The origin of periodontal infections

Enrichment of periodontal pathogens from the biofilms of healthy adults

Periodontitis is associated with shifts in the balance of the subgingival microbiome. Many species that predominate in disease have not been isolated from healthy sites, raising questions as to the origin of these putative pathogens. The study aim was to determine whether periodontal pathogens could be enriched from pooled saliva, plaque and tongue samples from dentally-healthy adult volunteers using growth media that simulate nutritional aspects of the inflamed subgingival environment. The microbiome was characterised before and after enrichment using established metagenomic approaches, and the data analysed bioinformatically to identify major functional changes. After three weeks, there was a shift from an inoculum in which Streptococcus, Haemophilus, Neisseria, Veillonella and Prevotella species predominated to biofilms comprising an increased abundance of taxa implicated in periodontitis, including Porphyromonas gingivalis, Fretibacterium fastidiosum, Filifactor alocis, Tannerella forsythia, and several Peptostreptococcus and Treponema spp., with concomitant decreases in health-associated species. Sixty-four species were present after enrichment that were undetectable in the inoculum, including Jonquetella anthropi, Desulfovibrio desulfuricans and Dialister invisus. These studies support the Ecological Plaque Hypothesis, providing evidence that putative periodontopathogens are present in health at low levels, but changes to the subgingival nutritional environment increase their competitiveness and drive deleterious changes to biofilm composition.

Phage puppet masters of the marine microbial realm

Viruses numerically dominate our oceans; however, we have only just begun to document the diversity, host range and infection dynamics of marine viruses, as well as the subsequent effects of infection on both host cell metabolism and oceanic biogeochemistry. Bacteriophages (that is, phages: viruses that infect bacteria) are highly abundant and are known to play critical roles in bacterial mortality, biogeochemical cycling and horizontal gene transfer. This Review Article summarizes current knowledge of marine viral ecology and highlights the importance of phage particles to the dissolved organic matter pool, as well as the complex interactions between phages and their bacterial hosts. We emphasize the newly recognized roles of phages as puppet masters of their bacterial hosts, where phages are capable of altering the metabolism of infected bacteria through the expression of auxiliary metabolic genes and the redirection of host gene expression patterns. Finally, we propose the 'royal family model' as a hypothesis to describe successional patterns of bacteria and phages over time in marine systems, where despite high richness and significant seasonal differences, only a small number of phages appear to continually dominate a given marine ecosystem. Although further testing is required, this model provides a framework for assessing the specificity and ecological consequences of phage-host dynamics.

Cathepsin C, Matrix Metalloproteinases, and their Tissue Inhibitors in Gingiva and Gingival Crevicular Fluid from Periodontitis-affected Patients

Successive active phases observed in periodontal diseases may be explained either by a sudden activation of the pro-forms of tissue-stored degradative enzymes such as metalloproteinases (MMPs) or by an imbalance between metalloproteinases and their tissue inhibitors (TIMPs). To discriminate between these two hypotheses, we quantified the levels, the percentage of active form, and the activities of four metalloproteinases (MMPs -1, -2, -3, and -9), as well as the levels of two tissue inhibitors of metalloproteinases (TIMP-1 and -2) and the activity of cathepsin C in tissue extract supernatants and their corresponding gingival crevicular fluid samples collected from periodontitis-affected and healthy patients. Our results supported evidence that tissue destruction results from an imbalance of metalloproteinases over their tissue inhibitors rather than from a sudden activation of the pro-forms of these enzymes. A significant reduction in the activity of cathepsin C also contributed to the degradative process.

Gingival diseases in childhood - a review

Children and adolescents are subject to a wide variety of gingival infections. Epidemiological studies indicate that gingivitis of varying severity is nearly a universal finding in children and adolescents. The shorter life span of the primary dentition may be the reason why in general little attention is given to periodontitis in children. Since early diagnosis is important for successful treatment, it is imperative that children receive a periodontal examination as part of their routine dental visit. Furthermore destructive periodontal disease occurs in children with certain systemic diseases. Indeed the presence of severe periodontitis may be an early sign of systemic disease. A general medical evaluation to determine if systemic diseases are present should be considered in children who exhibit severe periodontitis, especially if the disease appears resistant to therapy. Though periodontal health awareness and therapy are increasing day by day in our country compared to earlier days, it is much restricted to adults rather than children. Oral cavity examination in children is much oriented in hard tissue evaluation than soft tissue health. Hence, this article enlightens about the prevalence of various soft tissue diseases and importance of long term overall oral health maintenance in childhood.

Periodontitis: a host-mediated disruption of microbial homeostasis. Unlearning learned concepts

New concepts evolve when existing ones fail to address known factors adequately or are invalidated by new evidence. For decades periodontitis has been considered to be caused by specific bacteria or groups of bacteria and, accordingly, treatment protocols have largely been based on anti-infective therapies. However, close inspection of current data leads one to question whether these bacteria are the cause or the result of periodontitis. Good evidence is emerging to suggest that it is indeed the host response to oral bacteria that leads to the tissue changes noted in gingivitis. These changes lead to an altered subgingival environment that favors the emergence of 'periodontal pathogens' and the subsequent development of periodontitis if the genetic and external environmental conditions are favorable for disease development. Thus, it seems that it is indeed the initial early host-inflammatory and immune responses occurring during the development of gingivitis, and not specific bacteria or their so-called virulence factors, which determine whether periodontitis develops and progresses. In this review we consider these concepts and their potential to change the way in which we view and manage the inflammatory periodontal diseases.

