Incidence of bacteremia after chewing, tooth brushing and scaling in individuals with periodontal inflammation

Cardiovascular disease and the role of oral bacteria

In terms of the pathogenesis of cardiovascular disease (CVD) the focus has traditionally been on dyslipidemia. Over the decades our understanding of the pathogenesis of CVD has increased, and infections, including those caused by oral bacteria, are more likely involved in CVD progression than previously thought. While many studies have now shown an association between periodontal disease and CVD, the mechanisms underpinning this relationship remain unclear. This review gives a brief overview of the host-bacterial interactions in periodontal disease and virulence factors of oral bacteria before discussing the proposed mechanisms by which oral bacterial may facilitate the progression of CVD.

Bacteraemia following dental implants' placement

OBJECTIVE

To investigate the prevalence, duration and aetiology of bacteraemias following the placement of implants as well as the prophylactic efficacy of a chlorhexidine digluconate (CHX) mouthrinse.

MATERIAL AND METHODS

Fifty patients undergoing implant placement were randomly distributed into two groups:

CONTROL GROUP

30 patients with no prophylactic intervention before surgery. CHX group: 20 patients who performed a 0.2% CHX mouthrinse before surgery. Blood samples were collected at baseline, at 30 s after the insertion of implants and at 15 min after completion of the suturing of the mucoperiosteal flap. Samples were processed in the Bactec 9240, and the subculture and further identification of the isolates were performed using conventional microbiological techniques.

RESULTS

The prevalence of bacteraemias was 2% at baseline. In the control group, the prevalence of bacteraemias was 6.7% at 30 s and 3.3% at 15 min, but no statistically significant differences were achieved compared with the baseline percentage. In the CHX group, there were no positive cultures from blood samples obtained at 30 s or at 15 min.

CONCLUSIONS

Implant placement via a mucoperiosteal flap does not carry a significant risk of developing bacteraemias. The use of antibiotic prophylaxis for the prevention of focal infections such as bacterial endocarditis in "at-risk" patients undergoing dental implants is therefore questionable. Although its efficacy has not been confirmed statistically, we recommend a 0.2% CHX mouthrinse before treatment as proposed previously by the British Society for Antimicrobial Chemotherapy.

Invasion of human aortic endothelial cells by oral viridans group streptococci and induction of inflammatory cytokine production

Oral viridans group streptococci are the major commensal bacteria of the supragingival oral biofilm and have been detected in human atheromatous plaque. Atherosclerosis involves an ongoing inflammatory response, reportedly involving chronic infection caused by multiple pathogens. The aim of this study was to examine the invasion of human aortic endothelial cells (HAECs) by oral viridans group streptococci and the subsequent cytokine production by viable invaded HAECs. The invasion of HAECs by bacteria was examined using antibiotic protection assays and was visualized by confocal scanning laser microscopy. The inhibitory effects of catalase and cytochalasin D on the invasion of HAECs were also examined. The production of cytokines by invaded or infected HAECs was determined using enzyme-linked immunosorbent assays, and a real-time polymerase chain reaction method was used to evaluate the expression of cytokine messenger RNA. The oral streptococci tested were capable of invading HAECs. The number of invasive bacteria increased with the length of the co-culture period. After a certain co-culture period, some organisms were cytotoxic to the HAECs. Catalase and cytochalasin D inhibited the invasion of HAECs by the organism. HAECs invaded by Streptococcus mutans Xc, Streptococcus gordonii DL1 (Challis), Streptococcus gordonii ATCC 10558 and Streptococcus salivarius ATCC 13419 produced more cytokine(s) (interleukin-6, interleukin-8, monocyte chemoattractant protein-1) than non-invaded HAECs. The HAECs invaded by S. mutans Xc produced the largest amounts of cytokines, and the messenger RNA expression of cytokines by invaded HAECs increased markedly compared with that by non-invaded HAECs. These results suggest that oral streptococci may participate in the pathogenesis of atherosclerosis.

Periodontopathogens induce soluble P-selectin release by endothelial cells and platelets

INTRODUCTION

Soluble P-selectin plays a pivotal role in inflammation and the development of thrombotic and cardiovascular disease. Accordingly, elevated levels of soluble P-selectin are found in periodontitis and (other forms of) inflammatory diseases. However, the cellular source of soluble P-selectin in periodontitis and the effects of periodontopathogens on P-selectin release are unknown.

MATERIAL AND METHODS

Soluble P-selectin was determined in 26 patients with periodontitis and 19 controls. Furthermore, human endothelial cells and platelets were investigated for their ability to elicit soluble and surface P-selectin in response to periodontopathogens A. actinomycetemcomitans Y4 and P. gingivalis. Moreover surface E-selectin and ICAM-1 expression as well as NFκB translocation in response to these bacteria were determined on endothelial cells as well as the formation of platelet-leukocyte complexes.

RESULTS

Plasma levels of soluble P-selectin are significantly elevated in periodontitis and correlate with severity of disease and bacterial infection. Stimulation of endothelial cells with periodontopathogens results in rapid surface expression of P-selectin but does not induce NFκB translocation and subsequent de novo synthesis of P-selectin, E-selectin or ICAM-1. In platelets, bacterial stimulation leads to surface expression of P-selectin and fosters the formation of platelet-leukocyte aggregates within minutes. P-selectin is rapidly shed from the surface of platelets and endothelial cells and results in increased levels of soluble P-selectin.

