Subgingival microbiota of chilean patients with chronic periodontitis

Systemic antibiotics in the treatment of periodontitis

Despite the fact that several clinical studies have shown additional benefits when certain systemic antibiotics are used as adjuncts to periodontal treatment, clear guidelines for the use of these agents in the clinical practice are not yet available. Basic questions concerning the use of systemic antibiotics to treat periodontitis remain unanswered, such as: which drug(s) should be used; which patients would most benefit from treatment; which are the most effective protocols (i.e. doses and durations); and in which phase of the mechanical therapy should the drug(s) be administered? Although not all of those questions have been directly addressed by controlled randomized clinical trials, recent concepts related to the ecology of periodontal diseases, as well as the major advances in laboratory and clinical research methods that have occurred in the past decade, have significantly broadened our knowledge in this field. This article endeavored to provide a 'state of the art' overview on the use of systemic antibiotics in the treatment of periodontitis, based on the most recent literature on the topic as well as on a compilation of data from studies conducted at the Center of Clinical Trials at Guarulhos University (São Paulo, Brazil) from 2002 to 2012.

Prevalence of periodontal pathogens as predictor of the evolution of periodontal status

The aim of this study was to determine the relationship between the prevalence of Porphyromonas gingivalis, its fimA genotypes, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Treponema denticola and the evolution of periodontal health. In a longitudinal prospective study, samples of subgingival plaque were taken from 114 patients (37 with chronic periodontitis, 17 with gingivitis, and 60 periodontally healthy) in the course of a full periodontal examination. PCR was employed to determine the presence of the periodontopathogenic bacteria. Four years later, a second examination and sample collection were performed in 90 of these patients (20 with chronic periodontitis, 12 with gingivitis, and 58 periodontally healthy). T. forsythia, P. gingivalis, and T. denticola are the most prevalent bacteria in patients with chronic periodontitis (78.4%, 62.2 y 56.8%, respectively). The P. gingivalis bacterium and its fimA genotypes I, II, and IV showed the highest correlation between the baseline and follow-up assessments. P. gingivalis fimA genotype II and T. forsythia were associated to a significant degree with unfavourable periodontal evolution. Of the variables studied, P. gingivalis fimA genotype II and T. forsythia increase the risk of an unfavourable evolution of periodontal status.

Host response mechanisms in periodontal diseases

Periodontal diseases usually refer to common inflammatory disorders known as gingivitis and periodontitis, which are caused by a pathogenic microbiota in the subgingival biofilm, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola that trigger innate, inflammatory, and adaptive immune responses. These processes result in the destruction of the tissues surrounding and supporting the teeth, and eventually in tissue, bone and finally, tooth loss. The innate immune response constitutes a homeostatic system, which is the first line of defense, and is able to recognize invading microorganisms as non-self, triggering immune responses to eliminate them. In addition to the innate immunity, adaptive immunity cells and characteristic cytokines have been described as important players in the periodontal disease pathogenesis scenario, with a special attention to CD4⁺ T-cells (T-helper cells). Interestingly, the T cell-mediated adaptive immunity development is highly dependent on innate immunity-associated antigen presenting cells, which after antigen capture undergo into a maturation process and migrate towards the lymph nodes, where they produce distinct patterns of cytokines that will contribute to the subsequent polarization and activation of specific T CD4+ lymphocytes. Skeletal homeostasis depends on a dynamic balance between the activities of the bone-forming osteoblasts (OBLs) and bone-resorbing osteoclasts (OCLs). This balance is tightly controlled by various regulatory systems, such as the endocrine system, and is influenced by the immune system, an osteoimmunological regulation depending on lymphocyte- and macrophage-derived cytokines. All these cytokines and inflammatory mediators are capable of acting alone or in concert, to stimulate periodontal breakdown and collagen destruction via tissue-derived matrix metalloproteinases, a characterization of the progression of periodontitis as a stage that presents a significantly host immune and inflammatory response to the microbial challenge that determine of susceptibility to develop the destructive/progressive periodontitis under the influence of multiple behavioral, environmental and genetic factors.

Quantification of Selenomonas sputigena in Chronic Periodontitis in Smokers Using 16S rDNA Based PCR Analysis

BACKGROUND AND AIM

Selenomonas species have been associated with chronic periodontitis and have been implicated in converting periodontal health to disease. Scanty literature is available in Indian population. Hence, the objective of the study was to detect the prevalence of Selenomonas sputigena in healthy and chronic periodontitis by polymerase chain reaction (PCR) in Indian population and to check whether smoking affects the subgingival microflora of this organism in chronic periodontitis.

MATERIALS AND METHODS

A total of 60 subjects with severe chronic periodontitis with or without smoking and periodontal healthy subjects underwent clinical and microbiological assessment. A deep subgingival plaque sample was collected and genomic DNA was extracted from each sample and analysed for detection of Selnomonas sputigena using PCR. The frequency and quantification of bacteria were also estimated.