Periodontal disease immunology: 'double indemnity' in protecting the host

During the last two to three decades our understanding of the immunobiology of periodontal disease has increased exponentially, both with respect to the microbial agents triggering the disease process and the molecular mechanisms of the host engagement maintaining homeostasis or leading to collateral tissue damage. These foundational scientific findings have laid the groundwork for translating cell phenotype, receptor engagement, intracellular signaling pathways and effector functions into a 'picture' of the periodontium as the host responds to the 'danger signals' of the microbial ecology to maintain homeostasis or succumb to a disease process. These findings implicate the chronicity of the local response in attempting to manage the microbial challenge, creating a 'Double Indemnity' in some patients that does not 'insure' health for the periodontium. As importantly, in reflecting the title of this volume of Periodontology 2000, this review attempts to inform the community of how the science of periodontal immunology gestated, how continual probing of the biology of the disease has led to an evolution in our knowledge base and how more recent studies in the postgenomic era are revolutionizing our understanding of disease initiation, progression and resolution. Thus, there has been substantial progress in our understanding of the molecular mechanisms of host-bacteria interactions that result in the clinical presentation and outcomes of destructive periodontitis. The science has embarked from observations of variations in responses related to disease expression with a focus for utilization of the responses in diagnosis and therapeutic outcomes, to current investigations using cutting-edge fundamental biological processes to attempt to model the initiation and progression of soft- and hard-tissue destruction of the periodontium. As importantly, the next era in the immunobiology of periodontal disease will need to engage more sophisticated experimental designs for clinical studies to enable robust translation of basic biologic processes that are in action early in the transition from health to disease, those which stimulate microenvironmental changes that select for a more pathogenic microbial ecology and those that represent a rebalancing of the complex host responses and a resolution of inflammatory tissue destruction.

Gingival lymphatic drainage protects against Porphyromonas gingivalis-induced bone loss in mice

Periodontitis is characterized by tissue destruction and bone loss mainly due to inflammatory responses after bacterial challenge of the gingiva. Gingiva is supplied with lymphatics that drain interstitial fluid and transport immune cells to the lymph nodes for antigen presentation; yet, the role of lymphatics in periodontal disease development is unknown. To investigate the lymphatic function after periodontal infection, we used K14-VEGF receptor 3-Ig (K14) mice that lack lymphatics in gingiva. Mice were orally infected with human Porphyromonas gingivalis and observed for 42 days. The infected K14 mice developed significantly more bone loss than the wild-type mice, and were associated with an increased number of macrophages and major histocompatibility complex class II antigen-presenting cells in the bone resorptional areas. The infected transgenic mice expressed a significant higher periodontal level of several proinflammatory cytokines, whereas the plasma level of P. gingivalis IgG was significantly lower than in the wild-type mice. No differences were found in immune cell distribution in draining lymph nodes between the strains. Our results show that a strong periodontal inflammatory response and a weakened systemic humoral B-cell response took place in K14 mice after infection. We conclude that gingival lymphatics protect against P. gingivalis-induced periodontitis, and we speculate that they are critical in the protection by clearance of infection and by promotion of humoral immune responses.

Saliva: A diagnostic biomarker of periodontal diseases

Early detection of disease plays a crucial role in successful therapy. Early diagnosis and management reduces the severity and possible complications of the disease process. To overcome this challenge, medical researchers are devoted to finding molecular disease biomarkers that reveal a hidden lethal threat before the disease becomes complicated. Saliva, an important physiologic fluid, containing a highly complex mixture of substances, is rapidly gaining popularity as a diagnostic tool. Periodontal disease is a chronic disease of the oral cavity comprising a group of inflammatory conditions affecting the supporting structures of the dentition. In the field of periodontology, traditional clinical criteria are often insufficient for determining sites of active disease, for monitoring the response to therapy, or for measuring the degree of susceptibility to future disease progression. Saliva, as a mirror of oral and systemic health, is a valuable source for clinically relevant information because it contains biomarkers specific for the unique physiologic aspects of periodontal diseases. This review highlights the various potentials of saliva as a diagnostic biomarker for periodontal diseases.

Osteoporosis, the risk of vertebral fracture, and periodontal disease in an elderly group in Mexico City

OBJECTIVES

The aims of this study were to identify the possible association of osteoporosis, fracture risk and periodontitis, and consider the role of pharmacological treatment of osteoporosis and the periodontal condition.

METHODS

Patients aged 60 and older from the Mexican National Medical Science and Nutrition Institute Salvador Zubirán participated in the study. DXA was used to assess osteoporosis and risk of vertebral fracture. A modified version of the extent and severity index (ESI) was applied to evaluate periodontitis (cut-off point for attachment loss ≥ 4 mm) and all teeth were examined.

RESULTS

One hundred and sixty-six patients were examined, 88.6% were females, 47.0% had osteoporosis and 38.6% showed a high risk of fracture. The modified ESI was 5.13 mm (SD 1.4), 57.8% (SD 29.7). The model for periodontitis severity showed an association with oral hygiene (OR = 1.85) and use of osteoporosis medication (OR = 0.43). The model for the extent of periodontitis identified an association with smoking (OR = 2.37), osteoporosis (OR = 1.82) and osteoporosis medication (OR = 0.36). The model for tooth loss detected an association with fracture risk (OR = 3.02) and osteoporosis medication (OR = 0.33).

CONCLUSION

Periodontitis extent was associated with osteoporosis, and tooth loss with fracture risk.

Comparative gender differences in local and systemic concentrations of pro-inflammatory cytokines in rats with experimental periodontitis

BACKGROUND AND OBJECTIVE

There have been few studies of gender differences in response to periodontitis. Thus, we compared gender-specific differences in systemic cytokine concentrations in rats with and without ligature-induced periodontitis.

MATERIAL AND METHODS

Experimental periodontal disease was initiated in Sprague-Dawley rats by placing a ligature around the crowns of the second right maxillary molar tooth. Sham-operated control groups were also created. Two weeks later, the right and left maxillary quadrants of teeth, liver and serum were collected from all the rats, and uterine horns were collected from the female rats. Liver and uterine samples were ground in phosphate-buffered saline (10 mg of tissue/mL of phosphate-buffered saline + protease inhibitor) containing a protease inhibitor, and cytokine concentrations were determined by enzyme-linked immunosorbent assay. Digital radiographs were made of maxillary quadrants, and the distance from cemento-enamel junction to alveolar crest was measured using image analysis software. Data were compared by factorial analysis of variance and a post-hoc Tukey test.

RESULTS

Female rats with ligatures had greater, but not significantly different, alveolar bone loss than males with ligatures. However, they had higher serum concentrations of interleukin-6, tumor necrosis factor-alpha and C-reactive protein, and liver C-reactive protein (p < 0.05). These females also had higher interleukin-6, tumor necrosis factor-alpha and vascular endothelial growth factor concentrations within the uterine horn, compared to female controls (p < 0.05). Male animals with ligatures had lower serum concentrations of C-reactive protein and higher interleukin-6 and tumor necrosis factor-alpha concentrations within serum, compared to male controls (p < 0.05).

CONCLUSION

Our study suggests that females with periodontal disease have a greater risk for inflammatory-based systemic diseases than males.

