牙菌斑

牙菌斑是一种细菌性生物膜，为基质包裹的互相黏附，或黏附于牙面、牙间或修复体表面的软而未矿化的细菌性群体，不能被水冲去或漱掉。牙菌斑生物膜是整体生存的微生物生态群体，不同于悬浮的单个细菌，细菌凭借生物膜的独特结构黏附在一起生长，使细菌附着很紧，难以清除；另外，菌斑生物膜的形成是一种适应过程，使细菌能抵抗宿主防御功能、     

小分子化合物抗牙菌斑生物膜的研究进展

牙菌斑生物膜是引起龋病和牙周病的主要原因,生物膜中的细菌对抗生素和宿主防御的抵抗力显著高于浮游细菌。传统去除生物膜的方法存在许多不足之处,小分子化合物因细胞渗透性强和合成简单等优点,成为近年来研发生物膜抑制剂的热点。目前已经发现的小分子抗牙菌斑生物膜的化合物大致可分为三类:群体感应抑制剂、细菌粘附抑制剂和关键致病毒力因子抑制剂。本文对近年来小分子化合物在抗牙菌斑生物膜领域的研究进展作一综述。     

人体口腔微生物组群与牙菌斑生物膜

牙菌斑是由多种微生物组成的生物膜结构,口腔微生物之间的相互作用可以影响牙菌斑生物膜的性质、形成、毒力,以及微生物在生物膜结构中的定位和定植。生物膜内细菌之间存在的信号传导对生物膜的形成及其毒力具有影响。本文重点介绍人体口腔微生物组群与牙菌斑生物膜关系的最新研究进展。     

牙菌斑生物膜密度感应信号的研究进展

自然界细菌主要以生物膜形式生存。生物膜内细菌之间存在着各种信号交流以协调群体生理活动或竞争各类营养物质。口腔牙菌斑生物膜与龋病、牙周病密切相关。牙菌斑内的微生物信号传导近年来受到较多的关注并取得了研究进展。本文就近年来牙菌斑生物膜的信号传导研究作一综述。     

牙菌斑·生物膜·牙菌斑生物膜·生态膜·牙面生态膜

19世纪后期,学者由显微镜观察到牙齿表面有一种软而黏稠的沉积物,其中含有大量细菌。Williams(1897)称它为牙菌斑(dental bacterial plaque)。后来Dawes等(1963)指出:牙菌斑是一种附着牙面的软而黏稠,含有大量细菌且不易被清除的物质。从此,牙菌斑有了一个较准确的定义。上世纪80年代,许多研究者把细菌的生存状态称为生物膜(biofilm)。至90年代,口腔医学家认为牙菌斑也是一种生物膜,称为牙生物膜(dental biofilm)或牙菌斑生物膜(dental plaque biofilm)。Marsh(2004)认为牙菌斑是牙面上寄生的微生物群本身及其与宿主产生的多聚物包围的多…     

牙菌斑生物膜研究模型的进展

口腔微生物群落是典型的生物膜,牙菌斑生物膜是多种菌属组成的三维结构,黏附在牙齿表面,具有生物膜结构和微生物生理学的功能。牙菌斑生物膜是龋病和牙周病的主要致病因素,已有多种生物膜模型用于研究龋病的病因、预防和治疗的研究。这些龋病生物膜模型有助于研究者用一种可控、简化的方式来预测龋病的临床进展结果。目前,研究龋病微生物的模型有体外单菌种生物膜模型和多菌种生物膜模型。本文将从研究龋病的生物膜体外模型建立做一综述。     

牙菌斑生物膜的研究进展

牙菌斑生物膜是龋病和牙周病的始动因子。作为典型的细菌性生物膜^[1]，由链球菌属、乳杆菌属、放线菌属及其他菌属微生物细胞和细胞外多糖基质组成，各种细菌存在于宿主和细菌胞外多聚物基质包绕的立体三维结构中^[2]，相互黏附或附着、定植于牙表面及界面。经过动态的发展循环过程，     