RESULTS

All groups differed statistically significant in the frequency of detection of Selenomonas sputigena. On comparison of patients with chronic periodontitis in smokers and non-smokers, there was no statistically significant difference. When the results were quantified, statistically non-significant results were seen among all groups. Plaque index, gingival index, probing pocket depth and clinical attachment level were statistically non-significant in chronic periodontitis with smokers and non-smokers.

CONCLUSION

Prevalence of Selenomonas sputigena showed significant differences with respect to the frequency of detection when comparing the disease group to the healthy population. But no significant difference was seen when the results were quantified. Smoking has no influence on number of Selenomonas sputigena. This study highlights presence as well as quantity of the organism is very important in elucidating its role in causation and progression of the disease.

Incidence of periodontitis in Japanese patients with cardiovascular diseases: a comparison between abdominal aortic aneurysm and arrhythmia

Although there is a link between periodontitis and cardiovascular disease (CVD), the influence of periodontitis on CVD is unclear. The aim of this study was to assess the relationship between periodontal bacterial burden and CVD. We studied 142 patients with tachyarrhythmia (TA) and 25 patients with abdominal aortic aneurysm (AAA). We examined periodontitis and the presence of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Prevotella intermedia in the patients' saliva and subgingival plaque using PCR. We also measured serum antibody titers against the pathogens using ELISA. We found that the patients with AAA had fewer remaining teeth (14.6 ± 2.0 vs. 20.9 ± 0.7, P < 0.05) and deeper pocket depth (3.01 ± 0.26 vs. 2.52 ± 0.05 mm, P < 0.05) compared to the TA patients. The existence of each periodontal bacterium in their saliva or subgingival plaque and serum antibody titers was comparable between the two groups. Periodontitis may have a larger affect on aneurysm progression compared to arrhythmia.

Lessons learned and unlearned in periodontal microbiology

Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. In the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best-characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this article we will review how our comprehension of the structure and function of the subgingival microbiota has evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: (i) how the data obtained through molecular techniques have impacted our knowledge of the etiology of periodontal infections; (ii) the potential role of viruses in the etiopathogenesis of periodontal diseases; (iii) how concepts of microbial ecology have expanded our understanding of host-microbe interactions that might lead to periodontal diseases; (iv) the role of inflammation in the pathogenesis of periodontal diseases; and (v) the impact of these evolving concepts on therapeutic and preventive strategies to periodontal infections. We will conclude by reviewing how novel systems-biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and hopefully lead to a better understanding of their mechanisms.

Microbiological diversity of peri-implantitis biofilm by Sanger sequencing

BACKGROUND AND OBJECTIVE

To examine the microbial diversity associated with implants with or without peri-implantitis and to identify differences between the bacterial communities in these clinical conditions.

MATERIAL AND METHODS

Twenty subjects were assigned to a Control group consisting of subjects with healthy implants and a Test group consisting of subjects with peri-implantitis sites, as well as a healthy implant site (n = 10/group). In the Test group, subgingival biofilm samples were taken from the deepest sites of the diseased implant. In both groups, samples were collected from one site around a healthy implant. DNA was extracted and the 16S rRNA gene was amplified and sequenced, and the phylotypes were identified by comparison with known 16S rRNA sequences.

RESULTS

The phylogenetic identity of 1387 16S rRNA gene clones was determined. Healthy implants demonstrated higher proportions of Actinomyces, Atopobium, Gemella, Kingella and Rothia and lower levels of Campylobacter, Desulfobulbus, Dialister, Eubacterium, Filifactor, Mitsukella, Porphyromonas and Pseudoramibacter (Mann-Whitney U-test; P < 0.05). Fusobacterium nucleatum, Dialister invisus, Streptococcus sp. human oral taxon (HOT) 064, Filifactor alocis and Mitsuokella sp. HOT 131 presented a higher mean proportion, while Veillonella dispar, Actinomyces meyeri, Granulicatella adiacens showed lower mean proportions in the peri-implantitis sites when compared with healthy implants in both the Control and Test groups (Mann-Whitney U-test; P < 0.05).

CONCLUSION

Marked differences were observed in the composition of the subgingival biofilm between healthy and diseased implants. The biofilm associated with peri-implantitis harbored more pathogenic bacterial species from the orange complex and other "unusual" putative pathogens, such as F. alocis, D. invisus and Mitsuokella sp. HOT 131.

Microbial sampling process can change results of microbiological analysis in periodontitis diagnosis. A minireview

This minireview aims to verify the supposition that the microbial sampling process can change results of microbiological analysis in periodontitis diagnosis. The literature search via Pubmed yielded 52 appropriate articles for analysis. Of which 38% (20/52) described that the sampling sites were isolated from saliva, whereas 62% (32/52) did not. Also, 29% (15/52) declared that the microbial sampling was performed before probing pocket depth (PPD), whereas 71% (37/52) did not. Comparison of the results of microbiological analysis in these studies showed that the bacteria most frequently detected in periodontal pockets was variable. Therefore, a sampling process that includes both the microbial sample being taken before PPD and saliva isolation of the sampling sites is needed to ensure the accuracy of microbiological analysis in periodontitis diagnosis.

