氮离子溅射对镍铬合金表面细菌黏附的影响

背景：镍铬合金被广泛应用于口腔修复领域,大量实验正在进行其机械性能、抗腐蚀性能以及生物相容性的研究。 目的：观察氮离子溅射对镍铬合金表面细菌黏附能力的影响。 方法：制作镍铬合金试件144件,随机选出72件,采氮离子溅射法对其表面改性,镍铬合金组为对照组,氮离子溅射组为实验组。对两组试件表面黏附血型链球菌、黏性放线菌、白色念珠菌,分别进行细菌体外黏附实验。用菌落形成单位计数法统计分析氮离子溅射前后各种细菌黏附量的变化。 结果与结论：在细菌黏附24,48,168 h,上述3种细菌在实验组表面黏附量较对照组表面黏附量显著减少(P < 0.001)。提示,氮离子溅射可抑制镍铬合金表面细菌黏附。     

钛合金和钴铬合金表面白色念珠菌粘附的研究

目的比较钛合金(Ti-6Al-4V)和钴铬合金(Chromium-Cobalt alloy)表面白色念珠菌粘附能力的大小,研究表面粗糙度与细菌粘附的关系.方法将不同表面粗糙度的钛合金和钴铬合金试件进行白色念珠菌体外粘附试验,采用菌落形成计数法测定试件表面的细菌粘附量.结果各钛合金试件组的细菌粘附量均少于相同表面粗糙度的钴铬合金试件组,两种金属试件表面的细菌粘附量均随表面粗糙度的增大而增加.结论钛合金较钴铬合金更能减少由白色念珠菌引起的义齿性口炎等并发症,同时修复体表面严格的研磨抛光也能有效减少这些并发症.     

两种树脂基托细菌粘附情况的比较

目的 比较BPS注塑树脂和热凝基托树脂表面细菌粘附能力的大小.方法 将BPS注塑树脂和热凝基托树脂试件进行细菌体外粘附实验,采用菌落形成单位计数法测定血型链球菌、粘性放线菌和白色念珠菌粘附量的大小.结果 培养24h、48h、168h后,各BPS注塑树脂试件组的细菌粘附量均少于热凝基托树脂试件组.结论 BPS注塑树脂较热凝基托树脂更能减少血型链球菌、粘性放线菌和白色念珠菌在其表面的粘附.     

结核杆菌黏附不同人工关节假体材料的能力研究

背景：细菌黏附在假体表面大量繁殖并形成致密的生物膜,药物难以进入将其杀灭是人工关节置换后感染难治及复发的主要原因。 目的：观察不同人工关节假体材料性质、表面对结核杆菌黏附能力的影响。 方法：取钛合金和钴铬钼合金试样(均分光滑面和粗糙面两种),分别将结核杆菌与表皮葡萄球菌(对照菌液)经传代培养后由FITC标记,制成菌液;将菌液与试样37 ℃共同培养24 h;用荧光显微镜和电镜扫描观察两种细菌在上述4种不同试样的黏附情况。 结果与结论：表皮葡萄球菌和结核杆菌在钴铬钼合金表面的黏附面积均大于在钛合金表面的黏附面积;在同种材料中粗糙面比光滑面更容易发生细菌黏附;两种材料表面均可见表皮葡萄球菌形成生物膜,而结核杆菌则无生物膜形成。表明结核杆菌在钴铬钼合金、钛合金表面的黏附能力较差;材料性质和材料表面粗糙程度均对结核杆菌黏附力产生巨大影响;结核杆菌在钴铬钼合金和钛合金表面并无生物膜形成。     

激光焊接新型钴铬合金的力学性能

背景：新型钴铬合金为一种不含镍和铍等有害成分的齿科合金材料,但关于其激光焊接的研究尚未见报道。 目的：分析新型钴铬合金的激光焊接参数,优选激光焊接电压条件。 方法：铸造0.5 mm×6 mm×30 mm的新型钴铬合金试件60个,将试件分成6组。1组作为对照组;5组试件从中间断开,进行激光焊接,光斑直径设定为0.6 mm,脉冲持续时间10 ms,电压分别为220,250,280,310,340 V,焊后进行拉伸强度测试,记录拉伸强度和延伸率。 结果与结论：激光焊接新型钴铬合金拉伸强度随电压升高而增加。延伸率在电压低于280 V时,随电压增大而增加;高于280 V时,随电压增大而降低。电压为280 V时,激光焊接新型钴铬合金的拉伸强度为(679.94±46.87) MPa,延伸率为(5.91±0.38)%。提示电压280 V,脉冲持续时间10 ms,光斑直径0.6 mm条件下激光焊接新型钴铬合金的拉伸强度和延伸率均能满足临床要求。     

