Periodontitis and Cardiovascular Diseases. Consensus Report.

Background: In Europe cardiovascular disease (CVD) is responsible for 3.9 million deaths (45% of deaths), being ischaemic heart disease, stroke, hypertension (leading to heart failure) the major cause of these CVD related deaths. Periodontitis is also a chronic non-communicable disease (NCD) with a high prevalence, being severe periodontitis, affecting 11.2% of the world's population, the sixth most common human disease. Material and Methods: There is now a significant body of evidence to support independent associations between severe periodontitis and several NCDs, in particular CVD. In 2012 a joint workshop was held between the European Federation of Periodontology (EFP) and the American Academy of Periodontology to review the literature relating periodontitis and systemic diseases, including CVD. In the last five years important new scientific information has emerged providing important emerging evidence to support these associations. Results and Conclusions: The present review reports the proceedings of the workshop jointly organised by the EFP and the World Heart Federation (WHF), which has updated the existing epidemiological evidence for significant associations between periodontitis and CVD, the mechanistic links and the impact of periodontal therapy on cardiovascular and surrogate outcomes. This review has also focused on the potential risk and complications of periodontal therapy in patients on anti thrombotic therapy and has made recommendations for dentists, physicians and for patients visiting both the dental and medical practices.

Association between periodontitis and acute myocardial infarction: a case-control study of a nondiabetic population.

BACKGROUND AND OBJECTIVE: Periodontitis and acute myocardial infarction (AMI) are two diseases that share common risk factors. The role of periodontitis as an independent risk factor for cardiovascular disease has been under debate. The aim of this study was to investigate whether an association exists between periodontitis and AMI in a nondiabetic population, using multiple periodontal case definitions. MATERIAL AND METHODS: Periodontal examination was performed in 204 patients with AMI. The control group comprised 102 healthy subjects, without significant coronary disease, confirmed angiographically. Periodontitis was assessed using measurements of clinical attachment loss (CAL), probing depth and number of missing teeth. From these measurements, five different case definitions of periodontitis were generated. RESULTS: Using the continuous forms of periodontal measurements, the odds ratio (95% confidence interval) of the association with incident AMI was 1.74 (1.26-2.50), 1.83 (1.10-3.17) and 1.08 (1.06-1.13) for mean CAL, probing depth and number of missing teeth, respectively. A consistent positive association was observed regardless of the case definition of periodontitis. CONCLUSION: In this nondiabetic population, the association between periodontitis and AMI was consistent across different measurements and/or definitions of periodontitis. The strength of the association increased concomitantly with the robustness of the criteria used to define periodontitis.

Therapeutic management of a case of generalised aggressive periodontitis in an 8-year old child: 18-month results.

BACKGROUND: Generalised aggressive periodontitis (GAP) is a rare condition associated with rapid periodontal destruction, in multiple teeth. The paper aims to present a case of an 8-year old with GAP and discuss his response to treatment. CASE REPORT: An 8-year old male was referred to the postgraduate clinic of paediatric dentistry of the University of Athens due to increased mobility in his primary dentition. At initial clinical examination, plaque accumulation, gingival inflammation and temporary restorations were noted. Detailed periodontal examination revealed bleeding on probing, pocket depths of up to 9 mm and second degree mobility in primary teeth. Radiographic examination showed advanced bone loss and carious lesions. Microbiological analysis revealed increased percentages of peri-opathogens in pooled subgingival samples. Final diagnosis of GAP was made after ruling out any underlying systemic disorder. TREATMENT: Periodontal therapy involved non-surgical subgingival debridement, systemic administration of antibiotics and retention of periodontally involved teeth. FOLLOW-UP: This was based on a monthly recall program for the first 6 months and a 3-monthly regime thereafter. At 18-months after initial examination, a substantial improvement in clinical parameters was seen, while levels of periodontal pathogens were sustained at low levels. CONCLUSION: Non-surgical root debridement along with systemic administration of antibiotics and retention of the periodontally involved teeth, can be successful in achieving improvement and maintenance of periodontal health in the mixed dentition.

Periodontal condition of the mandibular anterior dentition in patients with conventional and self-ligating brackets.

