Systemic diseases caused by oral microorganisms

Is oral Streptococcus mutans with collagen-binding protein a risk factor for intracranial aneurysm rupture or formation?

OBJECTIVE

Streptococcus mutans (SM) with the collagen-binding protein Cnm is a unique member of the oral resident flora because it causes hemorrhagic vascular disorders. In the multicenter study, we examined the relationship between Cnm-positive SM (CP-SM) and intracranial aneurysm (IA) rupture, which remains unknown.

METHODS

Between May 2013 and June 2018, we collected whole saliva samples from 431 patients with ruptured IAs (RIAs) and 470 patients with unruptured IAs (UIAs). Data were collected on age, sex, smoking and drinking habits, family history of subarachnoid hemorrhage, aneurysm size, number of teeth, and comorbidities of lifestyle disease.

RESULTS

There was no difference in the positivity rate of patients with CP-SM between the patients with RIAs (17.2%) and those with UIAs (19.4%). The rate of positivity for CP-SM was significantly higher in all IAs <5 mm than in those ≥10 mm in diameter (P=0.0304). In the entire cohort, the rate of positivity for CP-SM was lower in larger aneurysms than in smaller aneurysms (P=0.0393).

CONCLUSIONS

The rate of positivity for CP-SM was lower among patients with large UIAs. These findings are consistent with the hypothesis that CP-SM plays a role in the formation of vulnerable IAs that tend to rupture before becoming larger.

Microbiota present in combined endodontic-periodontal diseases and its risks for endocarditis

INTRODUCTION

Infective endocarditis (IE) is an inflammatory disease usually caused by bacteria that enter the bloodstream and establish infections in the inner linings or valves of the heart, including blood vessels. Despite the availability of modern antimicrobial and surgical treatments, IE continues to cause substantial morbidity and mortality. Oral microbiota is considered one of the most significant risk factors for IE. The objective of this study was to evaluate the microbiota present in root canal (RC) and periodontal pocket (PP) clinical samples in cases with combined endo-periodontal lesions (EPL) to detect species related to IE using NGS.

METHODS

Microbial samples were collected from 15 RCs and their associated PPs, also from 05 RCs with vital pulp tissues (negative control, NC). Genomic studies associated with bioinformatics, combined with structuring of a database (genetic sequences of bacteria reported for infective endocarditis), allowed for the assessment of the microbial community at both sites. Functional prediction was conducted using PICRUSt2.

RESULTS

Parvimonas, Streptococcus, and Enterococcus were the major genera detected in the RCs and PPs. A total of 79, 96, and 11 species were identified in the RCs, PPs, and NCs, respectively. From them, a total of 34 species from RCs, 53 from PPs, and 2 from NCs were related to IE. Functional inference demonstrated that CR and PP microbiological profiles may not be the only risk factors for IE but may also be associated with systemic diseases, including myocarditis, human cytomegalovirus infection, bacterial invasion of epithelial cells, Huntington's disease, amyotrophic lateral sclerosis, and hypertrophic cardiomyopathy. Additionally, it was possible to predict antimicrobial resistance variants for broad-spectrum drugs, including ampicillin, tetracycline, and macrolides.

CONCLUSION

Microorganisms present in the combined EPL may not be the only risk factor for IE but also for systemic diseases. Antimicrobial resistance variants for broad-spectrum drugs were inferred based on PICRUSt-2. State-of-the-art sequencing combined with bioinformatics has proven to be a powerful tool for conducting studies on microbial communities and could considerably assist in the diagnosis of serious infections.

CLINICAL RELEVANCE

Few studies have investigated the microbiota in teeth compromised by combined endo-periodontal lesions (EPL), but none have correlated the microbiological findings to any systemic condition, particularly IE, using NGS techniques. In such cases, the presence of apical periodontitis and periodontal disease can increase IE risk in susceptible patients.

Fusobacterium nucleatum and its associated systemic diseases: epidemiologic studies and possible mechanisms

Background

Fusobacterium nucleatum (F. nucleatum) is an anaerobic oral commensal and the major coaggregation bridge organism linking early and late colonisers. In recent years, a large number of studies suggest that F. nucleatum is closely related to the development of various systemic diseases, such as cardiovascular diseases, adverse pregnancy outcomes, inflammatory bowel diseases, cancer, Alzheimer's disease, respiratory infection, rheumatoid arthritis, etc.

Objective

To review the effect of F. nucleatum on systemic diseases and its possible pathogenesis and to open new avenues for prevention and treatment of F. nucleatum-associated systemic diseases.

Design

The research included every article published up to July 2022 featuring the keywords 'Systemic diseases' OR 'Atherosclerotic cardiovascular diseases' OR 'Atherosclerosis' OR 'Adverse pregnancy outcomes' OR 'Inflammatory bowel disease' OR 'Ulcerative colitis' OR 'Crohn’s disease' OR 'Cancers' OR 'Oral squamous cell carcinomas' OR 'Gastrointestinal cancers' OR 'Colorectal cancer' OR 'Breast cancer' OR 'Genitourinary cancers' OR 'Alzheimer’s disease ' OR 'Rheumatoid arthritis' OR 'Respiratory diseases' AND 'Fusobacterium nucleatum' OR 'Periodontal pathogen' OR 'Oral microbiota' OR 'Porphyromonas gingivalis' and was conducted in the major medical databases.

Results

F. nucleatum can induce immune response and inflammation in the body through direct or indirect pathways, and thus affect the occurrence and development of systemic diseases. Only by continuing to investigate the pathogenic lifestyles of F. nucleatum will we discover the divergent pathways that may be leveraged for diagnostic, preventive and therapeutic purposes.

A Systematic Review and Meta-Analysis of the Association Between Periodontal Disease and Severe Mental Illness

BACKGROUND

Periodontal disease represents a global public health concern, with a disproportionate burden being borne by vulnerable populations. One such group is people with severe mental illness (SMI), and this study examined whether periodontal health is poorer in people with SMI than the general population.

METHODS

We conducted a systematic search for studies published before March 2021 on the periodontal health of people with SMI using the following databases: PubMed, PsycINFO, EMBASE, China National Knowledge Infrastructure, and Chongqing VIP. Outcomes were periodontitis, periodontal disease, and shallow and deep periodontal pockets. Results were compared with the general population.