Prevalence of fimA genotypes of Porphyromonas gingivalis and other periodontal bacteria in a Spanish population with chronic periodontitis

Objectives: The aim of this study was to determine the prevalence of the different fimA genotypes of Porphyromonas gingivalis in adult Spanish patients with chronic periodontitis, patients with gingivitis and periodontally healthy subjects, and the relationship between these genotypes and other periodontopathogenic bacteria. Study design: Samples of subgingival plaque were taken from 86 patients (33 with chronic periodontitis, 16 with gingivitis, and 37 periodontally healthy) in the course of a full periodontal examination. PCR was employed to determine the presence of the 6 fimA genotypes of Porphyromonas gingivalis (I-V and Ib) and of Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola. Results: Porphyromonas gingivalis fimA genotypes II and Ib were present in significantly higher percentages in periodontal patients (39.4% and 12.1% respectively) than in healthy or gingivitis subjects. The prevalence of Tannerella forsythia, Treponema denticola, and Porphyromonas gingivalis fimA genotype IV was significantly higher in the group that presented bleeding greater than 30%. A positive correlation was found between Porphyromonas gingivalis fimA genotype IV and Treponema denticola. Conclusions: A strong association between Porphyromonas gingivalis fimA genotypes II and Ib and chronic periodontitis exists in the Spanish population. The most prevalent genotype in periodontal patients is II.

Key words:Periodontitis, Porphyromonas gingivalis, fimA genotype, periodontal bacteria, polymerase chain reaction.

Effects of hyperbaric oxygen on aggressive periodontitis and subgingival anaerobes in Chinese patients

OBJECTIVE

To investigate the effects of hyperbaric oxygen (HBO2) on aggressive periodontitis (AgP), and subgingival obligate anaerobes in Chinese patients.

MATERIALS AND METHODS

Sixty cases of Chinese patients with AgP were randomly divided into two groups -the HBO2 group (30 cases) and the control group (30 cases). Study teeth were divided into four groups -: the HBO2 therapy, the HBO2 + scaling scaling group, the scaling group and the control group. Subgingival anaerobic organisms were measured with anaerobic culture, and number of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus was counted. Comparisons of changes in the clinical indices, and subgingival anaerobes were made between the groups.

RESULTS

Highly significant differences in gingival index (GI), probing depth (PD), attachment loss (AL), and Plaque index (PLI), and tooth odontoseisis (TO) were seen in the HBO2, the HBO2 + scaling and the scaling groups when compared with the control group (P<0.01). The number of subgingival anaerobes as well as the types of obligate anaerobes and facultative anaerobes and the number of Bacteroides melaninogenicus were reduced markedly in these three treatment groups. Highly statistical differences in clinical indices, subgingival anaerobe number and types of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus were found when comparisons were made between the HBO2 + scaling and the HBO2 groups, as well as between the HBO2 + scaling and the scaling groups. Clinical follow-ups indicated that the GI, PD, AL, TO, PLI and subgingival anaerobes number of the three therapeutic groups were reduced more severely than the control group.

CONCLUSIONS

HBO2 had good therapeutic effects on Chinese patients with AgP. HBO2 therapy combined with scaling and root planing was the most beneficial in the treatment of AgP. The therapeutic effect of HBO2 on AgP is most likely through inhibition of the growth of subgingival anaerobes. Clinical follow-ups suggest that the effect could last more than 2 years.

Synergistic effects of lipopolysaccharides from periodontopathic bacteria on pro-inflammatory cytokine production in an ex vivo whole blood model

Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia have been strongly associated with chronic periodontitis. This disease is characterized by an accumulation of inflammatory cells in periodontal tissue and subgingival sites. The secretion of high levels of inflammatory cytokines by those cells is believed to contribute to periodontal tissue destruction. The aim of this study was to investigate the inflammatory response of whole blood from periodontitis patients following challenges with whole cells of P. gingivalis, T. denticola, and T. forsythia or their lipopolysaccharides (LPS), individually and in combination. Whole blood collected from seven periodontitis patients was stimulated with whole cells or LPS and the production of interleukin (IL)-1beta, IL-6, IL-8, and tumor necrosis factor alpha (TNF-alpha) were quantified by enzyme-linked immunosorbent assays. The mono and mixed challenges with whole bacterial cells or LPS induced the secretion of high amounts of IL-1beta, IL-6, IL-8, and TNF-alpha by the mixed leukocyte population from periodontitis patients. In addition, P. gingivalis LPS, T. denticola LPS, and T. forsythia LPS acted in synergy to induce high levels of IL-1beta and TNF-alpha. This study suggests that P. gingivalis, T. denticola, and T. forsythia may contribute to the immunodestructive host response characteristic of periodontitis through synergistic effects of their LPS on the inflammatory response induced by a mixed population of leukocytes.