CONCLUSIONS

Periodontopathogens are able to directly cause activation of endothelial cells and platelets within minutes. Given that transient periodontitis-associated bacteremia commonly occurs after tooth brushing or chewing, our data suggest that reduction of periodontopathogens might result in potential cardiovascular benefits.

Association of serum immunoglobulin G (IgG) levels against two periodontal pathogens and prothrombotic state: a clinical pilot study

OBJECTIVE

Periodontitis is associated with cardiovascular diseases (CVD). In our previous studies a prothrombotic state has been observed in periodontitis, which contributes to the risk of CVD. The aim of this study was to investigate whether serum IgG levels against Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) in periodontitis were associated with a prothrombotic state.

MATERIALS AND METHODS

Patients with moderate (n = 38) and severe periodontitis (n = 30) and controls (n = 24) were recruited. We explored correlations between serum anti-Aa and anti-Pg IgG and plasma levels of markers of prothrombotic state (von Willebrand Factor [vWF], prothrombin fragment 1+2 [F1+2], plasminogen activator inhibitor-1 [PAI-1] and D-dimer). Multivariate analyses were performed considering several major potential contributing factors.

RESULTS

Periodontitis patients showed higher anti-Aa IgG (p = 0.015) than controls but not for Pg (p = 0.320). In periodontitis patients, body mass index and anti-Aa IgG showed a positive correlation with vWF (β = 0.297, p = 0.010 and β = 0.248, p = 0.033 respectively).

CONCLUSIONS

In periodontitis, infection with Aa together with other well accepted risk factors for CVD, may play a role in increasing the risk for prothrombotic state.

Oral care and bacteremia risk in mechanically ventilated adults

OBJECTIVE

Transient bacteremia occurs in healthy populations from toothbrushing. With the high incidence of bacteremia in the intensive care unit and toothbrushing as an oral care method, this study examined the incidence and clinical significance of transient bacteremia from toothbrushing in mechanically ventilated adults.

METHODS

Prospective pre- and post-test with all subjects (N = 30) receiving a toothbrushing intervention twice per day (up to 48 hours). The planned microbial analysis used DNA typing to identify organisms from oral and blood cultures collected immediately before, 1 minute, and 30 minutes after the interventions.

RESULTS

Seventeen percent of subjects had oral cultures that were positive for selected pathogens before the first toothbrushing intervention. None of the subjects had evidence of transient bacteremia by positive quantitative blood cultures before or after the toothbrushing interventions. Patient characteristics were not statistically significant predictors for systemic inflammatory response syndrome, length of hospital stay, or length of intubation.

CONCLUSION

The toothbrushing intervention did not induce transient bacteremia in this patient population.

Characterization of aortic aneurysms in cardiovascular disease patients harboring Porphyromonas gingivalis

OBJECTIVE

Porphyromonas gingivalis was recently shown to cause intimal hyperplasia in a mouse model by a novel cholesterol-independent mechanism, suggesting to be a pathogen-specific feature of cardiovascular diseases. The aim of this study was to characterize the clinical and histopathological features of aortic aneurysms in cardiovascular disease patients harboring oral P. gingivalis.

SUBJECT AND METHODS

Aortic aneurysm specimens were collected from 76 Japanese patients who underwent surgery, of whom dental plaque specimens were also collected from 31 patients. Bacterial DNA was extracted from each specimen to detect P. gingivalis by polymerase chain reaction. Histopathological analyses of the aortic aneurysm specimens, including immunohistochemical staining for embryonic myosin heavy chain isoform (SMemb) and S100 calcium-binding protein A9 (S100A9), were also performed.

RESULTS

The number of aneurysms occurring in the distal aorta was significantly higher in subjects positive for P. gingivalis in dental plaque compared with those who were negative. The expressions of S100A9 and SMemb were also significantly greater in the subjects positive for P. gingivalis in dental plaque. On the other hand, there were no significant differences in adipocellular accumulation between the groups.

CONCLUSIONS

These results suggest that aortic aneurysms in patients harboring oral P. gingivalis have greater expression of S100A9 and proliferative smooth muscle cells, which was different from the present patients without oral P. gingivalis.

Induced apoptosis of chondrocytes by Porphyromonas gingivalis as a possible pathway for cartilage loss in rheumatoid arthritis

The role of bacterial infections in the pathogenesis of rheumatoid arthritis (RA) has gained increasing interest. Patients with RA often exhibit periodontal disease, which is associated with pathogens like Porphyromonas gingivalis. The present study examines the direct effects of P. gingivalis on apoptosis of human chondrocytes (a feature of inflammatory joint diseases) as one can assume an interrelation of pathogenesis of RA and P. gingivalis infections. Primary chondrocytes were infected with P. gingivalis. Early apoptotic and dead cell analysis was performed using Annexin-V, 7AAD, and propidium iodide and examined by flow cytometry and fluorescence microscopy. Caspase activation and DNA fragmentation were determined by western blot analysis and TUNEL reaction. Flow cytometry and fluorescence microscopy demonstrated an increase of Annexin-V-positive early apoptotic chondrocytes after infection. Western blot showed upregulation of activated caspase-3 expression, and TUNEL reaction revealed considerable DNA fragmentation following infection. The data show that P. gingivalis promotes early and later stages of apoptosis of primary human chondrocytes, which might contribute to the joint damage seen in the pathogenesis of RA.