RESULTS

Seventeen studies had sufficient data for a random-effects meta-analysis, consisting of 4404 psychiatric patients and 95,411 controls. SMI was associated with an increased prevalence of periodontitis (odds ratio = 1.97, 95% confidence interval [CI] = 1.15-3.35) compared with the general population. People with SMI had 4.28 the odds of having periodontal disease compared with controls (95% CI = 2.54-7.21). They also had 3.65 the odds of shallow pockets (95% CI = 1.80-7.42) and 2.76 the odds of deep pockets (95% CI = 1.10-6.93).

CONCLUSIONS

Our findings highlight the increased prevalence and severity of periodontal disease in people with SMI. Oral health is often considered the gateway to overall health and should be a public health priority for this population.

Do Oral Pathogens Inhabit the Eye and Play a Role in Ocular Diseases?

Fascinatingly, the immune-privileged healthy eye has a small unique population of microbiota. The human microbiome project led to continuing interest in the ocular microbiome. Typically, ocular microflorae are commensals of low diversity that colonize the external and internal sites of the eye, without instigating any disorders. Ocular commensals modulate immunity and optimally regulate host defense against pathogenic invasion, both on the ocular surface and neuroretina. Yet, any alteration in this symbiotic relationship culminates in the perturbation of ocular homeostasis and shifts the equilibrium toward local or systemic inflammation and, in turn, impaired visual function. A compositional variation in the ocular microbiota is associated with surface disorders such as keratitis, blepharitis, and conjunctivitis. Nevertheless, innovative studies now implicate non-ocular microbial dysbiosis in glaucoma, age-related macular degeneration (AMD), uveitis, and diabetic retinopathy. Accordingly, prompt identification of the extra-ocular etiology and a methodical understanding of the mechanisms of invasion and host-microbial interaction is of paramount importance for preventative and therapeutic interventions for vision-threatening conditions. This review article aims to explore the current literature evidence to better comprehend the role of oral pathogens in the etiopathogenesis of ocular diseases, specifically AMD.

Oral Microbiome: Getting to Know and Befriend Neighbors, a Biological Approach

The oral microbiome, forming a biofilm that covers the oral structures, contains a high number of microorganisms. Biofilm formation starts from the salivary pellicle that allows bacterial adhesion–colonization–proliferation, co-aggregation and biofilm maturation in a complex microbial community. There is a constant bidirectional crosstalk between human host and its oral microbiome. The paper presents the fundamentals regarding the oral microbiome and its relationship to modulator factors, oral and systemic health. The modern studies of oral microorganisms and relationships with the host benefits are based on genomics, transcriptomics, proteomics and metabolomics. Pharmaceuticals such as antimicrobials, prebiotics, probiotics, surface active or abrasive agents and plant-derived ingredients may influence the oral microbiome. Many studies found associations between oral dysbiosis and systemic disorders, including autoimmune diseases, cardiovascular, diabetes, cancers and neurodegenerative disorders. We outline the general and individual factors influencing the host–microbial balance and the possibility to use the analysis of the oral microbiome in prevention, diagnosis and treatment in personalized medicine. Future therapies should take in account the restoration of the normal symbiotic relation with the oral microbiome.

Innate Phagocyte Polarization in the Oral Cavity

The oral cavity is a complex environment constantly exposed to antigens from food and the oral microbiota. Innate immune cells play an essential role in maintaining health and homeostasis in the oral environment. However, these cells also play a significant role in disease progression. This review will focus on two innate phagocytes in the oral cavity: macrophages and neutrophils, and examine their roles during homeostasis and disease development, with a focus on periodontal disease and cancer. Macrophages have a well-known ability to polarize and be activated towards a variety of phenotypes. Several studies have found that macrophages’ polarization changes can play an essential role in maintaining health in the oral cavity and contribute to disease. Recent data also finds that neutrophils display phenotypic heterogeneity in the oral cavity. In both cases, we focus on what is known about how these cellular changes alter these immune cells’ interactions with the oral microbiota, including how such changes can lead to worsening, rather than improving, disease states.

PERIODONTAL AND SYSTEMIC DISEASES: ERECTILE DYSFUNCTION

Periodontal hastalıklar toplumda yaygın bir şekilde görülmektedir. Son yıllarda yapılan çalışmalarla periodontal hastalıkların sistemik hastalıklara, benzer şekilde sistemik rahatsızlıklarında periodontal hastalıklara katkıda bulunabileceği bilinmektedir. Periodontal hastalıklar ve sistemik hastalıklar arasındaki bu iki yönlü ilişki son yıllarda dikkat çekici bir şekilde araştırmalara neden olmuştur. Bu konulardan biri de erektil disfonksiyondur. Periodontal hastalıkların erektil disfonksiyon ile ilişkisi ilgi çekicidir. Farklı etyolojiye sahip olan erektil disfonksiyonda periodontal hastalıkların etkisi son dönemde sıkça araştırılmıştır. Bu geleneksel derlemede, tedavi sağlayıcılara periodontal hastalıkların genel özellikleri, erektil disfonksiyonun genel özellikleri ve birbiri ile olan ilişkiler üzerinde durulacaktır.

The Existence of Periodontal Disease and Subsequent Ocular Diseases: A Population-Based Cohort Study

Background and objectives: We aimed to evaluate the correlation between periodontal disease (PD) and following ocular diseases via the National Health Insurance Research Database in Taiwan. Materials and Methods: A retrospective cohort study was conducted. Subjects were regarded as having PD according to the diagnostic codes. For comparison, each subject with PD was matched to one non-PD individual from the database after exclusion. The main outcome was defined as the development of infectious keratitis, endophthalmitis, orbital cellulitis, lacrimal duct infection, uveitis and infectious scleritis. Cox proportional hazard regression was used to yield the adjusted hazard ratios (aHR) of ocular diseases between the study and control groups. Results: A total of 426,594 subjects were enrolled in both the study and control groups. In the multivariable analysis, significantly higher rates of infectious keratitis (aHR: 1.094, 95% CI: 1.030–1.161), uveitis (aHR: 1.144, 95% CI: 1.074–1.218) and infectious scleritis (aHR: 1.270, 95% CI: 1.114–1.449) were found in the study group. Concerning the PD interval, infectious keratitis (aHR: 1.159, 95% CI: 1.041–1.291) and infectious scleritis (aHR: 1.345, 95% CI: 1.055–1.714) would significantly occur in PD patients with an interval shorter than two years, individuals with a PD interval that ranged from two to five years were under a higher risk of developing uveitis (aHR: 1.184, 95% CI: 1.065–1.315) and infectious scleritis (aHR: 1.386, 95% CI: 1.125–1.708), and the rate of uveitis (aHR: 1.149, 95% CI: 1.038–1.272) was significantly higher if PD persisted more than five years. Conclusions: The presence of PD was moderately associated with the risk of developing infectious keratitis, uveitis and infectious scleritis.

