慢性根尖周炎根管中8种厌氧菌检出分析

目的应用16SrRNA-PCR技术检测慢性根尖周炎患牙根管内8种厌氧菌的定植情况,分析根管细菌与患牙临床症状的关系。方法采集23例慢性根尖周炎患牙根管样本,提取样本细菌DNA,用细菌16SrRNA引物通过PCR扩增细菌基因片段检测细菌种类。结果23例样本均检出有细菌存在,待检细菌检出率达73.91%(17/23)。其中检出率最高的是中间普氏菌(39.13%),其次是牙龈卟啉菌(30.43%)和福赛斯类杆菌(21.74%),变黑普氏菌、齿垢密螺旋体和啮蚀艾肯氏菌均为13.04%,伴放线放线杆菌有1例检出,直肠弯曲杆菌未检出。中间普氏菌在有自发痛症状组检出率高于无自发痛症状组(P<0.05),其他细菌检出率组间比较差异无显著性。结论慢性根尖周炎患牙根管内以厌氧菌感染为主;根管内中间普氏菌感染与患牙自发痛症状相关。     

深龋乳牙根管细菌学分析

目的本研究的目的是对患有深龋的乳牙根管内细菌进行分析。方法选择12颗深龋乳牙，其中3颗有冷热刺激痛，其余9颗无临床症状。分别在微需氧(80％N2，10％H2，10％CO2)及厌氧条件(90％N2，10％CQ)下进行患牙根管细菌分离和鉴定。结果结果显示有症状牙的菌落形成单位(Colony Fomation Unit，简称CFU，下同)比无症状牙高，但二者间的差异无显著性。在这两组中，根管细菌的组成相似，并且与深龋的细菌组成相似。变链菌和乳杆菌占可培养细菌的比例比其它细菌高，差异有显著性，而且变链菌和乳杆菌的检出率比其它细菌高，差异亦有显著性。专性厌氧菌，如消化链球菌、韦荣氏菌、梭杆菌和普氏菌也有所检出，但其检出率和占可培养菌百分比均很低。结论微需氧致龋菌是乳牙龋源性牙髓炎的主要致病菌。     

口臭患者舌背菌群分析

目的分析口臭患者舌背菌群多样性变化的规律。方法采集7名口臭患者和4名健康者舌苔标本，使用通用引物扩增标本中所有细菌的16SrDNA片段，测序分析并构建舌背微生物的种系进化树。结果共检测212个克隆，口臭组136个，鉴定出42种微生物（包括9种尚不能确定的微生物）；对照组76个克隆，鉴定出23种微生物（包括7种尚不能确定的微生物）。2组标本中检出率最高、检出数目最多的菌种均为链球菌；其中17种已知细菌只在口臭患者舌苔上检出，检出率最高的是叶瘤杆菌（85．7％），殊异韦荣氏菌（71．4％）和Solobacterium moorei（57．1％）。结论口臭组舌背菌群的生物多样性高于对照组。叶瘤杆菌、殊异韦荣氏菌、Solobacterium moorei可能与口臭的产生相关，需进一步研究证实。     

牙周及根尖周脓肿厌氧菌培养分析

本文报告40例牙周脓肿和根尖周脓肿厌氧菌培养的结果。厌氧菌培养阳性37例(92.50％)共分离出98株厌氧菌,其中以革兰氏阴性杆菌最多54株(55.1％),革兰氏阳性球菌次之28株(28.59％)。革兰氏阳性杆菌11株(11.22％),韦荣氏球菌5株(5.11％)。这些厌氧菌的种类及分布与口腔正常菌群相似,提示:牙周脓肿和根尖周脓肿感染来源于口腔正常菌群。另外,37例培养阳性的病例中,单一菌种感染的只有4例(10.81％),其余33例分别为2—4种细菌感染,提示:牙周脓肿及根尖周脓肿的感染为混合性感染。24例牙周脓肿患者中,培养出69株厌氧菌,其中以革兰氏阴性杆菌最多41株(59.42％),提示革兰氏阴性杆菌是牙周脓肿的优势菌。     

感染根管中6种厌氧菌与症状或体征的相关性研究

目的：应用16S rRNA—PCR技术测定感染根管内6种细菌的检出率,分析根管内细菌种类与临床症状及体征的关系。方法：采集48例感染根管样本,按照临床症状或体征分为自发痛、叩痛、窦道3组,提取样本细菌基因组DNA,用PCR扩增细菌16S rRNA基因片段的方法检测细菌种类,计算检出率。结果：共检测48例样本,其中35例检测到待检细菌,检出率达72.9%。检出率最高的是牙髓卟啉单胞菌（35.4%）,其次是牙龈卟啉单胞菌（31.2%）和粪肠球菌（29.1%）,咽峡炎链球菌为（18.7%）,有2例能检出古菌,轻链球菌未检出。统计学分析显示,牙龈卟啉单胞菌与自发痛、粪肠球菌与窦道分别存在相关性（P〈0.05）。结论：根管感染是由多种细菌造成的;5种细菌是感染根管的优势菌;感染根管内牙龈卟啉单胞菌和粪肠球菌检出与临床相应症状或体征有相关性。     

