Porphyromonas gingivalis bacteremia increases the permeability of the blood-brain barrier via the Mfsd2a/Caveolin-1 mediated transcytosis pathway / 国际口腔科学杂志·英文版

Bacteremia induced by periodontal infection is an important factor for periodontitis to threaten general health. P. gingivalis DNA/virulence factors have been found in the brain tissues from patients with Alzheimer's disease (AD). The blood-brain barrier (BBB) is essential for keeping toxic substances from entering brain tissues. However, the effect of P. gingivalis bacteremia on BBB permeability and its underlying mechanism remains unclear. In the present study, rats were injected by tail vein with P. gingivalis three times a week for eight weeks to induce bacteremia. An in vitro BBB model infected with P. gingivalis was also established. We found that the infiltration of Evans blue dye and Albumin protein deposition in the rat brain tissues were increased in the rat brain tissues with P. gingivalis bacteremia and P. gingivalis could pass through the in vitro BBB model. Caveolae were detected after P. gingivalis infection in BMECs both in vivo and in vitro. Caveolin-1 (Cav-1) expression was enhanced after P. gingivalis infection. Downregulation of Cav-1 rescued P. gingivalis-enhanced BMECs permeability. We further found P. gingivalis-gingipain could be colocalized with Cav-1 and the strong hydrogen bonding between Cav-1 and arg-specific-gingipain (RgpA) were detected. Moreover, P. gingivalis significantly inhibited the major facilitator superfamily domain containing 2a (Mfsd2a) expression. Mfsd2a overexpression reversed P. gingivalis-increased BMECs permeability and Cav-1 expression. These results revealed that Mfsd2a/Cav-1 mediated transcytosis is a key pathway governing BBB BMECs permeability induced by P. gingivalis, which may contribute to P. gingivalis/virulence factors entrance and the subsequent neurological impairments.

Asociación del hábito de fumar con la periodontitis crónica y la artritis reumatoide / Association of smoking with chronic periodontitis and rheumatoid arthritis

Introducción: Porphyromonas gingivalis es un microorganismo presente en las periodontitis, productor de la enzima peptidil arginina desminasa, inductora de la citrulinación de proteínas que convierte en antígenos, y que son reconocidos por los anticuerpos antipéptido cíclico citrulinados, marcadores específicos de la artritis reumatoide. Estudios clínicos y epidemiológicos relacionan el hábito de fumar con la periodontitis y la artritis reumatoide. Objetivo: Evaluar la asociación entre el hábito de fumar, la periodontitis crónica y la artritis reumatoide. Métodos: Se realizó un estudio observacional, analítico, de corte transversal, de casos y controles de pacientes con diagnóstico de artritis reumatoide tratados en el Centro de Reumatología y pacientes atendidos por medicina interna en el Hospital Clínico Quirúrgico 10 de octubre de La Habana, en el periodo entre septiembre del 2017 y mayo del 2019. Se estudiaron las variables edad, sexo, hábito de fumar y estado periodontal evaluado a través del índice de enfermedad periodontal de Russell y el nivel de inserción clínica. Para identificar la asociación entre variables se empleó la prueba de ji al cuadrado y el odds ratio. Se respetaron las legislaciones éticas. Resultados: En el estudio prevaleció el grupo de 35 a 44 años y el sexo femenino. El hábito de fumar predominó en los pacientes artríticos, con manifiesto incremento de la prevalencia y gravedad de la enfermedad periodontal. Conclusiones: El hábito de fumar incrementó el riesgo de periodontitis crónica en ambos grupos, y con menos intensidad de riesgo en la artritis reumatoide.

Introduction: Porphyromonas gingivalis is a microorganism present in periodontitis, producer of the enzyme peptidyl arginine deminase that induces citrullination of proteins, turning them into antigens, which are recognized by anti-citrullinated cyclic peptide antibodies, specific markers of rheumatoid arthritis. Clinical and epidemiological studies link smoking with periodontitis and rheumatoid arthritis. Objective: To evaluate the association between smoking, the presence of chronic periodontitis and rheumatoid arthritis. Methods: An observational, analytical, cross-sectional study of cases and controls of patients with a diagnosis of rheumatoid arthritis treated at the Rheumatology Center and patients treated by Internal Medicine in 10 de Octubre Surgical- Clinic Hospital in Havana, between September 2017 and May 2019. The variables were: age, sex, smoking habit and periodontal status evaluated through the Russell Periodontal Disease Index and Level of Clinical Insertion. For the association and relationship between variables, the chi square and the odds ratio were used. Ethical legislation was respected. Results: In the study the group of 35 to 44 years old and the female sex prevailed. Smoking prevailed in arthritic patients with a remarkable increase in the prevalence and severity of periodontal disease. Conclusions: Smoking increased the risk of chronic periodontitis in both groups with less intensity of risk in rheumatoid arthritis.