Microbiologic and immunologic characteristics of periodontal disease in Hispanic americans with type 2 diabetes

BACKGROUND

The microbiology of periodontitis in type 1 diabetes has been reported, but less is known about type 2 diabetes. Moreover, these data have not linked microbial colonization, host response, and clinical presentation in type 1 or type 2 diabetes. The objectives of this study were to relate periodontal status, periodontal microorganisms, and host-response characteristics in Hispanic Americans with type 2 diabetes.

METHODS

Plaque and serum samples were obtained from 63 Hispanic American subjects with and without type 2 diabetes. The microbiology of subgingival plaque samples was evaluated using DNA checkerboard hybridization, and serum antibody to a battery of oral microorganisms was determined using an enzyme-linked immunosorbent assay.

RESULTS

In general, similar pathogens were present in periodontitis sites from subjects with and without type 2 diabetes, although the periodontitis sites in diabetes showed a higher frequency of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), and Campylobacter spp. Serum antibody to Campylobacter rectus was elevated in type 2 diabetes, whereas antibody to P. gingivalis and C. rectus were elevated in subjects with periodontitis, irrespective of diabetes status. Stratification of the population based upon antibody to P. gingivalis or C. rectus suggested a linkage between elevated antibody to P. gingivalis, increased frequency of diabetes, and significantly worse periodontitis.

CONCLUSION

The increased severity of periodontal disease with type 2 diabetes may reflect an alteration of the pathogenic potential of periodontal bacteria and/or a modification of the characteristics of the host's inflammatory response that may contribute to a breakdown in the homeostasis of the periodontium.

Periodontal microbiota in patients with coronary artery disease measured by real-time polymerase chain reaction: a case-control study

BACKGROUND

Recent data have shown that periodontal disease may increase the risk of occurrence of coronary heart disease in which inflammation initiated by bacteria and their compounds might be a common causal factor. This case-control study aimed at studying the relationship between periodontal disease and coronary artery disease (CAD) based on clinical and periodontal microbiologic parameters.

METHODS

A total of 90 male subjects, 48 to 80 years of age, were included in this study. Forty-five men had CAD (CAD+), which was confirmed by coronary angiography. Forty-five age-matched controls showed no history or symptoms of CAD (CAD-). All subjects underwent a clinical periodontal examination including assessment of tooth loss, probing depth, clinical attachment level, and bleeding on probing. In the CAD+ group, this examination took place 1 day before coronary angiography. Subgingival microbial samples were taken and evaluated by means of real-time polymerase chain reaction (RT-PCR) for the total amount of bacteria and the following periodontopathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Parvimonas micra (formerly Micromonas micros), Dialister pneumosintes, and Campylobacter rectus.

RESULTS

Compared to control subjects, CAD+ subjects had significantly deeper pockets (2.28 mm versus 2.96 mm; P <0.001) and greater attachment loss (2.85 mm versus 3.65 mm; P <0.001), and this difference remained statistically significant after adjusting for smoking. No significant differences were observed between cases and controls with regard to the number of teeth present. P. intermedia was the only periodontal pathogen that showed significantly higher mean counts in CAD+ subjects compared to CAD- subjects. Higher counts of total bacteria, P. micra, D. pneumosintes, and C. rectus were found in the CAD- group.

CONCLUSION

The results suggest that a relationship between periodontal disease and coronary heart disease exists, although P. intermedia was the only periodontopathogen related to CAD.

Rapid detection of Actinobacillus actinomycetemcomitans using a loop-mediated isothermal amplification method

INTRODUCTION

Actinobacillus actinomycetemcomitans has been implicated in the etiology of aggressive periodontitis. In this study, we applied a novel nucleic acid amplification method, called loop-mediated isothermal amplification (LAMP), which amplifies DNA with high specificity, efficiency and rapidity under isothermal conditions, allowing the rapid detection of A. actinomycetemcomitans.

METHODS

We designed the primers for detecting A. actinomycetemcomitans and evaluated the specificity and sensitivity of the assay.

RESULTS

The LAMP primers used in this study successfully amplified serotypes a-e of A. actinomycetemcomitans, while other oral bacteria were not amplified. By measuring the precipitation of magnesium pyrophosphate, we could quantify the chromosomal DNA of A. actinomycetemcomitans. The detection limits using the real-time turbidimetry analysis were 5.8 x 10(2)-5.8 x 10(7) copies of A. actinomycetemcomitans template DNA per reaction tube. In addition, the LAMP assay was used for the rapid detection of A. actinomycetemcomitans in clinical specimens from eight individuals. The results with the LAMP method were similar to those using conventional polymerase chain reaction.

CONCLUSION

Our results suggest that the LAMP-based assay is very useful for the rapid detection of A. actinomycetemcomitans.

Periodontal disease increases the risk of severe pre-eclampsia among pregnant women

AIM

To evaluate the possible link between the severity of periodontal disease and pre-eclampsia and to correlate this link to clinical periodontal parameters and interleukin (IL)-1beta, tumour necrosis factor-alpha (TNF-alpha), and prostaglandins (PGE(2)) levels in both gingival crevicular fluid (GCF) and serum.

MATERIAL AND METHODS

Fifty-nine pregnant women (20 mild pre-eclampsia, 18 severe pre-eclampsia, and 21 healthy pregnant women) were included in the study. Dental and periodontal recordings as well as GCF and blood samples were obtained within 48 h preceding delivery.

RESULTS

The results of multivariate logistic regression showed a highly significant association between mild to severe pre-eclampsia and severe periodontal disease (p<0.001). After adjusting for potential confounders (smoking, body weight, socioeconomic status, education level, and age), severe pre-eclamptic women were 3.78 (1.77-12.74) times more likely to present severe periodontal disease than normotensive pregnant women. This odds ratio (OR) was 2.43 (1.13-8.19) for mild pre-eclamptic women. IL-1beta, TNF-alpha, and PGE(2) levels in both serum and GCF were also significantly higher in the pre-eclamptic groups than the normotensive women.

CONCLUSIONS

These results indicate that the presence and severity of periodontal disease seems to increase the risk for not only the occurrence but also the severity of pre-eclampsia in pregnant women.

