Oral Microbiology

The periodontal pocket and likely caries lesions may act as a reservoir and source of dissemination and development of systemic infections. While periodontal pockets have been found to harbor several viral species, there is no information on its ability to serve as a reservoir for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have used a real-time polymerase chain reaction (RT-PCR) approach to evaluate SARS-CoV-2 in periodontal pockets and cavitated caries lesions in a cross-sectional study of 72 participants who were divided into six groups: symptomatic positive COVID-19 cases with periodontal pockets, symptomatic positive with cavitated caries lesions, asymptomatic positive with periodontal pockets, asymptomatic positive with cavitated caries lesions, positive control, and negative control. A total of 180 samples were interrogated by RT-PCR to amplify the SARS-CoV-2 E and S genes. SARS-CoV-2 was present in 41.7% of symptomatic positive COVID-19 cases with periodontal pockets and 16.7% of symptomatic positive with cavitated caries lesions. The mean Ct value of E and S genes in periodontal pockets patients were 36.06±0.46 and 30.06±6.73, respectively, and the mean Ct value for both genes in caries lesions patients were 35.73±4.14, and 34.78±1.93, respectively. The sensitivity, specificity, and accuracy to detect SARS-CoV-2 among periodontal pockets were 20.8% (95% CI 7.13-42.15), 100% (95% CI 73.54-100.0), and 47.2% (95% CI 30.22-64.51), respectively. Among cavitated caries lesions patients, they were 8.3% (95% CI 1.03-27.0), 100% (95% CI 73.54-100.0), and 38.9% (95% CI 23.14-56.54), respectively. SARS-CoV-2 can be detected in periodontal pockets and caries lesions, and these sites may act as reservoirs for the virus. However, the sensitivity of SARS-CoV-2 detection is low compared with other methods. To our knowledge, this report is the first to investigate the relationship between SARS-CoV-2 and periodontal pockets and caries.

Tetracycline resistance can be achieved through tet genes, which code for efflux pumps, ribosomal protection proteins and inactivation enzymes. Some of these genes have only been described in either Gram-positive or Gram-negative bacteria. This is the case of tet(B), which codes for an efflux pump and, so far, had only been found in Gram-negative bacteria. In this study, tet(B) was detected in two clinical Streptococcus oralis strains isolated from the gingival sulci of two subjects. In both cases, the gene was completely sequenced, yielding 100% shared identity and coverage with other previously published sequences of tet(B). Moreover, we studied the expression of tet(B) using RT-qPCR in the isolates grown with and without tetracycline, detecting constitutive expression in only one of the isolates, with no signs of expression in the other one. This is the first time that the presence and expression of the tet(B) gene has been confirmed in Gram-positive bacteria, which highlights the potential of the genus Streptococcus to become a reservoir and a disseminator of antibiotic resistance genes in an environment so prone to horizontal gene transfer as is the oral biofilm.

Recent findings indicate that the oral cavity acts as a bacterial reservoir and might contribute to the transmission of bacteria to the lower airways. Control of a potentially pathogenic microbiota might contribute to prevent the establishment of chronic infection in cystic fibrosis. We evaluated the presence of CF microorganisms in saliva and toothbrushes of CF patients and verify their possible transmission to lower airways. Methods: We assessed the presence of P. aeruginosa, S. aureus, S. maltophilia, A. xylosoxidans, S. marcescens, and yeasts in saliva, toothbrushes and sputum of 38 CF patients and assessed the clonal identity of the strains occurring contemporary in multiple sites by PFGE. Results: At least one of the investigated species was isolated from 60 saliva samples and 23 toothbrushes. S. aureus was the most abundant species, followed by Candida spp. 31 patients contemporary had the same species in sputum and saliva/toothbrush: in most cases, clonal identity of the strains among the different sites was confirmed. Conclusion: Toothbrushes may be sources of oral contamination and might act as reservoirs favoring transmission of potentially pathogenic microorganisms from the environment to the oral cavity and eventually to the LAW. Oral hygiene and toothbrush care are important strategies to prevent CF lung infections.

