牙周炎患者唾液中伴放线放线杆菌的检出状况分析

目的 检测不同类型牙周炎患者唾液中的伴放线放线杆菌(Actinobacillusactinomycetemcomitans,Aa),探讨唾液和集合龈下菌斑中Aa检出率的差异以及唾液中Aa的存在状况与牙周临床指标的关系. 方法 收集50例侵袭性牙周炎(aggressive periodontitis,AgP)患者、48例慢性牙周炎(chronic periedontitis,CP)患者和25例非牙周炎者的非刺激性全唾液和集合龈下菌斑,应用聚合酶链反应(PcR)技术检测两种样本中的Aa. 结果 Aa在AgP患者唾液中的检出率(32%)显著高于非牙周炎者(4%)和CP患者(15%),差异均有统计学意义(P<0.01,P<0.05),同时Aa在AgP患者唾液中的检出率也显著高于集合龈下菌斑样本(16%),差异亦有统计学意义(P<0.05).年龄≤30岁是唾液中存在Aa的危险指征(OR=3.23,P<0.05);出血指数≥3的位点超过70%与唾液中存在Aa有关(OR=19.21,P<0.01). 结论 AgP患者唾液样本中Aa的检出率明显高于集合龈下菌斑样本,亦高于CP患者和非牙周炎者,提示Aa可能参与AgP的发生和发展.     

实时荧光定量PCR检测牙周炎患者龈下菌斑的分布

目的 应用实时荧光定量PCR技术探索侵袭性牙周炎（aggressive periodontitis,AgP）、慢性牙周炎（chronic periodontitis,CP）患者龈下菌斑中伴放线聚集杆菌(A. actinomycetemcomitans,Aa)、牙龈卟啉单胞菌（P. gingivalis,Pg）的分布规律。方法 采集32例AgP、33例CP、32例牙周健康者的龈下菌斑,构建含有2种待测细菌基因片段的重组质粒,建立定量标准,采用TaqManMGB探针实时荧光定量PCR方法检测样本中细菌数量。结果 本实验构建的引物及TaqManMGB探针特异性及敏感性较好。AgP组龈下菌斑Aa的检出率高于CP组（P＜0.01）,但2种细菌数量在组间无显著差异,两组内Pg的检出率及数量都明显高于Aa（P＜0.001）,另外AgP组Aa的数量、CP组Pg数量与牙周探诊深度密切相关（P＜0.01及P＜0.001）。结论 龈下菌斑Aa的检出率可能与牙周炎类型存在一定关联,Aa可能并不是中国人群样本AgP患者龈下菌斑的优势菌,实时荧光定量PCR对牙周病学研究有广泛应用前景。     

侵袭性牙周炎和慢性牙周炎的龈下优势菌分析

目的 :分析侵袭性牙周炎 (aggressiveperiodontitis ,AgP)与慢性牙周炎 (chronicperiodontitis ,CP)的龈下优势菌群 ,为探讨牙周炎分类、病因和诊断提供实验依据。方法 :将中学生流调筛选 (16例 )及牙周病专科就诊(2 4例 )的AgP和CP患者 ,采集龈下菌斑样本 ,在厌氧菌基础培养基 (CDC)和选择性培养基 (TSBV)上培养分析。结果 :局限型AgP患者的伴放线放线杆菌 (Actinobacillusactinomycetemcomitans ,Aa)及兼性厌氧菌的检出率显著高于中度CP患者 (P <0 .0 5 ,P <0 .0 1) ,而广泛型AgP和重度CP患者的厌氧菌总数较局限型AgP和中度CP患者显著增加 (P <0 .0 5 )。结论 :局限型AgP和中度CP的龈下优势菌有明显差别 ,Aa是一个重要的危险因子。     