Relación entre Porphyromonas gingivalis y diabetes mellitus tipo 2: revisión sistemática exploratoria / Relationship between Porphyromonas gingivalis and Type 2 Diabetes Mellitus: Scoping review

Objetivo: analizar la relación entre Porphyromonas gingivalis y diabetes mellitus tipo 2, mediante una revisión sistemática exploratoria de la literatura científica publicada entre los años 2000 y 2019. Métodos: se utilizaron los siguientes términos MeSH: Porphyromonas gingivalis, diabetes mellitus type 2, periodontal disease, non insulin dependent diabetes. Se obtuvieron 346 resultados, de los cuales se seleccionaron 41 por título, se excluyeron 11 posterior a la lectura del abstract e introducción y 19 después de la lectura del texto completo. Finalmente, se incluyeron 11 artículos. Resultados: el lipopolisacárido de Porphyromonas gingivalis y su fimbria tipo II se relacionan con una mayor producción de citoquinas proinflamatorias como IL-6 y TNF-α, las cuales afectan las vías de señalización de la glucosa y se relacionan con insulinoresistencia. La dipeptidil peptidasa 4 de Porphyromonas gingivalis puede participar en la degradación de incretinas, lo cual afecta la producción de insulina en el huésped y promueve estados de hiperglicemia. El interactoma de Porphyromonas gingivalis puede superponerse con genes involucrados en resistencia a la insulina y diabetes mellitus tipo 2. Conclusión: según la evidencia científica publicada existen factores de virulencia y mecanismos por los cuales la Porphyromonas gingivalis influye en el desarrollo de insulinorresistencia y diabetes mellitus tipo 2.

Objective: To analyze the relationship between Porphyromonas gingivalis and Diabetes Mellitus Type 2 by reviewing the scientific literature published between 2000 and 2019. Methods: The following MeSH terms were used: Porphyromonas gingivalis, Diabetes Mellitus type 2, periodontal disease, non-insulin dependent diabetes. We obtained 346 results, of which 41 were selected by title, 11 were excluded after reading the abstract and introduction and 19 after reading the full text. Finally, 11 articles were included. Results: Porphyromonas gingivalis lipopolysaccharide and its type II fimbria are associated with increased production of proinflammatory cytokines such as IL-6 and TNF-α, which affect glucose signaling pathways and are related to insulin resistance. Porphyromonas gingivalis dipeptidyl peptidase 4 (PgDPP4) may participate in incretin degradation which affects host insulin production and promotes hyperglycemic states. The Porphyromonas gingivalis interactome may overlap with genes involved in insulin resistance and type 2 diabetes mellitus. Conclusion: According to published scientific evidence, there are virulence factors and mechanisms by which Porphyromonas gingivalis influences the development of insulin resistance and type 2 Diabetes Mellitus.

Porphyromonas gingivalis exacerbates ulcerative colitis via Porphyromonas gingivalis peptidylarginine deiminase / 国际口腔科学杂志·英文版

Ulcerative Colitis (UC) has been reported to be related to Porphyromonas gingivalis (P. gingivalis). Porphyromonas gingivalis peptidylarginine deiminase (PPAD), a virulence factor released by P. gingivalis, is known to induce inflammatory responses. To explore the pathological relationships between PPAD and UC, we used homologous recombination technology to construct a P. gingivalis strain in which the PPAD gene was deleted (Δppad) and a Δppad strain in which the PPAD gene was restored (comΔppad). C57BL/6 mice were orally gavaged with saline, P. gingivalis, Δppad, or comΔppad twice a week for the entire 40 days (days 0-40), and then, UC was induced by dextran sodium sulfate (DSS) solution for 10 days (days 31-40). P. gingivalis and comΔppad exacerbated DDS-induced colitis, which was determined by assessing the parameters of colon length, disease activity index, and histological activity index, but Δppad failed to exacerbate DDS-induced colitis. Flow cytometry and ELISA revealed that compared with Δppad, P. gingivalis, and comΔppad increased T helper 17 (Th17) cell numbers and interleukin (IL)-17 production but decreased regulatory T cells (Tregs) numbers and IL-10 production in the spleens of mice with UC. We also cocultured P. gingivalis, Δppad, or comΔppad with T lymphocytes in vitro and found that P. gingivalis and comΔppad significantly increased Th17 cell numbers and decreased Treg cell numbers. Immunofluorescence staining of colon tissue paraffin sections also confirmed these results. The results suggested that P. gingivalis exacerbated the severity of UC in part via PPAD.