An online database of proteomes for two-dimensional electrophoresis (2DE) gel data was constructed and it is now freely accessible through a web-based interface. Proteins from three oral bacteria, Streptococcus mutans UA159, Actinobacillus actinomycetemcomitans HK1651, and Porphyromonas gingivalis W83, whose genome databases are freely available, were separated by 2DE, and protein spots were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and identified. About 1000 spots from the gels of P. gingivalis W83 were extracted and analyzed by MALDI-TOF, and 330 proteins were identified. In addition, 160 of 240 spots of A. actinomycetemcomitans and 158 of 356 spots of S. mutans were identified. Information such as spot coordinates on the gels, protein names (predicted functions), molecular weights, isoelectroric points, and links to online databases, including Oral Pathogen Sequence Databases of the Los Alamos National Laboratory Bioscience Division (ORALGEN) and National Center for Biotechnology Information (NCBI) or The Institute Genomic Research (TIGR), were stored in tables accessible through the relational database management system MySQL on an Apache web server. To test for functionality of this database system, responses of S. mutans to environmental changes were analyzed using the database and 21 spots on the gel were identified as proteins whose expression had been increased or decreased by environmental pH change without in-gel trypsin digestion, protein extraction, or MALDI-TOF/TOF-MS (mass spectrometer) analysis. The identified proteins are agreement with those reported in previous papers on acid tolerance of S. mutans, demonstrating the usefulness of the system. This database is available at http://www.myamagu.dent.kyushu-u.ac.jp/~bioinformatics/index.html or http://www.bipos.mascat.nihon-u.ac.jp/index.html.

Background: Bioactive glass (BAG) is used as an antibacterial agent. This study aimed to assess the effect of addition of BAG to glass ionomer cement (GIC) on accumulation of Streptococcus mutans (S. mutans) and Lactobacilli around orthodontic bands. Material and Method: This clinical trial was conducted on 10 patients requiring orthodontic treatment with lingual arch and molar bands. In five patients, Fuji II SC GIC was used for cementation of the right and Fuji II SC containing 30wt% BAG was used for cementation of the left molar band. In the remaining five patients, Fuji II LC was used for cementation of the left and Fuji II SC containing 30wt% BAG was used for cementation of the right molar band. Formation of S. mutans and Lactobacillus colonies in the culture medium was assessed and number of colonies was counted using a colony counter. The data were analyzed by using paired t-test. Results: The mean number of total bacteria, aerobic Lactobacilli, anaerobic Lactobacilli and S. mutans was significantly different between the two cements with and without BAG such that the mean count of total bacteria, aerobic Lactobacilli, anaerobic Lactobacilli and S. mutans in Fuji II LC plus BAG was less than that in plain Fuji II SC cement. Conclusion: Addition of BAG to GIC decreases the accumulation of S. mutans and anaerobic and aerobic Lactobacilli around orthodontic bands. Key Message: The used cement can be effective in reducing the damaging effect of orthodontics' bands.

We aimed to determine the bacterial diversity of different oral micro-niches and to assess whether saliva and plaque samples are representative of oral microbial composition. We took minute samples from each surface of the individual teeth and gingival crevices of two healthy volunteers (112 samples per donor), as well as samples from the tongue dorsum and non-stimulated and stimulated saliva. DNA was extracted from 67 selected samples of each donor, and the 16S rRNA gene was amplified by PCR and pyrosequenced to obtain, on average, over 2,700 reads per sample, which were taxonomically assigned to obtain a geographic map of bacterial diversity at each tooth and sulcus location. Analysis of the data shows considerable differences in bacterial composition between teeth at different intra-oral locations and between surfaces of the same tooth. The most pronounced differences were observed in incisors and canines, where genera like Streptococcus were found at 40% to 70% on the vestibular surfaces but were almost absent on the lingual sides. Saliva samples, especially non-stimulated saliva, were not representative of supra-and subgingival plaque in the two individuals tested. We suggest that more precise sampling is required for the proper determination of oral microbial composition and to relate that diversity to epidemiological, clinical, and etiological parameters.

Candida albicans is an opportunistic, fungal pathogen of humans that frequently causes superficial infections of oral and vaginal mucosal surfaces of debilitated and susceptible individuals. The organism is however, commonly encountered as a commensal in healthy individuals where it is a component of the normal microflora. The key determinant in the type of relationship that Candida has with its host is how it interacts with the epithelial surface it colonises. A delicate balance clearly exists between the potentially damaging effects of Candida virulence factors and the nature of the immune response elicited by the host. Frequently, it is changes in host factors that lead to Candida seemingly changing from a commensal to pathogenic existence. However, given the often reported heterogeneity in morphological and biochemical factors that exist between Candida species and indeed strains of C. albicans, it may also be the fact that colonising strains differ in the way they exploit resou...