牙周炎患者基础治疗后牙龈卟啉单胞菌的定植研究

目的 通过对牙周炎患者龈下菌斑中牙龈卟啉单胞菌(Porphyromonas gingivalu,Pg)的检测,探讨慢性牙周炎(chronic periodontitis,CP)和侵袭性牙周炎(aggressive periodontitis,AgP)患者牙周基础治疗后Pg的定植规律.方法 选取90例CP患者和90例AgP患者,在牙周基础治疗前、治疗后6周、12周共采集龈下菌斑样本1620个,运用AmpliFluor终末点定量聚合酶链反应方法 检测Pg含量.结果 治疗后6周CP和AgP组Pg活动位点分别为61(22.6%)和66(24.4%)个,两者差异无统计学意义(P>0.05);治疗后6周Pg活动位点在治疗前检测的牙周临床指数高于Pg静止位点.治疗后12周两组Pg活动位点分别为96(35.6%)和18(6.7%)个,差异有统计学意义(P<0.05);治疗后12周Pg活动位点在治疗后6周时检测的牙周临床指数高于Pg静止位点.结论 在牙周基础治疗后6周时,CP和AgP患者Pg定植均已开始,仉是两组定植规律存在一定差异.在牙周基础治疗后,治疗前牙周组织炎性反应严重的龈下位点Pg易于定植.     

牙龈卟啉单胞菌在龈下菌斑和颊黏膜中的检测

目的　检测牙周健康者及牙周炎患者在颊黏膜和龈下菌斑中牙龈卟啉单胞菌的阳性率,探讨其与牙周炎发生和发展的关系。方法　选取40例牙周健康者和39例慢性牙周炎患者,分别收集颊黏膜和龈下菌斑样本,提取细菌DNA,设计细菌通用引物和牙龈卟啉单胞菌的特异引物用于PCR扩增,检测牙龈卟啉单胞菌的阳性率。结果　牙周健康组菌斑样本和颊黏膜样本牙龈卟啉单胞菌的阳性率分别为37·5%和32·5%,而牙周炎组菌斑样本和颊黏膜样本牙龈卟啉单胞菌的阳性率分别为69·23%和46·15%。牙周炎组菌斑的牙龈卟啉单胞菌阳性率高于牙周健康组,颊黏膜的牙龈卟啉单胞菌阳性率在组间无统计学差异;牙周炎组菌斑牙龈卟啉单胞菌阳性率高于颊黏膜, 牙周健康组两部位阳性率无统计学差异。结论　牙龈卟啉单胞菌除在菌斑中有高检出率外,在颊黏膜中也有较高的检出率,提示颊黏膜也是牙周细菌在口腔定植的重要部位,牙龈卟啉单胞菌也可在健康人群中检出,提示其有可能是口腔内固有菌群之一。     

侵袭性牙周炎病原微生物的检测

目的检测侵袭性牙周炎（AgP）患者和牙周健康者龈下菌斑中的7种病原微生物,旨在寻找AgP的主要致病微生物.方法应用以16S rRNA为基础的聚合酶链反应（PCR）技术,检测55例AgP患者和17名健康对照者龈下菌斑中的7种牙周病原微生物：伴放线放线杆菌（Aa）,牙龈卟啉单胞菌（Pg）,福赛坦氏菌（Tf）,牙密螺旋体（Td）,直肠弯曲杆菌（Cr）,中间普氏菌（Pi）,变黑普氏菌（Pn）.结果55例AgP患者中仅有1例检测出Aa,而在健康对照者中未检出该菌.Pg、Tf、Td和Cr在AgP组的检出率分别为81.8%、83.6%、80.0%和81.8%,显著高于健康对照者（17.6%、11.8%、5.9%、29.4%）,差异有统计学意义（P＜0.01）.结论Pd、Tf、Td和Cr 4种微生物在AgP患者中有较高的检出率,提示它们的共同定植可能在AgP中起重要作用.     

