口腔微生物生物膜分散物质的研究进展

生物膜是黏附在固体表面,包裹在自身产生的胞外多聚基质中的细菌群体。生物膜的形成和发展包括细菌的黏附、繁殖和分散。附着于某表面的生物膜将其中的细菌释放、分散到周围环境以传播到新的位置形成新的群落即生物膜的分散。生物膜分散是生物膜生长发展周期中一个重要的阶段,起到重要的传播作用。对许多致病菌而言,生物膜的分散能使生物膜的细菌转化为浮游状态,促进感染的扩散。生物膜的形成能提高细菌对抗微生物剂及宿主防御反应的抵抗力。在口腔中,口腔微生物能附着于口腔组织及修复体表面形成生物膜。人类龋病、牙周病是口腔的慢性感染性疾病,它们的发生与生物膜密切相关。生物膜分散机制是近年的研究热点,促进生物膜分散的新制剂可能成为攻克生物膜感染又一靶点。分散物质的临床意义和可能的临床应用具有广阔的前景。本文对口腔中能促进生物膜分散的分散物质作一综述。     

口腔中生物膜分散机制的研究进展

细菌生物膜是细菌在介质表面黏附生存的细菌群体,生物膜菌落的形成使得细菌更容易适应周围环境。在生物膜发展的最后一个阶段,细菌从生物膜菌落中分离出来然后分散到周围环境中,这个过程称为生物膜的分散。生物膜分散由酶促降解、种植传播、鼠李糖脂的产生等机制介导,并受到自身以及外界多种物理化学因素等调控。口腔中生物膜分散一方面使细菌得以从病灶扩散到新的部位导致感染性疾病的加重,而另一方面,分散开的细菌由于失去生物膜的保护而变得容易去除和杀灭。通过对生物膜分散机制的研究,找到促进生物膜分散的途径,解决治疗难治性细菌感染的难题,是近年来的研究热点。本文就生物膜形成发展、分散机制、调控和临床意义做一综述。     

D-型氨基酸对细菌生物膜解离分散的作用

生物膜是细菌主要的生存方式,受营养等因素的限制其存在的寿命有限,成熟生物膜分泌的某些因子促使生物膜解离,恢复细菌的单细胞浮游状态。促进生物膜的解离分散是目前的研究热点和前沿方向,D-型氨基酸对细菌生物膜的解离分散作用是新近几年来受到关注的研究领域,本文就D-型氨基酸对细菌生物膜相关作用的研究作一综述。     

口腔多菌种生物膜对防龋中药敏感性的实验研究

目的采用MBECTM-Device研究防龋中药五倍予多酚性化合物(GCE)、五倍子B(GCE-B)、蜂房95%组分(NVEI)对多菌种生物膜细菌的生长抑制作用,建立防龋中药药效学的药物敏感实验方法,为临床实验提供客观的药物作用的浓度范围。方法选择与龋病发生密切相关的4种口腔细菌形成多菌种生物膜,药物为GCE、GCE-B、NVEl,扫描电镜观察口腔细菌在MBEC州一Device上形成细菌生物膜的能力和形成情况;采用MBECn._HTP_Assav测定药物对口腔细菌的最小抑菌浓度(MIC)和对细菌生物膜的最小生物膜清除浓度(MBEC)。结果在MBFCm_Device提供的桩钉表面上I]腔细菌能形成良好的生物膜结构,从不同时段取出酌样本可以观察到细菌从定植粘附到生物膜形成以及生物膜成熟结构。GCE. GCE-B、NVEl对口腔细菌均有良好的抑制作用。GCE、GCE-B对口腔生物膜细菌有很好的抑制作用,但是NVEI对口腔生物膜细菌的抑制作用较差。药物对口腔生物膜细菌的MBEC是MIC的2-16倍。结论中药五倍子多酚性化合物和五倍子B对口腔生物膜细菌有很好的抑制和清除效应,MBEC比MIC能更客观地反映药物作用的浓度范围     