Oral candidiasis is a common opportunistic infection of the oral cavity caused by an overgrowth of Candida species, the commonest being the Candida albicans. It is one of the common side effect associated with long term use of systemic corticosteroids. The purpose of this case report is to discuss the Acute Pseudomembranous Candidiasis in 24 Negroid Female Libyan patient on long term use of systemic corticosteroids therapy who came to the department of Oral Medicine, Surgery, and Diagnosis at the Faculty of Dentistry, Libyan International Medical University with the clinical appearance of Acute Pseudomembranous Candidiasis.
Proper patient management with successful treatment protocol, and follow up were performed to overcome the patient presenting symptoms, and to eliminate the corticosteroids therapy related problems.

The present study was aimed to formulate and evaluate fast
dissolving oral films of Zolmitriptan using sodium alginate, xanthan
gum and sodium starch glycolate, guar gum. The suitable plasticizer
and its concentration were selected on the basis of flexibility, tensile
strength and stickiness of the film. The films are prepared by solvent
casting method and characterized by UV, FTIR studies. The films
were evaluated for disintegration time, Folding endurance, Tensile
Strength, Mouth dissolving time, Thickness, content uniformity and
In-vitro dissolution studies. The F5 formulation has given 98.5% drug
release within 6 minutes and has a tensile strength of 1.80 MPa.

Extracellular ATP (eATP) is an important intercellular
signaling molecule secreted by activated
immune cells or released by damaged cells. In
mammalian cells, a rapid increase of ATP concentration
in the extracellular space sends a danger
signal, which alerts the immune system of an
impending danger, resulting in recruitment and
priming of phagocytes. Recent studies show that
bacteria also release ATP into the extracellular
milieu, suggesting a potential role for eATP in
host–microbe interactions. It is currently unknown
if any oral bacteria release eATP. As eATP triggers
and amplifies innate immunity and inflammation,
we hypothesized that eATP secreted from
periodontal bacteria may contribute to inflammation
in periodontitis. The aims of this study were
to determine if periodontal bacteria secrete ATP,
and to determine the function of bacterially
derived eATP as an inducer of inflammation. Our
results showed that Aggregatibacter actinomycetemcomitans,
but not Porphyromonas gingivalis,
Prevotella intermedia, or Fusobacterium
nucleatum, secreted ATP into the culture supernatant.
Exposure of periodontal fibroblasts to
filter sterilized culture supernatant of A. actinomycetemcomitans
induced chemokine expression
in an eATP-dependent manner. This occurred
independently of cyclic adenosine monophosphate
and phospholipase C, suggesting that ionotrophic
P2X receptor is involved in sensing of
bacterial eATP. Silencing of P2X7 receptor in periodontal
fibroblasts led to a significant reduction
in bacterial eATP-induced chemokine response.
Furthermore, bacterial eATP served as a potent
chemoattractant for neutrophils and monocytes.
Collectively, our findings provide evidence for
secreted ATP of A. actinomycetemcomitans as a
novel virulence factor contributing to inflammation
during periodontal disease.

Dental transposition is a form of ectopic eruption with change in position of normal adjacent teeth. Its prevalence is very low in general population and could be frequently missed on oral examination. We present a rare case of dental transposition between left mandibular canine and first premolar in a 22 year old Libyan male patient.

The oral cavity of humans is inhabited by hundreds of bacterial species and some of them have a key role in the development of oral diseases, mainly dental caries and periodontitis. We describe for the first time the metagenome of the human oral cavity under health and diseased conditions, with a focus on supragingival dental plaque and cavities. Direct pyrosequencing of eight samples with different oral-health status produced 1 Gbp of sequence without the biases imposed by PCR or cloning. These data show that cavities are not dominated by Streptococcus mutans (the species originally identified as the ethiological agent of dental caries) but are in fact a complex community formed by tens of bacterial species, in agreement with the view that caries is a polymicrobial disease. The analysis of the reads indicated that the oral cavity is functionally a different environment from the gut, with many functional categories enriched in one of the two environments and depleted in the other. Individuals who had never suffered from dental caries showed an over-representation of several functional categories, like genes for antimicrobial peptides and quorum sensing. In addition, they did not have mutans streptococci but displayed high recruitment of other species. Several isolates belonging to these dominant bacteria in healthy individuals were cultured and shown to inhibit the growth of cariogenic bacteria, suggesting the use of these commensal bacterial strains as probiotics to promote oral health and prevent dental caries.