Occurrence of Aggregatibacter actinomycetemcomitans in Brazilian Indians from Umutina Reservation, Mato Grosso, Brazil

Aggregatibacter actinomycetemcomitans is associated with periodontal disease, especially localized aggressive periodontitis, produces a potent leukotoxin and its distribution is influenced by ethnic characteristics of the population.

Microbiological profile of untreated subjects with localized aggressive periodontitis

AIM

The microbial profile of localized aggressive periodontitis (LAgP) has not yet been determined. Therefore, the aim of this study was to evaluate the subgingival microbial composition of LAgP.

MATERIAL AND METHODS

One hundred and twenty subjects with LAgP (n=15), generalized aggressive periodontitis (GAgP, n=25), chronic periodontitis (ChP, n=30) or periodontal health (PH, n=50) underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analysed for their content of 38 bacterial species using checkerboard DNA-DNA hybridization.

RESULTS

Red complex and some orange complex species are the most numerous and prevalent periodontal pathogens in LAgP. The proportions of Aggregatibacter actinomycetemcomitans were elevated in shallow and intermediate pockets of LAgP subjects in comparison with those with GAgP or ChP, but not in deep sites. This species also showed a negative correlation with age and with the proportions of red complex pathogens. The host-compatible Actinomyces species were reduced in LAgP.

CONCLUSION

A. actinomycetemcomitans seems to be associated with the onset of LAgP, and Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter gracilis, Eubacterium nodatum and Prevotella intermedia play an important role in disease progression. Successful treatment of LAgP would involve a reduction in these pathogens and an increase in the Actinomyces species.

Yeast diversity in the oral microbiota of subjects with periodontitis: Candida albicans and Candida dubliniensis colonize the periodontal pockets

The term periodontitis encompasses several polymicrobial infectious diseases, of multifactorial etiology, with chronic and aggressive forms. In spite of the etiopathogenic differences between these two forms of the disease, few studies have analyzed the subgingival colonization by yeast. The objective of this investigation was to analyze the composition of the yeast microbiota present in the mucosa and subgingival sites of healthy individuals and patients with aggressive and chronic periodontitis. For this, samples were recovered from these two locations and the yeast recovered identified by phenotypic and genotypic methods. Patients with chronic periodontitis showed significant differences in relation to the other groups with respect to carrier status (69.2% versus 35.7% of healthy individuals; [chi(i)(2) test; p=0.014]), the total number of isolated colony forming units or CFU (mean and ranges 281.6 (0-6048) [K-W(2)=6.998; p=0.03]), the Simpson diversity index (I) in site b (I(b)=0.344 versus healthy subjet and aggresive periodontitis where I=0 [multiple t-test comparisons with the Bonferronni correction, p<0.05]), and the species profile. Interestingly, in spite of the varied profiles of the species present in the mucosa of the three groups analyzed we noted that only C. albicans and C. dubliniensis were capable of colonizing the periodontal pockets in patients with chronic periodontitis, while only C. albicans was identified in the subgingiva of healthy individuals and patients with aggressive periodontitis.

The gingipains: scissors and glue of the periodontal pathogen, Porphyromonas gingivalis

The anaerobic bacterium, Porphyromonas gingivalis, is associated with chronic periodontal disease (periodontitis or gum disease). The disease is not only the leading cause of tooth loss in the developed world, but is associated with a number of systemic diseases, such as cardiovascular disease and diabetes. The most potent virulence factors of this bacterium are the gingipains, three cysteine proteases that bind and cleave a wide range of host proteins. This article summarizes current knowledge of the structure and function of the enzymes, with a particular focus on what remains to be elucidated regarding the structure and function of the nonenzymatic adhesin domains of the high-molecular-weight forms of the proteases.

Demographic, clinical, and microbial aspects of chronic and aggressive periodontitis in Colombia: a multicenter study

BACKGROUND

The microbial profile of periodontal disease varies among different human populations. This study evaluated the demographic, clinical, and microbiologic aspects of periodontitis in a multigeographic sample in Colombia.

METHODS

Three hundred twenty-five patients with chronic periodontitis (CP), 158 patients with aggressive periodontitis (AgP), and 137 healthy-gingivitis controls from five regions of the country were studied. Clinical, microbial, and sociodemographic data were collected. Microbiologic identification was performed using polymerase chain reaction 16S rRNA gene on pooled subgingival samples, and the presence of Gram-negative enteric rods was evaluated by culture. Bivariate and multivariate logistic regression analyses were conducted.