D-氨基酸对细菌生物膜分散作用的研究进展

细菌是导致感染性疾病的主要来源,细菌分泌的胞外多糖等物质聚集可形成致密的生物膜,使抗生素难以对其发挥杀菌作用,甚至可产生耐药性。细菌生物膜的存在给临床治疗增加了难度。口腔牙菌斑生物膜是龋病发生发展的始动因素,因此,有效清除和控制牙菌斑生物膜是防治龋病的关键。D-氨基酸作为细菌生物膜信号分子,能促进生物膜分散,进而促进抗菌药物发挥杀菌作用。文章就D-氨基酸对细菌生物膜分散作用的研究进展做一综述,为临床上清除牙菌斑生物膜的治疗方案提供新的思路。     

分散蛋白B的研究进展

细菌自身合成的细胞外多糖是生物膜抵抗抗菌物质和宿主免疫成分的重要保护屏障,因此降解细胞外多糖或抑制其合成是目前研发抗生物膜药物的热点之一。分散蛋白B是近年来在牙周可疑致病菌伴放线嗜血杆菌生物膜中发现的一种β-己糖苷酶,具有降解细胞外多糖的作用,是一种潜在的临床抗微生物膜感染类药物。本文就分散蛋白B及其结构和作用机制以及应用等研究进展作一综述。     

根管生物膜及其临床控制的研究进展

生物膜是细菌赖以生存的环境,膜结构可以抵御外界因素如抗菌剂的影响,对细菌有保护作用.牙髓感染性疾病中根管生物膜的形成与疾病的治疗和预后密切相关,有关根管生物膜的研究将有利于找出能更有效地治疗牙髓感染性疾病的新方法.     

中药对口腔细菌生物膜作用的实验研究

目的用五倍子和蜂房的有效成分作为实验药物研究中药对口腔细菌生物膜结构、活性的影响及对生物膜中葡萄糖转移酶（GTF）活性的影响，探讨中药防龋的可能性。方法用荧光显微镜结合特异荧光染料标记口腔细菌生物膜中死菌和活菌的方法，研究实验药物对口腔细菌生物膜结构和活性的影响。硫酸铵沉淀法提取粗酶，Neson-Somogyi法测定还原糖，G250微量蛋白定量GTF还原糖计算GTF活性单位，评价实验药物对口腔细菌生物膜中GTF活性的影响。结果早期细菌定植黏附到形成成熟生物膜结构的过程中都存在一定数量的死菌。24h常态生物膜结构中活菌面积占主导地位，有少量死菌存在，细菌互相紧密黏附在一起，生物膜结构清晰。0．05％氯己定对24h细菌生物膜作用后，细菌总量明显下降，残存滞留的细菌基本为死菌。0．023％的NaF作用于细菌生物膜后，生物膜结构发生明显变化，细菌总量明显减少，存在的细菌以活菌为主。经4g／L五倍子多酚性化合物（GCE）、五倍子化学组分B（GCE-B）及32g／L蜂房化学组分1（NVE1）作用后，生物膜结构模糊不清，细菌散开，生物膜结构密度下降，其中死菌和活菌量基本相同。生物膜细菌总量减少，与24h常态生物膜相比，差异有统计学意义（P〈0．05）。各实验组活菌百分比与阴性对照组活菌百分比相比差异有统计学意义（P〈0．05）。24h口腔细菌生物膜经4g／L GCE以及32异／L NVE1作用后，GTF的活性受到明显抑制，与阴性对照组相比差异均有统计学意义（P〈0．05）。GCE-B在实验浓度下对GTF的活性未产生明显的抑制作用。结论五倍子和蜂房有效成分组成的实验药物对口腔细菌生物膜的抑制作用不单纯是对口腔生物膜细菌有杀灭作用，还可能通过对口腔细菌生物膜结构的改变调整其内部的细菌组成及抑制细菌生物膜中GTF活性而发挥作用。     

生物膜在口腔医源性感染中的作用及其防治研究进展

生物膜是自然界广泛存在的细菌生存方式,生物膜中的细菌与普通的游离细菌有着不同的特点,能够耐受外界环境中各种不利因素的侵袭。生物膜的存在可导致细菌性的医源性感染,也是牙科水道污染的原因。本文主要介绍了生物膜的形成机制、生物学特点以及在口腔医源性感染中的作用和相应的防治方法。     

牙周生物膜的特性及其控制

摘要牙周生物膜是引起牙周炎的重要原因,生物膜具有自身特殊的结构特点,由细菌通过非随机的共聚与粘附作用而形成。由于生物膜中细菌有特殊的生理状态,基质对抗生素的屏障作用,以及细菌代谢产物的作用等,使得生物膜的抗药性较浮游菌高出1000倍以上。机械清创与抗生素的合理应用可以有效地控制牙周生物膜。     