Increasing evidence has suggested an independent association between periodontitis and a range of comorbidities, for example cardiovascular disease, type 2 diabetes, rheumatoid arthritis, osteoporosis, Parkinson's disease, Alzheimer's disease, psoriasis, and respiratory infections. Shared inflammatory pathways are likely to contribute to this association, but distinct causal mechanisms remain to be defined. Some of these comorbid conditions may improve by periodontal treatment, and a bidirectional relationship may exist, where, for example, treatment of diabetes can improve periodontal status. The present article presents an overview of the evidence linking periodontitis with selected systemic diseases and calls for increased cooperation between dentists and medical doctors to provide optimal screening, treatment, and prevention of both periodontitis and its comorbidities.

Introduction: Alkaline-tolerant bacteria in primary infected
root canals could have enhanced survival capacity
against antimicrobials commonly used in root canal
treatment. The aims of this study were to isolate and
characterize alkaline-tolerant bacteria before endodontic
treatment (S1), after chemomechanical root canal
preparation (S2), and after calcium hydroxide dressing
(S3). Methods: Bacteriologic samples were obtained
from 43 primary infected root canals. Samples were
inoculated into culture media at a pH of 9 and incubated
anaerobically. The identities of bacterial isolates were
determined by 16S ribosomal RNA sequencing. Results:
All S1 samples were culture positive, with 70%
harboring bacteria tolerating a pH of 9. Gram-positive
bacteria Pseudoramibacter alactolyticus and
Streptococcus spp were the most frequently isolated
strains with a prevalence of 54%. Of 13 culture-positive
S2 samples, 8 isolates tolerated a pH of 9, namely
Streptococcus sanguinis, Enterococcus faecalis,
Enterobacter cancerogenus, Streptococcus
oralis, and Fusobacterium nucleatum. Seven of
these 8 isolates (88%) were correspondingly isolated
at S1. All 3 culture-positive S3 samples tolerated a pH
of 9, namely S. sanguinis and E. faecalis, which
were also isolated in the corresponding S1 and S2 samples.
Conclusions: We showed that the presence of
alkaline-tolerant Streptococcus and Enterococcus
spp in primary infected root canals could lead to their
persistence during and after root canal treatment and
could pose a challenge to current treatment efficacy.

The emerging antifungal resistance of Candida species along with the toxicity contained within some of these drugs has necessitated the discovery and application of new treatment modalities and the re-evaluation of age-old traditional remedies. The objective of this study was to test the antifungal activity of 7-Methyljuglone against Candida species showing resistance to fluconazole. Candida species were collected from patients attending a diabetes clinic in Misrata Diabetes Centre in Libya. Candida species were identified by culture on selective and chromogenic media and by API ID 32C biochemical testing. Antimicrobial susceptibility testing of the isolates to the antifungal fluconazole was performed using disk diffusion. The assay was performed using broth microdilution method with a 25 μg/ml fluconazole as a positive control. Of the 194 Candida isolates, 41 (21.13%) isolates were fluconazole resistant, 70 species were identified as C. albicans, 5 of them are resistance to fluconazole (2.57%). All 5 isolates of C. krusei are resistance to fluconazole, and 19 of 21 C. glabrate are resistance (9.79%). In total, 41 species are resistance to fluconazole, and 32 species are intermediate-resistance (16.49%). The results showed high activity of 7-Methyljuglolne with MIC’s ranging between 25 μg/ml - 0.390 μg/ml. These findings emphasize the crucial need for accurate screening, identification and susceptibility testing to prevent further spread of nosocomial and community acquired resistance. The antifungal effect of 7-Methyljuglone from Euclea natalensis was evaluated as an alternative bioactive agent for azole-resistant oral Candida species in DM patients.

Objective: The presence and survival of microorganisms on toothbrush bristles might play a role on the etiology of oral infections. The aim of this in vitro study was to evaluate the presence of bacterial contamination on new toothbrushes before oral contact. Materials and methods: Forty toothbrushes from five different manufacturers were used in this experimental study. Each manufacturer was divided according to conventional local of obtaining: industry, drugstore, market, and perfumery. The toothbrush heads were completely immersed into tubes containing 5.0 mL of sterile peptonated water (dilution 1:10). A group of eight tubes containing the sterile solution was used as control. After 21 days of anaerobic incubation, occurrence of contamination was visually evaluated and confirmed by light microscopy. Results: Bacterial growth in the medium, indicative of bristles contamination, was found in a total of 19 out of 40 samples (47.5%) evaluated: 6 out of 14 samples (42.85%) from industry group, 4 out of 8 samples (50.0%) from drugstore, 5 out of 10 samples (50.0%) from market, and 4 out of 8 samples (50.0%) from perfumery. Only the toothbrushes with bristles coated with chlorhexidine did not show contamination. The Gram-negative sporulating bacilli were the most prevalent form recovered. Conclusions: Except for chlorhexidine group, bacterial growth was observed in all groups evaluated irrespective local of obtaining. Microsc. Res. Tech. 00:000-000,