Amoebae in Chronic, Polymicrobial Endodontic Infections Are Associated with Altered Microbial Communities of Increased Virulence

BACKGROUND

Infections of the root canal space involve polymicrobial biofilms and lead to chronic, low grade inflammatory responses arising from the seeding of microbes and by-products. Acute exacerbation and/or disseminating infections occur when established microbial communities undergo sudden changes in phenotypic behaviour.

METHODS

Within clinical endodontic infections, we assessedcategorical determinants comprising, and changing microbial composition of, chronic polymicrobial infections and their association with amoebae. After standardised assessment, primary or secondary infections underwent sampling and DNA processing, targeting bacteria, fungi and amoebae, including 16S high-throughput sequencing. After taxonomic assignment, community composition was correlated with clinical signs and symptoms. Diversity and abundance analyses were carried out in relation to the presence of non-bacterial amplicons.

RESULTS

Clinical specimens revealed two distinct community clusters, where specific changes correlated with clinical signs. An association between the compositions of microbiomes was found between these groups and the presence of Entamoeba gingivalis in 44% of cases. When amoebae were present in endodontic infections, we demonstrate changes in microbial community structure that mirror those observed in treatment-resistant or recurrent infections.

CONCLUSIONS

Amoeba are present in endodontic infections at a high prevalence, and may promote increased virulence by enrichment for phagocytosis-resistant bacteria.

Eye on the Enigmatic Link: Dysbiotic Oral Pathogens in Ocular Diseases; The Flip Side

Mouth and associated structures were regarded as separate entities from the rest of the body. However, there is a paradigm shift in this conception and oral health is now considered as a fundamental part of overall well-being. In recent years, the subject of oral-foci of infection has attained a resurgence in terms of systemic morbidities while limited observations denote the implication of chronic oral inflammation in the pathogenesis of eye diseases. Hitherto, there is a paucity for mechanistic insights underlying the reported link between periodontal disease (PD) and ocular comorbidities. In light of prevailing scientific evidence, this review article will focus on the understudied theme, that is, the impact of oral dysbiosis in the induction and/or progression of inflammatory eye diseases like diabetic retinopathy, scleritis, uveitis, glaucoma, age-related macular degeneration (AMD). Furthermore, the plausible mechanisms by which periodontal microbiota may trigger immune dysfunction in the Oro-optic-network and promote the development of PD-associated AMD have been discussed.

The role of dental insurance in mitigating mortality among working-age U.S. adults with periodontitis

AIM

To assess the relationship of dental insurance with all-cause mortality and mortality due to cardiovascular diseases (CVD), diabetes mellitus (DM), and cerebrovascular diseases (CBD) among those with periodontitis.

MATERIALS AND METHODS

NHANES III and its associated mortality data set were used in this study. The outcome variables were "all-cause mortality" and "combined mortality" due to CVD, DM, and CBD. The independent variable was dental insurance stratified over periodontitis status. Unweighted frequencies with weighted column percentages were used for descriptive statistics, and chi-square test was applied for significance. Cox proportional hazard models were used for stratified multivariable analyses. All analyses were performed in SAS v9.4 accounting for survey data complexities. Significance level was kept at 5%.

RESULTS

The mortality was 14.58% for all-cause mortality and 4.06% for combined mortality among those with periodontitis in this study. Dental insurance significantly reduced the hazard of all-cause mortality among those with periodontitis (HR: 0.75; 95% CI: 0.61 - 0.93), adjusted for covariates. However, no association of dental insurance with combined mortality was observed among periodontitis group.

CONCLUSIONS

Dental insurance reduces hazard of all-cause mortality among those with periodontitis. Dental insurance ensures access to dentists and improves oral and dental health. Longitudinal study is needed to establish causality.

Unusual synchronous liver and brain abscesses infected by rare Aerococcus viridians in a patient with pulmonary arteriovenous malformations on FDG PET/CT: A case report and literature review

RATIONALE

Pulmonary arteriovenous malformations (PAVMs) complicated with multiple organ abscesses is an uncommon manifestation. Because of the low incidence of the disease, F-18 fluorodeoxyglucose positron emission tomography with computed tomography (F-FDG PET/CT) imaging studies for PAVMs complicated with multiple organ abscesses are scarce.

PATIENT CONCERNS

We report a case of a 54-year-old man presenting with PAVMs complicated with synchronous multiple organ abscesses founded by F-FDG PET/CT. F-FDG PET/CT revealed tortuous stripes and mass opacities with no significant FDG uptake in the left upper lung lobe. However, hypermetabolic lesions located in the anterior inferior segment of right hepatic lobe [with maximum standardized uptake value (SUVmax) of 10.7], and in the right basal ganglia with SUVmax of 14.1 were found by F-FDG PET/CT.

DIAGNOSES

A diagnosis of synchronous liver and brain abscesses infected by rare Aerococcus viridans was determined by tissue culture.

INTERVENTIONS

Vancomycin was provided intravenously, and oral linezolidate tablets were prescribed for anti-inflammatory treatment for 1 month. Liver and head magnetic resonance imaging was performed during the follow-up.

OUTCOMES

The lesion in the right basal ganglia was reduced, and the lesion in the right liver had disappeared, indicating the lesions were abscesses.

LESSONS

The present case indicated that the possibility of abscesses should be considered with patients with PAVMs, and whole-body F-FDG PET/CT is suggested to identify possible accompanying abscesses in multiple organs for PAVMs patients.

Far from the eyes, close to the heart: dysbiosis of gut microbiota and cardiovascular consequences

These days, the gut microbiota is universally recognized as an active organ that can modulate the overall host metabolism by promoting multiple functions, from digestion to the systemic maintenance of overall host physiology. Dysbiosis, the alteration of the complex ecologic system of gut microbes, is associated with and causally responsible for multiple types of pathologies. Among the latters, metabolic diseases such as type 2 diabetes and obesity are each distinguishable by a unique gut microbiota profile. Interestingly, the specific microbiota typically found in the blood of diabetic patients also has been observed at the level of atherosclerotic plaque. Here, we report evidence from the literature, as well as a few controversial reports, regarding the putative role of gut microbiota dysbiosis-induced cardiovascular diseases, such as atherosclerosis, which are common comorbidities of metabolic dysfunction.