乳牙感染根管内细菌与根尖周病临床症状的关系

本文对乳牙感染根管内细菌与根尖周病临床症状间的关系进行了探讨.本文按标准选择病例,其中慢性根尖周炎47例,急性根尖周炎28例.按急,慢性根尖周炎中各种不同症状,分别进行组合与分析.并按常规细菌学方法采集标本、培养、鉴定、计数.检测结果均经统计学处理.实验结果初步证实乳牙感染根管中的某些细菌与乳牙根尖周病临床症状间具有一定的关系,如:牙髓拟杆菌多存在于有急性症状的症例组中;其它厌氧菌在慢性根尖周炎组中占优势;产黑色素拟杆菌可能与严重松动叩痛有关,与肿胀和根尖透影无关.本研究对乳牙根尖周病的临床诊断方面,初步提供了细菌学的资料.对乳牙感染根管中细菌与根尖周病间复杂的微生态关系,尚需进一步加以探讨.     

乳牙根尖周病相关微生物研究进展

乳牙根尖周组织炎症的发生、发展及治疗效果与感染根管和根尖周病损组织内微生物的存在密切相关，不同的微生物可能与不同的临床症状及影像学表现有关联。为了解乳牙根尖周病相关微生物及其与临床症状或影像学表现的关系，文章就近年来乳牙根尖周病相关微生物的研究进展做一综述。     

乳牙急性根尖周脓肿细菌的DGGE分析

目的 用PCR-DGGE方法分析乳牙急性根尖周脓肿细菌,以期进一步阐明乳牙急性根尖周脓肿细菌病因学特点.方法 采取乳牙急性根尖周脓肿脓液,提取细菌总DNA,采用通用引物对细菌16S rRNA 基因的V2-V3区进行扩增,PCR产物进行变性梯度凝胶电泳,切取电泳的条带进行DNA回收,PCR再次扩增后进行克隆测序,鉴定细菌,分析细菌组成.结果 乳牙急性根尖周脓肿优势菌的检出从高到低依次是普雷沃菌90.9%,梭杆菌81.8%,消化链球菌63.6%,卟啉单胞菌45.5%,链球菌45.5%,真杆菌45.5%,乳酸杆菌27.3%,弯曲菌27.3%,密螺旋体27.3%,布雷德菌27.3%.结论 乳牙急性根尖周脓肿细菌存在个体差异,某些特定细菌以较高频率存在.细菌16S rRNA基因 PCR-DGGE,切胶,克隆测序方法除检测出培养法检出的细菌外,还检出难培养的和未预料到的细菌.     

产黑色素类杆菌群在牙髓坏死和根尖周疾病中的意义

本语言利用抗产黑色素类杆菌群共同抗原的单克隆抗体间接免疫荧光法，检测了101例牙髓坏死、根尖周病变感染根管中的产黑色素类杆菌群菌株，发现慢性根尖周炎急性发作时该菌群检出率明显上升，研究发现自发痛、叩痛、尖周区肿根管臭味、根尖阴影、根管渗液的出现与产黑色素类杆菌群有一定关系。     

80例口腔凳面部感染的厌氧菌分析

目的 确定８０例口腔颌面部感染的细菌类型，研究厌氧菌在其中的分布及厌氧菌代谢产物在其鉴定中的辅助作用。方法 对脓液标本进行分离培养，同时应用ＧＬＣ技术分析厌氧菌代谢产物辅助确定厌氧菌种、属。结果 ８０例口腔颌面部感染的脓液标本全部分离出细菌。厌氧菌检出率９５．００％，分布于８个属、２９个种，检出率高的厌氧菌依次为消化链球菌、消化球菌、类杆菌、菜杆菌、韦荣氏菌、真杆菌等。厌氧菌与需氧菌混合感染率为８     

Microbial analysis of canals of root-filled teeth with periapical lesions using polymerase chain reaction