Introduction: Microorganisms are able to survive and induce persistent infection in periapical tissues. The aim of this study was to investigate the composition of the microflora of persistent apical periodontitis lesions. Methods: Twenty-one apical lesion samples were obtained from 21 patients with chronic apical periodontitis by root end surgery and processed using aerobic or anaerobic culture techniques. All i solated strains were identified by 16S rDNA sequence analysis. Results: Seventy-four strains were isolated, belonging to 31 bacterial species obtained from the 20 apical lesions were isolated. The majority of the strains were facultative anaerobes (51.6%). Propionibacterium acnes, Staphylococcus epidermidis, P. aeruginosa and Fusobacterium nucleatum were isolated in 16.2%, 9.5%, 6.8% and 5.4% of the samples, respectively. Fifteen samples harboured more than one species. The predominant association was Propionibacterium acnes, Staphylococcus epidermidis and Fusobacterium nucleatum. Conclusion: The microbiota of persistent apical periodontitis lesions is composed by diverse types of microorganism with biofilm-forming capacity including P. acnes, S. epidermidis and F. nucleatum.

Next-generation sequencing technologies have revolutionized the analysis of microbial communities in diverse environments, including the human body. This article reviews several aspects of one of these technologies, the pyrosequencing technique, including its principles, applications, and significant contribution to the study of the human microbiome, with especial emphasis on the oral microbiome. The results brought about by pyrosequencing studies have significantly contributed to refining and augmenting the knowledge of the community membership and structure in and on the human body in healthy and diseased conditions. Because most oral infectious diseases are currently regarded as biofilm-related polymicrobial infections, highthroughput sequencing technologies have the potential to disclose specific patterns related to health or disease. Further advances in technology hold the perspective to have important implications in terms of accurate diagnosis and more effective preventive and therapeutic measures for common oral diseases.

Very recently, we discovered a vast new microbial self: the human microbiome. Our native microbiota interface with our biology and culture to influence our health, behavior, and quality of life, and yet we know very little about their origin, evolution, or ecology. With the advent of industrialization, globalization, and modern sanitation, it is intuitive that we have changed our relationship with microbes, but we have little information about the ancestral state of our microbiome, and we therefore lack a foundation for characterizing this change. High-throughput sequencing has opened up new opportunities in the field of paleomicrobiology, allowing us to investigate the evolution of the complex microbial ecologies that inhabit our bodies. By focusing on recent coprolite and dental calculus research, we explore how emerging research on ancient human microbiomes is changing the way we think about ancient disease and how archaeological studies can contribute to a medical understanding ...

Unlike other human microbiomes, the oral microbiome will cause disease in a majority of people during their lifetime, suggesting that it is currently in a state of dysbiosis rather than symbiosis 1,2. The human oral microbiome comprises more than 2,000 bacterial taxa, including a large number of opportunistic pathogens involved in periodontal, respiratory, cardiovascular and systemic diseases 3-7. Dental calculus, a complex, calcified bacterial biofilm formed from dental plaque, saliva and gingival crevicular fluid 8 , is emerging as a potential substrate for the direct investigation of the evolution of the oral microbiome and associated measures of oral health and diet 9,10. Recently, a DNA-based 16S rRNA phylotyping study identified the major bacterial phyla in dental calculus and argued for shifts in microbial diversity associated with the origins of agriculture and industrialization 11 , and, so far, five common oral bacteria have been identified in historic and prehistoric dental calculus using targeted PCR 12 , quantitative PCR (qPCR) 11 and immunohistochemistry 13. However, phylum-level community analysis and single-species targeted amplification are insufficient to characterize oral health and disease states, as this requires a deeper taxonomic and functional understanding of microbiome ecology 14. We present the first detailed analysis to our knowledge of ancient oral microbiome ecology and function at the genus and species levels, leading to a deeper understanding of recent evolution of the human oral microbiome. Focusing on the dental tissues of four adult human skeletons (G12, B17, B61 and B78) with evidence of mild to severe periodontal disease from the medieval monastic site of Dalheim, Germany (c. 950-1200 CE) (Supplementary Fig. 1), as well as modern dental calculus from nine individuals with known dental histories, we demonstrate for the first time, to our knowledge, that the human oral microbiome has long served as a

