牙周致病菌的共聚及其对人工牙根面黏附力的影响

目的比较具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌等牙周病致病菌彼此之间的共聚力大小,观察四者在具核梭杆菌介导下对人工牙根面黏附力的影响,了解牙周生物膜结构中细菌间可能存在的相互作用。方法目测具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌彼此间的共聚力,以放射性核素闪烁计数四者在具核梭杆菌黏附和未黏附状况下对胶原包被羟磷灰石（c—HA）的黏附间是否存在着差异。结果具核梭杆菌、牙龈啉单胞菌、中间普雷沃菌和伴放线嗜血菌彼此间存在着共聚作用,其中,具核梭杆菌与牙龈卟啉单胞菌、牙龈卟啉单胞菌与中间普雷沃菌间的共聚度均可达4度,具核梭杆菌与其他三菌间的共聚度均大于3度。牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌在具核梭杆菌黏附的状况下对c—HA的黏附率高于其在具核梭杆菌未黏附时的黏附率,具核梭杆菌在未黏附的状况下对c—HA的黏附率高于其在黏附后的黏附率。结论具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌彼此间均存在共聚关系,具核梭杆菌可能对其他牙周病致病菌定植于牙菌斑起到了桥梁作用。     

牙周致病菌的共聚及其对人工牙根面黏附力的影响

目的比较具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌等牙周病致病菌彼此之间的共聚力大小,观察四者在具核梭杆菌介导下对人工牙根面黏附力的影响,了解牙周生物膜结构中细菌间可能存在的相互作用。方法目测具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌彼此间的共聚力,以放射性核素闪烁计数四者在具核梭杆菌黏附和未黏附状况下对胶原包被羟磷灰石(c-HA)的黏附间是否存在着差异。结果具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌彼此间存在着共聚作用,其中,具核梭杆菌与牙龈卟啉单胞菌、牙龈卟啉单胞菌与中间普雷沃菌间的共聚度均可达4度,具核梭杆菌与其他三菌间的共聚度均大于3度。牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌在具核梭杆菌黏附的状况下对c-HA的黏附率高于其在具核梭杆菌未黏附时的黏附率,具核梭杆菌在未黏附的状况下对c-HA的黏附率高于其在黏附后的黏附率。结论具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和伴放线嗜血菌彼此间均存在共聚关系,具核梭杆菌可能对其他牙周病致病菌定植于牙菌斑起到了桥梁作用。     

根周细菌对胶原包被羟磷灰石粘附的体外实验研究

目的：细菌对牙面的粘附能力与其致龋性密切相关，本研究旨在比较对牙面具有粘附能力的变形链球菌ATCC25175、粘性放线菌ATCC15987、乳杆菌ATCC4546、牙龋卟啉菌ATCC33277及中间普氏菌ATCC25611对胶原包被羟磷灰石实验膜（C－HA）的粘附能力，探讨口腔细菌在根周疾病中的作用。方法：采用同位素闪烁计数法测定上述五种细菌对胶原处理的羟基磷灰石（C－HA）的粘附能力，以[^3H]胸腺嘧啶核苷为标记对细菌的粘附进行定量观察，用每分钟的同位素放射量CPM表示（counts per mintue）。结果：所有细菌对C－HA表面的粘附率均有统计学意义（P＜0．01），粘性放线菌对C－HA表面的粘附率显著高于其它细菌组，牙龋卟啉菌及乳杆菌对C－HA表面的粘附率次之，变形链球菌及中间普氏菌对C－HA表面的粘附能力最弱。结论：不同的根周细菌对胶原包被的羟磷灰石的选择性粘附作用不同，粘性放线菌、乳杆菌及牙龋卟啉菌对胶原具较强的亲和作用，在细菌的局部定植过程及疾病的进展中发挥重要作用。     