The objective of the present study was to investigate the presence of nine bacterial species in root-filled teeth associated with periapical lesions using a polymerase chain reaction analysis and to correlate these species with clinical features of the cases. DNA was extracted from 45 canal samples of root-filled teeth with periapical lesions. A PCR assay using species-specific primers of 16S rDNA and the downstream intergenic spacer region was used for microbial detection. Enterococcus faecalis was the most prevalent species, detected in 77.8% of the study teeth, followed by Peptostreptococcus micros, detected in 51.1%. Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia, and Prevotella nigrescens were detected in 35.6%, 22.2%, 11.1%, and 11.1% of the sampled teeth, respectively. Moreover, PCR detected Filifactor alocis in 26.7%, Treponema denticola in 24.4%, and Tannerella forsythia in 4.4% of the samples. T. denticola and P. micros were statistically associated with tenderness to percussion (p < 0.05). P. nigrescens was associated with the presence of spontaneous pain and abscess (p < 0.05). P. endodontalis and P. nigrescens were associated with purulent exudates (p < 0.05). Synergistic relationship was also observed between some species. The results of this study indicated that E. faecalis was the most frequently identified test species by PCR in teeth with failing endodontic treatment.     

Microbiological analysis of infected root canals from symptomatic and asymptomatic teeth with periapical periodontitis and the antimicrobial susceptibility of some isolated anaerobic bacteria

The purpose of the present study was to investigate the correlation between the composition of the bacterial flora isolated from infected root canals of teeth with apical periodontitis with the presence of clinical signs and symptoms, and to test the antibiotic susceptibility of five anaerobic bacteria mostly commonly found in the root canals of symptomatic teeth against various substances using the E-test. Microbial samples were taken from 48 root canals, 29 symptomatic and 19 asymptomatic, using adequate techniques. A total of 218 cultivable isolates were recovered from 48 different microbial species and 19 different genera. Root canals from symptomatic teeth harbored more obligate anaerobes and a bigger number of bacterial species than the asymptomatic teeth. More than 70% of the bacterial isolates were strict anaerobes. Statistical analysis used a Pearson Chi-squared test or a one-sided Fisher's Exact test as appropriate. Suggested relationships were found between specific microorganisms, especially gram-negative anaerobes, and the presence of spontaneous or previous pain, tenderness to percussion, pain on palpation and swelling amoxicillin, amoxicillin + clavulanate and cephaclor were effective against all the strains tested. The lowest susceptibility rate was presented by Prevotella intermedia/nigrescens against Penicillin G. Our results suggested that specific bacteria are associated with endodontic symptoms of infected teeth with periapical periodontitis and the majority of the anaerobic bacterial species tested were susceptible to all antibiotics studied.     

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目的应用聚合酶链式反应-变形梯度凝胶电泳（PCR—DGGE）技术检测慢性根尖周炎患牙根管内中间普菌和链球菌定植情况,分析根管内细菌与患牙症状间关系。方法2011年12月至2013年5月于北京大学深圳医院口腔科就诊的27例慢性根尖周炎患牙根管内细菌样本,提取DNA,利用16SrDNA引物进行PCR—DGGE技术分析。结果27例共检出细菌菌属17种。中间普菌在17例有症状组中检测出16例（94．1％）,在10例无症状组中检测出6例（60．0％）,两组检出率差异有统计学意义（P〈0．05）。链球菌在17例有症状组中均未检测出,在10例无症状组中检测出4例（40．0％）,两组检出率差异有统计学意义（P〈0．05）。结论慢性根尖周炎患牙以厌氧菌感染为主,根管内中间普菌、链球菌与临床症状相关。     

Combinations of bacterial species in endodontic infections

AIM: This study was undertaken to investigate combinations of bacteria found in root-canal infections of teeth with periapical bone destruction without clinical signs and symptoms. METHODOLOGY: Endodontic samples from 58 root canals were cultured anaerobically and microorganisms were counted and identified. Eighty-one combinations of microorganisms were found and tested for a symbiotic relationship using the Fisher's exact test and Odds ratio calculation. RESULTS: All samples contained microorganisms with a median CFU mL(-1) of 8x10(4) per sample. Strict anaerobic species accounted for 87% of the microflora. The most prevalent bacteria were Prevotella intermedia, Peptostreptococcus micros and Actinomyces odontolyticus, present in 33, 29 and 19%, respectively, of the cultured canals. A significant relationship (P<0.05) and an Odds ratio >2 were found between P. intermedia and P. micros, P. intermedia and P. oralis, A. odontolyticus and P. micros, Bifidobacterium spp. and Veillonella spp. Conclusions: These results indicate that endodontic pathogens do not occur at random but are found in specific combinations.     

Neutrophil elastase levels in periapical exudates of symptomatic and asymptomatic teeth

The aim of this study was to determine neutrophil elastase levels (NE) in periapical exudates and to evaluate its relationship with clinical signs and symptoms of endodontically involved teeth. A total of 42 teeth with periapical periodontitis of 37 patients were clinically examined and spontaneous pain, swelling, pain on palpation or percussion, sinus tract formation and pus discharge were recorded. Additionally, periapical lesion size was measured on periapical radiographs. Periapical exudate samples were obtained during routine root canal treatment by using paper points. Enzyme levels were determined by spectrophotometric assays using the NE specific substrate N-methoxysuccinil-Ala-Ala-Pro-Val-p-nitroanilide. The teeth with signs and symptoms showed higher NE levels than the teeth without symptoms (p<0.05). The differences were significant when NE levels were presented as total amounts instead of concentration. This study demonstrated that NE in periapical lesions related with clinical symptoms and total enzyme amount may be more reliable mode of data presentation.     