Biofilm and Dental Biomaterials

All treatment involving the use of biomaterials in the body can affect the host in positive or negative ways. The microbiological environment in the oral cavity is affected by the composition and shape of the biomaterials used for oral restorations. This may impair the patients’ oral health and sometimes their general health as well. Many factors determine the composition of the microbiota and the formation of biofilm in relation to biomaterials such as, surface roughness, surface energy and chemical composition, This paper aims to give an overview of the scientific literature regarding the association between the chemical, mechanical and physical properties of dental biomaterials and oral biofilm formation, with emphasis on current research and future perspectives.

Effect of periodontal therapy on circulating levels of endotoxin in women with periodontitis: a pilot clinical trial

CONTEXT

Periodontitis is a potential risk factor for adverse pregnancy outcomes due to the presence of a subgingival load of pathogenic bacteria. Instrumentation of periodontal pockets during treatment may result in bacteremia and/or endotoxemia.

AIMS

The aim of this pilot clinical trial was to determine the immediate post-scaling and root planing (SRP) level of circulating endotoxin in females presenting with chronic periodontitis.

SETTINGS AND DESIGN

A before-and-after pilot clinical trial among rural women of low socioeconomic status attending the outpatient department (OPD) for periodontitis.

MATERIALS AND METHODS

Twenty-four women aged 25-35 years, with at least five teeth having probing depth (PD) ≥ 5 mm, were selected for the study. The clinical trial was divided into three phases: phase 0 (screening), phase I (just before scaling), and phase II (15 min after scaling). Phase 0, one day prior to SRP, was used to assess the eligibility of the patients and record the periodontal status. Endotoxin levels were assessed by a semiquantitative gel-clot assay, the limulus amoebocyte lysate (Lonza®), at phase I and phase II.

STATISTICAL ANALYSIS USED

The Chi-square test was used for statistical analysis.

RESULTS

There was significant increase of endotoxins levels (P<.05) immediately after scaling (15 min).

CONCLUSIONS

SRP can lead to endotoxemia, possibly by release of endotoxins by bacteria of periodontal origin, into the systemic circulation.

Oral infection, regular alcohol drinking pattern, and myocardial infarction

Oral infections have been associated with an increased risk for myocardial infarction (MI) and other cardiovascular diseases (CVD). Conversely, low, regular alcohol consumption is associated with a lower association of CVD. The objective was to test the novel hypothesis that oral infections are modified by regular alcohol drinking which has the effect of lowering the incidence of MI's. The effect has been observed where tooth extractions where carried out due to infections and compared with extractions unconnected to infections. Oral infections and in particular periodontal infections impose an infectious load on the health in many people. In its advanced forms (periodontal pockets ≥ 6mm) periodontitis affects ∼10-15% of adults. The infection runs a chronic course with exacerbations. The bacteria cause local infection destructive to the supporting tissues of the teeth and have been detected in systemic diseases through bacterial products and bacteria entering the circulation. The often persistent, long term history of chronic periodontal infection in individuals is a challenge to the immune system. Over 700 oral bacteria and other microorganisms have been identified, many of which are virulent. Control of the level of oral microbiota is through well known oral hygiene measures. Alcohol by being bactericidal is a factor that may reduce the bacterial level in the oral cavity. If this effect truly exists, it should be observed through reduction of infections in the mouth. Tooth extraction is the ultimate consequence of periodontal and dental infections and a reduction of tooth extraction due to infections should therefore be observed. The hypothesis was tested using the screening data of the Oslo II-study in a cross sectional analysis. The Oslo-study included men aged 48-67 years. The main finding was that the effect of a drinking pattern of 2-7 times per week reduced the risk of MI among men who had a history of tooth extractions due to infections versus tooth extraction for other causes or no extractions. This hypothesis supports an explanation as to why oral infection is a weaker independent risk factor for CVD in some studies. It also gives an indication of the reason for an added benefit by a regular drinking pattern as part of the Mediterranean diet. The important consequence of this hypothesis is the added importance of optimal oral hygiene for the prevention of CVD as well as for the benefit of good oral health.

From ophthalmologist to dentist via radiology

Background:

The aim of this paper was to analyze the causes of orbital cellulitis in connection with covert dental changes as well as to establish the role of radiological procedures in the final diagnosis and further treatment of such cases.

Material/Methods:

Thirty-two patients, aged 25–56, 22 women and 10 men were diagnosed and treated between January 2007 and April 2011 at the Pomeranian Medical University in Szczecin. The patients were examined in the infirmary of the ophthalmological department due to unilateral blepharo-oedema, abrupt pain and vision disturbances; in 5 cases, body temperature increased up to 37.8°C was observed. Next, the patients underwent conventional X-ray examinations of the orbit to exclude any foreign bodies in the eyeball, as well as pantomographies to evaluate the dental status. Visible periapical or periodontal changes in dentition were analyzed with intraoral X-rays with the use of DIGORA System 2.1. Changes found in 3 patients on pantomograms and connected with iatrogenic procedures were further evaluated with CT (64 lines and 128 layers) in frontal, sagittal and axial projections. Orbital disorders were also diagnosed by an ophthalmologist and radiologist with Doppler ultrasound (US) examinations. A linear transducer of 7.5–10 MHz to observe the morphology and vascularity of the eyeball was applied.

Results:

Iatrogenic treatment was the cause of sinusitis and cellulitis in three cases: incorrectly implanted dental implant in one case, root of the 3^rd molar pushed into the sinus in the second case, and communication between the maxillary alveolar process and the sinus after extraction in case of the third patient. Asymptomatic periapical osteolysis, periodontal disease or dead teeth were found in all cases. Diagnosis of orbital cellulitis of dental origin was determined on the basis of clinical, radiographic and ultrasound findings. Ophthalmologic and dental treatment was applied simultaneously.

Conclusions:

Co-operation between ophthalmologists, radiologists and dentists is necessary during the treatment of such orbital diseases.

A case of odontogenic brain abscess arising from covert dental sepsis

Odontogenic infections can spread to any organ of the body and in some cases cause life threatening infections. We report a case of multiple odontogenic brain abscesses resulting from undetected tooth decay. Whereas most odontogenic brain abscesses occur following dental treatment, this report documents brain abscesses prior to dental treatment, signifying the dangers of covert dental infections. This case report updates the literature on the topic of odontogenic brain abscesses.