LPS from Porphyromonas gingivalis increases the sensitivity of contractile response mediated by endothelin-B (ET(B)) receptors in cultured endothelium-intact rat coronary arteries

The purpose of our study was to examine if lipopolysaccharide (LPS) from Porphyromonas gingivalis (P.g.) modifies the vasomotor responses to Endothelin-1 (ET-1) and Sarafotoxin 6c (S6c) in rat coronary arteries. The arteries were studied directly or following organ culture for 24 h in absence and presence of 2.5EU/ml LPS. The contractile responses of coronary arteries were investigated by using the selective ETB receptor agonist S6c (1 pM-0.3 μM) and ET-1 (1 pM-0.3 μM). The functional studies demonstrated an augmented contractile response only to S6c in isolated rat coronary arteries after organ culture (with or without LPS). These contractile responses by S6c were blocked by the selective ETB receptor antagonist BQ788 in both vessel groups. The augmented contractile response to S6c was supported by immunohistochemistry, where a significant increase in fluorescence intensity for ETB receptors in smooth muscle cells was observed after organ culture. The presence of LPS in the culture medium significantly increased the sensitivity of endothelium-intact coronary artery to S6c as compared to endothelium-denuded segments. Our results showed a significant increase in both ETB receptor protein levels and S6c-induced maximal contraction in coronary arteries upon 24 h of organ culture, which was further sensitized by LPS.

Systemic endotoxin levels in chronic indolent periodontal infections

BACKGROUND AND OBJECTIVE

Periodontal disease has been linked with an increased risk of various systemic diseases. A plausible biologic explanation for this link includes the opportunity for oral pathogens to translocate to the circulation as a result of breakdown in integrity of the oral epithelium. This study refined a methodology used to detect endotoxin activity in the serum of subjects with indolent periodontal infections.

MATERIAL AND METHODS

The QCL Kinetic Chromogenic Assay (Cambrex) is a kinetic measure of endotoxin activity. Sera from 211 pregnant women with periodontitis enrolled in the Obstetrics and Periodontal Therapy Trial were used to develop the assay further and to evaluate the detection of endotoxin activity that might accompany a low-level bacteremia in chronic periodontitis.

RESULTS

We optimized the system to increase the sensitivity and reproducibility of the assay. The refined system was able to detect endotoxin activity in serum at > 0.0125 EU/mL. At baseline (13-16 wk of gestation), 35.5% of the women were positive for endotoxin activity (1.62 +/- 2.21; range: 0.38-15 EU/mL).

CONCLUSION

This report describes a sensitive measure of endotoxin activity in serum. The procedure allowed us to document levels of this microbial virulence factor in serum of individuals with indolent infections such as periodontal disease.

"Gum bug, leave my heart alone!"--epidemiologic and mechanistic evidence linking periodontal infections and atherosclerosis

Evidence from epidemiologic studies suggests that periodontal infections are independently associated with subclinical and clinical atherosclerotic vascular disease. Although the strength of the reported associations is modest, the consistency of the data across diverse populations and a variety of exposure and outcome variables suggests that the findings are not spurious or attributable only to the effects of confounders. Analysis of limited data from interventional studies suggests that periodontal treatment generally results in favorable effects on subclinical markers of atherosclerosis, although such analysis also indicates considerable heterogeneity in responses. Experimental mechanistic in vitro and in vivo studies have established the plausibility of a link between periodontal infections and atherogenesis, and have identified biological pathways by which these effects may be mediated. However, the utilized models are mostly mono-infections of host cells by a limited number of 'model' periodontal pathogens, and therefore may not adequately portray human periodontitis as a polymicrobial, biofilm-mediated disease. Future research must identify in vivo pathways in humans that may (i) lead to periodontitis-induced atherogenesis, or (ii) result in treatment-induced reduction of atherosclerosis risk. Data from these studies will be essential for determining whether periodontal interventions have a role in the primary or secondary prevention of atherosclerosis.

Mechanisms of oral bacteria-induced platelet activation

The oral cavity is inhabited by over 500 different bacterial species that normally exist in ecological balance both with each other and with the host. When this equilibrium is disturbed, an overgrowth of individual organisms can occur, which, in turn, can lead to the onset of pathological processes, notably dental caries and periodontitis. Generally, bacteraemias occur more frequently in individuals with periodontal disease, and these bacteraemias have been implicated in the development of a range of systemic diseases, including atherothrombotic disorders. The mechanism underlying this relationship remains to be precisely defined, although studies have shown a link between bacteria of oral origin and platelet activation. Several orally derived species of bacteria interact with platelets, including those of the Streptococcus ( Streptococcus sanguinis , Streptococcus mutans , Streptococcus agalactiae , Streptococcus pyogenes , Streptococcus gordonii , Streptococcus pneumoniae , Streptococcus mitis ) and Staphylococcus ( Staphylococcus epidermidis , Staphylococcus capitis ) genera, as well as Pseudomonas aeruginosa and Porphyromonas gingivalis . In addition, some members of both the Streptococcus and the Staphylococcus genera, as well as Porphyromonas gingivalis , can activate platelets in vitro. The current review describes the heterogeneous mechanisms of platelet activation employed by individual bacterial species. The pathological and clinical implications of platelet activation by orally derived bacteria are discussed.