Salivary thiols and enzyme markers of cell damage in periodontal disease

OBJECTIVES

Recent studies describe the potential use of biochemical markers in the evaluation of the severity of periodontitis; moreover, patients suffering from periodontitis frequently complain of halitosis (breath malodour), mainly depending on volatile compounds (e.g. hydrogen sulphide, methyl mercaptan, etc.) produced by anaerobic metabolism of oral bacteria and involving sulphur-containing amino acids. In this study, salivary sulphur compounds, such as cysteine, cysteinylglycine and glutathione and some markers of cellular damage (lactate dehydrogenase and aspartate amino transferase), were measured in periodontitis patients and correlated with the periodontal probing pocket's depth.

DESIGN AND METHODS

Twenty-two periodontitis patients and forty control subjects were studied for the salivary activities of lactate dehydrogenase and aspartate aminotransferase and cysteine, cysteinylglycine and glutathione concentrations. The periodontitis patients were divided into two subgroups based on the severity of periodontal disease, expressed as median periodontal probing pocket depth (> or <5 mm). Enzyme activities were measured by using an automated clinical analyzer; cysteine, cysteinylglycine and glutathione concentrations were measured by HPLC equipped with fluorescence detector.

RESULTS

A statistically significant increase of the salivary parameters level (cysteine, cysteinylglycine, glutathione, aspartate aminotransferase and lactate dehydrogenase) was found in the patient subgroup with periodontal probing pocket depth >5 mm, the salivary cysteine concentrations showing the most significant correlation.

CONCLUSIONS

Salivary cysteine, a direct precursor of hydrogen sulphide, could be considered reliable markers for the oral tissue damage severity in periodontitis patients.

Functional Polymorphisms in the Matrix Metalloproteinase-9 Gene in Relation to Severity of Chronic Periodontitis

BACKGROUND

Members of the matrix metalloproteinase (MMP) family are implicated in the chronic remodeling in periodontal diseases. Therefore, we performed a case-control study to investigate a plausible association between susceptibility to chronic periodontitis (CP) and the polymorphisms in the MMP-9 (gelatinase B) gene.

METHODS

Using polymerase chain reaction with subsequent restriction analyses, MMP-9 -1562C/T and R+279Q variants were determined in 304 subjects (169 patients with CP, 76 with a mild to moderate form and 93 with severe generalized CP, and 135 age- and gender-matched unrelated control subjects).

RESULTS

The distribution of the MMP-9 -1562C/T and R+279Q genotypes and alleles did not significantly differ between cases and controls. However, the frequency of the T variant at position -1562 was marginally higher in patients with severe disease compared to those with mild to moderate forms (P <0.05; P(corr) >0.05). In further analysis, the -1562T allele was associated with a severe form of CP in men (odds ratio: 3.87; 95% confidence interval: 1.40 to 10.65; P <0.01 and P(corr) <0.05 for allele; P <0.05 and P(corr) >0.05 for genotype) but not in women.

CONCLUSION

These findings suggest that genetic polymorphisms of the MMP-9 gene are not associated with the susceptibility to CP in the Czech population; however, the promoter variant may influence the severity of the disease in men.

Paxillin phosphorylation and integrin expression in osteoblasts infected by Porphyromonas gingivalis

OBJECTIVE

We investigated early biological events initiated by Porphyromonas gingivalis infection of human osteoblasts, focusing on tyrosine-phosphorylation and the expression of key components in focal adhesion and cell signalling.

DESIGN

Human primary osteoblasts were challenged for 1h with Porphyromonas gingivalis. Tyrosine-phosphorylation of paxillin and focal adhesion kinase (FAK) was examined by Western blotting. Changes in alpha3- and beta1-integrin mRNA expression were quantified by RT-PCR.

RESULTS

Tyrosine-phosphorylation of paxillin was proportional to the size of the Porphyromonas gingivalis inoculum. FAK, a potential kinase for paxillin, was not activated. The amount of alpha3- and beta1-integrins, determined by Western blotting, did not vary significantly, while the corresponding mRNA levels fell significantly when a large bacterial inoculum was used.

CONCLUSIONS

These results indicate that Porphyromonas gingivalis infection of osteoblasts in vitro triggers tyrosine-phosphorylation of paxillin but not FAK and modify alpha3- and beta1-integrin mRNA expression. This infection thus appears to have different effects on components with essential roles in focal adhesion (paxillin) and cell signalling (FAK and integrins).

Actinobacillus actinomycetemcomitansserotype-specific genotypes and periodontal status in Brazilian subjects

Periodontitis is associated with members of the oral microbiota, such as Actinobacillus actino mycetem comitans. To our knowledge, this is the first study to evaluate, by PCR, the occurrence of the six known bacterium serotypes that included subjects with and without periodontitis. Our group comprised 49 Brazilian subjects. We studied 146 bacterial isolates from 23 patients with aggressive or chronic periodontitis and 26 subgingival specimens from subjects with or without periodontitis, all originating in our collection. Serotypes b and c were observed in similar frequencies, and no subject harboured d, e, or f serotype strains. Around 78% subjects had single-serotype infection. Mixed infection was seen only in aggressive periodontitis patients. An association between serotype b and healthy periodontium and between serotype c and chronic periodontitis was observed. Our results diverge from those previously reported, which may be explained by specific distribution patterns in distinct populations. The association of different serotypes with the same periodontal status or conversely of a serotype with different periodontal conditions indicates that organism serotyping should not be used as a sole reliable marker for predicting the outcome of the infection. Evaluation of factors involved in human oral cavity colonization by subsets of A. actinomycetemcomitans is essential for elucidating organism-host-environment relationships.Key words: Actinobacillus actinomycetemcomitans, genotyping, serotyping, periodontitis.

Periodontitis in humans and non-human primates: oral-systemic linkage inducing acute phase proteins

BACKGROUND

The acute phase response (APR) represents a systemic counterpart to the localized inflammatory response. This report describes patient-oriented and non-human primate model studies to determine the effect of periodontal disease on systemic acute phase proteins (APP).

METHODS

Patient-oriented studies included comparison of the levels of APP, using enzyme-linked immunosorbent assay (ELISA), with the presence and severity of periodontitis in localized chronic periodontitis (LCP), generalized aggressive periodontitis (GAP), and Sjogren's syndrome (SS) patients. The non-human primate experiments evaluated the serum level of APPs under natural conditions, following mechanical hygiene, experimental gingivitis, and during ligature-induced periodontitis.