Can a chronic dental infection be considered a cause of cardiovascular disease? A review of the literature

Cardiovascular diseases (CVD) have a complex etiology determined by risk factors, which are in turn associated to a strong genetic component and to environmental factors. In the biological background for the development of CVD, low-grade chronic inflammation plays a role as a pathogenetic determinant of atherosclerosis. Dental infections have been associated with CVD. Periodontal disease is a chronic infection of the supporting tissues of the tooth that can lead to teeth loss. In recent years, a number of reports have demonstrated the possible relationship between periodontal disease and CVD. Apical periodontitis, on the other hand, is the late consequence of an endodontic infection, which is caused by the persistence of coronal caries and involves the root canal system of the tooth. Most of the time, it is a chronic infection. Some studies have found a correlation between a "composite status" of oral health (eg. caries, tooth loss, periodontal disease) and CVD, but only a few of them have addressed the association between apical periodontitis and CVD. This "state of the art" paper represents the first stage of an incoming study on the relationship between chronic endodontic infection and CVD.

Streptococcus mutans autolysin AtlA is a fibronectin-binding protein and contributes to bacterial survival in the bloodstream and virulence for infective endocarditis

Streptococcus mutans, a commensal of the human oral cavity, can survive in the bloodstream and cause infective endocarditis (IE). However, the virulence factors associated with this manifestation of disease are not known. Here, we demonstrate that AtlA, an autolysin of S. mutans is a newly identified fibronectin (Fn) binding protein and contributes to bacterial resistance to phagocytosis and survival in the bloodstream. Interestingly, prior exposure to plasma at low concentrations was sufficient to enhance bacterial survival in the circulation. Calcium ions at physiological plasma concentrations induced maturation of AtlA from the 104-90 kDa isoform resulting in increased Fn binding and resistance to phagocytosis. An isogenic mutant strain defective in AtlA expression exhibited reduced survival and virulence when tested in a rat model of IE compared with the wild-type and complemented strains. The data presented suggest that plasma components utilized by S. mutans enhanced survival in the circulation and AtlA is a virulence factor associated with infective endocarditis.

Ribotyping of bacteria from root canal and blood of patients receiving endodontic therapy

DNA restriction patterns and corresponding ribotypes of 26 bacterial isolates (Propionibacterium acnes, Peptostreptococcus prevotii, Fusobacterium nucleatum, Prevotella intermedia, Prevotella nigrescens, Actinomyces israelii, Streptococcus intermedius, and Streptococcus sanguis) recovered from patients with infected root canals and their peripheral blood, collected during and after endodontic therapy, were examined. Eleven additional reference strains including type strains were also examined. Purified DNA was digested with BglI,EcoRI, and HindIII. Hybridization was carried out with a digoxigenin-labeled cDNA probe obtained by reverse transcription of Escherichia coli 16S + 23S rRNA. Ribotypes of the bacteria recovered from root canal and blood showed identical characteristics within the patients, and differed between the patients. The results were confirmed when the similarity coefficient (S(AB)) of the ribotypes from the isolates were assessed by the Dendron computer-assisted system. These results suggested that the bacteria isolated from the blood originated from the root canal.

Bacterial translocation as a source of Dacron-graft contamination in experimental aortic operation: the importance of controlling SIRS

BACKGROUND

Several experimental studies have shown the beneficial effects of nitric oxide (NO) in the modulation of the systemic inflammatory response syndrome (SIRS). Nitric oxide is involved in and affects almost all stages in the development of inflammation. We have attempted to ascertain whether the nitric oxide donor molsidomine prevents aortic graft contamination through control of the SIRS and a decrease in bacterial translocation (BT).

METHODS

Twenty-four mini-pigs were divided into 4 groups. The animals were subjected to suprarenal aortic/iliac cross-clamping (for 30 minutes) and by-pass with a Dacron-collagen prosthetic graft impregnated in rifampicin. Groups: 1) sham (aortic dissection alone); 2) cross-clamping and bypass; 3) hemorrhage of 40% of total blood volume before cross-clamping and by-pass; and 4) the same as in group 3 but also including the administration of the NO donor molsidomine (4 mg/kg) 5 minutes before cross-clamping.

VARIABLES

1) bacteriology of mesenteric lymph nodes (MLN), kidney, blood, and prosthesis; 2) serum TNF-alpha (ELISA); and 3) iNOS expression in kidney and liver (Western blot).

RESULTS

Aortic cross-clamping with or without hemorrhage was associated with BT in 80% and 100% of the animals, respectively. About 86% of the bacteria isolated in the graft were also present in MLN. This contamination coincided with an increase in TNF-alpha and with a greater expression of iNOS. Molsidomine administration decreased TNF-alpha and iNOS, decreased BT (from 100% to 20% of the animals), and decreased graft contamination (from 83% to 20%).

CONCLUSIONS

The present model induces high levels of BT and SIRS, both acted as sources of contamination for the implanted Dacron graft. Molsidomine administration decreased the presence of bacteria in the graft by controlling BT and modulating SIRS.

Endocarditis-associated oral streptococci promote rapid differentiation of monocytes into mature dendritic cells

Endocarditis is frequently attributable to oral streptococci, but mechanisms of pathogenesis are not well understood, although monocytes appear to be important. High titers of interleukin-12 (IL-12) are produced by peripheral blood mononuclear cells (PBMC) after engaging Streptococcus mutans, but monocytes in developing endocardial vegetations tend to disappear rather than become macrophages. These data prompted the hypothesis that streptococcus-infected monocytes differentiate into short-lived IL-12-producing dendritic cells (DCs) rather than macrophages. PBMC from healthy subjects were stimulated with six isolates of oral streptococci, three nonstreptococcal oral bacteria, or IL-4 plus granulocyte-macrophage colony-stimulating factor, and the appearance of cells with markers typical of mature DCs (CD83(+), CD86(+), CD11c(+), and CD14(-)) was monitored. Supernatant fluids from the PBMC cultures were harvested and IL-12 p70 levels were determined. S. mutans-stimulated monocytes were analyzed for their ability to elicit allogeneic mixed-lymphocyte reactions. All streptococci examined, except one strain of Streptococcus oralis (35037), rapidly induced up-regulation of CD83 and CD86 and a loss of CD14 in the CD11c(+) monocyte population within 20 h. Induction of IL-12 was CD14 dependent and correlated with streptococcal isolates that promoted the DC phenotype. Major histocompatibility complex (MHC) class II expression was up-regulated by S. mutans, and these cells were short-lived and elicited potent allogeneic mixed-lymphocyte reactions typical of DCs. In summary, monocytes stimulated with endocarditis-associated oral streptococci rapidly exhibited the DC phenotype and functions. These data suggest that the initiation of bacterial endocarditis by oral streptococci may involve monocyte-to-DC differentiation, and this may help explain the low levels of macrophages in the site.