Placental syncytiotrophoblast constitutes a major barrier to vertical transmission of Listeria monocytogenes

Listeria monocytogenes is an important cause of maternal-fetal infections and serves as a model organism to study these important but poorly understood events. L. monocytogenes can infect non-phagocytic cells by two means: direct invasion and cell-to-cell spread. The relative contribution of each method to placental infection is controversial, as is the anatomical site of invasion. Here, we report for the first time the use of first trimester placental organ cultures to quantitatively analyze L. monocytogenes infection of the human placenta. Contrary to previous reports, we found that the syncytiotrophoblast, which constitutes most of the placental surface and is bathed in maternal blood, was highly resistant to L. monocytogenes infection by either internalin-mediated invasion or cell-to-cell spread. Instead, extravillous cytotrophoblasts-which anchor the placenta in the decidua (uterine lining) and abundantly express E-cadherin-served as the primary portal of entry for L. monocytogenes from both extracellular and intracellular compartments. Subsequent bacterial dissemination to the villous stroma, where fetal capillaries are found, was hampered by further cellular and histological barriers. Our study suggests the placenta has evolved multiple mechanisms to resist pathogen infection, especially from maternal blood. These findings provide a novel explanation why almost all placental pathogens have intracellular life cycles: they may need maternal cells to reach the decidua and infect the placenta.

Masticatory dysfunction is associated with worse functional ability: a population-based study

AIM

Because of the ageing of populations, disability has become an emergent problem from the clinical, social, and economic perspectives. Nevertheless, the determinants of disability in older subjects are still unclear. We assessed the association between self-assessed masticatory dysfunction (MD) and functional ability in older subjects.

MATERIALS AND METHODS

We analysed data of all 350 subjects aged 75+ living in Tuscania (Italy). Functional ability was estimated using the Katz' activities of daily living (ADLs), and the Lawton and Brody instrumental activities of daily living (IADLs) scales.

RESULTS

MD was reported by 145 (41%) participants. Disability in the ADLs and IADLs was found in 37 (25%) and 53 (37%) of participants with MD, respectively, but only in 11 (5%) and 30 (15%) of the other participants (p<0.001). MD was associated with disability in the ADLs [odds ratio (OR)=2.40, 95% confidence interval (CI)=1.05-5.51], and IADLs (OR=2.77, 95% CI=1.07-7.16) in logistic regression, after adjusting. The association of MD with disability was stronger among subjects aged 80+.

CONCLUSIONS

MD is independently associated with disability in community-dwelling elderly. Further studies are needed to evaluate the impact of early detection and correction of MD on the preservation of functional status in older populations.

Effects of Porphyromonas gingivalis on cell cycle progression and apoptosis of primary human chondrocytes

BACKGROUND

It has been suggested that bacterial infections have a role in the pathogenesis of rheumatoid arthritis (RA). P gingivalis, a Gram-negative, anaerobic rod, is one of the major pathogens associated with periodontal disease.

OBJECTIVE

To examine P gingivalis infection and its effects on cell cycle progression and apoptosis of human articular chondrocytes.

METHODS

Primary human chondrocytes cultured in monolayers were challenged with P gingivalis. Infection and invasion of P gingivalis into chondrocytes was analysed by scanning electron microscopy, double immunofluorescence and by antibiotic protection and invasion assay. Cell cycle progression of infected chondrocytes was evaluated by flow cytometry. Also, cell apoptosis was visualised by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) of DNA strand breaks and by western blot analysis.

RESULTS

Data showed that P gingivalis could adhere and infect primary human chondrocytes. After chondrocyte infection, intracellular localisation of P gingivalis was noted. Flow cytometry analyses demonstrated affected cell cycle progression, with an increase of the G(1) phase and a significant decrease of the G(2) phase after infection. In addition, increased apoptosis of P gingivalis-infected chondrocytes was visualised by TUNEL assay and by upregulation of caspase-3 protein expression.

CONCLUSION

These data demonstrate that P gingivalis infects primary human chondrocytes and affects cellular responses, which might contribute to the tissue damage seen in the pathogenesis of rheumatoid arthritis.

Tooth loss and cognitive impairment

OBJECTIVES

Chronic subclinical inflammation may elevate the risk of cognitive impairment. Periodontitis is associated with subclinical inflammation and accounts in part for tooth loss. The hypothesis was tested that periodontitis and tooth loss as a proxy of chronic periodontitis is associated with cognitive impairment in the elderly.

SUBJECTS AND METHODS

The population-based Study of Health in Pomerania comprises 1336 subjects (60-79 years). Cognitive impairment was assessed with the Mini-Mental Status Examination (MMSE). Tobit regression analyses were adjusted for potential confounders.

RESULTS

A decreased number of teeth was associated with lower MMSE scores in females (p<0.001) and males (p=0.007) in age-adjusted models. In the fully adjusted models, tooth loss was associated with cognitive impairment in females (p=0.002) but not in males (p=0.825).

CONCLUSIONS

A significant association between tooth loss and cognitive impairment was found in females that was not accounted for by potential confounders. Former periodontitis may account for this association as periodontitis was frequently the cause for tooth extractions.