左氧氟沙星浸涂生物材料防止生物膜形成的体外研究

目的观察左氧氟沙星（LFX）浸涂生物材料在体外对铜绿假单胞菌黏附、定植及生物膜形成的影响。方法配置LFX与外消旋聚乳酸（PDLLA）比值（w／w）为1：4、1：32的丙酮溶液,分别浸涂聚氯乙烯（PVC）材料10min制备LFX浸涂生物材料,按LFX浓度分为LFX高浓度组和LFX低浓度组,以PVC材料（PVC组）作为对照。3组材料分别浸没在含铜绿假单胞菌PA01（细菌浓度为1X108CFU／m1）的LB培养液中,37℃孵育24、72h,分别进行各组材料表面细菌计数及扫描电子显微镜观察。结果孵育24h,LFX高浓度组、LFX低浓度组和PVC组材料表面细菌计数分别为8．02（7．93～8．08）、8．10（8．03～8．20）和8．36（8．26～8．49）logloCFU／ml;孵育72h,LFX高浓度组、LFX低浓度组和PVC组材料表面细菌计数分别为7．77（7．64～7．87）、8．31（8．14—8．44）和8．74（8．50～8．99）logloCFU／ml,LFX浸涂材料表面细菌计数均显著低于PVC组（均P〈O．05）。扫描电子显微镜观察显示,孵育24h,LFX高浓度组和LFX低浓度组材料表面见散在单个细菌,PVC组材料表面大量细菌分散存在;孵育72h,LFX高浓度组和LFX低浓度组材料表面未见细菌,PVC组材料表面可见微菌落及“珊瑚状”生物膜形成。结论LFX浸涂生物材料可抑制铜绿假单胞菌黏附、定植及生物膜的形成。     

芍药苷对白色念珠菌生物膜的作用

背景：研究证实中药赤芍有效成分对白色念珠菌有较好的抑制作用,但其单体芍药苷对白色念珠菌生物膜是否有抑制作用未见报道。  目的：观察芍药苷对体外白色念珠菌生物膜的影响。 方法：用RPMI-1640分别按2倍稀释法制备5个浓度梯度(4,2,1,0.5,0.25 g/L)的芍药苷溶液。用RPMI-1640稀释洗必泰为5个浓度梯度(2%,1%,0.5%,0.25%,0.125%)。采用琼脂扩散法检测不同浓度梯度芍药苷或洗必泰对白色念珠菌的抑菌直径。MTT法检测不同浓度洗必泰或芍药苷对白色念珠菌细胞黏附的作用,以及对白色念珠菌生物膜的抑制作用,并且利用激光共聚焦扫描显微镜和死菌活菌荧光染色技术相结合方法观察常态及药物作用下的白色念珠菌生物膜。 结果与结论：洗必泰与芍药苷均有抑菌能力,抑菌环直径与药物浓度呈正相关;除2 g/L芍药苷组与1%,2%洗必泰组抑菌环直径无差异外,其余组间两两比较差异均有显著性意义。不同质量浓度芍药苷对白色念珠菌的细胞黏附都具有抑制作用,对白色念珠菌生物膜也具有抑制作用,且抑制率与药物质量浓度呈正相关。观察48 h时常态生物膜结构中大部分是活菌,有少量死菌存在;随芍药苷质量浓度改变白色念珠菌生物膜中死菌比例不断增高,其抑菌活性相对弱于洗必泰。表明芍药苷对体外白色念珠菌生物膜有较明显的抑制作用。|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：     

TiAl6Vi4表面超疏水修饰后的体外抑菌实验

背景：研究表明,材料表面亲、疏水性(即表面浸润性)是影响细菌黏附的重要原因。 目的：探讨钛金属TiAl₆Vi₄表面超疏水改性后对金黄色葡萄球菌的抑菌作用。 方法：将TiAl6Vi4板块经砂纸、酸溶液抛光和超声清洗后,随机分组：超疏水表面组采用电化学阳极氧化法在TiAl₆Vi₄表面制备TiO₂纳米管薄膜,并通过氟硅烷自组装修饰;亲水表面组采用电化学阳极氧化法在TiAl₆Vi₄表面制备TiO₂纳米管薄膜;疏水表面组对TiAl₆Vi₄表面行氟硅烷自组装修饰,分别测量3组表面的接触角。将3组样品浸泡于金黄色葡萄球菌菌液中2 h,观察样品表面细菌黏附和分布状态,以及浸泡过样品剩余菌液的A值。 结果与结论：亲水表面组表面多数金葡菌彼此聚集、重叠,呈葡萄串形态;疏水表面组表面细菌有聚在一起的趋势,但没有彼此重叠、覆盖,只是单层排列,没有形成葡萄串表面;超疏水表面组表面细菌分散排布,一般只有两三个细菌在一起,不成串,不重叠。3组表面随着亲水性的降低细菌数量逐渐减少,以超疏水表面组为最少,而且细菌相互分离的也更加明显。超疏水表面组剩余菌液的A值明显高于亲水表面组和疏水表面组(P < 0.05)。表明钛金属表面超疏水修饰能有效抑制金黄色葡萄球菌贴附。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：     