RESULTS

Analysis of the LCP population showed what appeared to be a threshold of periodontal disease severity required for elevating the C-reactive protein (CRP) and haptoglobin (HG). The results demonstrated a significant elevation in CRP in the GAP versus the control groups, as well as lower levels of all mediators in healthy non-smokers (HNS) versus smokers (HS), suggesting that these systemic inflammatory markers were altered in response to challenge by noxious materials from smoking. Significantly different levels of CRP, HG, and alpha1-antiproteinase were noted in the SS patients suggesting that the autoimmune aspects of Sjögren's syndrome may impact upon oral health and systemic responses. Parallel evidence was also obtained from the primate studies. Providing mechanical oral hygiene, which significantly lowered clinical inflammation and bleeding of the gingiva, decreased the serum APP levels. Both CRP and fibrinogen were significantly elevated during progressing periodontitis, which also appeared to have an impact on serum lipids and lipoproteins.

CONCLUSIONS

These findings supported results relating chronic oral infections and the inflammation of periodontitis as contributors to and/or triggers for systemic inflammatory responses. Finally, similarities in the clinical and microbiological parameters of gingival inflammation and periodontitis between humans and non-human primates was extended to identification of changes in serum APP in the non-human primates that appeared to be in direct response to the induction of progressing periodontitis. These systemic changes provide additional evidence for the biological plausibility of periodontal infections contributing to various systemic diseases.

Periodontal disease as a risk factor for pre-eclampsia: a case control study

OBJECTIVE

To investigate the association between periodontal disease and pre-eclampsia, while controlling known risk factors for pre-eclampsia.

METHODS

A matched case-control study was carried out on 41 pre-eclamptic women and 41 normotensive, healthy, pregnant, control women. The pre-eclamptic women and controls were individually matched for age, gravidity, parity, smoking and prenatal care. The number of teeth and the number of restorations and decay on all tooth surfaces, and clinical periodontal parameters, excluding third molars were determined within 48 h before delivery. The relation of independent variables to pre-eclampsia was assessed using conditional multiple logistic regression analysis on subject-based data.

RESULTS

There were no statistically significant differences in mean percentages of sites with plaque between groups. The mean probing depth (PD) and mean clinical attachment level (CAL) for pre-eclamptic patients were significantly greater compared to those of normotensive patients (P < 0.01). The percentage of sites exhibiting bleeding on probing (BOP) (P < 0.05), the number of sites with PD >/= 4 mm and with CAL >/= 3 mm was significantly higher among pre-eclamptic patients than those with normotensive patients (P < 0.01). Conditional multiple logistic regression analysis indicated that periodontal disease and triglycerides level were significantly associated with pre-eclampsia. Other independent variables (maternal body weight and serum total cholesterol level) did not appear to be associated with pre-eclampsia. Conditional multiple logistic regression results showed that pre-eclamptic patients were 3.47 (95% CI = 1.07-11.95) times more likely to have periodontal disease than normotensive patients.

CONCLUSION

The present study shows that maternal periodontal disease during pregnancy is associated with an increased risk for the development of pre-eclampsia. The higher incidence of periodontal disease parameters in pre-eclamptic group would suggest a possible role for periodontal disease in the development of pre-eclampsia. The nature both of periodontitis and pre-eclampsia is multifactorial, and caution should be exercised when implicating periodontal disease in causation of pre-eclampsia.

Position paper: periodontal diseases of children and adolescents

Children and adolescents are subject to several periodontal diseases. Although there is a much lower prevalence of destructive periodontal diseases in children than in adults, children can develop severe forms of periodontitis. In some cases, this destructive disease is a manifestation of a known underlying systemic disease. In other young patients, the underlying cause for increased susceptibility and early onset of disease is unknown. These diseases are often familial, suggesting a genetic predisposition for aggressive disease. Current modalities for managing periodontal diseases of children and adolescents may include antibiotic therapy in combination with non-surgical and/or surgical therapy. Since early diagnosis ensures the greatest chance for successful treatment, it is important that children receive a periodontal examination as part of their routine dental visits.

Rate of cultivable subgingival periodontopathogenic bacteria in chronic periodontitis

Although microbiological studies have identified more than 400 bacterial species in periodontal pockets, only a limited number have been implicated as periodontal pathogens. The purpose of this study was to investigate the incidence of cultivable subgingival periodontopathogenic bacteria in chronic periodontitis. Bacterial samples were collected with sterile paper points from the deepest periodontal pockets ((5 mm) of 203 patients: 92 males and 111 females, aged 35-55 years. The samples were cultured under anaerobic and capnophilic conditions using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and a commercial rapid test system. The isolates were Actinobacillus actinomycetemcomitans (26.8%), Porphyromonas gingivalis (21.9%), Capnocytophaga sputigena (16.7%), Eikenella corrodens (13.2%), Prevotella intermedia (10.5 %), Prevotella disiens (3.1%), Peptostreptococcus micros (2.9%), Capnocytophaga gingivalis (2.2%), Prevotella corporis (1.8%), Peptostreptococcus magnus (1.3%) and Fusobacterium nucleatum (0.4%). No periodontopathogenic bacterial growth was observed in 14 of the samples (6.2%). The number of samples associated with monobacterial growth and polybacterial growth were 74.9% and 18.2% respectively. It is concluded that the bacterial composition associated with a number of patients' samples is quite complex, and that some of cultivable anaerobic and capnophilic bacteria act as periodontal pathogens in chronic periodontitis.

The genetic relatedness of Porphyromonas gingivalis clinical and laboratory strains assessed by analysis of insertion sequence (IS) element distribution

OBJECTIVES

Porphyromonas gingivalis is frequently found in periodontitis lesions. This organism contains a large number of insertion sequence (IS) elements. We sought to determine the distribution of seven IS elements from strain W83 among nine P. gingivalis laboratory strains and nine clinical isolates and to use these findings to determine strain relationships.

METHODS

Southern blots of BamHI digested genomic DNA digests were probed with insertion sequence elements ISPg1-7.

RESULTS

The restriction fragment length polymorphism (RFLP) patterns revealed that five of the nine laboratory strains, including strain W83, were nearly identical for all seven IS elements. Two of nine clinical isolates were similar to the five laboratory strains. Two of the four remaining laboratory strains had similar or identical RFLP patterns. The remaining two laboratory strains had limited similarity to clinical strains. Four of the clinical isolates had identical RFLP patterns for all seven IS elements. The three remaining clinical isolates were unique in their RFLP patterns. Several strains lacked from one to four of the IS elements. Similar strain relationships were suggested regardless of the IS element examined.