Dental care and oral disease in alcohol-dependent persons

Dental/Oral health of alcohol-dependent persons and substance abusers is often neglected. It is not clear that alcohol dependence has effects on oral health beyond those expected in nonalcoholic persons of similar socioeconomic status (SES). Study objectives were to examine the personal dental care habits, ability to access professional dental care, and the types of services received and to examine their effect on the oral health of alcohol-dependent persons and substance abusers. Forty Diagnostic and Statistical Manual of Mental Disorders, Third Edition Revised-diagnosed alcohol-dependent persons and a comparison group of 25 non-alcohol-dependent subjects matched for race, age, gender, and SES were recruited. Subjects were medically healthy. Each subject received a comprehensive oral/dental examination, and an interview was conducted to record personal dental hygiene habits, ability to access professional dental care, and types of dental services provided. No statistical differences were found between the oral care habits of the groups. Forty-four percent of all subjects had access to charity professional dental care. Tooth extraction was the main dental service they received. Seventy-five percent of subjects brushed their teeth once or more per day. In the non-alcohol-dependent group, brushing frequency was inversely associated with plaque levels (p < .05); in the alcohol-dependent group, brushing frequency showed no statistical effect on plaque levels. Access to professional dental care was inversely associated with periodontitis in the alcohol-dependent group (p < .05). Alcohol dependence may increase plaque levels above that seen in race, gender, age, and SES-matched controls, but professional dental care can limit the subsequent development of periodontal disease in these people.

Soluble CD14 in periodontitis

Lipopolysaccharide (LPS) binds to soluble (s)CD14. We investigated which factors contribute to variations in sCD14 levels in periodontitis, a chronic infectious disease of tooth-supporting tissues associated with endotoxemia and leading to inflammation and subsequently loss of teeth. The sCD14 levels were determined by ELISA in healthy controls (n=57) and untreated patients (59 moderate and 46 severe) and their relation with markers of systemic inflammation (C-reactive protein levels, and leukocyte, neutrophil and lymphocyte counts) was assessed. Anti-Aggregatibacter actinomycetemcomitans and anti-Porphyromonas gingivalis IgG levels were established by ELISA and CD14(-260) genotype was determined in a TaqMan allelic discrimination assay. Increased levels of sCD14 were more frequent among periodontitis patients (P=0.026) and showed a severity-dependence with increasing levels of periodontal breakdown (P=0.008). In patients, levels of sCD14 correlated positively with CRP (P=0.043), leukocyte numbers (P=0.011) and negatively with anti-A. actinomycetemcomitans IgG (P=0.007). In a multivariate analysis, sCD14 levels were predicted by ethnicity, age, educational level, and in Caucasian subjects also by the severity of periodontal destruction, but not by anti-P. gingivalis IgG or the CD14(-260) genotype. Periodontitis is associated with elevated levels of sCD14.

Update on bacteraemia related to dental procedures

The oral microbiota is highly diverse consisting of more than 700 bacterial species. Notably, only half of these species can so far be cultivated. This may have an impact on how to interpret negative findings in blood cultures. The present paper gives an overview of the current knowledge on bacteraemia after common oral procedures such as tooth extraction, root scaling, periodontal probing, suture removal, orthodontic treatment, tooth restoration, non-surgical root canal treatment, chewing, tooth brushing, flossing, and use of tooth sticks. The possible relationship between periodontitis-related bacteraemia and cardiovascular diseases is also considered, as well as bacteraemia after oral procedures compared to procedures representing irritation or minor trauma to other mucosae. It may be that patients never seeing a dentist are more unfitted as blood donors than those recently having seen one.

Bacteraemia due to dental flossing

AIMS

The aims of this study were to (1) investigate the incidence of bacteraemia following flossing in subjects with chronic periodontitis or periodontal health; (2) identify the micro-organisms in detected bacteraemias; and (3) identify any patient or clinical factors associated with such bacteraemia.

MATERIAL AND METHODS

Baseline blood samples were obtained from 30 individuals with chronic periodontitis (17 M:13 F, 29-75 years) and 30 with periodontal health (17 M:13 F, 28-71 years) following a non-invasive examination. Each subject's teeth were then flossed in a standardized manner and blood samples obtained 30 s and 10 min. after flossing cessation. Blood samples were cultured in a BACTEC system and positive samples subcultured for identification.

RESULTS

Forty per cent of periodontitis subjects and 41% of periodontally healthy subjects tested positive for bacteraemia following flossing. Viridans streptococci, which are commonly implicated in infective endocarditis (IE), were isolated from 19% of positive subjects and accounted for 35% of microbial isolates. Twenty per cent of subjects had a detectable bacteraemia at 10 min. post-flossing. No patient or clinical factors were significantly associated with post-flossing bacteraemia.

CONCLUSIONS

Dental flossing can produce bacteraemia in periodontally healthy and periodontally diseased individuals at a rate comparable with that caused by some dental treatments for which antibiotic prophylaxis is given to prevent IE.