牙龈卟啉单胞菌和伴放线聚集杆菌在江苏汉族牙周炎人群中的分布研究

目的:从龈下菌斑总菌数、牙龈卟啉单胞菌(P.gingivalis)、伴放线聚集杆菌(A.actinomycetemcomitans)及白细胞毒素(LTX)在江苏汉族牙周炎人群中分布的角度,比较牙周病2018年新分类与1999年分类.方法:纳入73名牙周炎患者和26名牙周健康者,分别按照牙周病2018年新分类与1999年...     

伴2型糖尿病的慢性牙周炎牙周可疑致病菌的检测

目的 检测伴2型糖尿病(diabetes mellitus,DM)的慢性牙周炎(chronic periodontitis,CP)患者龈下菌斑中牙周可疑致病菌的种类和构成,从微生物学角度探讨牙周炎与DM的相互作用机制.方法 采集伴2型DM的CP患者154例(DM组)、不伴DM的单纯CP患者120例(CP组)及40名全身及牙周健康者(N组)的龈下集合菌斑,传统酚-氯仿法提取菌斑DNA,以牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg),伴放线放线杆菌(Actinobacillus actinomycetemcomitans,Aa),具核梭杆菌(Fusobacterium nucleatum,Fn),中间普氏菌(Prevotella intermedia,Pi),福塞坦氏菌(Tannerella forsythia,Tf),齿垢密螺旋体(Treponema denticola,Td)为目标菌,应用以16SrRNA为基础的聚合酶链反应(PCR)技术对龈下菌群进行检测.结果 Pg、Aa、Fn、Pi、Tf、Td在DM组中均可检出;与CP组相比,在性别、年龄、牙周状况基本一致的情况下,轻度牙周炎者DM组Pi的检出率为35%(8/23),CP组为65%(13/20),两组间差异有统计学意义(P<0.05);重度牙周炎者DM组Pg、Aa、Tf的检出率分别为78%(72/92)、27%(25/92)、67%(62/92),CP组分别为58%(35/60)、17%(10/60)、43%(26/60),DM组均显著高于CP组,差异有统计学意义(P<0.05).同时,DM组Aa、Tf PCR产物的平均灰度值(average gradation,AVG)比值显著高于CP组,Pi的AVG比值明显低于CP组,P<0.05.结论 与单纯CP相比,伴2型DM的牙周炎患者龈下菌斑中Pg、Aa、Tf的数量增多,Pi的数量减少.     

伴2型糖尿病的慢性牙周炎牙周可疑致病菌的检测

目的 检测伴2型糖尿病(diabetes mellitus,DM)的慢性牙周炎(chronic periodontitis,CP)患者龈下菌斑中牙周可疑致病菌的种类和构成,从微生物学角度探讨牙周炎与DM的相互作用机制.方法 采集伴2型DM的CP患者154例(DM组)、不伴DM的单纯CP患者120例(CP组)及40名全身及牙周健康者(N组)的龈下集合菌斑,传统酚-氯仿法提取菌斑DNA,以牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg),伴放线放线杆菌(Actinobacillus actinomycetemcomitans,Aa),具核梭杆菌(Fusobacterium nucleatum,Fn),中间普氏菌(Prevotella intermedia,Pi),福塞坦氏菌(Tannerella forsythia,Tf),齿垢密螺旋体(Treponema denticola,Td)为目标菌,应用以16SrRNA为基础的聚合酶链反应(PCR)技术对龈下菌群进行检测.结果 Pg、Aa、Fn、Pi、Tf、Td在DM组中均可检出;与CP组相比,在性别、年龄、牙周状况基本一致的情况下,轻度牙周炎者DM组Pi的检出率为35%(8/23),CP组为65%(13/20),两组间差异有统计学意义(P<0.05);重度牙周炎者DM组Pg、Aa、Tf的检出率分别为78%(72/92)、27%(25/92)、67%(62/92),CP组分别为58%(35/60)、17%(10/60)、43%(26/60),DM组均显著高于CP组,差异有统计学意义(P<0.05).同时,DM组Aa、Tf PCR产物的平均灰度值(average gradation,AVG)比值显著高于CP组,Pi的AVG比值明显低于CP组,P<0.05.结论 与单纯CP相比,伴2型DM的牙周炎患者龈下菌斑中Pg、Aa、Tf的数量增多,Pi的数量减少.     