Associations of endodontic symptoms and signs with particular combinations of specific bacteria

Significant associations have been reported between (a) specific bacterial species isolated from root canals and (b) between individual bacterial species and endodontic symptoms and signs. The prime objective of this study was to determine whether particular combinations of specific bacteria are associated with individual endodontic symptoms and signs. Seventy root canals were investigated microbiologically taking care to maintain the viability of obligate anaerobes, which accounted for 64% of the total species isolated, including Peptostreptococcus micros, Prevotella melaninogenica, Prevotella oralis, Eubacterium aerofaciens, Eubacterium lentum, Fusobacterium nucleatum, Prevotella buccae and Prevotella intermedia. Significant associations were found between individual clinical features and the following pairs of species: (a) pain (37 cases) and Peptostreptococcus spp./Prevotella spp., Peptostreptococcus spp./Prevotella melaninogenica, Pstr. micros/Prev. melaninogenica (all P < 0.01); (b) swelling (23 cases) and Pstr. micros/Prevotella spp. (P < 0.01); (c)‘Wet’canal (57 cases) and Prevotella spp./Eubacterium spp. (P < 0.01), Peptostreptococcus spp./Eubacterium spp. (P < 0.05). Thus data from this investigation suggests that statistically significant associations exist between individual endodontic symptoms and signs and particular combinations of specific bacteria.     

长春地区儿童乳牙急慢性根尖周炎根管内厌氧菌的分析

目的 对长春地区60例儿童急慢性根尖周炎患者的感染根管进行厌氧菌分离鉴定，为指导临床选择用药奠定基础。方法 利用智能化细菌鉴定和药敏系统-ATB快速鉴定仪分离培养和鉴定细菌。结果 98．3％（59／60）的患牙共检出厌氧菌144株，平均每例标本检出2．44株。结论 乳牙急性根尖周炎感染根管内的优势菌以梭杆菌为主，慢性根尖周炎感染根管内的优势菌以放线菌为主。     

Periopathogenic bacteria in persistent periapical lesions: an in vivo prospective study

BACKGROUND: The aim of this in vivo prospective study was to detect the presence of periopathogenic bacteria in persistent periapical lesions and to compare the reliability of two different methods: anaerobic culture and the DNA hybridization technique. METHODS: Samples were obtained from 24 patients with persistent periapical lesions referred for surgical endodontic treatment. A sterile paper point was inserted into the periapical lesion for 10 seconds. The point was stored in sterile transfer tubes and analyzed by DNA hybridization. Tissue samples were transported in transfer medium and analyzed further using anaerobic culture. RESULTS: At least one periodontal pathogenic bacterium was found in seven of 24 cases. Bacterial species present were Treponema denticola (three cases), Porphyromonas gingivalis (three cases), Tannerella forsythensis (four cases), Prevotella intermedia (one case), and Actinobacillus actinomycetemcomitans (three cases). No particular signs or symptoms were associated with the presence of these bacterial species. Anaerobic culture failed to identify any of the periopathogenic bacteria. CONCLUSIONS: Periodontal pathogenic bacterial DNA can be detected in persistent periapical lesions. Anaerobic cultures failed to detect the periodontal pathogenic bacteria in positive hybridization assays, suggesting that standard culture methods lack sensitivity or that hybridization assays are flawed with low specificity. The clinical significance of the presence of bacterial DNA in persistent periapical lesions remains to be determined.     

Bacterial invasion of non-exposed dental pulp

Anaerobic procedures were adopted to demonstrate the early bacterial invasion of non-exposed dental pulps, and to isolate and identify the bacteria. Of 19 freshly extracted teeth which originally exhibited deep dentinal lesions, clinical examination and electric pulp testing showed that nine of them had no pulpal exposure. Thus the pulps of these teeth were covered by clinically sound dentine beneath the carious lesion. Bacteria were found to have invaded the pulps of six of these nine teeth. The predominant bacteria were obligate anaerobes belonging to the genera Eubacterium, Propionibacterium and Actinomyces. Other obligate anaerobes were Lactobacillus, Peptostreptococcus, Veillonella and Streptococcus. The bacterial composition resembled that of the deep layers of dentinal lesions described previously, suggesting that the bacteria isolated in this study had passed through some individual dentinal tubules, to invade the dental pulp.