原位菌斑生物膜的一种完整获得方法和结构研究

目的:通过对一种方法获得原位牙菌斑生物膜的结构分析,证明这种方法的可行性。方法:选择安装有局部可摘义齿的志愿者在基托表面粘贴塑料片的方法,在塑料片上可获得1、4、24h牙菌斑生物膜,并用激光共聚焦扫描显微镜进行结构的观察和分析。结果:牙菌斑生物膜的细菌、基质清楚可见,1、4、24h菌斑生物膜的平均厚度分别是(21.41±0.03)μm,(34.03±0.02)μm,(58.53±0.03)μm。结论:这种方法获取的菌斑生物膜结构完整、简便可行,是一种很好的获取原位牙菌斑生物膜的方法,可为进一步的实验提供平台。     

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。     

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牙菌斑是一种细菌性生物膜。菌斑控制是个人口腔卫生保健及龋病、牙周病防治的必要措施。菌斑控制的方法很多,其中有机械性措施和化学方法,然而每种方法又有其各自的局限性。近年来,光动力疗法在口腔抗菌方面的研究取得了一定进展,声动力疗法继光动力疗法在微生物领域的研究将具有重要的临床应用价值。本文就菌斑控制的方法做一综述。     

Effect of xylitol on salivary β‐glucosidase in humans

Dental biofilm – in which a diverse set of microorganisms are embedded in a complex polysaccharide matrix that adheres to oral components – is one of the most complex microbial communities in the human body. As biofilm formation is related to oral infections, such as caries and periodontal diseases, strategies for biofilm control are crucial for maintaining oral health. Xylitol, a synthetic sugar used as a sucrose substitute, has been shown to reduce biofilm formation. However, its precise mechanism of action on biofilm reduction has so far not been elucidated. Previous studies demonstrate that bacterial β‐glucosidase action is crucial for biofilm formation. Here, we investigated the correlation between salivary β‐glucosidase activity and dental plaque occurrence. We found a positive correlation between enzymatic activity and the presence of dental biofilm. We observed that xylitol inhibits β‐glucosidase in human saliva. Kinetic studies also confirmed that xylitol acts as a mixed type inhibitor of salivary β‐glucosidase. Based on our data, we suggest that xylitol impairs oral biofilm formation by the inhibition of bacterial β‐glucosidase, which is essential for biofilm formation in the oral cavity.     

The bacterial biofilm and the possibilities of chemical plaque control. Literature review

Most microorganisms in the oral cavity attach to surfaces and form matrix-embedded biofilms. Biofilms are structured and spatially organized, composed of consortia of interacting microorganisms. The properties of the mass of biofilm are different from that of the simple sum of the component species. The older the plaque (biofilm) is the more structurally organized and become more resistant to environmental attacks. The bacterial community favors the growth of obligatory anaerobic microorganisms. The most effective means of the elimination of matured biofilm is the mechanical disruption of the interbacterial protective matrix and removal of bacterial colonies. The antiseptic agents are primarily effective in the prevention of biofilm formation and anticipation of the maturation of the bacterial plaque. Bacteria in matured biofilms are less susceptible to antimicrobial agents because several physical and biological factors protect the bacterial consortia. To kill bacteria in a matured, well organized biofilm, significantly higher concentration and longer exposition are required. Antiseptic mouthrinses in a conventional dose and time can only reach the superficial bacteria while the bacteria in the depth of the biofilm remains intact. Therefore, the efficacy of any antiseptic mouthwash depends not just on its microbicidal properties demonstrated in vitro, but also on its ability to penetrate the organized biofilm on the teeth. Recent studies have demonstrated that both bisbiguanid compounds and essential oils are capable of penetrating the biofilm, and reduce established plaque and gingivitis. The essential oils showed high penetrability and were more effective on organized biofilm than stannous fluorides or triclosan copolymer antiplaque agents.     

Metabolomic effects of xylitol and fluoride on plaque biofilm in vivo

Dental caries is initiated by demineralization of the tooth surface through acid production from sugar by plaque biofilm. Fluoride and xylitol have been used worldwide as caries-preventive reagents, based on in vitro-proven inhibitory mechanisms on bacterial acid production. We attempted to confirm the inhibitory mechanisms of fluoride and xylitol in vivo by performing metabolome analysis on the central carbon metabolism in supragingival plaque using the combination of capillary electrophoresis and a time-of-flight mass spectrometer. Fluoride (225 and 900 ppm F(-)) inhibited lactate production from 10% glucose by 34% and 46%, respectively, along with the increase in 3-phosphoglycerate and the decrease in phosphoenolpyruvate in the EMP pathway in supragingival plaque. These results confirmed that fluoride inhibited bacterial enolase in the EMP pathway and subsequently repressed acid production in vivo. In contrast, 10% xylitol had no effect on acid production and the metabolome profile in supragingival plaque, although xylitol 5-phosphate was produced. These results suggest that xylitol is not an inhibitor of plaque acid production but rather a non-fermentative sugar alcohol. Metabolome analyses of plaque biofilm can be applied for monitoring the efficacy of dietary components and medicines for plaque biofilm, leading to the development of effective plaque control.     