RESULTS

Porphyromonas gingivalis occurred in 71.5% of individuals with periodontitis, Tannerella forsythensis occurred in 58.5%, Campylobacter rectus occurred in 57.5%, Actinobacillus actinomycetemcomitans occurred in 23.6%, and enteric rods occurred in 34.5%. P. gingivalis was more common in CP and AgP than controls. A. actinomycetemcomitans was increased in AgP compared to controls and patients with CP. T. forsythensis, C. rectus, and Eikenella corrodens had a low presence in the West Pacific and Central regions, and enteric rods were increased in the Central region (P <0.05). Other sociodemographic factors were not associated with these microorganisms.

CONCLUSIONS

Geographic regions do not influence the microbiota, but the microbiota may vary by geographic region. P. gingivalis, T. forsythensis, and C. rectus are the most prevalent periodontophatic microorganisms in Colombia. A. actinomycetemcomitans was more common in AgP, and a large percentage of the population studied had enteric rods in the subgingival plaque.

Potentiel pathogénique de Porphyromonas gingivalis, Treponema denticola et Tannerella forsythia, le complexe bactérien rouge associé à la parodontite

Periodontitis are mixed bacterial infections leading to destruction of tooth-supporting tissues, including periodontal ligament and alveolar bone. Among over 500 bacterial species living in the oral cavity, a bacterial complex named "red complex" and made of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia has been strongly related to advanced periodontal lesions. While periodontopathogenic bacteria are the primary etiologic factor of periodontitis, tissue destruction essentially results from the host immune response to the bacterial challenge. Members of the red complex are Gram negative anaerobic bacteria expressing numerous virulence factors allowing bacteria to colonize the subgingival sites, to disturb the host defense system, to invade and destroy periodontal tissue as well as to promote the immunodestructive host response. This article reviews current knowledge of the pathogenic mechanisms of bacteria of the red complex leading to tissue and alveolar bone destruction observed during periodontitis.

An overview of the epidemiology of periodontal diseases in Latin America

The aim of the present review was to identify the presence of periodontal diseases and the relative importance of known risk factors in Latin American countries. The retrieved data are sparse and inconsistent, lacking information for the majority of the countries. Gingivitis is ubiquitous in the region, affecting all ages independently of the socioeconomic background. The extension of bleeding may vary greatly, ranging from 40% to 70% of sites. The prevalence of aggressive periodontitis is higher in Latin America than in industrialized countries. Prevalence ranges from 0.3% to 4.5%, and the localized form is the less prevalent. The prevalence of chronic periodontitis is high, with a large variation (40-80%) probably due to differences in methodology and diagnostic criteria. Regional differences may be relevant. Known risk factors are present in the populations studied. Non-modifiable factors such as age, gender and genetics have been associated in Brazilian and Chilean populations. Tobacco smoking and diabetes are relevant risk factors. The importance of socioeconomic status, although present as a risk factor, has been largely underestimated. Oral hygiene is extremely deficient in the area although it is a cultural habit in most populations. It can be concluded that periodontal diseases are highly prevalent in Latin American populations. Its prevalence and extent are associated with known risk factors. Oral hygiene habits are deficient. Well designed epidemiological studies with external validity are needed.

Association of Eubacterium nodatum and Treponema denticola with human periodontitis lesions

BACKGROUND

The purpose of the present investigation was to compare the levels, proportions and percentage of sites colonized by 40 bacterial species in subgingival plaque samples from periodontally healthy subjects and patients with chronic periodontitis to seek possible pathogens other than the consensus pathogens Porphyromonas gingivalis and Tannerella forsythia.

METHOD

Subgingival plaque samples were taken from the mesial aspect of each tooth in 635 subjects with chronic periodontitis and 189 periodontally healthy subjects. The samples were individually analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization (total samples = 21,832). Mean counts, % DNA probe counts and percentage of sites colonized at >10(5) were determined for each species in each subject and then averaged in each clinical group. Significance of difference between groups was determined using the Mann-Whitney test. Association between combinations of species and periodontal status was examined by stepwise logistic regression analysis. Analyses were repeated using a subset of subjects from both clinical groups who had proportions of P. gingivalis plus T. forsythia less than the median (4.42%) found in periodontally healthy subjects. All analyses were adjusted for multiple comparisons.

RESULTS

For the 824 subjects the consensus pathogens P. gingivalis and T. forsythia as well as Eubacterium nodatum and Treponema denticola had significantly higher mean counts, proportions and percentage of sites colonized in samples from subjects with periodontitis than from periodontally healthy subjects. There were significantly more Capnocytophaga gingivalis, Streptococcus gordonii and Veillonella parvula in periodontally healthy subjects. E. nodatum, T. denticola, Streptococcus oralis, Streptococcus intermedius, Fusobacterium nucleatum ssp. vincentii all had higher counts and proportions in diseased than healthy subjects who had low proportions of P. gingivalis and T. forsythia. Logistic regression analysis indicated that the same species groups were associated with disease status after adjusting for the proportions of the other species.