OBJECTIVES: To explore whether the use of self-ligating brackets is associated with better values for periodontal indices because of the lack of elastomeric modules and concomitantly, reduced availability of retentive sites for microbial colonization and plaque accumulation. SETTING AND SAMPLE POPULATION: Private practice of the first author. Patients were selected using the following inclusion criteria: age range 12-17 years, fixed appliances on both arches, aligned mandibular arch, and absence of oral habits and anterior crossbites. MATERIALS AND METHODS: Prospective cohort investigation. Participants were grouped for bracket type, thus 50 patients formed the conventional bracket cohort and 50 patients the self-ligating bracket cohort. Both cohorts were followed with the purpose to examine periodontal status. Average length of follow-up was 18 months. This time period was considered adequate for a proportion of study participants to experience the outcome of interest. Outcome variables were plaque index, gingival index, calculus index, and probing depth for the two bracket cohorts. RESULTS: No difference was found in the indices recorded between the two bracket cohorts studied. CONCLUSION: Under the conditions as applied in this study, the self-ligating brackets do not have an advantage over conventional brackets with respect to the periodontal status of the mandibular anterior teeth.

Long-term periodontal status of patients with mandibular lingual fixed retention.

The purpose of this study was to evaluate the periodontal tissues of patients with mandibular fixed retention for long or short periods of time. A total of 64 individuals were selected for this study using the following inclusion criteria: long-term lingual fixed retention; identical type of lingual fixed retainer bonded with the same materials; no cavities, restorations, or fractures of the mandibular anterior teeth; absence of habits and occlusal interferences; and canine guidance bilaterally. The resultant sample comprised 32 patients (mean age 25 years) who had been in retention for a mean period of 9.65 years (range 9-11 years) and an equal number retained for a period between 3 and 6 months. Plaque, gingival, and calculus indices, probing pocket depth, marginal recession, and bone level at the mandibular six anterior teeth were recorded for both groups. Demographic, clinical, and radiographic data were investigated with conventional descriptive statistics. Comparisons of the different variables between the two participant groups (long- and short-term retention) were carried out using a Mann-Whitney test for indices (plaque, gingival, and calculus), and a Fisher's exact test (two sided) for the remaining variables. No significant difference was found with respect to the plaque and gingival indices and bone level between the two groups. The long-term group presented higher calculus accumulation, greater marginal recession, and increased probing depth (P < 0.05). The results of this study raise the question of the appropriateness of lingual fixed retainers as a standard retention plan for all patients regardless of their attitude to dental hygiene. They also emphasize the importance of individual variability and cautious application of retention protocols after a thorough consideration of issues related to the anatomy of tissues and oral hygiene.

Generation of inflammatory stimuli: how bacteria set up inflammatory responses in the gingiva.

OBJECTIVES: The primary aetiologic factor of periodontal disease is the bacterial biofilm. Gram-positive and gram-negative bacteria possess a plethora of structural or secreted components that may cause direct destruction to periodontal tissues or stimulate host cells to activate a wide range of inflammatory responses. These responses are intended to eliminate the microbial challenge, but may often cause further tissue damage. METHODS: This review has been divided into three parts: (a) bacterial virulence factors, which includes basic information on bacterial virulence factors, and the principle inflammatory responses that host cells elicit against these factors, (b) main receptors and signalling pathways, which includes basic information about the main receptors that interact with the bacterial virulence factors, the nature of these interactions, and the activated signalling pathways that lead to inflammatory responses, and (c) initiation of inflammation, which includes a model by which the virulence factors may interact with host cells and lead to inflammatory responses in the gingiva. FINDINGS AND CONCLUSIONS: Bacterial components/virulence factors may be involved in modulating inflammatory responses and include: lipopolysaccharides (LPS), peptidoglycans, lipotechoic acids, fimbriae, proteases, heat-shock proteins, formyl-methionyl peptides, and toxins. Potential host cell receptors involved in recognizing bacterial components and initiating signalling pathways that lead to inflammatory responses include: Toll-like receptors (TLRs), CD14, nucleotide-binding oligomerization domain proteins (Nod) and G-protein-coupled receptors, including formyl-methionyl peptide receptors and protease-activated receptors. Of the above bacterial and host molecules, evidence from experimental animal studies implicate LPS, fimbriae, proteases, TLRs, and CD14 in periodontal tissue or alveolar bone destruction. However, evidence verifying the involvement of any of the above molecules in periodontal tissue destruction in humans does not exist.