Porphyromonas gingivalis and its impact on periodontal health and systemic diseases: a concise review

Periodontitis is defined as a multifactorial chronic inflammatory disease, associated to a dys-biotic biofilm and characterized by the progressive destruction of the periodontal attachment. Clinical studies have revealed the presence of 10 to 15 bacterial species that are potential periodontal pathogens in adults. From these, the most cited are Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Tannerella forsythia. The aim of this article is to review P. gingivalis' characteristics and impact on periodontal and systemic health. Different studies have reported a relation between the presence of P. gingivalis and periodontal disea-se. P. gingivalis was one of the most frequently detected species in aggressive and chronic periodontitis. This is due to its unique ability to avoid the host's immune response and con-tribute to the development of the destructive process. P. gingivalis, although only present in low frequency, is pathogenic because of its ability to induce dysbiotic microbial communities. There is more evidence that P. gingivalis might invade cardiovascular cells and tissues causing inflammation. It has been suggested that NLRP3 inflammasome plays a key role in the deve-lopment of vascular inflammation and atherosclerosis. The repeated exposure to P. gingiva-lis, produces neuroinflammation, neurodegeneration and formation of intra and extracellular amyloid plaques, which are pathognomonic signs of Alzheimer's disease

Different engagement of TLR2 and TLR4 in Porphyromonas gingivalis vs. ligature-induced periodontal bone loss

Abstract This study was conducted to investigate the roles of different Toll-like receptor (TLR) signaling in Porphyromonas gingivalis (P. gingivalis)-induced and ligature-induced experimental periodontal bone resorption in mice. Wild-type (WT), TLR2 knockout (KO), TLR4KO, and TLR2&4 KO mice with C57/BL6 background were divided into three groups: control, P. gingivalis infection, and ligation. Live P. gingivalis or silk ligatures were placed in the sulcus around maxillary second molars over a 2-week period. Images were captured by digital stereomicroscopy, and the bone resorption area was measured with ImageJ software. The protein expression level of gingival RANKL was measured by ELISA. The gingival mRNA levels of RANKL, IL-1β, TNF-α, and IL-10 were detected by RT-qPCR. The results showed that P. gingivalis induced significant periodontal bone resorption in WT mice and TLR2 KO mice but not in TLR4 KO mice or TLR2&4 KO mice. For all four types of mice, ligation induced significant bone loss compared with that in control groups, and this bone loss was significantly higher than that in the P. gingivalis infection group. RANKL protein expression was significantly increased in the ligation group compared with that in the control group for all four types of mice, and in the P. gingivalis infection group of WT, TLR2 KO, and TLR4 KO mice. Expression patterns of RANKL, IL-1β, TNF-α, and IL-10 mRNA were different in the P. gingivalis infection group and the ligation group in different types of mice. In summary, P. gingivalis-induced periodontal bone resorption is TLR4-dependent, whereas ligation-induced periodontal bone resorption is neither TLR2- nor TLR4-dependent.

Porphyromonas gingivalis, patógeno de relevancia en la enfermedad periodontal / Porphyromonas gingivalis, pathogen of interest in periodontal disease

Porphyromonas gingivalis (P.Gingivalis) es un microorganismo comprometido en el inicio y progresión de la enfermedad periodontal crónica y agresiva, y es considerado su principal agente etiológico. Esta bacteria cuenta con una serie de factores de virulencia que le permiten, iniciar el proceso infeccioso, perpetuar la infección y también transformar la placa dental benigna en una comunidad microbiana patógena. Estudiar sus factores de virulencia y su capacidad de modular la respuesta inmunológica del huésped es muy importante para comprender el papel de este patógeno en el desarrollo y establecimiento de la enfermedad. Esta revisión proporciona una visiónactual sobre los factores de virulencia y su impacto sobre la respuesta inmunológica en relación con la patogénesis de la enfermedad periodontal.