伴2型糖尿病的慢性牙周炎牙周可疑致病菌的检测

目的 检测伴2型糖尿病(diabetes mellitus,DM)的慢性牙周炎(chronic periodontitis,CP)患者龈下菌斑中牙周可疑致病菌的种类和构成,从微生物学角度探讨牙周炎与DM的相互作用机制.方法 采集伴2型DM的CP患者154例(DM组)、不伴DM的单纯CP患者120例(CP组)及40名全身及牙周健康者(N组)的龈下集合菌斑,传统酚-氯仿法提取菌斑DNA,以牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg),伴放线放线杆菌(Actinobacillus actinomycetemcomitans,Aa),具核梭杆菌(Fusobacterium nucleatum,Fn),中间普氏菌(Prevotella intermedia,Pi),福塞坦氏菌(Tannerella forsythia,Tf),齿垢密螺旋体(Treponema denticola,Td)为目标菌,应用以16SrRNA为基础的聚合酶链反应(PCR)技术对龈下菌群进行检测.结果 Pg、Aa、Fn、Pi、Tf、Td在DM组中均可检出;与CP组相比,在性别、年龄、牙周状况基本一致的情况下,轻度牙周炎者DM组Pi的检出率为35%(8/23),CP组为65%(13/20),两组间差异有统计学意义(P<0.05);重度牙周炎者DM组Pg、Aa、Tf的检出率分别为78%(72/92)、27%(25/92)、67%(62/92),CP组分别为58%(35/60)、17%(10/60)、43%(26/60),DM组均显著高于CP组,差异有统计学意义(P<0.05).同时,DM组Aa、Tf PCR产物的平均灰度值(average gradation,AVG)比值显著高于CP组,Pi的AVG比值明显低于CP组,P<0.05.结论 与单纯CP相比,伴2型DM的牙周炎患者龈下菌斑中Pg、Aa、Tf的数量增多,Pi的数量减少.     

Immunoglobulin G subclass antibody profiles in Porphyromonas gingivalis-associated aggressive and chronic periodontitis patients

BACKGROUND/AIMS: The immunoglobulin G (IgG) antibody response is considered to be protective and beneficial for the control of periodontal lesions. This study analysed IgG subclass antibody levels of Porphyromonas gingivalis in patients with both aggressive periodontitis (AgP) and chronic periodontitis (CP). METHODS: Subgingival plaque and peripheral blood samples were collected from patients with localized AgP (n = 13), generalized AgP (n = 28) and generalized CP (n = 27) and from 14 periodontally healthy controls. P. gingivalis was identified in subgingival pockets using a polymerase chain reaction. Simultaneously, serum IgG subclass antibody against P. gingivalis whole cells/P. gingivalis fimbriae were measured using enzyme-linked immunosorbent assay. RESULTS: P. gingivalis was frequently detected in periodontitis patients. Anti-P. gingivalis whole cell IgG1 was elevated in all P. gingivalis-positive patients in the three periodontitis groups. Although increased anti-P. gingivalis IgG1 was also observed in the bacterium-positive healthy controls, the level was lower than that found in the three periodontitis groups. Levels of IgG1, IgG2, IgG3 and IgG4 to P. gingivalis did not differ among bacterium-positive patients in the three periodontitis groups; a significant increase of IgG2 level was not observed in localized AgP. Anti-fimbriae IgG subclass levels of IgG1, IgG2 and IgG4 did not differ among bacterium-positive subjects in all groups, while the anti-fimbriae IgG3 level in generalized CP was significantly higher than that in localized and generalized AgP. CONCLUSIONS: P. gingivalis infection elicited an IgG subclass antibody response in both periodontitis patients and healthy subjects, while higher anti-P. gingivalis IgG1 levels were found in the three periodontitis groups compared with the healthy control group.     