Effect of periodontal disease treatment during pregnancy on preterm birth incidence: a metaanalysis of randomized trials

We conducted a metaanalysis of randomized controlled trials to determine whether periodontal disease treatment with scaling and/or root planing during pregnancy may reduce preterm birth (PTB) or low birthweight (LBW) infant incidence. Treatment resulted in significantly lower PTB (odds ratio [OR], 0.55; 95% confidence interval [CI], 0.35-0.86; P = .008) and borderline significantly lower LBW (OR, 0.48; 95% CI, 0.23-1.00; P = .049), whereas no difference was found for spontaneous abortion/stillbirth (OR, 0.73; 95% CI, 0.41-1.31; P = .292). Subgroup analysis suggested significant effect of treatment in the absence of history of PTB or LBW (OR, 0.48; 95% CI, 0.29-0.77; P = .003) and less severe periodontal disease as defined by probing depth (OR, 0.49; 95% CI, 0.28-0.87; P = .014) or bleeding on probing site (OR, 0.37; 95% CI, 0.14-0.95; P = .04). If ongoing large and well-designed randomized trials support our results, we might need to reassess current practice or at least be cautious prior to rejecting treatment of periodontal disease with scaling and/or root planing during pregnancy.

Infected total ankle arthroplasty following routine dental procedure

Level of Evidence: V, Case Report

Changes in serum interleukin-6, C-reactive protein and thrombomodulin levels under periodontal ultrasonic debridement

AIM

This study aimed to compare the effect of single-visit full-mouth mechanical debridement (FMD) and quadrant-wise mechanical debridement (QMD) on the levels of serum interleukin (IL)-6, C-reactive protein (CRP) and soluble thrombomodulin.

MATERIAL AND METHODS

Thirty-six subjects with chronic periodontitis were randomly allocated to three groups: undergoing QMD, single-visit FMD with povidone iodine or with water. Serum IL-6 and soluble thrombomodulin were measured by enzyme-linked immunosorbent assay, and serum CRP was measured by the latex-enhanced nephelometric method.

RESULTS

Serum IL-6 level increased significantly immediately after debridement in all the three groups, with this increase being greatest in the full-mouth groups. However, the increase in the full-mouth groups was not significantly higher than that of quadrant-wise group. In the quadrant-wise group, serum IL-6 level decreased significantly 1 month after debridement compared with baseline. Serum-soluble thrombomodulin decreased significantly in the full-mouth groups but not in the quadrant-wise group. Changes in CRP level were not significant at baseline or after debridement in all the three groups.

CONCLUSIONS

FMD increased serum IL-6 and reduced serum-soluble thrombomodulin to a greater extent than QMD, suggesting that the former technique has stronger transient effects on systemic vascular endothelial functions than the latter.

Increased TLR4 expression in murine placentas after oral infection with periodontal pathogens

Maternal periodontitis has emerged as a putative risk factor for preterm births in humans. The periodontitis-associated dental biofilm is thought to serve as an important source of oral bacteria and related virulence factors that hematogenously disseminate and affect the fetoplacental unit; however the underlying biological mechanisms are yet to be fully elucidated. This study hypothesized that an oral infection with the human periodontal pathogens Campylobacter rectus and Porphyromonas gingivalis is able to induce fetal growth restriction, placental inflammation and enhance Toll-like receptors type 4 (TLR4) expression in a murine pregnancy model. Female Balb/C mice (n = 40) were orally infected with C. rectus and/or P. gingivalis over a 16-week period and mated once/week. Pregnant mice were sacrificed at embryonic day (E) 16.5 and placentas were collected and analyzed for TLR4 mRNA levels and qualitative protein expression by real-time PCR and immunofluorescence. TLR4 mRNA expression was found to be increased in the C. rectus-infected group (1.98 +/- 0.886-fold difference, P < 0.01, ANOVA) compared to controls. Microscopic analysis of murine placentas showed enhanced immunofluorescence of TLR4 in trophoblasts, mainly in the placental labyrinth layer. Also, combined oral infection with C. rectus and P. gingivalis significantly reduced the overall fecundity compared to controls (16.7% vs. 75%, infected vs. non-infected mice respectively, P = 0.03, Kaplan-Meier). The results supported an enhanced placental TLR4 expression after oral infection with periodontal pathogens. The TLR4 pathway has been implicated in the pathogenesis of preterm births; therefore the abnormal regulation of placental TLR4 may give new insights into how maternal periodontitis and periodontal pathogens might be linked to placental inflammation and preterm birth pathogenesis.

Cardiovascular disease and periodontitis: an update on the associations and risk

BACKGROUND

Associations between periodontitis and cardiovascular diseases have been recognized.

MATERIAL AND METHODS

New literature since the last European Workshop on Periodontology has been reviewed.

RESULTS

The lack of reliable epidemiological data on disease prevalence makes an assessment of the associations and risks between periodontitis and cardiovascular diseases difficult. Two recent meta-analysis reports have identified associations between periodontitis and cardiovascular diseases (odds ratios: 1.1-2.2). Different surrogate markers for both disease entities, including serum biomarkers, have been investigated. Brachial artery flow-mediated dilatation, and carotid intima media thickness have in some studies been linked to periodontitis. Studies are needed to confirm early results of improvements of such surrogate markers following periodontal therapy. While intensive periodontal therapy may enhance inflammatory responses and impair vascular functions, studies are needed to assess the outcome of periodontal therapies in subjects with confirmed cardiovascular conditions. Tooth eradication may also reduce the systemic inflammatory burden of individuals with severe periodontitis. The role of confounders remain unclear.

CONCLUSIONS

Periodontitis may contribute to cardiovascular disease and stroke in susceptible subjects. Properly powered longitudinal case-control and intervention trials are needed to identify how periodontitis and periodontal interventions may have an impact on cardiovascular diseases.