Periodontal pathogen-specicfic antibodies predict birth weight [abstract]

OBJECTIVE: This study evaluated the relationship between periodontal disease and low birth weight (LBW) in a predominantly black population. METHODS: Using the nested case-control design, we evaluated the periodontal pathogen specific maternal serum IgG levels during pregnancy in relation to birth weight, while controlling for the known risk factors for LBW. RESULTS: There was a significant negative correlation (r= -0.37; p= 0.004) between the birth rate of the infant and Porphyromonas gingivalis (Pg) specific maternal serum IgG levels (LBW group - mean/SE 14.73ñ4.67 ug/ml; p= 0.003). Regression analysis indicated that one unit increase of IgG against Pg in the mother resulted in 5.07g decrease in the birth weight of the infant (p=0.005). CONCLUSION: Our ability to demonstrate a significant difference in the serum IgG levels, against at least one periodontal pathogen (Pg) lends further credibility to the biologic plausibility of the association between poor periodontal health and LBW, and the temporal sequence of this association. (AU)

The association between Porphyromonas gingivalis-specific maternal serum IgG and low birth weight.

BACKGROUND: In Alabama, low birth weight (LBW) infants are about 20 times more likely to die before their first birthday compared to normal birth weight infants. While the rate of LBW has been consistently higher among African Americans compared to whites, there has been a gradual increase in LBW for both African Americans and whites over the last 15 years. In an attempt to identify modifiable risk factors for LBW, we have previously reported that a pregnant woman's poor periodontal health may be an independent risk factor for low birth weight. METHODS: A predominantly African American and socioeconomically homogeneous group of 448 women was followed from the second trimester of their first pregnancy. Thirty-nine LBW cases were observed at the end of follow-up. Using 17 preterm LBW cases and 63 randomly selected controls from the above cohort, the periodontal pathogen-specific maternal serum IgG levels during the second trimester of pregnancy were evaluated in relation to birth weight of the infant, while controlling for known risk factors for LBW. RESULTS: Porphyromonas gingivalis (P.g.)-specific maternal serum IgG levels were higher in the LBW group (mean 58.05, SE = 20.00 microg/ml) compared to the normal birth weight (NBW) group (mean 13.45, SE = 3.92 microg/ml; P= 0.004). Women with higher levels of P.g.-specific IgG had higher odds of giving birth to LBW infants (odds ratio [OR] = 4.1; 95% confidence interval [CI] for odds ratio = 1.3 to 12.8). This association remained significant after controlling for smoking, age, IgG levels against other selected periodontal pathogens, and race. CONCLUSIONS: Low birth weight deliveries were associated with a higher maternal serum antibody level against P. gingivalis at mid-trimester.

Maternal periodontitis and prematurity. Part I: Obstetric outcome of prematurity and growth restriction.