Low prevalence of subgingival viruses in periodontitis patients

Background: Viruses such as Human Cytomegalovirus (HCMV) and Epstein–Barr virus (EBV) have been proposed to be periodontal pathogens. The aim of this study was to analyse the presence of herpesvirus DNA in subgingival plaque samples of patients with different forms of periodontitis and in healthy periodontia.
Materials and Methods: A total of 140 ethnically mixed (prevalently Caucasian) subjects took part in the study. Sixteen were affected by localized aggressive periodontitis (LAgP), 64 by generalized aggressive periodontitis (GAgP), 20 by chronic periodontitis (CP) and 40 were periodontally healthy. Polymerase chain reaction (PCR) analyses were performed to detect HCMV and EBV. Sera were tested for anti-HCMV and EBV IgG antibodies. PCRs for herpes simplex (HSV) and varicella zoster virus (VZV) were performed in subgingival samples from a subset of 20 AgP subjects.
Results: HCMV DNA was not detected in any plaque samples. EBV DNA was detected in four LAgP (25%), two GAgP (3%) subjects and four healthy individuals (10%). HSV DNA and VZV DNA were not detected in the subset of studied individuals.
Conclusions: This study challenges the previously reported high prevalence of herpesvirus DNA in subgingival samples from periodontitis patients and so questions whether they act as pathogens in such patients.     

侵袭性牙周炎与慢性牙周炎病变位点中人巨细胞病毒的定量检测

目的 应用实时荧光定量PCR方法 检测侵袭性牙周炎(AgP)及慢性牙周炎(CP)患者龈下样本中人巨细胞病毒(HCMV)的DNA载量,探讨HCMV感染与牙周炎之间的关系.方法 选择18例AgP患者、24例CP患者及15例牙周健康对照者,收集龈下样本114例.构建含有HCMV高保守片段的重组质粒,制备标准品DNA模板,建立...     

Immunoglobulin G subclass antibody profiles in Porphyromonas gingivalis‐associated aggressive and chronic periodontitis patients

Background/aims: The immunoglobulin G (IgG) antibody response is considered to be protective and beneficial for the control of periodontal lesions. This study analysed IgG subclass antibody levels of Porphyromonas gingivalis in patients with both aggressive periodontitis (AgP) and chronic periodontitis (CP). Methods: Subgingival plaque and peripheral blood samples were collected from patients with localized AgP (n = 13), generalized AgP (n = 28) and generalized CP (n = 27) and from 14 periodontally healthy controls. P. gingivalis was identified in subgingival pockets using a polymerase chain reaction. Simultaneously, serum IgG subclass antibody against P. gingivalis whole cells/P. gingivalis fimbriae were measured using enzyme‐linked immunosorbent assay. Results: P. gingivalis was frequently detected in periodontitis patients. Anti‐P. gingivalis whole cell IgG1 was elevated in all P. gingivalis‐positive patients in the three periodontitis groups. Although increased anti‐P. gingivalis IgG1 was also observed in the bacterium‐positive healthy controls, the level was lower than that found in the three periodontitis groups. Levels of IgG1, IgG2, IgG3 and IgG4 to P. gingivalis did not differ among bacterium‐positive patients in the three periodontitis groups; a significant increase of IgG2 level was not observed in localized AgP. Anti‐fimbriae IgG subclass levels of IgG1, IgG2 and IgG4 did not differ among bacterium‐positive subjects in all groups, while the anti‐fimbriae IgG3 level in generalized CP was significantly higher than that in localized and generalized AgP. Conclusions: P. gingivalis infection elicited an IgG subclass antibody response in both periodontitis patients and healthy subjects, while higher anti‐P. gingivalis IgG1 levels were found in the three periodontitis groups compared with the healthy control group.     