Capnocytophagaspp. in Periodontitis Patients Manifesting Diabetes Mellitus

BACKGROUND

The subgingival microflora in patients presenting concurrently with periodontitis and diabetes mellitus (DM) are poorly understood. While traditional putative periodontal pathogens are implicated, research involving other oral organisms; e.g., Capnocytophaga spp., is lacking. These organisms produce a range of bacterial enzymes relevant to periodontal breakdown. It is inferred that periodontal bacteria acquire systemic access through the ulcerated periodontal pocket surface; conclusive evidence supporting this notion is limited. The aims of this investigation were to: 1) quantify and identify Capnocytophaga spp. present in healthy and diseased sites in periodontitis patients with and without DM, and 2) isolate periodontal pathogens from these patients' blood.

METHODS

Twenty-one DM-periodontitis and 25 periodontitis patients were recruited. Subgingival plaque was collected from three healthy and three diseased sites per subject. Capnocytophaga spp. and total (facultative and obligate) anaerobic counts from each site were estimated. Capnocytophaga spp. were identified using 16S rRNA polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP). Statistical analyses were performed using multilevel modeling. Blood samples were subjected to HbA(1c) estimation and bacterial culture.

RESULTS

A total of 848 Capnocytophaga spp. were isolated and identified. Significantly higher numbers of Capnocytophaga spp. (P <0.001) and anaerobes (P <0.001) were present in diseased sites in DM-periodontitis subjects compared to healthy sites in non-DM-periodontitis and DM-periodontitis subjects. C. ochracea (and variant) and C. granulosa were the most prevalent species. Blood samples were negative for Capnocytophaga spp.

CONCLUSIONS

Total mean counts for Capnocytophaga spp. were significantly higher in DM-periodontitis subjects versus non-DM-periodontitis (P = 0.025) and at diseased sites versus healthy sites (P <0.001). Analysis of individual species revealed that the outcome varied with site status and DM status.

Virulence factors of Enterococcus faecalis: relationship to endodontic disease

Enterococcus faecalis is a micro-organism that can survive extreme challenges. Its pathogenicity ranges from life-threatening diseases in compromised individuals to less severe conditions, such as infection of obturated root canals with chronic apical periodontitis. In the latter situation, the infecting organisms are partly shielded from the defense mechanisms of the body. In this article, we review the virulence factors of E. faecalis that may be related to endodontic infection and the periradicular inflammatory response. The most-cited virulence factors are aggregation substance, surface adhesins, sex pheromones, lipoteichoic acid, extracellular superoxide production, the lytic enzymes gelatinase and hyaluronidase, and the toxin cytolysin. Each of them may be associated with various stages of an endodontic infection as well as with periapical inflammation. While some products of the bacterium may be directly linked to damage of the periradicular tissues, a large part of the tissue damage is probably mediated by the host response to the bacterium and its products.

Isolation and characterization of subgingival staphylococci from periodontitis patients and controls

OBJECTIVES

To isolate and characterize subgingival staphylococci from patients with periodontal disease and from periodontally healthy controls, to evaluate the periodontal environment as a potential source for systemic staphylococcal infections.

METHODS

Periopaper strips were used to isolate subgingival staphylococci from 28 patients with chronic periodontitis and 28 periodontally healthy age and sex-matched controls. Staphylococci were identified by microbiological methods and antibiotic resistance profiles determined.

RESULTS

Staphylococci were isolated from 54% diseased subgingival and 43% healthy subgingival sites in over 50% periodontitis patients and from 29% healthy subgingival sites in 54% controls. No significant differences in the frequency of isolation or numbers of staphylococci isolated from diseased and healthy sites were noted. Staphylococcus epidermidis was the predominant oral species. Seventy per cent (115 of 165) of all isolates were penicillin-resistant.

CONCLUSIONS

Subgingival staphylococci are present in both periodontitis patients and controls. In periodontitis there is an increased risk of bacteraemia because of the increased dentogingival surface area. The dental and periodontal health of patients at risk from haematogenous infections should therefore be maintained at a high level. Antibiotic resistance profiles of the oral staphylococcal isolates suggest that amoxicillin may no longer be a suitable antibiotic for prophylaxis against systemic infections such as prosthetic valve endocarditis.

Bacterial concentrations determine the ability to implant in the root canal system and translocate to lymph nodes in germ-free mice

The purpose of this study was to evaluate the influence of the infecting dose on bacterial colonization in root canal systems (RCS) and translocation to the submandibular lymph node (SML) of gnotobiotic (germ-free) mice. RCS were inoculated with 10(2) and 10(1) colony-forming units (CFU) of Enterococcus faecalis (ATCC 4083) or 10(5), 10(4), 10(3), and 10(2) CFU of Prevotella nigrescens (ATCC 33563). E. faecalis implanted in 83.3% of the cases, for both inocula. Translocation was detected in 58.3% of lymph nodes for the 10(2) CFU inoculum and in 33.3% of lymph nodes for the 10(1) CFU inoculum. P. nigrescens implanted in 25%, 16.7%, 8.3%, and 0%, for the 10(5), 10(4), 10(3), and 10(2) CFU inocula, respectively, and did not translocate at any of the concentrations used. These results indicate that E. faecalis was able to implant in the RCS and translocate to the SML, whereas P. nigrescens implanted in lower percentages in the RCS and did not translocate to the SML.

Relationship between oral health and mortality rate

BACKGROUND/AIMS

Some symptoms of diseases or causes of death are often related to oral health, especially cardiovascular diseases. The purpose of this study was to investigate the relationship between poor oral health and mortality risk, especially when cases of fatal cardiovascular diseases were excluded.

MATERIAL AND METHODS

An odontological investigation was made on a sample of 1393 individuals, aged 18-65 years, in 1970 in the County of Stockholm with a follow-up in 1997, when the mortality rate and causes of death in the sample during the time period 1971-1996 were registered. Oral health was defined as a sum of scores for number of missing teeth, apical lesions, caries lesions and marginal bone loss.

RESULTS

A significant correlation was found between poor oral health and an increased mortality risk even when persons dying from cardiovascular diseases were excluded from the analyses.