Posible papel de Porphyromonas gingivalis en el desarrollo de la artritis reumatoide / Possible role of Porphyromonas gingivalis in the develpment of rheumatoid arthritis

Varios estudios han sugerido una asociación entre la periodontitissevera, la prevalencia de la bacteria Porphyromonas gingivalis y el desarrollo de artritis reumatoide. Como fundamento de esta relación, se ha observado que esta bacteria secreta una enzima, peptidil-arginina deiminasa, que es capaz de citrulinar proteínas del hospedero y así favorecer una respuesta autoinmune. Sin embargo, debido a la heterogeneidad de diseños experimentales, selección de pacientes y valoración de los desenlaces, los resultados no han mostrado la reproducibilidad deseada. Asimismo, observaciones recientes apuntan a que la actividad enzimática podría ser generada por otras especies bacterianas, lo que hace más compleja su relación. Sin embargo, por otro lado, algunos estudios sugieren que el tratamiento periodontal puede limitar el desarrollo de la artritis reumatoide.

Various studies have suggested a link between severe periodontitis,the prevalence of Porphyromonas gingivalis, and the development ofrheumatoid arthritis. As evidence of this relationship, P. gingivalis hasbeen found to secrete an enzyme, peptidyl arginine deiminase, which isable to citrullinate host proteins and thus help activate an autoimmuneresponse. However, due to the heterogeneity of experimental designs,patient selection, and assessment of clinical outcomes, the results havenot shown the desired reproducibility. Furthermore, recent fi ndingsindicate that the enzymatic activity may be produced by other species ofbacteria, which suggests the relationship is more complex. However, anumber of studies have shown that periodontal treatment could inhibitthe development of rheumatoid arthritis.

Alteraciones morfo-cardiovasculares producidas por bacterias periodontopatógenas en modelo murino / Morphological and cardiovascular alterations produced by periodontopathic bacteria in a murine model

Diferentes autores han descrito a la enfermedad periodontal como un factor de riesgo de ateroesclerosis. Este estudio tuvo como objetivo determinar la posible relación entre las bacterias periodontopatógenas y alteraciones cardiovasculares en modelos murinos con ingesta hiperlipídica. Se utilizaron 30 ratas Wistar divididas en un grupo control (n=5) y tres grupos experimentales (n=15): Grupo I (n=5): dieta normal e infectados; Grupo II (n=5): dieta hiperlipídica y sin infectar y Grupo III (n=5): dieta hiperlipídica e infectados. La infección del surco gingival se logró previa sedación a través de hilos de sutura contaminados, colocados durante 6 días consecutivos, con Pophyromonas gingivalis (P. gingivalis) (5x10a-4 UFC) y Agregatibacter actinomycetemcomitans (A. actinomycetemcomitans) (5x10-4 UFC) obtnidas de muestras de pacientes con periodontitis crónica. A los 30 días posinfección se fijaron muestras de corazón y arteria aorta para su procesamiento. En el grupo control no se encontraron alteraciones. En el grupo I se observó en el endocardio valvular abundante exudado fibrinoleucocitario y focos hemorrágicos. En el miocardio, neovascularización y sufusiones hemorrágicos y en la pared de vasos arteriales, engrosamiento intimal. En el grupo II se observaron depósitos lipídicos en el interior de las células endoteliales, estrías grasas y pequeños ateromas. El grupo III mostró en un 100 por ciento de los casos, placas ateromatosas bien detalladas con abundante depósito de colesterol, calcificaciones, hemorragias y neovascularización. La suma de estos factores de riesgo: dieta hiperlipídica e infección con bacterias periodontopatógenas, potenciarían la expresión de alteraciones cardíacas y coronarias, incrementando la formación de ateromas

Factores de virulencia de Prophyromonas gingivalis / Virulence factors of Porphyromonas gingivalis

Porphyromonas gingivalis es un microorganismo implicado en el inicio y progresión de la enfermedad periodontal crónica y agresiva, y es considerado como su principal agente etiológico. Esta bacteria cuenta con una serie de factores de virulencia importantes para su persistencia dentro de los tejidos y su resistencia al tratamiento que le permiten, primer, iniciar el proceso infeccioso a través demecanismos como la colonización, invasión y replicación dentro de las células epiteliales y fibroblastos y luego, evadir y manipular el sistema inmune del huésped y de esta forma establecer una infección crónica y por último, destruir los tejidos del huésped por medio de varias proteasas, colagenasas y enzimas. Estudiar estos factores de virulencia es muy importante para comprender el papel de este patógeno en el desarrollo y establecimiento de la enfermedad periodontal y reconcoer la importancia del control microbiológico para alcanzar el éxito en la terapia periodontal. Por otro lado, este patógeno parece estar envuelto en algunas de las manifestaciones sistémicas que genera la enfermedad periodontal no tratada. En estudio in vitro y de experimentación, ha sido vinculado con mecanismos que generan desde bajo peso al nacer, artritis reumatoidea, disfunción endotelial y peroxidación de lípidos. Estas implicaciones del patógeno periodontal lo hacen también interesante desde el punto de vista de la salud general de las comunidades.

