吸水性及牛血清白蛋白在材料表面的吸附性.结果 SiO2与HA纳米级均匀地分散在材料的一侧,材料的吸水率为45％ ～ 50％,牛血清白蛋白在材料表面的吸附率约为5％,表明材料具有较好的生物相容性.结论 成功制备1种生物相容性较好的有机/无机复合人工软骨材料.

Objective To prepare a kind of novel artificial cartilage and study its cell biocopatibility.Methods Polyhydroxyethyl methacrylate (PHEMA),0.5％ silica and 1％-5％ hydroxyapatite were mixed to prepare the composites.The composites were characterized by Fourier transform infrared spectroscopy (FTIR),scanning electron microscopy (SEM),swelling ratio (SR) measurement and the absorption of bovine serum albumin (BSA).Results Inorganic particles were n nanoscopic diameter and uniformly dispersed on side of the matrices.The swelling ratio of hydrogels was 45％-50％.The absorption of BSA on the surface of composite membrane was about 5％,indicating the good biocompatibility.Conclusion A biocompatible organic/inorganic complex artificial cartilage was prepared.

目的探讨洗必泰葡萄糖酸盐(CHX)作为根管冲洗试剂,对多物种细菌生物膜的影响。方法在Ⅰ型胶原包被的羟磷灰石片上制备多物种细菌生物膜,应用2%CHX冲洗,处理3min后,激光扫描共聚焦显微镜观察灭菌效果。结果经过有氧或厌氧培养3周的多物种细菌生物膜生长状态良好;应用2%CHX处理有氧培养或厌氧培养多物种细菌生物膜可以杀灭一部分细菌,死菌比例分别为(33.0±3.0)%、(40.0±2.8)%,无菌去离子水几乎没有杀灭细菌的能力(P0.05)。结论 CHX具有明显的杀灭多物种细菌生物膜的作用,但是尚不能达到完美的根管冲洗消毒效果。

Objective To evaluate the effect of chlorhexidine digluconate(CHX),a solution for root canal irrigation,on multispecies biofilms in vitro.Methods CHX(2%)was used to irrigate multispecies biofilms,which were formed on sterile hydroxyapatite disk coated with type Ⅰ collagen.Three minutes later,the antibacterial effect was examined by confocal laser scanning microscopy(CLSM).Results The multispecies biofilms incubated in aerobic and anaerobic hydroxyapatite disks for three weeks grew well.CHX could kill some of the bacterial cells in the multispecies biofilms in both aerobic group(33.0 ± 3.0)% and anaerobic group(40.0±2.8)%,but neither did deionized water(P<0.05).Conclusion CHX has bactericidal effects against multispecies biofilms invitro.However,using CHX alone can not obtain an optimal outcome of root canal irriga-tion.

目的探讨纳米羟磷灰石(nano-HA)溶液与过氧化氢(HP)溶液对釉质表面的影响。方法应用体外牛切牙制备釉质块标本72个,随机分为6组:去离子水(DW)组、HP+DW组、nano-HA+HP组、nano-HA+HP混合组、HP+nano-HA组、nano-HA+DW组。采用扫描电子显微镜和原子力显微镜观察处理前后的釉质表面结构,X线衍射检测表层釉质晶体结晶度的改变。结果 HP+DW组经处理后,釉质呈明显的脱矿表现,表面粗糙不平,颗粒间隙增大,出现明显孔隙,显微硬度明显降低,结晶度降低。在nano-HA+HP组、nano-HA+HP混合组、HP+nano-HA组处理后的釉质,其表面变得平整,显微硬度较HP+DW组的标本明显增加,结晶度有所增高。结论 HP溶液可以显著改变釉质的表面形态、降低其硬度和结晶度。nano-HA溶液与HP溶液联用特别是混合使用,可显著减少釉质表面的形态改变、降低显微硬度和结晶度。

Objective To explore the effect of nano-hydroxyapatite(nano-HA) solution and hydrogen peroxide (HP) solution on the enamel surface. Methods Seventy-two bovine enamel blocks were randomly divided into six groups: Deionized water(DW) group, HP+DW group, nano-HA+HP group, nano-HA+HP mixed group, HP+nano-HA group, nano-HA+DW group. Before and after the experiment, the samples were subsequently evaluated by microhard-ness tester through scanning electron microscope, atomic force microscope and X-ray diffraction. Results After the treatment, significant microhardness loss and morphological change of enamel and decreased crystallinity can be ob-served in HP+DW group, in the nano-HA+HP group or nano-HA+HP mixed group or HP+nano-HA group, enamel surface become smooth, microhardness increased significantly than the HP+DW group and the crystallinity bounced. Conclusion HP solution can lead to significant morphology change of the enamel surface, hardness loss and crys-tallinity decreased. The solu