口腔金属材料安全性、相容性以及功能性的评价

背景：口腔固定修复金属材料在人体内会对机体产生一定的影响,因此选择最佳的口腔生物材料可以减少对人体的损害。 目的：分析不同口腔修复固定金属材料的生物性能,为口腔生物材料的选择提供辅助信息。 方法：研究分析各种常用口腔修复固定金属材料的生物学性能,包括摩擦学性能、细胞相容性以及耐腐蚀性能,并比较各种口腔修复固定材料的生物学性能,以明确最佳的口腔生物材料选择应用。 结果与结论：以金、钛为基质的合金材料表现出较高的生物性能,从抗摩擦性能、细胞相容性以及耐腐蚀性能均表现出较好的生物相容性,而银钯合金、钴铬合金的生物相容性与纯钛和金、钛合金相比较略低,镍铬合金的生物相容性最差,因此在进行口腔修复固定材料选择时,应选取以金、钛为基质的合金材料以及纯钛,尽量避免选择镍铬合金材料。     

钛种植体基台和不同合金的体外耐腐蚀性能

背景：各种医用生物材料在应用于口腔环境之前,除了对其机械性能和理、化学性能予以严格的考察之外,还需要进行口腔环境耐腐蚀性实验,以保证材料的生物相容性。目的：分析钛种植体基台和不同钛合金的体外耐腐蚀性能。方法：构建体外人工唾液腐蚀环境,pH=6.0,温度(37±0.5) ℃,利用动电位极化技术、扫描电镜、X射线衍射等方式评估钛合金、金合金、镍铬合金及钛种植体基台在人工唾液中浸泡24 h的耐腐蚀性能。结果与结论：不同合金的稳态电位不同,其中金合金钝化区范围最大,其次为钛种植体基台和钛合金,镍铬合金钝化区范围最小。经过24 h的人工唾液浸泡后,不同材料的表面均开始出现钝化膜,扫描电镜显示,镍铬合金表面可见明显的腐蚀痕迹,出现大量直径较大的深点蚀坑,其余3种合金均未出现明显腐蚀现象;镍铬合金表面铬、钼、铝含量均出现减少现象,镍、氧含量增加,其余合金表面未出现明显改变;镍铬合金表面生成 Cr₂O₃,钛种植体基台及钛合金表面均生成TiO₂,金合金表面仍为Au、Pt单相存在,未生成化合物。表明钛合金与钛种植体基台具有相似的耐腐蚀性能,且差于金合金,但优于镍铬合金。 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     

TiO2-xNx抗菌托槽的抑菌性能

 背景：有研究表明TiO_2-xN_x薄膜对变形链球菌、黏性放线菌及白色念珠菌具有良好的抗菌效果。目的：进一步评价TiO_2-xN_x薄膜托槽的抗菌性能。 方法：纳入10例正畸患者,将口内牙齿以上下中线分为左右两侧,分别粘接普通金属托槽和TiO_2-xN_x薄膜托槽,在矫治前、矫治后1,2,3,4周检测正畸菌斑指数、牙龈指数、龈沟出血指数及釉质脱矿指数。结果与结论：普通金属托槽组矫治后1,2,3,4周的正畸菌斑指数、牙龈指数、龈沟出血指数及釉质脱矿指数均高于矫治前(P < 0.05);TiO_2-xN_x薄膜托槽组矫治后3周的牙龈指数高于矫治前(P < 0.05),矫治后1,2,3周的龈沟出血指数高于矫治前(P < 0.05),矫治后2,3,4周的釉质脱矿指数高于矫治前(P < 0.05);TiO_2-xN_x薄膜托槽组矫治后1-4周的正畸菌斑指数、龈沟出血指数均低于普通金属托槽组(P < 0.05),矫治后2-4周的牙龈指数、釉质脱矿指数均低于普通金属托槽组(P < 0.05)。表明TiO_2-xN_x薄膜托槽具有较好的抗菌效果,可更好地控制和清除菌斑。中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Coagglutination reactions between Candida albicans and oral bacteria