Aim. This study investigated the effect of Dodonaea viscosa var. angustifolia (DVA) on the virulence properties of cariogenic Streptococcus mutans and Porphyromonas gingivalis implicated in periodontal diseases. Methods. S. mutans was cultured in tryptone broth containing a crude leaf extract of DVA for 16 hours, and the pH was measured after 10, 12, 14, and 16 h. Biofilms of S. mutans were grown on glass slides for 48 hours and exposed to plant extract for 30 minutes; the adherent cells were reincubated and the pH was measured at various time intervals. Minimum bactericidal concentration of the extracts against the four periodontal pathogens was determined. The effect of the subinhibitory concentration of plant extract on the production of proteinases by P. gingivalis was also evaluated. Results. DVA had no effect on acid production by S. mutans biofilms; however, it significantly inhibited acid production in planktonic cells. Periodontal pathogens were completely eliminated at low concentrations ranging from 0.09 to 0.02 mg/mL of crude plant extracts. At subinhibitory concentrations, DVA significantly reduced Arg-gingipain (24%) and Lys-gingipain (53%) production by P. gingivalis (í µí±ƒ ≤ 0.01). Conclusions. These results suggest that DVA has the potential to be used to control oral infections including dental caries and periodontal diseases.

In Mexico, more than 80% of the population is infected with Helicobacter pylori. The frequency of H. pylori detection in the oral cavity is unknown, as its relationship with gastroesophageal pathology. To detect the presence of H. pylori in the oral cavity in Mexican population by PCR and to determine its association with gastroesophageal disease. Patients were divided into two groups with different clinic conditions from whom gastric biopsy, dental plaque, and saliva samples were taken and analyzed. The first group comprised of hospitalized patients, the majority of whom were diagnosed with gastroesophageal disease, while the second group was selected from a dental clinic (ambulatory population) the majority of whom appeared to be healthy subjects. H. pylori was detected in gastric biopsy, dental plaque and saliva samples by PCR using a set of specific primers for the signal sequence of the vacuolating cytotoxin gene; detection of H. pylori in general was higher in gastric biopsy and dental plaque samples than in saliva samples. Detection of H. pylori in the oral cavity is significantly (P = 0.0001) associated with patients presenting gastroesophageal disease, while healthy subjects and those with other non-gastric disease do not present with H. pylori in their oral cavity. H. pylori detection in the oral cavity is associated to gastroesophageal disease. In addition, it is suggested that all patients presenting gastric symptoms and H. pylori detection in the oral cavity would begin bacterial treatment immediately.

For many years, a common and painful oral mucosal ulcer termed as "Recurrent Aphthous Stomatitis" remains a mystery affecting the oral cavity as a whole. Its etiopathogenesis is still unclear though its prevalence is high. Researchers, dental practitioners have been trying to reveal its underlying secrets that have been creating a major drawback in the treatment strategy but in the end it remains the same. In this article, we have tried to describe briefly about the etiology and clinical features of recurrent aphthous stomatitis along with the diagnosis and management options by searching out the literatures available until now.