CONCLUSIONS

This investigation confirmed the strong association of P. gingivalis and T. forsythia with chronic periodontitis and emphasized a strong association of E. nodatum and T. denticola with periodontitis whether in the presence or absence of high levels of the consensus pathogens. Other species, including S. oralis, Eikenella corrodens, S. intermedius and F. nucleatum ssp. vincentii, were associated with disease when P. gingivalis and T. forsythia were present in low proportions.

Molecular analysis of the subgingival microbiota in health and disease

This investigation provides molecular analyses of the periodontal microbiota in health and disease. Subgingival samples from 47 volunteers with healthy gingivae or clinically diagnosed chronic periodontitis were characterized by PCR-denaturing gradient gel electrophoresis (DGGE) with primers specific for the V2-V3 region of the eubacterial 16S rRNA gene. A hierarchical dendrogram was constructed from band patterns. All unique PCR amplicons (DGGE bands) were sequenced for identity. Samples were also analyzed for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythensis by multiplex PCR. Associations of patient age, gender, and smoking status together with the presence of each unique band and putative periodontal pathogens with disease were assessed by logistic regression. Periodontal pockets were colonized by complex eubacterial communities (10 to 40 distinct DGGE bands) with substantial individual variation in the community profile. Species diversity in health and disease was determined by the Shannon-Weaver index of diversity and compared by the Mann-Whitney U test. Sequence analyses of DGGE amplicons indicated the occurrence of many nontypical oral species and eubacteria previously associated with this environment. With the exception of T. forsythensis, the putative pathogens were not detected by DGGE. Multiplex PCR, however, detected T. forsythensis, A. actinomycetemcomitans, and P. gingivalis in 9% 16%, and 29% of the patients with disease, respectively. The presence of A. actinomycetemcomitans was significantly associated with disease (P < 0.01). Statistical analyses indicated that the presence of Treponema socranskii and Pseudomonas sp. was a significant predictor of disease (P < 0.05) and that there was no significant difference (P > 0.05) in terms of eubacterial species diversity between health and disease.

Effects of metronidazole plus amoxicillin as the only therapy on the microbiological and clinical parameters of untreated chronic periodontitis

AIM

To determine the effect of metronidazole plus amoxicillin (M+A) as the sole therapy, on the subgingival microbiota of chronic periodontitis.

MATERIAL AND METHODS

Twenty-two patients with untreated chronic periodontitis were randomly assigned to a group that received M+A for 7 days, or to a group receiving scaling and root planing (SRP) and two placebos. Clinical measurements including sites with plaque, bleeding on probing (BOP), probing depth (PD) and attachment level (AL) were made at baseline, 3, 6, 9 and 12 months. Subgingival plaque samples were taken from all teeth at baseline 3, 6, 9 and 12 months for the counts of 40 subgingival species using checkerboard DNA-DNA hybridization.

RESULTS

Mean PD was reduced from 2.80+/-0.45 at baseline to 1.95+/-0.05 at 12 months (P<0.001) and from 2.39+/-0.41 to 1.95+/-0.10 (P<0.001) in the M+A- and SRP-treated patients, respectively. Corresponding values for relative mean AL were 10.07+/-1.30-9.77+/-0.34 (P<0.001) and 9.94+/-0.28-9.77+/-0.26 (P<0.001). Percentage of sites exhibiting BOP were 40.6+/-18.3-14.0+/-1.4 (P<0.001), and 38.5+/-5.1-19.0+/-2.8 (P<0.001) in the M+A and SRP groups, respectively. Mean total DNA probe counts and counts of the majority of the 40 test species were significantly reduced over time in both groups, with no significant differences detected at any time point between groups. At 12 months many of the species were still present at significantly lowered levels compared with their baseline counts in both groups.

CONCLUSIONS

Changes in clinical and microbiological parameters were similar after receiving systemically administered M+A as the sole therapy or after receiving SRP only.

Risk factors and prevalence of periodontitis in community-dwelling elders in Mexico

AIM

The objective of this study was to determine whether an association existed between chronic systemic diseases/conditions, risk factors common in old age, and the extent and severity of chronic periodontal disease.

MATERIALS AND METHODS

Sociodemographic and lifestyle characteristics were examined by contrasting rural, urban-marginal, and urban social environments in Central Mexico. Data were analysed with Analysis of Variance, chi2 tests, and multivariable logistic regression.

RESULTS

A total of 473 adults 60 years old and over were interviewed; 315 were also examined and underwent laboratory assays (participation rate, 66%); women, 62%; mean age 73+/-8 years; 23% edentulous. The distribution of periodontitis by sociodemographic variables showed differences across locales (73% low-urban, 57% middle-urban, 29% rural). The regression model indicated that periodontitis was more frequently associated with low-urban locale, higher systolic blood pressure, higher body mass index, and worse calculus readings, with an interaction whereby being obese and having a high calculus index was associated with a high probability of having periodontitis.