CONCLUSIONS

Transposition and recombination between IS elements are not sufficiently pervasive to obscure strain relationships, though this does not preclude the possibility that such events play an important role in allowing P. gingivalis to adapt to new environments. Given the level of genetic diversity observed, it may be especially important to examine genetically diverse strains when drawing conclusions based on the W83 P. gingivalis genomic database.

Development of a 5' fluorogenic nuclease-based real-time PCR assay for quantitative detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis

A 5' nuclease TaqMan PCR was developed for the quantitative detection of the periodontopathic bacteria Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. The relative numbers of bacteria were measured by the comparative threshold cycle method. This simplified method is a way of obtaining the relative quantities of these organisms from specimens and of monitoring the effect of therapy.

The role of CD4+ cells in vivo on the induction of the immune response to Porphyromonas gingivalis in mice

BACKGROUND

It has previously been suggested that CD4+ T cells play a pivotal role in regulating the immune response to periodontal pathogens. The aim of the present study therefore was to determine delayed type hypersensitivity (DTH), spleen cell proliferation, serum and splenic anti-Porphyromonas gingivalis antibody levels, and lesion sizes following challenge with viable P. gingivalis in CD4-depleted BALB/c mice immunized with P. gingivalis outer membrane proteins (OMP).

METHODS

Four groups of BALB/c mice were used. Groups 1 and 2 were injected intraperitoneally (ip) with saline for 3 consecutive days and then weekly throughout the experiment. Groups 3 and 4 were injected ip with rat immunoglobulin and a monoclonal rat anti-mouse CD4 antibody, respectively. Two days later, group 1 mice were injected ip with saline only, while all the other groups were immunized ip with P gingivalis OMP weekly for 3 weeks. One week later following the last immunization of OMP, 3 separate experiments were conducted to determine: 1) the DTH response to P gingivalis OMP by measuring footpad swelling; 2) the levels of antibodies to P gingivalis in serum samples and spleen cell cultures using an enzyme-linked immunosorbent assay, as well as spleen cell proliferation after stimulation with OMP; and 3) the lesion sizes after a subcutaneous challenge with viable P. gingivalis cells.

RESULTS

In CD4+ T-cell-depleted mice (group 4), the DTH response and antigen-stimulated cell proliferation were significantly suppressed when compared to groups 2 and 3. Similarly, the levels of serum and splenic IgM, IgG, and all IgG subclass antibodies to P. gingivalis OMP were depressed. Delayed healing of P gingivalis-induced lesions was also observed in the CD4+ T-cell-depleted group.

CONCLUSIONS

This study has shown that depletion of CD4+ T cells prior to immunization with P gingivalis OMP led to the suppression of both the humoral and cell-mediated immune response to this microorganism and that this was associated with delayed healing. These results suggest that the induction of the immune response to P. gingivalis is a CD4+ T-cell-dependent mechanism and that CD4+ T cells are important in the healing process.

Identification and testing of Porphyromonas gingivalis virulence genes with a pPGIVET system

An in vivo expression technology (IVET) system was designed to identify previously unknown virulence genes of Porphyromonas gingivalis. Fourteen ivi (for in vivo induced) genes that are induced during infection in a mouse abscess model were identified in our study. Of these, seven had homology to genes in the NCBI database, and the rest had no homology to reported DNA sequences. In order to determine virulence-related properties of these genes, three mutant strains, deleted of ivi8 (no homology to genes in the database), ivi10 (homologous to a putative TonB-dependent outer membrane receptor protein), and ivi11 (an immunoreactive 33-kDa antigen PG125 in P. gingivalis), were created. The mutants were tested in a mouse abscess model for alterations in virulence relative to the wild type by a competition assay in BALB/c mice. After 5 days we observed the enrichment of the wild-type strain over mutant strains Deltaivi10 and Deltaivi11, which indicated that mutant strains Deltaivi10 and Deltaivi11 are less able to survive in this model than the wild-type strain, while Deltaivi8 survives as well as the wild-type strain. We propose that knockout of these ivi genes reduced the ability of the mutated P. gingivalis to survive and cause infection compared to the wild-type strain at the site of injection. Also, in separate experiments, groups of mice were challenged with subcutaneous injections of each individual mutant strain (Deltaivi8, Deltaivi10, and Deltaivi11) or with the wild-type strain alone and were then examined to assess their general health status. The results showed that knockout of these ivi genes conferred a reduction in virulence. The ability of the mutants to invade KB cells compared to the wild type was also determined. Interestingly, the CFU counts of the mutant strain Deltaivi10 recovered from KB cells were eight times lower than those of the wild type, indicating that this mutant has a lower capacity for invasion. These results demonstrate that IVET is a powerful tool in discovering virulence genes and the significant role that ivi genes play in the pathogenesis of this species.

Flow-cytometric analysis of lymphocyte subsets and mCD14 expression in patients with various periodontitis categories

BACKGROUND

Membrane-bound CD14 (mCD14) is expressed mainly on circulating monocytes and tissue macrophages. It is one of the receptors, which act at the recognition of lipopolysaccharides by host cells. Periodontopathic bacteria result in activation of cellular and humoral immune responses.

AIM

The aim of the present study was to analyze the peripheral blood mCD14 concentrations as well as cell surface markers of lymphocyte subsets in periodontitis patients of various categories.

MATERIALS AND METHODS

Peripheral blood samples were obtained from 22 early onset periodontitis (EOP), 10 adult periodontitis (AP) patients and 13 systemically and periodontally healthy control subjects. Three-color flow cytometry and a panel of relevant monoclonal antibodies were used to determine the percent expression of various cell surface markers on peripheral blood mononuclear cells (PBMCs). The results were tested statistically by one-way variance analysis and Newman Keuls test.

RESULTS

No significant difference was observed between the study groups with regard to the relative counts of B-cells, T-cells, T-helper, T-cytotoxic/suppressor, activated T-cells and natural killer cells. EOP patients expressed significantly lower level of interleukin-2 receptor (IL-2R) when compared with AP patients (6.08% and 19.3% respectively) (p<0.05). The level of mCD14 in EOP patients (7.18%) was lower than that of AP patients (9.3%) and the control subjects (9.2%), but the differences were not statistically significant.