Oral Conditions and Pregnancy (OCAP) is a 5-year prospective study of pregnant women designed to determine whether maternal periodontal disease contributes to the risk for prematurity and growth restriction in the presence of traditional obstetric risk factors. Full-mouth periodontal examinations were conducted at enrollment (prior to 26 weeks gestational age) and again within 48 hours postpartum to assess changes in periodontal status during pregnancy. Maternal periodontal disease status at antepartum, using a 3-level disease classification (health, mild, moderate-severe) as well as incident periodontal disease progression during pregnancy were used as measures of exposures for examining associations with the pregnancy outcomes of preterm birth by gestational age (GA) and birth weight (BW) adjusting for race, age, food stamp eligibility, marital status, previous preterm births, first birth, chorioamnionitis, bacterial vaginosis, and smoking. Interim data from the first 814 deliveries demonstrate that maternal periodontal disease at antepartum and incidence/progression of periodontal disease are significantly associated with a higher prevalence rate of preterm births, BW < 2,500 g, and smaller birth weight for gestational age. For example, among periodontally healthy mothers the unadjusted prevalence of births of GA < 28 weeks was 1.1%. This was higher among mothers with mild periodontal disease (3.5%) and highest among mothers with moderate-severe periodontal disease (11.1%). The adjusted prevalence rates among GA outcomes were significantly different for mothers with mild periodontal disease (n = 566) and moderate-severe disease (n = 45) by pair-wise comparisons to the periodontally healthy reference group (n = 201) at P = 0.017 and P < 0.0001, respectively. A similar pattern was seen for increased prevalence of low birth weight deliveries among mothers with antepartum periodontal disease. For example, there were no births of BW < 1000 g among periodontally healthy mothers, but the adjusted rate was 6.1% and 11.4% for mild and moderate-severe periodontal disease (P = 0.0006 and P < 0.0001), respectively. Periodontal disease incidence/progression during pregnancy was associated with significantly smaller births for gestational age adjusting for race, parity, and baby gender. In summary, the present study, although preliminary in nature, provides evidence that maternal periodontal disease and incident progression are significant contributors to obstetric risk for preterm delivery, low birth weight and low weight for gestational age. These studies underscore the need for further consideration of periodontal disease as a potentially new and modifiable risk for preterm birth and growth restriction.

Maternal periodontitis and prematurity. Part II: Maternal infection and fetal exposure.

Clinical data from the first 812 deliveries from a cohort study of pregnant mothers entitled Oral Conditions and Pregnancy (OCAP) demonstrate that both antepartum maternal periodontal disease and incidence/progression of periodontal disease are associated with preterm birth and growth restriction after adjusting for traditional obstetric risk factors. In the current study we present measures of maternal periodontal infection using whole chromosomal DNA probes to identify 15 periodontal organisms within maternal periodontal plaque sampled at delivery. In addition, maternal postpartum IgG antibody and fetal exposure, as indexed by fetal cord blood IgM level to these 15 maternal oral pathogens, was measured by whole bacterial immunoblots. The potential role of maternal infection with specific organisms within 2 bacterial complexes most often associated with periodontitis, conventionally termed "Orange" (Campylobacter rectus, Fusobacterium nucleatum, Peptostreptococcus micros, Prevotella nigrescens, and Prevotella intermedia) and "Red" (Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola) complexes, respectively, to prematurity was investigated by relating the presence of oral infection, maternal IgG, and fetal cord IgM, comparing full-term to preterm (gestational age < 37 weeks). The prevalence of 8 periodontal pathogens was similar among term and preterm mothers at postpartum. There was a 2.9-fold higher prevalence of IgM seropositivity for one or more organisms of the Orange or Red complex among preterm babies, as compared to term babies (19.9% versus 6.9%, respectively, P = 0.0015, chi square). Specifically, the prevalence of positive fetal IgM to C. rectus was significantly higher for preterm as compared to full-term neonates (20.0% versus 6.3%, P = 0.0002, as well as P. intermedia (8.8% versus 1.1%, P = 0.0003). A lack of maternal IgG antibody to organisms of the Red complex was associated with an increased rate of prematurity with an odds ratio (OR) = 2.2; confidence interval (CI) 1.48 to 3.79), consistent with the concept that maternal antibody protects the fetus from exposure and resultant prematurity. The highest rate of prematurity (66.7%) was observed among those mothers without a protective Red complex IgG response coupled with a fetal IgM response to Orange complex microbes (combined OR 10.3; P < 0.0001). These data support the concept that maternal periodontal infection in the absence of a protective maternal antibody response is associated with systemic dissemination of oral organisms that translocate to the fetus resulting in prematurity. The high prevalence of elevated fetal IgM to C. rectus among premature infants raises the possibility that this specific maternal oral pathogen may serve as a primary fetal infectious agent eliciting prematurity.

Cytokine responses of oral epithelial cells to Porphyromonas gingivalis infection.