Occurrence of periodontal pathogens among patients with chronic periodontitis

The aim of the present study was to evaluate the presence of the periodontal pathogens that form the red complex (Tannerella forsythia, Porphyromonas gingivalis and Treponema denticola) and Aggregatibacter actinomycetemcomitans in patients with chronic periodontitis. The sample consisted of 29 patients with a clinical and radiographic diagnosis of chronic periodontitis based on the criteria of the American Academy of Periodontology (3). Samples for microbiological analysis were collected from the four sites of greatest probing depth in each patient, totaling 116 samples. These samples were processed using conventional polymerase chain reaction, which achieved the following positive results: 46.6% for P. gingivalis, 41.4% for T. forsythia, 33.6% for T. denticola and 27.6% for A. actinomycetemcomitans. P. gingivalis and T. forsythia were more prevalent (p < 0.05) in periodontal pockets ≥ 8 mm. The combinations T. forsythia + P. gingivalis (23.2%) and T. forsythia + P. gingivalis + T. denticola (20.0%) were more frequent in sites with a probing depth ≥ 8 mm. Associations with the simultaneous presence of A. actinomycetemcomitans + P. gingivalis, A. actinomycetemcomitans + T. forsythia, P. gingivalis + T. forsythia and T. forsythia + T. denticola were statistically significant (p < 0.05). It was concluded that the red complex pathogens are related to chronic periodontitis, presenting a higher occurrence in deep periodontal pockets. Moreover, the simultaneous presence of these bacteria in deep sites suggests a symbiotic relationship between these virulent species, favoring, in this way, a further progression of periodontal disease.

Virulencia y variabilidad de Porphyromonas gingivalis y Aggregatibacter actinomycetemcomitans y su asociación a la periodontitis / Virulence and variability on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans and their association to periodontitis

Las periodontitis son un conjunto de patologías de naturaleza inflamatoria y etiología infecciosa producidas por el biofilm patogénico subgingival. Porphyromonas gingivalis y Aggregatibacter actinomycetemcomitans son bacterias periodonto-patógenas que pueden causar daño directo a las estructuras periodontales a través de los diversos factores de virulencia que expresan. Sobre la base de estos factores de virulencia, distintos genotipos y serotipos bacterianos se han descrito, cada uno de ellos con una potencial variable patogenicidad. En esta revisión bibliográfica se describen diferentes factores de virulencia de P. gingivalis y A. actinomycetemcomitans y se discute la variable inmunogenicidad y patogenicidad de los distintos genotipos y serotipos descritos para ellos. Tanto P. gingivalis como A. actinomycetemcomitans poseen diversos factores de virulencia asociados al inicio, progresión y severidad de las periodontitis. En P. gingivalis, los factores de virulencia para los cuales se describen distintos genotipos y/o serotipos son fimbria, LPS y cápsula bacteriana, y en A. actinomycetemcomitans son leucotoxina A, Cdt y LPS. Cada uno de estos distintos genotipos y serotipos induce una respuesta inmuno-inflamatoria diferente en el hospedero y, por lo tanto, se podrían asociar a una variable patogenicidad y podrían determinar las características clínicas de la enfermedad.

Periodontitis represents a heterogenic group of periodontal infections elicited by bacteria residing at the subgingival biofilm. Although this biofilm is constituted by a broad variety of bacterial species, only a limited number has been associated with the periodontitis aetiology, among them Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Both P. gingivalis and A. actinomycetemcomitans express a number of virulence factors that contribute to direct tissue damage and, based on them, distinct genotypes and serotypes have been described, each one with a potential variable pathogenicity. This review aimed to analyze the different virulence factors described for P. gingivalis and A. actinomycetemcomitans and to discuss the variable immunogenicity and pathogenicity of their serotypes and genotypes. P. gingivalis and A. actinomycetemcomitans express different virulence factors and they determine the initiation, progression, and severity of periodontitis. In P. gingivalis, distinct serotypes and/or genotypes are described based on fimbriae, LPS, and capsule. Additionally, in A. actinomycetemcomitans distinct serotypes and/or genotypes are described based on leucotoxin A, Cdt, and LPS. These distinct serotypes and genotypes induce a differential immunoinflammatory response and, thus, could be associated with variations in pathogenicity and reflected in clinic characteristics of the disease.