CONCLUSIONS

The low level of IL-2R in the EOP group may be interpreted as an insufficient responsiveness to the periodontopathogens, which may be ultimately related with the more severe tissue destruction. Though not significant, the reduced expression of mCD14 in EOP group may also be related with the immune system deficiencies in these patients.

Microbiological characteristics of subgingival microbiota in adult periodontitis, localized juvenile periodontitis and rapidly progressive periodontitis subjects

OBJECTIVE

To describe the prevalence of the cultivable subgingival microbiota in periodontal diseases and to draw attention to the polymicrobial nature of periodontic infections.

METHODS

The study population consisted of 95 patients, 51 females and 44 males, aged 14-62 years. Twenty-nine patients exhibited adult periodontitis (AP), six localized juvenile periodontitis (LJP), and 60 rapidly progressive periodontitis (RPP). Two to four pooled bacterial samples were obtained from each patient. Samples were collected with sterile paper points from the deepest periodontal pockets. The samples were cultured under anaerobic and microaerophilic conditions using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and by a commercial rapid test system.

RESULTS

Prevotella intermedia and Capnocytophaga spp. were the most frequently detected microorganisms in all diagnostic groups. Porphyromonas gingivalis and Peptostreptococcus micros were found more frequently in AP and RPP patients, while Actinobacillus actinomycetemcomitans and Eikenella corrodens were associated with AP, LJP and RPP patients. The other bacterial species, including Actinomyces spp., Streptococcus spp. and Eubacterium spp., were detected at different levels in the three disease groups.

CONCLUSIONS

The data show the complexity of the subgingival microbiota associated with different periodontal disease groups, indicating that the detection frequency and levels of recovery of some periodontal pathogens are different in teeth affected by different forms of periodontal disease.

Expression of matrix metalloproteinases in healthy and diseased human gingiva

BACKGROUND, AIMS

The aim of our study was to investigate the patterns of several metalloproteinases (MMP-1, MMP-2 and MT1-MMP) mRNAs expression using a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and to correlate them with clinical parameters and bacteriological diagnosis in healthy versus diseased human gingiva.

METHODS

To identify the cell origin of MMP production, in situ hybridization (ISH) was also performed for the MMPs on the same samples. 17 gingival biopsies were collected (13 affected by advanced periodontitis and 4 healthy used as controls) and plaque index, gingival index, pocket depth and bleeding on probing were measured. Subgingival microbial samples were also collected to be analysed by a DNA probe technique. The biopsies were processed both for RT-PCR and ISH. We also investigated a model for bacterial induced MMP expression in human gingival fibroblasts (HGF) infected by Eikenella corrodens.

RESULTS

We found an expression of the mRNA encoding MMP-1 only in diseased gingiva but at low levels relative to beta-actin (mean+/-SD: diseased versus healthy: 0.013+/-0.024 versus 0). Although the frequencies and levels of mRNA encoding for MMP-2 or MT1-MMP are not significantly different between each group (mean+/-SD: 0.329+/-0.344 versus 0.137+/-0.219 for MMP-2; 0.485+/-0.374 versus 0.466+/-0.296 for MT1-MMP), using ISH, we observed an expression of both mRNAs in fibroblasts of pathological specimens at sites that histologically showed signs of chronic inflammation and connective tissue remodelling. In vitro infection of HGF by Eikenella corrodens stimulated 3-fold the production of the mRNA encoding MMP-2 while other mRNAs remained unchanged.

CONCLUSION

Our results did not reveal significant differences in the expression of mRNAs encoding for the MMPs between healthy and periodontitis-affected patients, reflecting the great heterogeneity in the periodontal status of individuals. However, they indicate that gingival fibroblasts are an active source of MMP-2 production in response to a periopathogen.

Association between periodontal disease and acute myocardial infarction

BACKGROUND

Coronary heart disease is the leading cause of morbidity and mortality throughout the world. Well-known risk factors independently or combined participate in both myocardial infarction and atherosclerosis. Recent data have shown that viral and bacterial infections may also contribute to the acute thromboembolic events. The aim of the present study was to investigate the possible association between periodontal health and coronary heart disease in patients with acute myocardial infarction and chronic coronary heart disease.

METHODS

A total of 120 patients, 60 with acute myocardial infarction (AMI) and 60 with chronic coronary heart disease (CCHD) were included in this study. The patients in the AMI group (50 men and 10 women; mean age 53.8 +/- 9.5 years) were admitted to the Department of Cardiology, University Hospital of Ege because of AMI. The CCHD patients group (42 men and 18 women; mean age 58.5 +/- 11.6 years) had no documented history of recent acute coronary events. All patients were clinically examined and completed a medical questionnaire. Missing teeth, restorations, probing depth (PD) and bleeding on probing (BOP) were recorded. Blood samples were taken on admission for measurements of serum total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL-cholesterol), low density lipoprotein cholesterol (LDL-cholesterol), and fasting blood glucose level. Sample proportions were compared by chi square test, quantitative variables with Student t test. The relation of clinical parameters and conventional risk factors to AMI was assessed with logistic regression analysis.

RESULTS

The number of sites with PD > or = 4 mm, the percentage of sites exhibiting BOP, smoking status, total cholesterol, LDL-cholesterol, and triglycerides were statistically different between AMI and CCHD groups (P <0.05). Logistic regression analysis showed that the percentage of sites exhibiting BOP, the number of sites with PD > or = 4, the number of restorations, smoking status, and triglycerides levels were significantly associated with AMI (P <0.05).

CONCLUSIONS

The results of this study indicate that periodontal disease may be associated with acute myocardial infarction. To our knowledge, this is the first study that reports the importance of periodontal health in the occurrence of acute myocardial infarction in a Turkish population. We propose that prospective randomized studies are needed to determine whether periodontal disease is a risk factor in the occurrence of acute myocardial infarction.

The relationship between bone mineral density and periodontitis in postmenopausal women

BACKGROUND

Systemic bone loss has been proposed as a risk factor for periodontal disease; however, the relationship between these two diseases is still not clear. The objective of this study was to assess the relationship between systemic bone mineral density and periodontal disease, controlling for known confounders.