血链球菌对牙周可疑致病菌体外拮抗作用的研究

目的体外研究血链球菌与牙周可疑致病菌的相互关系,探讨血链球菌全菌细胞、培养上清液对牙周可疑致病菌的拮抗作用。方法分别采用交叉双层培养基法和微量琼脂糖弥散法测定血链球菌全菌细胞和培养上清液对牙龈卟啉单胞菌、中间普雷沃菌、具核梭杆菌的拮抗作用。结果血链球菌全菌细胞均能拮抗这3种牙周可疑致病菌的生长;而其培养上清液无拮抗作用。结论血链球菌在牙周微生态系中起有益菌的作用,同时交叉双层培养基法是一种简便易行的测定血链球菌抑菌活性的方法。     

臭氧水溶液对牙周可疑致病菌作用的研究

目的：评价臭氧水溶液对常见牙周可疑致病菌的杀菌效果。方法：采用细菌悬液定量实验法,测定不同浓度的臭氧水溶液对牙龈卟啉单胞菌（P．g）ATCC33277、伴放线菌嗜血菌（H．a）ATCC29522、具核梭杆菌（F．n）ATCC10957和牙龈卟啉单胞菌临床分离株作用30、60、90、120 s 的杀菌率,阳性对照组采用不同浓度的过氧化氢溶液,阴性对照组采用蒸馏水。实验样本在厌氧培养72 h 后进行菌落计数并计算杀菌率。结果：臭氧水溶液对几种牙周可疑致病菌均有杀灭效果,且杀菌率随浓度的增加而提高（P ＜0．01）。对 P．g 标准株和临床分离株的杀菌率差异无统计学意义（P ＞0．05）。线性回归分析臭氧水溶液对3种细菌杀灭作用的浓度影响因素β值均大于0．95,时间影响因素β值均小于0．11。结论：臭氧水溶液对牙龈卟啉单胞菌、伴放线菌嗜血菌和具核梭杆菌具有浓度依赖性杀灭效果。     

牙周可疑致病菌的传播性研究进展

现代分子生物学的快速进展为微生物的分类学研究提供了多种高敏感度的方法,使研究各类细菌的传播途径成为可能。近年来研究表明牙周可疑致病菌可交互传播,本文着重就其中与牙周疾病关系密切的相关细菌在人群中传播的可能性及途径的研究进展进行综述。     

未获培养微生物与牙周可疑致病菌的牙周共生状态

目的：探索未获培养微生物与牙周可疑致病菌的共生关系。方法：使用基于16SrRNA基因检测的PCR法，对慢性牙周炎患者龈下菌斑中牙周可疑致病微生物和代表性未获培养微生物进行检测，通过KAPPA检验分析任意两种细菌对间的关系。结果：在56个细菌对中发现6对细菌的KAPPA值具有显著性。结论：Pg／T.d、B．f/T．d、B．f／F.n细菌组合的共生关系与文献报道一致，AU126／P．n、AU126／F．n、AU126／X112细菌对间的共生关系显示了未获培养微生物在龈下菌群中扮演的角色。     

牙周可疑致病菌对口腔黏膜上皮的粘附和侵入

牙周可疑致病菌可以通过细胞内途径、细胞旁途径以及细菌的某些表面蛋白侵入口腔黏膜上皮。侵入上皮组织后，细菌仍能适应环境的改变而生存，同时引起宿主细胞的一系列反应。本文对牙周可疑致病菌粘附、入侵口腔上皮的可能机制，以及入侵后引起的自身和上皮细胞改变作一综述。     

富组蛋白中和牙周可疑致病菌内毒素作用的实验研究

目的：研究人腮腺唾液富组蛋白对牙周可疑致病菌内毒素的中和作用。方法：采用改良Ｗｅｓｔｐｈａｌ热酚水法提取并纯化牙龈卟啉菌（４７－Ａ株）和具核酸杆菌（临床分离株）的内毒素,用鲎试验试管法观察ＨＲＰ－５对这两株细菌的内毒素的中和作用。结果：在本实验条件下,ＨＲＰ－５（１０μｇ／ｍｌ）能轻度抑制大肠杆菌、牙龈卟啉菌及具核酸杆菌的内毒素（１ｎｇ／ｍｌ）的鲎活性。结论：相同浓度的ＨＲＰ－５对需氧的大肠杆菌和     