CONCLUSION

Poor oral health was found to be a risk indicator of all-cause mortality. The lack of specificity of the associations between oral health and mortality strengthens the hypothesis that the significant correlations could be explained by not identified confounding factors.

DNA probes and primers in dental practice

In clinical microbiology, molecular genetic techniques are increasingly being used to detect and/or differentiate uncultivable, anaerobic, or fastidious microorganisms. During the past decade, DNA probe hybridization and in vitro amplification by polymerase chain reaction have also been introduced to detect oral pathogens. The present review describes experiences with methods and commercial test systems for the detection of pathogens in periodontitis and caries.

The Sequential Failure of Osseointegrated Submerged Implants

This report presents a case of sequential failure of nonrestored implants that were osseointegrated and submerged for 3 years. The suspected causes of failure were investigated and analyzed. These included anatomic, physiologic, traumatic, and pathogenic factors. The findings of this report compliment other literature and contribute to the comprehensive classification of implant failure based on osseointegration criteria.

Hemisection for treatment of an advanced endodontic-periodontal lesion: a case report

AIM

To emphasize the importance of primary endodontic treatment when dealing with endo-perio lesions and to demonstrate the considerable healing potential of the endodontic aspect.

CASE REPORT

After several years of unsuccessful symptomatic periodontal treatment, an advanced endo-perio lesion on a right-mandibular first molar was successfully treated by root-canal treatment and hemisection after the re-evaluation of the lesion. This successful treatment appeared to have a positive effect on the patient's general well-being.

KEY LEARNING POINTS

The origin of a combined endo-perio lesion is indicated by its clinical and radiographic appearance. The periodontal situation is often misinterpreted. The prognosis for the endodontic element of treatment is excellent. Local pathologic processes in the oral cavity may affect a patient's general health.

Penetration of propylene glycol into dentine

AIM

This study aimed to evaluate penetration of propylene glycol into root dentine.

METHODOLOGY

Safranin O in propylene glycol and in distilled water were introduced into root canals with and without artificial smear layer. Dye diffusion through dentinal tubules was determined spectrophotometrically. The time required for dye to exit through the apical foramen using propylene glycol and distilled water as vehicles was also determined. The extent and areas of dye penetration on the split surfaces of roots were assessed using Adobe Photoshop and NIH Image Software.

RESULTS

Propylene glycol allowed dye to exit faster through the apical foramen. The area and depth of dye penetration with propylene glycol was significantly greater than with distilled water (P < 0.0001). Smear layer significantly delayed the penetration of dye.

CONCLUSION

Propylene glycol delivered dye through the root canal system rapidly and more effectively indicating its potential use in delivering intracanal medicaments.

The perceived benefit of endodontic retreatment

AIM

There is substantial variation amongst dentists in the management of symptom-free periapical lesions in root-filled teeth. It has been suggested that this variation can be understood as clinicians' choice of different cut-off points on a continuous periapical health scale (the 'Praxis Concept (PC) theory'). Based on this suggestion, an individual's inclination to propose retreatment can be expressed in the Retreatment Preference Score (RPS). In the present study it was hypothesized that: (i) the PC theory is valid amongst experienced endodontists; and that (ii) interindividual variation in RPS can be explained by a corresponding variation in the perceived benefit of endodontic retreatment.

METHODOLOGY

The RPS was determined for 16 experienced Swedish endodontists. The retreatment benefit (RTB) was defined as the gain in utility when a root-filled tooth with a persistent periapical lesion ('health state B') moved to a state where the lesion had healed ('health state A'). For each individual the utility values of the two health states were measured by means of the standard gamble technique.

RESULTS

The RPS and RTB were found to be subjected to substantial inter- and intrarater variation. The decision makers acted in accordance with the PC theory. No significant correlation between RPS and RTB was detected.

CONCLUSIONS

Findings suggest that the PC theory is valid amongst endodontic experts. The study did not support the notion that the more potential utility that could be produced, the more the individual dentist should tend to perform retreatment. However, alternative consequentialist strategies focusing low risk taking may be involved.

Systemic release of endotoxins induced by gentle mastication: association with periodontitis severity

BACKGROUND

Periodontitis has recently been identified as a potential risk factor for systemic pathologies such as cardiovascular disease, the hypothesis being that periodontal pockets could release pro-inflammatory bacterial components, for instance endotoxins, into the bloodstream. It is known that the oral cavity can be a source of circulating bacteria, but this has never been shown for bacterial endotoxins, and no evidence exists so far that the risk of systemic injury is related to the severity of periodontitis. The aim of the present study was to test the influence of gentle mastication on the occurrence of endotoxemia in patients with or without periodontal disease.

METHODS

A total of 67 subjects were periodontally examined and grouped according to their periodontal status. This classification was based on an original index of severity of periodontal disease (periodontal index for risk of infectiousness, PIRI) aimed at reflecting the individual risk of systemic injury from the periodontal niches. Thus, the patients were classified into 3 risk groups: low, PIRI = 0; n = 25; moderate, 1 < or = PIRI < or = 5, n = 27; and high 6 < or = PIRI < or = 10, n = 15. Blood samples were collected before and 5 to 10 minutes after a standardized session of gentle mastication for detection of circulating endotoxins. Blood samples were tested with a chromogenic limulus amoebocyte lysate assay.

RESULTS

Overall, blood levels of endotoxin after mastication were found to be significantly higher than before mastication (0.89 +/- 3.3 pg/ml versus 3.0 +/- 5.8 pg/ml; P= 0.0002). Likewise, the incidence of positive endotoxemia rose from 6% before mastication to 24% after mastication (P = 0.001). When accounting for the PIRI index, endotoxin levels and positive endotoxemia proved to be significantly higher in patients with severe periodontal disease than in the subjects with low or moderate periodontitis.

CONCLUSIONS

Gentle mastication is able to induce the release of bacterial endotoxins from oral origin into the bloodstream, especially when patients have severe periodontal disease. This finding suggests that a diseased periodontium can be a major and underestimated source of chronic, or even permanent, release of bacterial pro-inflammatory components into the bloodstream.

Secondary abscess formation in pituitary adenoma after tooth extraction. Case report

The presence of an abscess in a pituitary tumor is a very rare finding. The authors report the case of a 69-year-old man with a pituitary adenoma confirmed by neuroimaging results, in whom a high fever, meningismus, and left-sided ophthalmoplegia developed 4 days after tooth extraction. The results of serial cranial magnetic resonance imaging were highly indicative of an abscess formation within the pituitary adenoma. During surgery the tumor was approached transsphenoidally and removed. Histological examination confirmed the presence of an abscess formation within the pituitary adenoma. It is most likely that the tooth extraction caused a bacteremia, which led to an inflammation with abscess formation within the pituitary adenoma. The authors conclude that invasive dental procedures should be avoided before planned resection of a pituitary adenoma.