慢性根尖周炎根尖生物膜的扫描电镜观察

目的：观察慢性根尖周炎根尖表面细菌生物膜分布及其超微结构。方法：扫描电镜观察新鲜拔除的24颗离体牙根尖表面,其中5颗为正畸或阻生拔除的活髓牙,5颗为X-ray显示根尖区正常的死髓牙,14颗为X-ay显示根尖区已有慢性病变的患牙。结果：在根尖区正常的活髓牙和死髓牙根尖表面均没有发现细菌生物膜;而在有慢性根尖病变的14颗患牙根尖表面,全部观察到了细菌生物膜的存在。这些生物膜分布于根尖表面的部分区域,可由单一细菌形成也可由多种微生物组成。结论：慢性根尖周炎根尖表面部分区域存在有细菌生物膜,其超微结构特征因细菌组成不同而异。     

口腔生物膜体外模型的建立和应用评估

目的：通过建立体外生物膜模型，模拟口腔内生态环境以探索生物膜在龋病发生发展中的作用。方法：利用发酵罐与恒流培养室的组合构建简易的体外生物膜模型，通过恒流培养室内液体培养基连续的流动循环，模拟出口腔内液体持续冲刷的生态环境。在羟磷灰石片上定植4种口腔常驻菌，以形成实验性生物膜，并通过每12h定时给以蔗糖底物，模拟致龋环境，观察系统中实验菌CFU计数、pH动态变化等各项反应及不同环境下所形成生物膜的微结构变化。结果：本研究建立的系统能较好的控制各项实验参数，加入蔗糖底物后表现出明显的致龋反应。结论：本组建立的体外模型有着良好的可靠性与可重复性，可用于对口腔生物膜的各项体外研究。     

Predation of oral pathogens by Bdellovibrio bacteriovorus 109J

Periodontal diseases are multifactorial infections elicited by a complex of primarily gram‐negative bacteria that interact with host tissues and lead to the destruction of the periodontal structures. Bdellovibrio bacteriovorus is a gram‐negative bacterium that preys upon other gram‐negative bacteria. It was previously shown that B. bacteriovorus has an ability to attack and remove surface‐attached bacteria or biofilms. In this study, we examined the host specificity of B. bacteriovorus strain 109J and its ability to prey on oral pathogens associated with periodontitis, including; Aggregatibacter actinomycetemcomitans, Eikenella corrodens, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis and Tannerella forsythia. We further demonstrated that B. bacteriovorus 109J has an ability to remove biofilms of Ei. corrodens as well as biofilms composed of A. actinomycetemcomitans. Bdellovibrio bacteriovorus was able to remove A. actinomycetemcomitans biofilms developed on hydroxyapatite surfaces and in the presence of saliva, as well as to detach metabolically inactive biofilms. Experiments aimed at enhancing the biofilm removal aptitude of B. bacteriovorus with the aid of extracellular‐polymeric‐substance‐degrading enzymes demonstrated that proteinase‐K inhibits predation. However, treating A. actinomycetemcomitans biofilms with DspB, a poly‐N‐acetylglucosamine (PGA) ‐hydrolysing enzyme, increased biofilm removal. Increased biofilm removal was also recorded when A. actinomycetemcomitans PGA‐defective mutants were used as host cells, suggesting that PGA degradation could enhance the removal of A. actinomycetemcomitans biofilm by B. bacteriovorus.     

珊瑚骨粉、口腔修复膜应用于即刻种植的临床研究

目的:选择合适的适应征进行微创拔牙后行即刻种植术,观察人工珊瑚颗粒、海奥生物膜行GBR技术,应用于前牙区即刻种植成骨效果.方法:25例前牙冠根折伴骨吸收患者进行即刻种植手术.微创拔除残根,牙槽窝嵴周少量骨缺损或伴唇侧骨壁洞穿,常规预备后植入种植体,种植体与牙槽窝骨壁间隙内、骨缺损处植入人工珊瑚颗粒(天博骨粉),盖海奥口腔修复膜,种植体均为潜入式愈合,二期手术后常规修复.观察二期手术及修复后6月或1年植骨区外形及牙龈状况.结果:二期手术时牙槽嵴成骨明显,包绕种植体颈周,二期手术修复后6月或1年牙槽外形均较植骨前丰满,牙龈质地、色泽良好.结论:珊瑚骨粉颗粒联合海奥生物膜应用于即刻种植修复少量骨缺损,成骨效果可靠.     