Increased levels of Porphyromonas gingivalis are associated with ischemic and hemorrhagic cerebrovascular disease in humans: an in vivo study

OBJECTIVE: This study investigated the role of periodontal disease in the development of stroke or cerebral infarction in patients by evaluating the clinical periodontal conditions and the subgingival levels of periodontopathogens. MATERIAL AND METHODS: Twenty patients with ischemic (I-CVA) or hemorrhagic (H-CVA) cerebrovascular episodes (test group) and 60 systemically healthy patients (control group) were evaluated for: probing depth, clinical attachment level, bleeding on probing and plaque index. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were both identified and quantified in subgingival plaque samples by conventional and real-time PCR, respectively. RESULTS: The test group showed a significant increase in each of the following parameters: pocket depth, clinical attachment loss, bleeding on probing, plaque index and number of missing teeth when compared to control values (p<0.05, unpaired t-test). Likewise, the test group had increased numbers of sites that were contaminated with P. gingivalis (60 percentx10 percent; p<0.001; chi-squared test) and displayed greater prevalence of periodontal disease, with an odds ratio of 48.06 (95 percent CI: 5.96-387.72; p<0.001). Notably, a positive correlation between probing depth and the levels of P. gingivalis in ischemic stroke was found (r=0.60; p=0.03; Spearman's rank correlation coefficient test). A. actinomycetemcomitans DNA was not detected in any of the groups by conventional or real-time PCR. CONCLUSIONS: Stroke patients had deeper pockets, more severe attachment loss, increased bleeding on probing, increased plaque indexes, and in their pockets harbored increased levels of P. gingivalis. These findings suggest that periodontal disease is a risk factor for the development of cerebral hemorrhage or infarction. Early treatment of periodontitis may counteract the development of cerebrovascular episodes.

Etiología y terapia de la periodontitis agresiva: estado actual / Etiology and therapy of aggressive periodontitis: an update

La periodontitis agresiva es una patología de etiología multifactorial que se presenta en pacientes sistémicamente sanos, con rápida pérdida de inserción y ósea, acompañada de agregación familiar. Puede ser localizada o generalizada, siendo las bacterias predominantes el actinobacillus actinomycetemcomitans y la porphyromona gingivalis. Ellas desencadenan una respuesta inmuno-inflamatoria, la cual es la mayor responsable de la gran destrucción tisular. Se ha sugerido que la presencia de virus del tipo herpes pueda jugar un rol importante ne este cuadro. La terapia básica y el mantenimienot son, como en toda la patología gingivo-periodontal, la base del tratamiento. La cirugía reconstructiva y la terapia farmacológica antimicrobiana, han mostrado ser altamente efectivas y de utilización frecuente

Assessment of pathogens microorganisms of periapical abscess in primary teeth

Dental abscess is considered as one of the most common complications of untreated caries in children. Microorganisms are known as major causes for the pulp and periradicular pathosis. Black - pigmented, gram -negative anaerobes, belonging to species of porphyromonas and prevotella [bacteroides] play an important role in causing clinical signs and symptoms related to pulp and periradicular disease. The aim of this investigation was to assess the presence of two main pathogenic microorganisms named porphyromonas gingivalis and prevotella melaninogenica in abscessed primary teeth. Forty children aged 4-10 years were selected with no systemic disease and no antibiotic consumption during the last two weeks of sampling. Selected teeth were presenting swelling and pain at observation stage as signs of acute abscess. The diagnostic technique of porphyromonas gingivalis and prevotella melaningenica was the use of DNA formulation reading by means of PCR technique. Results showed that of the 40 samples, 35 [%87.5] were positive for porphyromonas gingivalis, 34 [%85] were positive for prevotella melaninogenica. However, it seems that more work is required for more precise antibiotic therapy of dental abscess in children. The presence of two well known species of microorganisms in periapical abscess of primary teeth was confirmed

A microbiota na patogênese da doença periodontal / The role of microbiota in periodontal disease

O papel da microbiota na patogênese da doença periodontal ainda desperta grande interesse em função de sua complexidade. Vários trabalhos são abordados mostrando a presença de Actinobacillus actinomycetemcomitans e Porphyromonas gingivalis em diferentes populações do mundo. A verificação de patógenos que possam levar à ocorrência de periodontite é de fundamental importância quando se busca forma de prevenção para doenças periodontais