METHODS

The study population included 70 postmenopausal Caucasian women aged 51 to 78 (mean +/- SD: 62.10 +/- 7.1 years). Skeletal bone mineral density (BMD) was assessed by dual energy x-ray absorptiometry (DXA) at the neck, trochanter, intertrochanter, Ward's triangle, and total regions of the femur, and from the anterior-posterior view of the lumbar spine. Periodontal disease severity was represented by clinical attachment loss (CAL) and interproximal alveolar bone loss (ABL). Other measures of periodontal status included probing depth (PD), supragingival plaque, gingival bleeding on probing, and calculus. DXA and oral examinations were performed by calibrated examiners. Partial correlation coefficients (r) were obtained from multiple linear regression analysis adjusting for age, age at menopause, estrogen supplementation, cigarette smoking, body mass index, and supragingival plaque.

RESULTS

Mean ABL was significantly correlated with BMD of the trochanter (r =- 0.27), Ward's triangle (r = -0.26), and total regions of the femur (r = -0.25). Mean CAL appeared to be related to BMD consistently at all regions of the skeleton, although the association did not reach statistical significance.

CONCLUSIONS

We can conclude that skeletal BMD is related to interproximal alveolar bone loss and, to a lesser extent, to clinical attachment loss, implicating postmenopausal osteopenia as a risk indicator for periodontal disease in postmenopausal Caucasian women.

Characterization of Porphyromonas gingivalis insertion sequence-like element ISPg5

Porphyromonas gingivalis, a black-pigmented, gram-negative anaerobe, is found in periodontitis lesions, and its presence in subgingival plaque significantly increases the risk for periodontitis. In contrast to many bacterial pathogens, P. gingivalis strains display considerable variability, which is likely due to genetic exchange and intragenomic changes. To explore the latter possibility, we have studied the occurrence of insertion sequence (IS)-like elements in P. gingivalis W83 by utilizing a convenient and rapid method of capturing IS-like sequences and through analysis of the genome sequence of P. gingivalis strain W83. We adapted the method of Matsutani et al. (S. Matsutani, H. Ohtsubo, Y. Maeda, and E. Ohtsubo, J. Mol. Biol. 196:445-455, 1987) to isolate and clone rapidly annealing DNA sequences characteristic of repetitive regions within a genome. We show that in P. gingivalis strain W83, such sequences include (i) nucleotide sequence with homology to tRNA genes, (ii) a previously described IS element, and (iii) a novel IS-like element. Analysis of the P. gingivalis genome sequence for the distribution of the least used tetranucleotide, CTAG, identified regions in many of the initial 218 contigs which contained CTAG clusters. Examination of these CTAG clusters led to the discovery of 11 copies of the same novel IS-like element identified by the repeated sequence capture method of Matsutani et al. This new 1,512-bp IS-like element, designated ISPg5, has features of the IS3 family of IS elements. When a recombinant plasmid containing much of ISPg5 was used in Southern analysis of several P. gingivalis strains, including clinical isolates, diversity among strains was apparent. This suggests that ISPg5 and other IS elements may contribute to strain diversity and can be used for strain fingerprinting.

Antigenic specificity of gingival crevicular fluid antibody to Actinobacillus actinomycetemcomitans

Elevated antibody levels to periodontopathogens in GCF have been identified and used as support for local antibody synthesis in periodontitis. This study examined both cross-sectional and longitudinal GCF samples for the antigenic specificity of antibody in the fluid. GCF samples were collected from each tooth of 27 periodontitis patients infected with A. actinomycetemcomitans. Levels of IgG antibody in the GCF were assessed by means of an ELISA and compared with serum for determination of local elevations. A proportion of those GCF samples that exhibited significantly elevated antibody were examined by Western immunoblotting to outer membrane antigens from A. actinomycetemcomitans. Homologous sera were also examined for comparison of antibody specificities. Of the sites with elevated IgG antibody, 87% were colonized by A. actinomycetemcomitans; however, 46% of sites with A. actinomycetemcomitans infection did not have elevated antibody. Cross-sectional studies identified a 78 to 100% agreement between the antibody specificities in GCF and those in serum. Additionally, patterns of antibody reactivity in both GCF and serum in the subjects were often very distinctive. Longitudinal alterations in GCF antibody were examined in 15 patients through a monitoring interval of up to 2 years and showed a general conservation of specificities. However, 7/15 patients exhibited a definite acquisition of different antibody specificities during the monitoring. These results describe a relationship between elevated local antibody and A. actinomycetemcomitans infection. Furthermore, the antibody specificities in serum appear to reflect generally the local response to this pathogen.

Genetic heterogeneity in Prevotella intermedia, Prevotella nigrescens, Prevotella corporis and related species isolated from oral and nonoral sites

Prevotella intermedia (43 isolates), Prevotella nigrescens (55) and Prevotella corporis (8) from oral and nonoral sites were distinguished by species-specific DNA fragments, after hybridization of DNA fragments with ribosomal RNA (ribotyping). Eight strains previously identified as P. intermedia did not have these specific fragments. P. nigrescens, P. intermedia and P. corporis formed separate clusters in dendrograms constructed using clustering with an unweighted pair group method with arithmetic averages of similarity values derived from ribotype patterns, with 10 subclusters in P. intermedia isolates and 26 in P. nigrescens. Nine groups of P. intermedia isolates and 6 of P. nigrescens shared identical patterns. Specific ribotypes or species were not associated with particular diseases when all isolates were analyzed. However, results from organisms isolated by one laboratory using consistent clinical reporting indicated that P. intermedia was associated with more severe forms of periodontitis and P. nigrescens with mild to moderate disease.

Intrafamilial Transmission of Black-pigmented, Putative Periodontal Pathogens

Porphyromonas gingivalis and Prevotella intermedia are black-pigmented, putative periodontopathogenic bacteria considered to cause some forms of periodontal disease. Porphyromonas gingivalis and P. intermedia can be transmitted between humans and produce periodontal disease in susceptible hosts. In this article, studies using molecular typing methods for determining the transmission of black-pigmented, putative periodontopathogens between family members are reviewed. As individuals living close to each other are more prone to transmit bacteria, the studies on transmission of periodontopathogens have been performed on family members. It has been shown that black-pigmented bacteria are not only transferred between spouses but also between parents and child. Since only a limited number of studies have been done, longitudinal and controlled studies should be carried out to elucidate further the transmittance potential of these bacteria.