牙周可疑致病菌对口腔黏膜上皮的粘附和侵入

牙周可疑致病菌可以通过细胞内途径、细胞旁途径以及细菌的某些表面蛋白侵入口腔黏膜上皮。侵入上皮组织后,细菌仍能适应环境的改变而生存,同时引起宿主细胞的一系列反应。本文对牙周可疑致病菌粘附、入侵口腔上皮的可能机制,以及入侵后引起的自身和上皮细胞改变作一综述。     

牙周致病菌内毒素耐受的研究进展

内毒素耐受(endotoxin tolerance)是指先前的脂多糖(lipopolysaccharide,LPS)刺激使机体或体外培养的细胞对后续刺激反应性降低的一种现象,可能导致炎症因子释放的减少,进而在牙周炎发生发展过程中发挥重要作用。本文就牙周致病菌内毒素耐受的作用和机制的研究进展作一综述。     

Antimicrobial activity of silver nitrate against periodontal pathogens

Metal ions were evaluated as potential antimicrobial agents suitable for local delivery in the oral cavity for the treatment of periodontitis. Silver nitrate, copper chloride, and zinc chloride were tested for antimicrobial activity in in vitro killing assays conducted in phosphate buffered saline with a series of oral bacteria including gram-negative periodontal pathogens and gram-positive streptococci. Copper and zinc salts failed to exhibit strong and consistent activity against periodontal pathogens. In contrast, silver at a concentration of 0.5 microg/mL produced a 3 log10 reduction in colony forming units (CFU)/mL or greater against all periodontal pathogens tested including Porphyromonas gingivalis, Prevotella intermedia, Prevotella denticola, Bacteroides forsythus, Fusobacterium nucleatum vincentii, Campylobacter gracilis, Campylobacter rectus, Eikenella corrodens, and Actinobacillus actinomycetemcomitans. In comparison, substantially higher concentrations of silver nitrate failed to kill oral streptococci. A silver nitrate concentration of 25 microg/mL produced log10 reductions in CFU/mL of 3.5-5 in killing assays performed in human serum against P. gingivalis, demonstrating the ability of silver to retain activity in a biological medium similar to that encountered in vivo in the periodontal pocket. These results identify silver nitrate, an antimicrobial that may possess advantages over traditional antibiotics, as a potential agent for controlled release local delivery in the oral cavity for the treatment of periodontitis.     

Association between betel quid chewing, periodontal status and periodontal pathogens

The present investigation examined whether an association exists between betel quid chewing and signs of periodontal disease and determined the prevalence of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis by polymerase chain reaction. The periodontal status of 34 betel quid chewers and 32 non-betel quid chewers were compared. A significantly higher prevalence of bleeding on probing was found in betel quid chewers than non-chewers among the subjects with higher plaque level, greater gingival inflammation, deeper probing depth or greater attachment loss. Also, the results suggested that betel quid chewers may harbor higher levels of infection with A. actinomycetemcomitans and P. gingivalis than non-betel quid chewers. The association persists after adjusting for severity of the clinical parameters. In conclusion, betel quid chewing was associated with a higher prevalence of bleeding on probing where higher clinical levels of disease existed, and with a likelihood of subgingival infection with A. actinomycetemcomitans and P. gingivalis.     

Comparison of profiles of key periodontal pathogens in periodontium and endodontium

Abstract – Despite the established anatomical relationship between the periodontal and pulpal tissues, bacterial migration between endodontium and periodontium is still under discussion. The objective of this study was an investigation of profiles of periodontal pathogens in pulpal and periodontal diseases affecting the same tooth by means of 16S rRNA gene directed polymerase chain reaction (PCR). 31 intact teeth with both pulp and marginal infections were investigated. The diagnosis was based on clinical and radiological examination. Samples were taken from the gingival sulcus or periodontal pocket, respectively, with sterile paper points before trepanation of the teeth. After trepanation sterile paper points and Hedstroem files were used for taking samples from the root canal. Specific PCR methods were used to detect the presence of the following pathogens: Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola. In addition, quantitative competitive PCR was used to determine the total bacterial count of the samples. The investigated pathogens were proven to be present in the endondontium in all disease categories. Particularly in endodontic samples of "chronic apical periodontitis" and "chronic adult periodontitis" profiles of the periodontal pathogens were found. The results confirmed that periodontal pathogens often accompany endodontic infections and supported the idea that the periodontic-endodontic interrelationships should be considered as critical pathways which might contribute to refractory courses of endodontic or periodontal diseases.     