CONCLUSIONS

Overall periodontal conditions were fair. While we identified oral, systemic, and social variables that modulated the experience of periodontitis, it would appear that urban, low social class elders appeared to have worse periodontal conditions.

Description of the Subgingival Microbiota of Periodontally Untreated Mexican Subjects: Chronic Periodontitis and Periodontal Health

BACKGROUND

Recent studies have suggested that changes in the prevalence and/or proportion of distinct microorganisms characterize the subgingival microbial profiles of populations around the world. At present, no information is available on the subgingival microbiota of Mexican subjects. The purpose of the present study was to determine the microbial composition of subgingival plaque in Mexican subjects with untreated chronic periodontitis.

METHODS

A total of 44 chronic periodontitis and 20 periodontally healthy subjects (who were currently non-smokers) were selected. Clinical measurements including plaque accumulation, gingival erythema, bleeding on probing, suppuration, probing depth, and attachment level were recorded at six sites of every tooth. Up to 28 subgingival plaque samples were obtained from each subject and individually analyzed to determine the levels, proportion, and prevalence of 40 microbial species using the checkerboard DNA-DNA hybridization technique.

RESULTS

Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythensis were the only species that presented higher mean levels in periodontitis subjects. The proportions of P. gingivalis (P<0.001), T. forsythensis (P<0.01), and red complex species (P. gingivalis, T. forsythensis, and T. denticola; P<0.001) as a group were also significantly higher in periodontitis subjects. Periodontally healthy subjects harbored a significantly larger proportion of Actinomyces species (P<0.05). No significant differences were detected in the percentage of carriers of any of the species tested.

CONCLUSIONS

Our results revealed that the subgingival microbiota of untreated chronic periodontitis Mexican subjects was characterized by increases in the level, prevalence, and proportion of classic periodontal pathogens. However, the prevalence and proportion of specific microbial species varied significantly from the results of other reports on subjects from different geographical locations.

Inflammatory responses of a macrophage/epithelial cell co-culture model to mono and mixed infections with Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia

Accumulated evidence points to Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia as three major etiologic agents of chronic periodontitis. Epithelial cells and macrophages play a major role in the host response to periodontopathogens, and the secretion of inflammatory mediators and matrix metalloproteinases (MMPs) by these host cells is believed to contribute to periodontal tissue destruction. The aim of this study was to investigate the inflammatory response of a macrophage/epithelial cell co-culture model following mono or mixed infections with the above three periodontopathogens. An in vitro co-culture model composed of epithelial-like transformed cells (HeLa cell line) and macrophage-like cells (phorbol myristic acid-differentiated U937 monocytic cell line) was challenged with whole cells or lipopolysaccharides (LPS) of P. gingivalis, T. denticola, and T. forsythia, individually and in combination. Following stimulation, the production of interleukin-1 beta (IL-1beta), IL-6, IL-8, tumor necrosis factor alpha (TNF-alpha), regulated on activation normal T cell expressed and secreted (RANTES), prostaglandin E2 (PGE2), and MMP-9 were quantified by enzyme-linked immunoassays. We observed that mono or mixed infections of the co-culture model induced the secretion of IL-1beta, IL-6, IL-8, PGE2, and MMP-9. P. gingivalis and T. forsythia induced an increase in RANTES secretion, whereas T. denticola alone or in combination resulted in a significant decrease in RANTES levels. All LPS challenges induced an increase in chemokine, MMP-9, and PGE2 production. No synergistic effect on the production of cytokines, chemokines, PGE2, and MMP-9 was observed for any of the bacterial or LPS mixtures tested. This study supports the view that P. gingivalis, T. denticola, and T. forsythia may induce high levels of pro-inflammatory mediators and MMP-9 in periodontal lesions, thus contributing to the progression of periodontitis.

Analytical epidemiology of periodontitis

AIMS

To review the literature related to the analytical epidemiology of periodontitis generated over the past decade. This review does not deal with descriptive epidemiologic studies of the prevalence, extent and severity of periodontitis with respect to global geography, but focuses exclusively on analytical epidemiology issues, including the challenges posed by the use of different case definitions across studies, current theories and models of disease progression, and risk factors associated with the onset and progression of periodontitis.

METHODS

Relevant publications in the English language were identified after Medline and PubMed database searches.

FINDINGS AND CONCLUSIONS

There is a conspicuous lack of uniformity in the definition of periodontitis used in epidemiologic studies, and findings from different research groups are not readily interpretable. There is a lack of studies that specifically address the distinction between factors responsible for the onset of periodontitis versus those affecting its progression. Colonization by specific bacteria at high levels, smoking, and poorly controlled diabetes have been established as risk factors for periodontitis, while a number of putative factors, including specific gene polymorphisms, have been identified in association studies. There is a clear need for longitudinal prospective studies that address hypotheses emerging from the cross-sectional data and include established risk factors as covariates along with new exposures of interest. Intervention studies, fulfilling the "targeting" step of the risk assessment process, are particularly warranted. Obvious candidates in this context are studies of the efficacy of elimination of specific bacterial species and of smoking cessation interventions as an alternative to the traditional broad anti-plaque approach in the prevention and control of periodontitis. Ideally, such studies should have a randomized-controlled trial design.