An agglutination assay for detecting intermicrobial adherence between the cells of Candida albicans and various oral bacteria is described. Strains of Streptococcus sanguis, S. salivarius, S. mutans, S. mitis, Fusobacterium nucleatum and Actinomyces viscosus all coagglutinated with C. albicans. No interaction could be demonstrated between the cells of Bacteroides melaninogenicus and those of C. albicans. Preliminary investigations of these interactions suggest that binding of F. nucleatum and A. viscosus to C. albicans is mediated by bacterial proteins, possibly lectins. Other mechanisms must account for the binding of oral streptococci to C. albicans. The possible implications of these findings in relation to oral mucosal colonisation and oral candidal clearance are discussed.     

口腔纳米载银无机抗菌材料的抗菌性能

背景：纳米载银无机抗菌剂具有抗菌谱广、抗菌能力强等特点,是目前口腔无机抗菌材料研究的热点之一。 目的：研究纳米载银无机抗菌材料的抗菌性能及抗菌机制,为基础实验研究和临床应用提供参考信息。 方法：研究多种口腔纳米载银无机抗菌材料对常见病原菌如变形链球菌、白色念珠菌以及粘性放线菌等的抗菌性能,其中包括最低杀菌浓度以及抗菌率等,同时进行对比分析。并且研究纳米载银无机抗菌材料的抗菌机制,明确其优点与不足。 结果与结论：口腔纳米载银无机抗菌材料具有较广的抗菌谱,对变形链球菌、乳酸杆菌、粘性放线菌、白色念珠菌、牙龈卟啉单胞菌、金黄色葡萄球菌以及大肠埃希菌等均具有较强的抗菌性能,最低杀菌浓度较低,而抗菌率较高。但是同一纳米载银无机抗菌材料对不同的病原菌,其最低杀菌浓度不同,抗菌率也不同,而不同的纳米载银无机抗菌材料对同一病原菌的最低杀菌浓度也不相同,抗菌率也不同。     

Adherence of Streptococcus mutans to an E-glass fiber-reinforced composite and conventional restorative materials used in prosthetic dentistry

The adherence of Streptococcus mutans to E-glass used in fiber-reinforced composites, denture base polymer, and four other restoratives was investigated. The materials were studied with and without a parotid saliva and serum pellicle. Specimens of the studied materials (E-glass, denture base polymer, titanium, cobalt-chromium alloy, gold alloy, and grained feldspar ceramic) were incubated in a suspension of S. mutans, allowing initial adhesion to occur. The degree of bacterial adhesion was studied using scanning electron microscopy (SEM). The studied uncoated materials showed rather similar adhesion of S. mutans. Saliva coating resulted in a decrease of adherence to all materials except glass. With a saliva pellicle E-glass showed the strongest ability to bind S. mutans, and it differed significantly from the other studied materials. Serum coating markedly decreased adhesion to all materials, and only minor differences among the studied materials were observed. The results of this study suggest that the studied restoratives are rather similar with respect to S. mutans adhesion and that a saliva pellicle may promote adhesion of S. mutans to glass fibers.     

Salivary-agglutinin-mediated adherence of Streptococcus mutans to early plaque bacteria.

Interspecies binding is important in the colonization of the oral cavity by bacteria. Streptococcus mutans can adhere to other plaque bacteria, such as Streptococcus sanguis and Actinomyces viscosus, and this adherence is enhanced by saliva. The salivary and bacterial molecules that mediate this interaction were investigated. Salivary agglutinin, a mucinlike glycoprotein known to mediate the aggregation of many oral streptococci in vitro, was found to mediate the adherence of S. mutans to S. sanguis or A. viscosus. Adherence of S. mutans to saliva- or agglutinin-coated S. sanguis and A. viscosus was inhibited by antibodies to the bacterial agglutinin receptor. Expression of the S. sanguis receptor (SSP-5) gene in Enterococcus faecalis increased adhesion of this organism to saliva- or agglutinin-coated S. sanguis and A. viscosus. This interaction could be inhibited by antibodies to the agglutinin receptor. The results suggest that salivary agglutinin can promote adherence of S. mutans to S. sanguis and A. viscosus through interactions with the agglutinin receptor on S. mutans.     

Predominant cultivable flora isolated from human root surface caries plaque.