Background/aim: To examine the proportions of 40 bacterial species in samples from 8 oral soft tissue surfaces and saliva in systemically healthy adult subjects and to compare these microbiotas with those of supra- and subgingival plaque.
Methods: Microbial samples were taken from 8 oral soft tissue surfaces of 225 systemically healthy subjects using a ‘‘buccal brush’’. Saliva was taken by expectoration. Forty-four of these subjects provided additional supra- and subgingival plaque samples. Samples were individually evaluated for their content of 40 bacterial species using checkerboard DNA–DNA hybridization. The percentage of total DNA probe count was determined for each species, at each sample location and averaged across subjects. The significance of differences among the proportions of the 40 test species at different sample locations was sought in the 225 and 44 subjects separately using the Quade test and adjusted for multiple comparisons. Cluster analysis was performed using the proportions of the 40 species at the different sample locations using the minimum similarity coefficient and an average unweighted linkage sort. The proportions of each species were averaged across subjects in the resulting cluster groups and the significance of differences was tested using the t-test and ANOVA.
Results: Microbial profiles differed markedly among sample locations in the 225 subjects, with 34 of 40 species differing significantly. Proportions of Veillonella parvula and Prevotella melaninogenica were higher in saliva and on the lateral and dorsal surfaces of the tongue, while Streptococcus mitis and S. oralis were in significantly lower proportions in saliva and on the tongue dorsum. Cluster analysis resulted in the formation of 2 clusters with >85% similarity. Cluster 1 comprised saliva, lateral and dorsal tongue surfaces, while Cluster 2 comprised the remaining soft tissue locations. V. parvula, P. melaninogenica, Eikenella corrodens, Neisseria mucosa, Actinomyces odontolyticus, Fusobacterium periodonticum, F. nucleatum ss vincentii and Porphyromonas gingivalis were in significantly higher proportions in Cluster 1 and S. mitis, S. oralis and S. noxia were significantly higher in Cluster 2. These findings were confirmed using data from the 44 subjects providing plaque samples. The microbial profiles of supra- and subgingival plaque differed from the other sample locations, particularly in the increased proportions of the Actinomyces species. Species of different genera exhibited different proportions on the various intraoral surfaces, but even within the genus Streptococcus, there were differences in colonization patterns. S. oralis, S. mitis and S. constellatus colonized the soft tissues and saliva in higher proportions than the samples from the teeth, while the other 4 streptococcal species examined colonized the dental surfaces in proportions comparable to the soft tissue locations and saliva.
Conclusions: Proportions of bacterial species differed markedly on different intraoral surfaces. The microbiota of saliva was most similar to that of the dorsal and lateral surfaces of the tongue. The microbiotas of the soft tissues resembled each other more than the microbiotas that colonized the teeth both above and below the gingival margin.

Genes are transferred between bacteria in dental plaque by transduction, conjugation, and transformation. Membrane vesicles can also provide a mechanism for horizontal gene transfer. DNA transfer is considered bacterial sex, but the transfer is not parallel to processes that we associate with sex in higher organisms. Several examples of bacterial gene transfer in the oral cavity are given in this review. How frequently this occurs in dental plaque is not clear, but evidence suggests that it affects a number of the major genera present. It has been estimated that new sequences in genomes established through horizontal gene transfer can constitute up to 30% of bacterial genomes. Gene transfer can be both inter-and intrageneric, and it can also affect transient organisms. The transferred DNA can be integrated or recombined in the recipient's chromosome or remain as an extrachromosomal inheritable element. This can make dental plaque a reservoir for antimicrobial resistance genes. The ability to transfer DNA is important for bacteria, making them better adapted to the harsh environment of the human mouth, and promoting their survival, virulence, and pathogenicity.

Background: In Mexico, more than 80% of the population is infected with Helicobacter pylori. The frequency of H. pylori detection in the oral cavity is unknown, as its relationship with gastroesophageal pathology. Aim: To detect the presence of H. pylori in the oral cavity in ...

Few studies have focused on the bacterial species associated with the deterioration of the dental and gingival health of children with congenital heart defects (CHD). The aims of this study were (1) to examine the dental plaque of children with CHD in order to quantify bacterial load and altered bacterial composition compared with children without CHD; and (2) to investigate the correlation between the level of caries and gingivitis and dental biofilm bacteria among those children. In this cross-sectional study, participants were children (3-12 years) recruited in Khartoum State, Sudan. A total of 80 CHD cases from the Ahmed Gasim Cardiac Centre and 80 healthy controls from randomly selected schools and kindergartens were included. Participants underwent clinical oral examinations for caries (decayed, missing, and filled teeth indices [DMFT] for primary dentition, and DMFT for permanent dentition), and gingivitis (simplified gingival index [GI]). Pooled dental biofilm samples were o...

Salivary protein levels have been studied in periodontitis. However, there is lack of information on salivary cytokine levels in early gingival inflammation. The aim of this study was to determine salivary levels of vascular endothelial growth factor (VEGF), interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1, IL-1β, and IL-1 receptor antagonist (IL-1Ra) in gingival inflammation. Twenty-eight systemically and orally healthy nonsmokers abstained from oral hygiene protocols for 10 days. After that, self-performed cleaning was resumed for 14 days. Plaque and gingival indexes were measured, and saliva samples were collected at days 1, 4, 7, 10, and 24. Salivary cytokines were detected with Luminex®-xMAP™. Salivary IL-1β, IL-1Ra, and VEGF levels decreased after 10 days' development of experimental gingivitis and reached baseline levels at the end of the 2-week resolution period. Salivary IL-8 levels decreased and remained low during development and resolution of experimental gingivitis. Initial inflammation in gingival tissues is associated with a decrease in inflammatory cytokines in saliva. Further studies are needed to evaluate if inflammatory cytokines bind to their functional receptors within the gingival tissue during early gingivitis, which may limits their spillover to the gingival crevice and ultimately saliva.