Eikenella corrodens in the human oral cavity

The prevalence and distribution of the putative periodontal pathogen Eikenella corrodens in the human oral cavity was examined. A total of 508 oral bacterial samples were taken from 10 periodontally healthy adults (PH), 11 adult periodontitis patients (AP), and 6 localized juvenile periodontitis patients (LJP). From each subject, samples of supra- and subgingival plaque were obtained from six to eight teeth as well as samples from buccal mucosa, lateral and dorsal surfaces of tongue, tonsil, and saliva. E. corrodens was cultured from 70% of healthy subjects and 100% of periodontitis patients. Dental plaque appears to be the main oral ecological niche of E. corrodens in PH subjects since it was found in, respectively, 26% and 31% of supra- and subgingival plaque samples and rarely found in other oral sites in these subjects. It was found in 59% of both supra- and subgingival plaque samples from AP subjects, as well as 48% and 64% of supra- and subgingival plaque samples of LJP subjects. In contrast to healthy subjects, E. corrodens was found on the buccal mucosa, tongue, tonsil and in the saliva of patients with periodontitis. The microorganism constituted, on average, 1% to 2% of the total cultivable bacteria in supra- and subgingival plaque samples. The prevalence of E. corrodens in plaque samples was higher in AP and LJP subjects and was significantly different from PH subjects. Within the AP group, the prevalence of E. corrodens in subgingival plaque is significantly higher from sites with GI greater than or equal to 2. These data suggest that E. corrodens is an indigenous oral microorganism which may be an opportunistic pathogen associated with gingival inflammation.     

Microbial Analysis of Subgingival Plaque Samples Compared to That of Whole Saliva in Patients With Periodontitis

Background: The detection of special bacterial species in patients with periodontitis is considered to be useful for clinical diagnosis and treatment. The collection of subgingival plaque samples is the common way for the determination of periodontopathic bacteria. However, recently, salivary analysis has been discussed as an advantageous future diagnostic method for periodontitis because it offers simple quantitative sampling and the possibility to assess various bacteria. The aim of this cross‐sectional study is to investigate whether there is a correlation between the results of different bacterial species in saliva and subgingival plaque samples from individuals with aggressive periodontitis (AgP) and chronic periodontitis (CP). Methods: Whole saliva and subgingival plaque samples from the deepest pocket of each quadrant were collected from 43 patients with CP and 33 patients with AgP. Twenty different bacterial species from both samplings were determined by the 16S ribosomal RNA‐based polymerase chain reaction with microarray technique. Results: All bacterial species were detected in salivary and subgingival plaque samples. For Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, as well as Actinomyces viscosus, Campylobacter rectus/showae, Prevotella intermedia, Parvimonas micra, Eubacterium nodatum, and Campylobacter gracilis, a significant positive correlation between salivary and subgingival plaque samples was detected in patients with both types of periodontitis. There were no significant differences in bacteria in salivary and subgingival plaque samples between AgP and CP. Conclusion: Salivary analysis might be discussed as a potential alternative to subgingival plaque sampling for microbiologic analysis in both AgP and CP.     