Accumulating evidence indicates that epithelia are not merely mechanical barriers but also important elements of the innate immune system. The present study was performed to examine cytokine responses of oral epithelial cells after infection with the periodontal pathogen Porphyromonas gingivalis. The KB-cell line and primary cultures of periodontal pocket epithelium were infected with P. gingivalis for assessment of bacterial invasion by an antibiotic protection assay, and examination of expression of interleukin-1 beta, interleukin-6, interleukin-8, and tumor necrosis factor-alpha by in situ hybridization and immunohistochemistry. We observed that P. gingivalis induces a strong cytokine response, positively correlated with the adhesive/invasive potential of the infecting strain, in both KB cells and primary cultures. These findings indicate that the epithelial cells of the periodontal pocket are an integral part of the immune system, eliciting cytokine responses to a bacterial challenge. In this context, the adhesive/invasive phenotype of P. gingivalis appears to contribute to pathogenicity.

The synthetic chemoattractant Trp-Lys-Tyr-Met-Val-DMet activates neutrophils preferentially through the lipoxin A(4) receptor.

A D-methionine-containing peptide, Trp-Lys-Tyr-Met-Val-D-Met-NH(2) (WKYMVm), featuring a unique receptor specificity was investigated with respect to its ability to activate neutrophil effector functions. The peptide was found to be more potent than the N-formylated peptide N-formyl-Met-Leu-Phe (fMLF) at inducing neutrophil chemotaxis, mobilization of neutrophil complement receptor 3 (CR3), and activation of the neutrophil NADPH-oxidase. The fact that binding of fML[(3)H]F was inhibited by both fMLF and WKYMVm suggests that N-formyl peptide receptor (FPR) is shared by these peptides. However, the neutrophil response induced by the WKYMVm peptide was insensitive to the fMLF antagonists, cyclosporin H, and Boc-FLFLF that specifically block the function of the FPR. These results suggest that even though WKYMVm may bind FPR the cells are activated preferentially through a receptor distinct from the FPR. Using transfected HL-60 cells expressing either the FPR or its neutrophil homologue FPRL1, also referred to as LXA(4)R because it has been shown to bind lipoxin A(4), we show that WKYMVm is about 300-fold more active at mobilizing intracellular calcium through FPRL1 than through FPR. The WKYMVm activates FPRL1-expressing cells in a cyclosporin H-independent manner with an EC(50 )of around 75 pmol/L, whereas it activates FPR-expressing cells with an EC(50 )of around 25 nmol/L. The observation that exudated cells are primed in their response to WKYMVm suggests that FPRL1/LXA(4)R like FPR is stored in mobilizable organelles. (Blood. 2000;95:1810-1818)

Periodontal medicine: emerging concepts in pregnancy outcomes.

The term periodontal medicine encompasses the study of the contribution of periodontal infections on several systemic conditions such as atherosclerosis, myocardial infarction, stroke, diabetes, and premature delivery. The early reports of a linkage between periodontitis and systemic conditions are gaining further support from additional epidemiological studies. The evidence continues to suggest that maternal periodontitis may bean important risk factor or risk indicator for pregnancies culminating in preterm low birth-weight deliveries. Potential mechanisms by which infectious challenge of periodontal origin and systemic inflammation may serve as a potential modifier of parturition are discussed. Furthermore, preliminary data are presented, supporting a hypothetical model in which periodontal pathogens disseminate systemically within the mother and gain access to the foetal compartment. Several aspects of this hypothetical model remain to be elucidated. Only the clarification of the mechanisms of pathogenesis of both periodontitis and premature deliveries will ultimately allow for accurate diagnoses and successful therapies. The concept of diagnosing and treating a periodontal patient to minimise the deleterious effects of this chronic infectious and inflammatory condition on systemic conditions represents both an unprecedented challenge and opportunity to our profession.

Periodontitis-atherosclerosis syndrome: an expanded model of pathogenesis.