Plaque samples were obtained from tooth surfaces exhibiting typical lesions of root surface caries and were immediately cultured by a continuous anaerobic procedure. The bacterial composition of root caries flora was determined on individual samples. Representative isolates from each specimen were characterized by morphological and physiological criteria. In addition, fluorescent antibody reagents were used to confirm the identification of Streptococcus mutans and Actinomyces viscosus. The plaque samples could be divided into two groups on the basis of the presence or absence of S. mutans in the plaque. In group I plaques, S. mutans comprised 30 percent of the total cultivable flora. S. sanguis was either not found or was present in very low number. In group II plaques, S. mutans was not detected, and S. sanguis formed 48 percent of the total plaque flora. A. viscosus was the dominant organism in all plaque samples, accounting for 47 percent of the group I isolates and 41 percent of the group II isolates.     

Growth rates of Actinomyces viscosus and Streptococcus mutans during early colonization of tooth surfaces in gnotobiotic rats.

Germfree Osborne-Mendel rats were monoassociated with Actinomyces viscosus or Streptococcus mutans. The adherence and subsequent growth of these organisms on the tooth surface was studied by means of total viable cell counts. Both A. viscosus and S. mutans showed a lag phase and an exponential growth phase, similar to logarithmic growth in batch cultures. The exponential growth rates of S. mutans and A. viscosus were 0.63 h-1 (doubling time [td] = 1.1 h) and 0.24 h-1 (td = 2.9 h), respectively. After a period of rapid growth, the rate declined and the populations approached a steady state. The presence of a sucrose-containing diet did not significantly influence the exponential growth rates of A. viscosus and S. mutans, but had a slight negative effect on the initial adherence of S. mutans at the tooth surface.     

Specific and nonspecific inhibition of adhesion of oral actinomyces and streptococci to erythrocytes and polystyrene by caseinoglycopeptide derivatives.

Various caseinoglycopeptide derivatives prepared from mammalian milk were evaluated as inhibitors of hemagglutinations mediated by Actinomyces viscosus Ny1, Streptococcus sanguis OMZ9, and, for comparative purposes, plant lectins from Arachis hypogaea and Bauhinia purpurea. It was found that recognition of the beta-D-galactose-(1----3)-2-acetamido-2-deoxy-D-galactose carbohydrate chain by Actinomyces viscosus Ny1 organisms and Arachis hypogaea and B. purpurea agglutinins had similar structural requirements; in all cases, the desialylated bovine caseinoglycomacropeptide, on which several units of the above mentioned disaccharide are clustered, behaved as the most potent hemagglutination inhibitor. By contrast, none of the preparations tested inhibited erythrocyte agglutination by S. sanguis OMZ9. Thus, the desialylated bovine caseinoglycomacropeptide acts as a potent and specific inhibitor of oral Actinomyces adhesion to cell membranes (a soft surface) and could be used as a probe for the study of recognition mechanisms mediated by Actinomyces galactose-binding lectins. During the present study, both native and desialylated variants of the same bovine glycomacropeptide also totally prevented the adhesion of Actinomyces viscosus Ny1, S. sanguis OMZ9, and S. mutans OMZ176 to polystyrene surfaces. Comparative evaluations of various structurally different compounds gave the following results. Neither mono- nor disaccharides related to caseinoglycopeptide carbohydrates prevented adhesion; highly positively or negatively charged polypeptides and polysaccharides were either not or only moderately active. Besides these glycomacropeptides, an inhibitory activity was also exhibited by other mucin-type glycoproteins carrying short O-linked carbohydrate chains (including bovine submaxillary mucin), polyethylene glycol, and bovine serum albumin. Consequently, caseinoglycopeptide prevention of oral bacterial adhesion to polystyrene tubes (a hard surface) takes place with no species specificity and can be compared to nonspecific inhibition exhibited by various polymers with very different structural characteristics.     

Dextran-mediated interbacterial aggregation between dextran-synthesizing streptococci and Actinomyces viscosus.

Streptococcus sanguis and Streptococcus mutans bind to the surface of Actinomyces viscosus, producing large microbial aggregates. Aggregates form rapidly and are not easily dissociated by vigorous mixing. The binding is mediated by dextran. Glucose-grown streptococci will not aggregate unless they are first mixed with high-molecular-weight dextran. Aggregation is induced with dextrans isolated from Leuconostoc, S. sanguis, or S. mutans. Sucrose-grown streptococci will adhere to A. viscosus without the addition of an exogenous source of dextran. A. viscosus will bind dextran and then bind glucose-grown streptococci. Aggregation occurs over a wide pH range and is dependent on cations. The aggregating activity of A. viscosus is both protease and heat sensitive. The aggregating activity of S. sanguis is heat stable but sensitive to dextranase.