Regulation of matrix metalloproteinase production by cytokines,pharmacological agents and periodontal pathogens in human periodontal ligament fibroblast cultures

Matrix metalloproteinases (MMPs). produced by both infiltrating and resident cells of the periodontium, play a role in physiologic and pathologic events. It is recognized that an imbalance between activated MMPs and their endogenous inhibitors leads to pathologic breakdown of the extracellular matrix during periodontitis. To date, little is known about the regulation of MMP synthesis and secretion in human periodontal ligament fibroblasts (PDLFs). The purpose of this study was to examine the effects of cytokines, pharmacological agents (protein synthesis inhibitor and protein kinase C inhibitors) and predominant periodontal pathogens (Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis) on MMP production in human PDLFs using gelatin zymography. The gelatin zymograms revealed that the main gelatinase secreted by human PDLFs migrated at 72 kDa and represents MMP-2. Minor gelatinolytic bands were also observed at 92 kDa regions that correspond to MMP-9. We found that A. actinomycetemcomitans, P. gingivalis and IL-1alpha can elevate MMP-2 secretion in human PDLFs. These results indicate that periodontal pathogens and inflammatory cytokines play an important role in tissue destruction and disintegration of extracellular matrix in periodontal diseases. Thus, activation of MMPs may be one of the distinct host degradative pathways in the pathogenesis of periodontitis. In addition, H7, staurosporine, cycloheximide and TGF-beta could suppress MMP-2 production. Agents that target protein synthesis or the protein kinase C pathway in human PDLFs inhibit MMP-2 production, and such inhibition may contribute to the pathogenesis of periodontal inflammation. Taken together, these findings suggest a possible new therapeutic approach, involving the use of drugs that modify host-response mechanisms to suppress or inhibit MMP-mediated tissue destruction.     

Endodontic pathogens in periodontal disease augmentation

Abstract. Periapical pathology indicating endodontic infection, when present in periodontitis-affected teeth, has recently been shown to be correlated to marginal periodontal breakdown. This has been associated with patency of dentinal tubules in the tooth cervix, an area normally devoid of cementum following periodontal therapy. These studies are, however hampered by that only circumstantial evidence such as presence of periapical destruction have been applied as criteria of endodontic infection. The aim of the present investigation was to assess the effects of endodontic pathogens on marginal periodontal wound healing on root surfaces devoid of cementum but surrounded by healthy periodontal membrane. Significant differences between infected and non-infected teeth were found with respect to pathological pocket and connective tissue: The experimental defects were covered by approximately 20% more pocket epithelium in infected teeth while defects in non-Infected teeth showed approximately 10% more connective tissue coverage. It was concluded, that an intra-canal infection of endodontic pathogens stimulates epitelial downgrowth along denuded dentin surfaces with marginal communication. Extrapolated to the clinical situation, endodontic infections in periodontitis-prone patients may augment periodontitis propagation.     

血链球菌在牙周病微生态防治中的作用研究--Ⅰ血链球菌对牙周可疑致病菌的拮抗作用

目的：对血链球菌全菌细胞和培养上清液的抗牙周可疑致病菌的作用进行研究。方法：分别采用常规打孔法和微量琼脂糖弥散法测定血链球菌全菌细胞和培养上清液的抗菌活性。结果：血链球菌JFr菌株全菌细胞菌悬液对中间普氏菌、牙龈卟啉单胞菌和具核梭杆菌的生长均有抑制作用。血链球菌培养上清液未见抑菌活性。丧失α-溶血能力的血链球菌变异株无这种抑菌作用。血链球菌JFr菌株对中间普氏菌临床分离株21—3的生长产生抑制作用的同时可见β-溶血反应。结论：血链球菌与牙周可疑致病菌之间的作用是相当复杂的，作用机制和结果在不同情况下可能有所不同。