Microbiology of odontogenic bacteremia: beyond endocarditis

SUMMARY

The human gingival niche is a unique microbial habitat. In this habitat, biofilm organisms exist in harmony, attached to either enamel or cemental surfaces of the tooth as well as to the crevicular epithelium, subjacent to a rich vascular plexus underneath. Due to this extraordinary anatomical juxtaposition, plaque biofilm bacteria have a ready portal of ingress into the systemic circulation in both health and disease. Yet the frequency, magnitude, and etiology of bacteremias due to oral origin and the consequent end organ infections are not clear and have not recently been evaluated. In this comprehensive review, we address the available literature on triggering events, incidence, and diversity of odontogenic bacteremias. The nature of the infective agents and end organ infections (other than endocarditis) is also described, with an emphasis on the challenge of establishing the link between odontogenic infections and related systemic, focal infections.

Elevated platelet and leukocyte response to oral bacteria in periodontitis

BACKGROUND

Periodontitis is associated with an increased risk for cardiovascular diseases (CVD), but the underlying mechanisms are poorly understood. Recently, we showed that platelets from periodontitis patients are more activated than those from controls.

OBJECTIVE

Given the regularly occurring bacteremic episodes in periodontitis patients, we hypothesized that platelets and/or leukocytes from periodontitis patients are more sensitive to stimulation by oral bacteria, in particular the known periodontal pathogens, than platelets from control subjects.

METHODS

Three-color flow cytometry analysis was performed to quantify activation of platelets (P-selectin, PAC-1, CD63) and leukocytes (CD11b) in whole blood from patients with periodontitis (n = 19) and controls (n = 18), with and without stimulation by oral bacteria. Phagocytosis was assessed by using green-fluorescent protein (GFP)-expressing Aggregatibacter actinomycetemcomitans (Aa).

RESULTS

Neutrophils and monocytes were activated by all species of oral bacteria tested, but no differences were observed between patients and controls. In response to several species of oral bacteria, platelets from periodontitis patients showed, compared with controls, increased exposure of P-selectin (P = 0.027) and increased formation of platelet-monocyte complexes (P = 0.040). Platelet-leukocyte complexes bound and/or phagocytosed more GFP-Aa than platelet-free leukocytes (for neutrophils and monocytes, in both patients and controls, P < 0.001).

CONCLUSIONS

In periodontitis, increased platelet response to oral bacteria is paralleled by increased formation of platelet-leukocyte complexes with elevated capacity for bacterial clearance. We speculate that activated platelets and leukocytes might contribute to increased atherothrombotic activity.

Inflammation as a potential mediator for the association between periodontal disease and Alzheimer's disease

Periodontal disease (PDD) is associated with increased risk of cardiovascular disease, cerebrovascular disease, and mortality in many studies, while other studies have begun to suggest an association of PDD with Alzheimer's disease (AD). This paper discusses how infectious pathogens and systemic infection may play a role in AD. The roles of infection and inflammation are addressed specifically with regard to known AD pathologic lesions including senile plaques, neuron death, neurofibrillary tangles, and cerebrovascular changes. A testable model of proposed pathways between periodontal infection and AD is presented including three possible mechanisms: a) direct effects of infectious pathogens, b) inflammatory response to pathogens, and c) the effects on vascular integrity. The role of gene polymorphisms is discussed, including apolipoprotein (APOE) varepsilon4 as a pro-inflammatory and pro-infection genotype.

Genotypic characterization of Porphyromonas gingivalis isolated from subgingival plaque and blood sample in positive bacteremia subjects with periodontitis

AIM

The objective of this study was to investigate clonal relationship among Porphyromonas gingivalis isolated from subgingival plaque and blood samples in positive transient bacteremia subjects with periodontitis.

MATERIAL AND METHODS

Unrelated patients with general chronic periodontitis or general aggressive periodontitis requiring scaling and root planing (SRP) were included in the study. Genotyping of each isolate was performed using pulsed field gel electrophoresis technique. Genetic relatedness of strains isolated within an individual or between different patients was determined by dendogram analysis.

RESULTS

Following SRP, from 16 patients, seven patients showed positive P. gingivalis bacteremia and nine were negative. Thirty-two strains were isolated from subgingival plaque and blood samples before and during induced transient bacteremia. The majority of the patients harboured one clonal type. Two patients showed different clones in plaque and blood samples suggesting that more than one clone can be found in subgingival plaque. P. gingivalis isolates from periodontitis patients after transient bacteremia following SRP, revealed a high heterogeneity among isolates.

CONCLUSION

In 6/16 subjects the same P. gingivalis isolate was found in the blood and in oral cavity. P. gingivalis heterogeneity suggests no association of a unique clonal type with transient bacteremia.

New British and American guidelines for the antibiotic prophylaxis of infective endocarditis: do the changes make sense? A critical review

PURPOSE OF REVIEW

The British Society for Antimicrobial Chemotherapy and the American Heart Association have radically revised their guidelines for the antibiotic prophylaxis of endocarditis. This review discusses the evidence behind the most controversial changes and considers possible future developments.

RECENT FINDINGS

The new guidelines emphasize good oral hygiene for preventing viridans streptococcal endocarditis. Antibiotic prophylaxis for dental procedures is only recommended for patients with the highest-risk cardiac conditions. American Heart Association guidelines no longer recommend prophylaxis for urological and gastrointestinal procedures.