In vitro models for oral malodor

A model is a representation of some real phenomena and contains aspects or elements of the real system to be modeled. The model reflects (or duplicates) the type of behavior (or mechanisms) seen in the real system. The main characteristic of any model is the mapping of elements or parameters found in the system being studied (e.g. tongue dorsum biofilm in situ ) on to the model being devised (e.g. laboratory perfusion biofilm). Such parameters include correct physico-chemical (abiotic) conditions as well as biotic conditions that occur in both model and reality. The main purpose of a model is to provide information that better explains the processes observed or thought to occur in the real system. Such models can be abstract (mental, conceptual, theoretical, mathematical or computational) or 'physical', e.g. in the form of a real disaggregated in vitro system or laboratory model. A wide range of different model systems have been used in oral biofilm research. These will be briefly reviewed with special emphasis on those models that have contributed most to knowledge in breath odor research. The different model systems used in breath odor research are compared. Finally, the requirements for developing an overall 'bad breath model' from considering the processes as a whole (real oral cavity, substrates in saliva, biotransformation by tongue microflora, odor gases in the breath) and extending this to the detection of malodor by the human nose will be outlined and discussed.     

Pathophysiology of sinusitis of odontogenic origin

Sinusitis of odontogenic origin, which is frequently encountered in routine otolaryngological and dental clinical practice, has been described as a reactive maxillary inflammation secondary to maxillary tooth infection or trauma to an odontogenic disease of maxillary bone, dental extractions, implant placement, or endodontic treatment impairing the integrity of the Schneiderian membrane. The aim of the present review was to investigate and discuss the most recent pathophysiological findings, predisposing odontogenic factors, microbiology, and the possible involvement of bacterial biofilms (BB) in the development of sinusitis. The narrative literature review showed that there might be a correlation between the bacteria present in pathological teeth in communication with the sinus and those found in infected sinus. The formation of a BB might be also involved in the etiopathogenesis of sinusitis of odontogenic origin. In conclusion, the true origin of odontogenic sinusitis is still unresolved. In clinical terms, the choice of suitable therapy depends on the characteristics of the biofilm. Further microbiological studies are required to better investigate the role of BB.     

Biofilm growth of Lactobacillus species is promoted by Actinomyces species and Streptococcus mutans

The ability of oral bacteria to integrate within a biofilm is pivotal to their survival. A dependence on the amount of biofilm growth by noncoaggregating Lactobacillus rhamnosus and Lactobacillus plantarum on coculture with Actinomyces naeslundii, Actinomyces gerencseriae, Streptococcus mutans and Veillonella parvula was investigated using an artificial-mouth culture system. Biofilm formation by the lactobacilli in mono-culture was poor. In coculture with Actinomyces species the amount of L. rhamnosus increased 7-20 times and L. plantarum 4-7 times compared to its mono-culture biofilm. S. mutans also promoted substantial biofilm growth of lactobacilli but V. parvula had no effect. We conclude that these Actinomyces species promoted growth of key Lactobacillus species in a biofilm, as did S. mutans to a smaller extent, and that the ability of individual bacteria to form mono-culture biofilms is not necessarily an indicator of their survival and pathogenic potential in a complex multispecies biofilm community.     

Removal of Streptococcus mutans biofilm by bubbles

BACKGROUND: Air bubbles had been shown to remove particles and bacteria from surfaces, but they had not yet been studied regarding the removal of mature biofilm from a surface. METHODS: Streptococcus mutans were grown as a biofilm on glass coverslips and were exposed to a fluid stream with or without bubbles. Three parameters (stream velocity, gas fraction, and bubble size) were varied in the bubble stream to determine which conditions best remove the biofilm. RESULTS: At low velocities bubbles enhance biofilm removal compared with the liquid alone. Stream conditions that were shown to be the most effective in removing biofilm were large bubbles at low gas fractions. CONCLUSIONS: These results suggest that flowing bubble streams may be a desirable feature to incorporate into oral hygiene products to remove accumulated biofilms such as dental plaque.