In Vitro Biofilm Formation on Titanium and Zirconia Implant Surfaces

Background: It has been hypothesized that zirconia might have a reduced bacterial adhesion compared with titanium; however, results from experimental studies are rather controversial. The aim of the present study is to compare biofilm formation on zirconia and titanium implant surfaces using an in vitro three‐species biofilm and human plaque samples. Methods: Experimental disks made of titanium (Ti) or zirconia (ZrO₂) with a machined (M) or a sandblasted (SLA) and acid‐etched (ZLA) surface topography were produced. An in vitro three‐species biofilm or human plaque samples were applied for bacterial adhesion to each type of disk, which after 72 hours of incubation was assessed using an anaerobic flow chamber model. Results: Zirconia showed a statistically significant reduction in three‐species biofilm thickness compared with titanium (ZrO₂‐M: 8.41 μm; ZrO₂‐ZLA: 17.47 μm; Ti‐M: 13.12 μm; Ti‐SLA: 21.97 μm); however, no differences were found regarding three‐species‐biofilm mass and metabolism. Human plaque analysis showed optical density values of 0.06 and 0.08 for ZrO₂‐M and ZrO₂‐ZLA, and values of 0.1 and 0.13 for Ti‐M and Ti‐SLA, respectively; indicating a statistically significant reduction in human biofilm mass on zirconia compared with titanium. Additionally, zirconia revealed a statistically significant reduction in human plaque thickness (ZrO₂‐M: 9.04 μm; ZrO₂‐ZLA: 13.83 μm; Ti‐M: 13.42 μm; Ti‐SLA: 21.3 μm) but a similar human plaque metabolism compared with titanium. Conclusion: Zirconia implant surfaces showed a statistically significant reduction in human plaque biofilm formation after 72 hours of incubation in an experimental anaerobic flow chamber model compared with titanium implant surfaces.     

种植体愈合帽表面细菌生物膜结构初探

目的：研究口腔内纯钛种植体短期内表面细菌生物膜的结构，并探讨细菌生物膜结构与口腔卫生环境的相关性。方法：从12例种植患者获得术后6周复诊时取下的12枚完整的ITI种植体愈合帽，运用激光共聚焦显微镜对愈合帽表面生物膜的结构、分布等性质进行定性观察和定量分析，并分析了与牙菌斑指数的关系。结果：种植术后6周的12枚种植体愈合帽表面均广泛存在细菌生物膜，但分布不均，与愈合帽表面的位置有关。生物膜的厚度及范围与牙菌斑指数呈正相关。结论：术后短期内种植体愈合帽表面细菌生物膜的结构与口腔临床指标间存在一定的相关性。     

Synergistic use of ultrasound and sonic motion for removal of dental plaque bacteria

Proving that an idea has merit for further investigation is one of the earliest steps in product development. This proof of concept can be effectively studied in a dynamic, multidisciplinary environment where ideas can be quickly tested in a manner related to final product use. In this article, the authors demonstrate the fecundity of a multidisciplinary environment by reviewing their early work that shows that ultrasound could be added to a power toothbrush to enhance the removal of dental plaque bacteria. They hypothesized that sonic brush head motion would generate bubbles in a dentifrice so that ultrasound beamed into that slurry would cause those bubbles to expand and contract in a manner that would dislodge the plaque bacteria adherent to the tooth surfaces. In this work, Streptococcus mutans bacteria adherent to various surfaces was used as a model of dental plaque on human teeth. Prototype power toothbrushes were created using commercially available and custom components so that the ultrasound and sonic processes could be individually modified and applied. Research demonstrated that the combination of sonic and ultrasound processes could synergistically remove S mutans biofilm. This finding established the proof of concept that eventually led to the development of a power toothbrush that uses both ultrasound and sonic activity.