Is the observed association between periodontitis and atherosclerosis causal?

Most of the documentation of possible causal links between periodontitis and atherosclerosis-related diseases appears indirect or circumstantial. There is, however, an increasing number of both experimental and longitudinal epidemiological studies which seem to support a causal relationship. A critical evaluation of the epidemiological data available might therefore be appropriate. The present study is based on a literature search using Ovid medical data base covering the period from 1989 to October 2000 and applying specific inclusion criteria. Based on a critical evaluation of the 14 investigations selected from a total of 21 retrieved from the search, a causal relationship between periodontitis and atherosclerosis-related diseases appeared possible. However, the nature both of periodontitis and atherosclerosis is multifactorial, and caution should be exercised when implicating periodontal disease in the causation of atherosclerotic disorders.

Apical periodontitis and related factors in an adult Lithuanian population

OBJECTIVES

The objectives of this investigation were to study determinants of apical periodontitis among Lithuanians who were 35 to 44 years old and to study possible associations between apical periodontitis, relevant general diseases, and perceived general health.

STUDY DESIGN

Information was collected from a randomly selected sample, consisting of 147 individuals from Vilnius, Lithuania. Aspects of oral and general health, health-related habits and attitudes, and social parameters were used as independent variables, with various aspects of apical periodontitis as the dependent variable. Associations were tested by regression analysis.

RESULTS

Apical periodontitis was highly prevalent in this Lithuanian population. Oral health-related variables showed the strongest association with apical periodontitis. Decayed and filled teeth scores were found to be strongly associated with periapical disease, and sound teeth were strongly associated with periapical health. In addition, behavioral variables were found to be important disease determinants.

CONCLUSIONS

Apical periodontitis appeared to be an oral health problem closely related to dental caries. No association could be detected between general diseases and apical periodontitis, but an association between perceived general health and apical periodontitis was demonstrated.

The oral cavity as a reservoir of bacterial pathogens for focal infections

Dental procedures, but more importantly, oral infections and poor oral health can provoke the introduction of oral microorganisms into the bloodstream or the lymphatic system. The subsequent attachment and multiplication of these bacteria on tissues or organs can lead to focal oral infections. Pathogenic agents may also remain at their primary oral site but the toxins liberated can reach an organ or tissue via the bloodstream and cause metastatic injury. Finally, metastatic inflammation may result from an immunological injury caused by oral bacteria or their soluble products that enter the bloodstream and react with circulating specific antibodies to form macromolecular complexes.

Detection of bacterial virulence genes associated with infective endocarditis in infected root canals

AIM

The aim of this study was to examine whether bacteria associated with root canals possess genes that might predispose to bacterial colonization of the endocardium.

METHODOLOGY

Oligonucleotides were designed from DNA sequences encoding the functional binding regions of streptococcal fibronectin-binding protein (FnBP) and staphylococcal fibrinogen-binding protein (FgBP). The specificity and cross-reactivity of the oligonucleotide primers were investigated; streptococcal primers were tested for recognition of FnBP genes in other strains of streptococci, and the staphylococcal primers for detection of FgBP from other staphylococci. Interspecies specificity of these primers was also investigated. In a pilot clinical study, the pulp chambers of 16 nonvital teeth without sinus tracts, were opened aseptically. Root canal samples were collected, along with samples from the gingival sulcus and anterior nares. From these samples DNA was extracted, subjected to polymerase chain reaction (PCR) and analysed by agarose gel electrophoresis.

RESULTS

Using the streptococcal FnBP primers, PCR bands were amplified from eight root canal samples, eight gingival samples and three nasal samples. With the staphylococcal primers, PCR bands were amplified from seven root canals, 11 gingival and nine nasal samples. This study showed that PCR could be used to detect bacteria in root canals that possess genes with homology to functional regions of those encoding FnBP or FgBP.

CONCLUSIONS

If bacteria in root canals possess FnBP or FgBP, they may have the potential to cause infective endocarditis.

Brain abscesses caused by oral infection

Brain abscesses are rare but can be life-threatening infections. Recent progress in microbiological classification and identification has indicated that they are sometimes caused by oral infection and dental treatment. It has been postulated that oral microorganisms may enter the cranium by several pathways: 1) by direct extension, 2) by hematogenous spread, 3) by local lymphatics, and 4) indirectly, by extraoral odontogenic infection. In the direct extension, oral infections spread along the fascial planes. Hematogenous spreading occurs along the facial, angular, ophthalmic, or other veins which lack valves, through the cavernous sinus and into the cranium. Another hematogenous pathway is through the general circulation. Oral bacteria may cause systemic infections, e.g., endocarditis, and then indirectly initiate brain abscess. Microbiota, complications, and the prevention and management of odontogenic brain abscesses are also discussed in this review.

Anaerobic bacteremia and fungemia in patients undergoing endodontic therapy: an overview

Oral focal infection, a concept neglected for several decades, is a subject of controversy. Recent progress in classification and identification of oral microorganisms has renewed interest in focal infection. The aim of this study was to use phenotypic and genetic methods to trace microorganisms released into the bloodstream during and after endodontic treatment back to their presumed source--the root canal. Microbiological samples were taken from the root canals of 26 patients with asymptomatic apical periodontitis of single-rooted teeth. The blood of the patients was drawn during and 10 minutes after endodontic therapy. Microorganisms in blood were collected after anaerobic lysis filtration and cultured anaerobically on blood agar plates. The phenotypic methods used for characterization and tracing of microorganisms in blood and root canals were: biochemical and antimicrobial susceptibility test, SDS-PAGE of whole-cell soluble proteins, and gas chromatography of cellular fatty acids. Phenotypic data were verified by DNA restriction patterns and corresponding ribotypes of the root canal and blood isolates by using a computer-assisted system fro gel analysis. All root canals contained anaerobic bacteria. The frequency of bacteremia varied from 31% to 54%. The microorganisms from the root canal and blood presented identical phenotype and genetic characteristics within the patients examined. These characteristics differed between patients. The present study demonstrated that endodontic treatment can be the cause of anaerobic bacteremia and fungemia. The phenotypic and genetic methods used appeared valuable for tracing microorganisms in the blood back to their origin.