Prevalence of periodontal pathogens in Brazilians with aggressive or chronic periodontitis

OBJECTIVES

Previous studies suggest differences between geographically and racially distinct populations in the prevalence of periodontopathic bacteria as well as greater periodontal destruction associated with infection by highly leucotoxic Actinobacillus actinomycetemcomitans. The present study examined these hypotheses in Brazilians with aggressive or chronic periodontitis.

MATERIALS AND METHODS

Clinical, radiographical, and microbiological assessments were performed on 25 aggressive periodontitis and 178 chronic periodontitis patients including 71 males and 132 females, 15-69 years of age.

RESULTS

The prevalence of Porphyromonas gingivalis was similar to that of other South American populations. The prevalence of A. actinomycetemcomitans and its highly leucotoxic subgroup was higher in Brazilians. Highly leucotoxic A. actinomycetemcomitans was more prevalent in aggressive periodontitis (chi2=27.83) and positively associated with deep pockets (>6 mm, chi2=18.26) and young age (<29 years, chi2=18.68). Greater mean attachment loss was found in subjects with highly leucotoxic A. actinomycetemcomitans than in subjects with minimally leucotoxic (p=0.0029) or subjects not infected (p=0.0001).

CONCLUSION

These data support the hypothesis of differences between populations in the prevalence of periodontopathic bacteria and of greater attachment loss in sites infected with highly leucotoxic A. actinomycetemcomitans. Detection of highly leucotoxic A. actinomycetemcomitans in children and adolescents may be a useful marker for aggressive periodontitis.

Future treatment and diagnostic strategies for periodontal diseases

Many new technologies have been developed or are being developed that could enhance the ability to diagnose, predict, and treat periodontitis. Newer treatment strategies may allow clinicians to achieve limited or more robust regeneration of the periodontium. New or refreshed approaches to disease control are being pursued that will benefit those suffering from chronic periodontal disease. In addition to novel therapeutics, there has been increasing focus on the development of more sensitive and specific diagnostic tests for periodontal diseases. Such tests will allow the clinician to determine whether a patient has active disease and what sort of attachment loss might be expected if the patient is not treated. By developing newer diagnostic tests, it also may be possible to detect and monitor active disease during therapy.

Subgingival microbiota of chronic periodontitis subjects from different geographic locations

BACKGROUND

Most clinical studies assume that the subgingival microbiota is similar from one geographic location to another. The purpose of the present investigation was to examine the composition of the subgingival microbiota in chronic periodontitis subjects from four countries.

METHOD

Subjects with chronic periodontitis (N, Sweden=101; USA=115; Brazil=58; Chile=26) were recruited. Subjects were measured at baseline for plaque, gingivitis, bleeding on probing (BOP), suppuration, pocket depth (PD) and attachment level (AL) at six sites per tooth. Subgingival plaque samples taken from the mesial aspect of each tooth at baseline were individually analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization (total samples=6036). % DNA probe counts comprised by each species was determined for each site and averaged across sites in each subject. Significance of differences in proportions of each species among countries was determined using ancova adjusting for age, mean pocket depth, gender and smoking status. p-Values were adjusted for multiple comparisons.

RESULTS

On average, all species were detected in samples from subjects in the four countries. Thirteen species differed significantly in adjusted mean proportions among countries even after adjusting for multiple comparisons. Porphyromonas gingivalis, one species that differed in proportions among countries, comprised adjusted means of 7.5, 11.9, 1.6 and 6.6% of the microbiota in subjects from Brazil, Chile, Sweden and USA (p<0.001), while mean proportions of Treponema denticola were 6.7, 4.2, 0.8 and 2.3, respectively (p<0.001). In contrast, a key periodontal pathogen, Tannerella forsythensis, exhibited mean proportions ranging from 6.2-8.5% and did not differ significantly among countries. Besides these species, prominent species in Brazil were Actinomyces naeslundii genospecies 1 and 2 (8.4%, 7.2%) and Prevotella intermedia (6.5%); in Chile, Prevotella melaninogenica (6.4%) and Neisseria mucosa (5.3%); in Sweden A. naeslundii genospecies 2 (8.4%), Capnocytophaga gingivalis (7.1%) and Peptostreptococcus micros (5.0%); in USA A. naeslundii genospecies 2 (7.5%), P. intermedia (6.8%) and C. gingivalis (6.1%).

CONCLUSIONS

The microbial profiles of subgingival plaque samples from chronic periodontitis subjects in four countries showed surprisingly marked differences. These differences persisted after adjusting for age, mean pocket depth, gender and smoking status.