The early reports of a linkage between periodontitis and atherosclerosis have garnered further support by additional data generated by several investigative teams in many different countries. The evidence continues to suggest that periodontitis may be an important risk factor or risk indicator for cardiovascular pathology for some individuals. The term periodontitis-atherosclerosis syndrome (PAS) is proposed as a new diagnostic term to describe this condition in these individuals. Current evidence, albeit preliminary in nature, which describes a cluster of clinical signs and symptoms that are associated with this condition, is presented. It is clear that this syndrome will require considerable study and refinement before a definitive diagnosis and treatment plan can be formulated. Potential mechanisms by which systemic inflammation and infectious challenge of periodontal origin may serve as a potential modifier of cardiovascular disease are discussed in the context of a detailed working model of pathogenesis. This hypothetical model embraces many cellular and molecular components of atherogenesis and thromboembolic diseases from the perspective of periodontitis pathogenesis. Many aspects of the hypothetical model remain unproved; however, it is our opinion that only through the clarification of the mechanisms of pathogenesis can we ultimately construct a knowledge framework for accurate diagnoses and successful therapies. The concept of diagnosing and treating a periodontal patient to minimize the deleterious effects of this chronic infectious and inflammatory condition on the cardiovascular system represents an unprecedented challenge to our profession.

The concept of "risk" and the emerging discipline of periodontal medicine.

Dental clinicians intuitively weigh patient risks for developing disease and use that information for making treatment decisions and recommendations. Periodontitis, for instance, is one oral disease with documented risk factors including smoking, specific plaque bacteria and diabetes mellitus. While this link between systemic disease and periodontitis was thought to be unidirectional, mounting evidence in the last decade suggests that the relationship may be bi-directional. Cross sectional and case control studies indicate that periodontitis may confer two and seven-fold elevations in risk for cardiovascular disease and premature low birth weight respectively. While these early studies indicate potential associations between oral and systemic health, they support the central hypothesis that periodontitis triggers both local and systemic host inflammatory responses. Consequently, a new discipline, periodontal medicine, has emerged in dentistry which seeks to further define these interrelationships through scientific inquiry. Ultimately, this new knowledge may prove useful in intervention strategies to reduce patient risks and prevent systemic disease outcomes. This manuscript clarifies the concept of risk, traces the emergence of periodontal medicine and serves as a resource for the oral health professional in assessing and utilizing the current evidence on periodontal-systemic disease connections.

"Checkerboard" versus culture: a comparison between two methods for identification of subgingival microbiota.

The present study compared the "checkerboard" DNA-DNA hybridization methodology with culture techniques for the analysis of the composition of the subgingival microbiota. 70 subjects, presenting with a variety of periodontal conditions, contributed with a total of 283 subgingival plaque samples analyzed with respect to the following species: Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens, Fusobacterium nucleatum, Campylobacter rectus, Eikenella corrodens, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, Streptococcus sanguis and Streptococcus mutans. Species identification and quantification was performed by (i) the checkerboard method, using whole genomic, digoxigenin labeled DNA probes; and (ii) culture, including non-selective and selective media in combination with routine biochemical testing using commercial test panels. We found that the checkerboard technology resulted in higher prevalence figures for half of the species tested when compared to culture data. If the latter were used as the reference, checkerboard detection sensitivities ranged from 0.17 to 0.86, specificities from 0.17 to 1.0, and diagnostic accuracies from 0.51 to 0.81, depending on bacterial species. The use of the checkerboard data as the reference resulted in detection sensitivities for the culture procedures between 0.24 and 1.0 and specificities between 0.21 and 0.87. The checkerboard methodology resulted in statistically significant higher bacterial counts for the majority of the species. It was further observed that, for most species, the higher the total number colony-forming units in the sample, the higher the discrepancy between the results obtained by the two techniques.

Porphyromonas gingivalis infection of oral epithelium inhibits neutrophil transepithelial migration.

Periodontal diseases are inflammatory disorders caused by microorganisms of dental plaque that colonize the gingival sulcus and, subsequently, the periodontal pocket. As in other mucosal infections, the host response to plaque bacteria is characterized by an influx of polymorphonuclear leukocytes (PMNs) to the gingival crevice. Neutrophil migration through the epithelial lining of the gingival pocket is thought to be the first line of defense against plaque bacteria. In order to model this phenomenon in vitro, we used the oral epithelial cell line KB and human PMNs in the Transwell system and examined the impact of Porphyromonas gingivalis-epithelial cell interactions on subsequent PMN transepithelial migration. We demonstrate here that P. gingivalis infection of oral epithelial cells failed to trigger transmigration of PMNs. Furthermore, it significantly inhibited neutrophil transmigration actively induced by stimuli such as N-formylmethionyl leucyl phenylalanine, interleukin-8 (IL-8), and the intestinal pathogen enterotoxigenic Escherichia coli. The ability of P. gingivalis to block PMN transmigration was strongly positively correlated with the ability to adhere to and invade epithelial cells. In addition, P. gingivalis attenuated the production of IL-8 and the expression of intercellular adhesion molecule 1 by epithelial cells. The ability of P. gingivalis to block neutrophil migration across an intact epithelial barrier may critically impair the potential of the host to confront the bacterial challenge and thus may play an important role in the pathogenesis of periodontal disease.