Subgingival microbial profiles in refractory periodontal disease

BACKGROUND/AIM: The purpose of the present investigation was to examine subgingival microbial profiles associated with refractory periodontitis and to seek such profiles in periodontally healthy, periodontally well-maintained elder and untreated periodontitis subjects. METHODS: 36 subjects were defined as refractory on the basis of further attachment loss after scaling and root planing, surgery and systemically administered antibiotics. A total of 890 subgingival plaque samples (mean/subject=24.7) were taken from the mesial aspect of each tooth in each subject at baseline and individually processed for their content of 40 subgingival taxa using checkerboard DNA-DNA hybridization. Cluster analysis was performed on mean within subject species counts using the chord coefficient and an average unweighted linkage sort. Significant differences among clusters for individual and complexes of species were sought using the Kruskal Wallis test. The microbial profiles of the refractory subjects were compared with those of 27 periodontally healthy subjects (n plaque samples=708), 35 periodontally well-maintained elder subjects (n plaque samples=801) and 115 untreated adult periodontitis subjects (n plaque samples=2871). RESULTS: 28 of 36 refractory subjects fell into 4 clusters with >29% similarity. 10 of 40 species and 4 of 7 complexes differed significantly among clusters. Profile (Cluster) I (n=4) was characterized by high proportions of "yellow" and "green" complex species, profile II (n=3) by low total counts and high proportions of "orange" and "purple" complex species, profile III (n=9) by high total counts and counts of Actinomyces and "purple" complex species, profile IV (n=12) by high proportions of "red" and "orange" complex species. The mean profiles of each cluster were subjected to cluster analysis with microbial data from 4380 (mean 24.7) baseline subgingival plaque samples from 27 periodontally healthy, 35 treated, well-maintained elders and 115 untreated adult periodontitis subjects. 12 clusters were formed with >41% similarity. 3 of the refractory profiles were detected in 3 cluster groups. Profile II in a cluster of 1 healthy, 1 elder and 4 untreated periodontitis subjects; profile III in a cluster of 1 healthy, 2 elder and 12 periodontitis subjects; Profile IV, with 1 healthy and 5 untreated periodontitis subjects. The profile not detected in non refractory subjects was dominated by Streptococcus species. 9 clusters did not harbor refractory profiles. 11.1% of healthy, 8.6% of elder and 18.3% of periodontitis subjects were in clusters exhibiting refractory microbial profiles. CONCLUSIONS: 4 subgingival microbial profiles were detected among refractory subjects. "Refractory microbial profiles" could be detected in subjects who had not yet exhibited refractory disease.     

Relationship of Actinobacillus actinomycetemcomitans serotypes to periodontal condition: prevalence and proportions in subgingival plaque

No study available has utilized the new classification scheme (the consensus report of the American Academy of Periodontology 1999) to determine the prevalence of Actinobacillus actinomycetemcomitans in different periodontal conditions. The purpose of this study was to investigate prevalence and proportions of A. actinomycetemcomitans serotypes in subgingival plaque samples from a young Taiwanese population with aggressive periodontitis, chronic periodontitis and no periodontal disease. A total of 221 subgingival plaque samples from 171 diseased subjects (70 had aggressive periodontitis, and 101 had chronic periodontitis) (mean age 25.0 +/- 8.2 yr) and 50 periodontally healthy subjects (mean age 18.4 +/- 9.5 yr) were screened for A. actinomycetemcomitans. Serotypes of A. actinomycetemcomitans were determined by an indirect immunofluorescence assay using serotype-specific polyclonal antisera to A. actinomycetemcomitans strains ATCC 29523 (serotype a), ATCC 43728 (serotype b) and ATCC 33384 (serotype c). Prevalence (% of positive samples) of A. actinomycetemcomitans was 84.3% in aggressive periodontitis, 60.4% in chronic periodontitis, and 64.0% in periodontally healthy subjects. Proportions of A. actinomycetemcomitans (mean percentage per total bacteria) in periodontally healthy subjects were significantly lower than in aggressive periodontitis subjects. The proportion of serotype b in subjects with aggressive periodontitis and subjects with chronic periodontitis were significantly greater than that in periodontally healthy subjects. The proportion of serotype c in periodontally healthy subjects was much higher than that in chronic periodontitis subjects. The results of this study suggest that prevalence and proportions of A. actinomycetemcomitans are significantly greater in patients with aggressive periodontitis than in those with chronic periodontitis. Serotype b is the predominant serotype of A. actinomycetemcomitans in patients with diseased periodontal conditions. Serotype c is a more common serotype detected in periodontally healthy subjects.