SUMMARY

While only up to 6% of endocarditis cases may be prevented by antibiotic prophylaxis there is controversy as to what to recommend for the individual cardiac patient undergoing a given procedure. The new guidelines about dental prophylaxis are based on epidemiological studies that failed to include sufficient subjects undergoing specific interventions. When considering viridans streptococcal rather than total bacteraemia rates, asserting that the prevalence of bacteraemia after invasive dental procedures is similar to that after toothbrushing may be incorrect. The British Society for Antimicrobial Chemotherapy report probably overestimates the risk of fatal anaphylaxis after an oral dose of amoxicillin. In contrast, the American Heart Association guidelines comment on the absence of any reports of fatal anaphylaxis associated with the antibiotic prophylaxis of endocarditis.

Antibiotic prophylaxis before invasive dental procedures in patients with arthroplasties of the hip and knee

More than a million hip replacements are carried out each year worldwide, and the number of other artificial joints inserted is also rising, so that infections associated with arthroplasties have become more common. However, there is a paucity of literature on infections due to haematogenous seeding following dental procedures. We reviewed the published literature to establish the current knowledge on this problem and to determine the evidence for routine antibiotic prophylaxis prior to a dental procedure.

We found that antimicrobial prophylaxis before dental interventions in patients with artificial joints lacks evidence-based information and thus cannot be universally recommended.

Colonization of maternal and fetal tissues by Porphyromonas gingivalis is strain-dependent in a rodent animal model

OBJECTIVE

The objective of this study was to develop a rodent model of Porphyromonas gingivalis infection during pregnancy.

STUDY DESIGN

Sprague Dawley rats were infected intravenously with 10(5), 10(7), or 10(9) CFU per dam of P gingivalis strain W83, ATCC 33277, or A7436 at gestational day 14 and necropsied at gestational day 18. Maternal organs were cultured to assess the spread of the infection. Six fetal units (placenta, amniotic fluid, membranes, and fetus) per dam were cultured; additional fetal units were examined by histopathology. Polymerase chain reaction was performed on placentas.

RESULTS

Colonization rates were dependent on the strain of P gingivalis used and the infection dose. At an infection dose of 10(9) CFU/dam, P gingivalis W83, ATCC 33277, or A7436 was detected in 33%, 83%, or 100% of placentas, respectively. Epithelial hyperplasia, cellular necrosis, and inflammatory infiltrate were observed in infected placental tissues.

CONCLUSION

This study demonstrated that P gingivalis can invade both maternal and fetal tissues, resulting in chorioamnionitis and placentitis.

Bacteremia associated with toothbrushing and dental extraction

BACKGROUND

Antibiotic prophylaxis recommendations for the prevention of infective endocarditis are based in part on studies of bacteremia from dental procedures, but toothbrushing may pose a greater threat. The purpose of this study was to compare the incidence, duration, nature, and magnitude of endocarditis-related bacteremia from single-tooth extraction and toothbrushing and to determine the impact of amoxicillin prophylaxis on single-tooth extraction.

METHODS AND RESULTS

In this double-blind, placebo-controlled study, 290 subjects were randomized to (1) toothbrushing, (2) single-tooth extraction with amoxicillin prophylaxis, or (3) single-tooth extraction with identical placebo. Blood was drawn for bacterial culturing and identification at 6 time points before, during, and after these interventions. The focus of our analysis was on bacterial species reported to cause infective endocarditis. We identified 98 bacterial species, 32 of which are reported to cause endocarditis. Cumulative incidence of endocarditis-related bacteria from all 6 blood draws was 23%, 33%, and 60% for the toothbrushing, extraction-amoxicillin, and extraction-placebo groups, respectively (P<0.0001). Significant differences were identified among the 3 groups at draws 2, 3, 4, and 5 (all P<0.05). Amoxicillin resulted in a significant decrease in positive cultures (P<0.0001).

CONCLUSIONS

Although amoxicillin has a significant impact on bacteremia resulting from a single-tooth extraction, given the greater frequency for oral hygiene, toothbrushing may be a greater threat for individuals at risk for infective endocarditis.

Periodontitis is associated with platelet activation

There is an epidemiological association between periodontitis and cardiovascular disease (CVD). In periodontitis, low grade systemic inflammation and bacteremia occur regularly. Such events may contribute to platelet activation and subsequent pro-coagulant state. This study aimed to investigate platelet activation in periodontitis patients. The study is composed of two parts. In the first part, plasma levels of soluble(s) P-selectin and sCD40 ligand were measured as general markers of platelet activation in periodontitis patients (n=85) and in healthy controls (n=35). In the second part, surface-exposed P-selectin and the ligand-binding conformation of the glycoprotein IIb-IIIa complex (binding of PAC-1 antibody) were determined on individual platelets in whole blood of periodontitis patients (n=18) and controls (n=16). Patients had significantly elevated plasma levels of sP-selectin (P<0.001) and increased binding of PAC-1 on isolated platelets (P=0.033). Platelet activation was more pronounced in the patients with more severe periodontal disease, showing a severity-dependence. The levels of sCD40 ligand and of platelet-bound P-selectin were not increased. Periodontitis is associated with increased platelet activation. Since platelet activation contributes to a pro-coagulant state and constitutes a risk for atherothrombosis, platelet activation in periodontitis may partly explain the epidemiological association between periodontitis and CVD.