Subgingival microbiota in adult Chinese: prevalence and relation to periodontal disease progression.

The "checkerboard" Dna-Dna hybridization technology was used to study the epidemiology of 18 microbial species associated with various states of periodontal health and disease, in a sample of 148 Chinese subjects never exposed to systematic dental therapeutic intervention, aged 30 to 39 and 50 to 59 years. Our aims were to: 1) describe the prevalence of these microorganisms; 2) correlate the microbiological and clinical profiles of the subjects; and 3) examine the association between the microbiological variables and the longitudinal changes of periodontal status that occurred over a preceding 10-year period. A maximum of 14 subgingival samples were obtained from each subject-1,864 in all. The frequency of occurrence of the 18 species examined was high in this Chinese population, on both the subject and the tooth site level. However, all species were not found equally capable of reaching high numbers in the subgingival samples and, as a rule, colonized heavily only limited proportions of tooth sites within each mouth. There was a profound increase of certain species such as Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus in deep pockets or progressing sites. Multivariate techniques using the subgingival profile could effectively discriminate between deep/shallow pockets and progressing/ stable tooth sites. The microbiological variables showed an enhanced discriminating potential when classifications were performed on the individual subject level. Colonization by P. gingivalis, B. forsythus, Campylobacter rectus, and T. denticola at levels exceeding certain thresholds entailed a significantly increased probability (odds ratios > 4) for an individual subject to harbor deep pockets or progressing tooth sites.

Cellular events concurrent with Porphyromonas gingivalis invasion of oral epithelium in vitro.

The aim of the present study was to elucidate events related to receptor function, signal transmission and cytoskeletal rearrangements concurrent with Porphyromonas gingivalis invasion of oral epithelial cells in vitro. Porphyromonas gingivalis strain FDC 381 and the KB cell line (ATCC CCL 17) were used in a previously described antibiotic protection assay. The involvement of a receptor-mediated endocytosis pathway in the internalization process was demonstrated after treatment of the epithelial cells with monodansylcadaverine and ouabain, substances that inhibit formation of coated pits, resulting in reduction in the number of invading P. gingivalis: Treatment of the epithelial cells with the protein kinase (PK) inhibitor staurosporine and the tyrosine-specific PK inhibitor genistein was also found to significantly decrease the number of invading bacteria, suggesting involvement of tyrosine phosphorylation in signal transduction during invasion. This was further supported by the identification of a 43 kD protein acting as a substrate for tyrosine phosphorylation subsequent to the microbial-host cell interaction. Tyrosine phosphorylation of the 43 kD protein was strongly reduced by treatment with PK inhibitors. The decrease in invasion observed after treatment of epithelial cells with colchicine and nocodazole, inhibitors of microtubuli polymerization, suggested that the bacterial-receptor interaction and the phosphotyrosine-dependent intracellular signalling trigger an internalization process involving rearrangements of cytoskeletal microtubuli.

Porphyromonas gingivalis FDC381 multiplies and persists within human oral epithelial cells in vitro.

Porphyromonas gingivalis FDC381 replication and persistence within KB epithelial cells in vitro were studied by means of an antibiotic protection assay and electron microscopy. Intracellular counts decreased during the first 24 h; showed a threefold increase during the second day, indicating intracellular multiplication; and after 8 days declined to levels approximating 40% of the initial invasion. The ability of P. gingivalis to persist and multiply within epithelial cells may constitute a pathogenic mechanism in periodontal disease.