This study evaluated the influence of the exposure of mineral trioxide aggregate (MTA) - with and without calcium chloride (CaCl2) - to phosphate-buffered saline (PBS) on apical microleakage. Sixty root segments were divided into 4 experimental groups (n=15). Apical cavities were filled with MTA with or without CaCl2, and the root canals dressed with a moistened cotton pellet or PBS: 1) MTA/cotton pellet; 2) MTA/PBS; 3) MTA+ 10%CaCl2/cotton pellet; 4) MTA+10%CaCl2/PBS. After 2 months, E. faecalis penetration was analyzed along the apical plugs. Samples were observed weekly for 70 days, and leakage was detected by turbidity of the medium in contact with the root segment. Teeth in the control groups (n=2) were either made
RESUMO
O presente estudo avaliou a influência da exposição do agregado de trióxido mineral (MTA) – com e sem cloreto de cálcio (CaCl2) – ao tampão fosfato-salino (PBS) sobre a microinfiltração apical. Sessenta segmentos radiculares foram divididos em 4 grupos experimentais (n=15). As cavidades apicais foram preenchidas com MTA, com ou sem CaCl2, e os canais radiculares receberam uma bolinha de algodão umedecida ou PBS, como medicação intracanal: 1) MTA/ bolinha de algodão umedecida; 2) MTA/PBS; 3) MTA+10% CaCl2/ bolinha de algodão umedecida; 4) MTA+10%CaCl2/PBS. Após 2 meses, a penetração de E. faecalis ao longo dos plugs apicais foi avaliada. As amostras foram observadas semanal- mente durante 70 dias e a infiltração detectada através da turbidez do meio em contato com os segmentos radiculares.
completely impermeable or kept without an apical plug. The Kaplan–Meier method was used to analyze survival and the Log- rank test was used to compare the survival curves (p<0.05). All specimens in the positive control group showed evidence of leakage within 24h, while none in the negative control group showed leakage up to 70 days. There was no statistically significant difference among the experimental groups (p=0.102). The use of PBS as intracanal dressing may improve MTA sealing ability, but cannot prevent bacterial leakage. The addition of CaCl2 to the MTA did not improve MTA sealing ability.

This study compared salivary bacterial profiles in two groups having a 10-fold difference in levels of caries experience, as it was hypothesized that the composition of the salivary microbiota might associate with the levels of caries experience. Bacterial profiles in stimulated saliva samples from 85 individuals with low levels of caries experience (healthy group) and 79 individuals with high levels of caries experience (caries group) were analyzed by means of the Human Oral Microbiome Identification Next Generation Sequencing (HOMINGS) technique. Subsequently, saliva samples from caries-free individuals in the healthy group (n = 57) and the caries group (n = 31) were compared. A significantly higher α-diversity (p < 0.0001) and a twofold higher relative abundance of Neisseria, Haemophilus, and Fusobacterium were recorded in saliva samples from the healthy group compared with the caries group. Differences observed were more pronounced when limiting the analyses to caries-free individuals in each group. Data from this cross-sectional analysis suggest that low levels of caries experience might associate with a characteristic salivary bacterial composition different from that in individuals with high caries experience. Consequently, longitudinal studies are required to determine if the composition of the salivary microbiota might be a predictive factor of caries risk at the individual level.

The aim of this longitudinal study was to determine salivary levels of total IgA, IgG and IgM in 84 preterm and 214 full-term infants, from birth to 18 months of age. Unstimulated whole saliva was collected from each infant at birth, and subsequently at 3-monthly intervals. Immunoglobulin levels were estimated using an ELISA technique. At birth, IgA was detected in 147/214 (69%) full-term infants but only 47/84 (56%) preterm infants (P &amp;lt; 0.01). In the case of IgG, 61% of full-term and 56% of preterm infants showed detectable levels, whereas IgM was found in 71% and 73%, respectively. Levels of IgA and IgG rose from birth to 18 months, whereas IgM levels did not change significantly. Increases in salivary levels of IgA were associated with introduction of solid foods (P &amp;lt; 0.001), as well as tooth eruption (P &amp;lt; 0.001). Our results indicate that the majority of full-term and preterm infants are orally immunocompetent at birth.