Association of red complex, A. actinomycetemcomitans and non-oral bacteria with periodontal diseases

Altered oral microbiota of drug-resistant organism carriers exhibit impaired gram-negative pathogen inhibition

The oral microbiome has been understudied as a reservoir for clinical pathogens, including drug-resistant strains. Understanding how alterations in microbiome functioning render this site vulnerable to colonization is essential, as multidrug-resistant organisms (MDRO) carriage is a major risk factor for developing serious infections. To advance our knowledge of oral MDRO carriage and protection against pathogen colonization conferred by native microbiota, we examined microbiomes from individuals colonized by MDROs (n=33) and non-colonized age-matched controls (n=30). Shotgun metagenomic analyses of oral swabs from study participants revealed significant differences in microbial communities with depletion of Streptococcus spp. among those colonized by multidrug-resistant gram-negative bacilli (RGNB), compared to non-carriers. We utilized metagenomic sequencing to characterize the oral resistome and find antimicrobial resistance genes are present in higher abundance among RNGB carriers versus non-carriers. High-throughput co-culture screening revealed oral bacteria isolated from MDRO non-carriers demonstrate greater inhibition of gram-negative pathogens, compared to isolates from carriers. Moreover, biosynthetic gene clusters from streptococci are found in higher abundance from non-carrier microbiomes, compared to RGNB carrier microbiomes. Bioactivity-guided fractionation of extracts from Streptococcus isolate SID2657 demonstrated evidence of strong E. coli and A. baumannii inhibition in a murine model of infection. Together, this provides evidence that oral microbiota shape this dynamic microbial community and may serve as an untapped source for much-needed antimicrobial small-molecules.

Analysis of in vitro expression of virulence genes related to antibiotic and disinfectant resistance in Escherichia coli as an emerging periodontal pathogen

The collective involvement of virulence markers of Escherichia coli as an emerging pathogen associated with periodontitis remains unexplained. This study aimed to implement an in vitro model of infection using a human epithelial cell line to determine the virulome expression related to the antibiotic and disinfectant resistance genotype and pulse field gel electrophoresis (PFGE) type in E. coli strains isolated from patients with periodontal diseases. We studied 100 strains of E. coli isolated from patients with gingivitis (n = 12), moderate periodontitis (n = 59), and chronic periodontitis (n = 29). The identification of E. coli and antibiotic and disinfectant resistance genes was performed through PCR. To promote the expression of virulence genes in the strains, an in vitro infection model was used in the human epithelial cell line A549. RNA was extracted using the QIAcube robotic equipment and reverse transcription to cDNA was performed using the QuantiTect reverse transcription kit (Qiagen). The determination of virulence gene expression was performed through real-time PCR. Overall, the most frequently expressed adhesion genes among the isolated strains of gingivitis, moderate periodontitis, and chronic periodontitis were fimH (48%), iha (37%), and papA (18%); those for toxins were usp (33%); those for iron acquisition were feoB (84%), fyuA (62%), irp-2 (61%), and iroN (35%); those for protectins were traT (50%), KpsMT (35%), and ompT (28%); and those for pathogenicity islands were malX (45%). The most common antibiotic and disinfectant resistance genes among gingivitis, moderate periodontitis, and chronic periodontitis strains were sul-2 (43%), blaSHV (47%), blaTEM (45%), tet(A) (41%), dfrA1 (32%), marR-marO (57%), and qacEA1 (79%). The findings revealed the existence of a wide distribution of virulome expression profiles related to the antibiotic and disinfectant resistance genotype and PFGE type in periodontal strains of E. coli. These findings may contribute toward improving the prevention and treatment measures for periodontal diseases associated with E. coli.

Molecular Genetic Analysis of Perioperative Colonization by Infection-Related Microorganisms in Patients Receiving Intraoral Microvascular Grafts

Background/Objectives: In oral and maxillofacial surgery, the reconstruction of defects often involves the transfer of skin tissue into the oral cavity utilizing microvascular grafts. This study investigates postoperative changes in microbial colonization following intraoral microvascular transplantation, as well as potential influencing factors. Methods: In 37 patients undergoing intraoral reconstructions, pre- and postoperative swabs were taken from the donor and recipient regions to quantify the seven selected marker bacteria using TaqMan PCRs. Patient-specific factors and clinical data were also recorded. Results: The infection-associated Acinetobacter baumannii tended to decrease postoperatively, while the infectious pathogens Pseudomonas aeruginosa, Enterococcus faecalis and the family of Enterobacteriaceae showed a postoperative increase without being directly associated with a clinical infection. Streptococcus mitis showed a significant postoperative decrease on buccal mucosa and increase on the graft surface (oral dysbiosis) and was significantly reduced or displaced by other bacteria (e.g., Mycoplasma salivarium, positive selection) when treated with ampicillin/sulbactam. Conclusions: The cutaneous microbiome of the graft adapts to the local intraoral environment. Postoperative shifts in oral bacterial colonization and an increase in infection-relevant bacteria were observed. These perioperative changes in colonization are also influenced by the administration of ampicillin/sulbactam. Consequently, single doses of antibiotics appear to be more beneficial compared to longer-term preventive use.

Influence of METTL3 knockdown on PDLSC osteogenesis in E. coli LPS-induced inflammation

OBJECTIVE

This study aimed to investigate the effect of METTL3 knockdown on osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) in the weak inflammation microenvironments, as well as the underlying mechanisms.

MATERIALS AND METHODS

PDLSCs were stimulated by lipopolysaccharide from Escherichia coli (E. coli LPS), followed by quantification of METTL3. METTL3 expression was assessed using RT-qPCR and Western blot analysis in periodontitis. METTL3 knockdown PDLSCs were stimulated with or without E. coli LPS. The evaluation included proinflammatory cytokines, osteogenic markers, ALP activity, and mineralized nodules. Bioinformatics analysis and Western blot determined the association between METTL3 and the PI3K/Akt pathway.

RESULTS

METTL3 was overexpressed in periodontitis. METTL3 knockdown in PDLSCs reduced proinflammatory cytokines, osteogenic markers, ALP activity, and mineralized nodules in both environments. Bioinformatics analysis suggested a link between METTL3 and the PI3K/Akt pathway. METTL3 knockdown inhibited PI3K/Akt signaling pathway activation.

CONCLUSION

METTL3 knockdown might inhibit osteogenesis in PDLSCs through the inactivation of PI3K/Akt signaling pathway. Concomitant findings might shed novel light on the roles and potential mechanisms of METTL3 in the LPS-stimulated inflammatory microenvironments of PDLSCs.

Acinetobacter baumannii as an oro-dental pathogen: a red alert!!

OBJECTIVES

This review highlights the existence and association of Acinetobacter baumannii with the oro-dental diseases, transforming this systemic pathogen into an oral pathogen. The review also hypothesizes possible reasons for the categorization of this pathogen as code blue due to its stealthy entry into the oral cavity.

METHODOLOGY

Study data were retrieved from various search engines reporting specifically on the association of A. baumannii in dental diseases and tray set-ups. Articles were also examined regarding obtained outcomes on A. baumannii biofilm formation, iron acquisitions, magnitude of antimicrobial resistance, and its role in the oral cancers.

RESULTS

A. baumannii is associated with the oro-dental diseases and various virulence factors attribute for the establishment and progression of oro-mucosal infections. Its presence in the oral cavity is frequent in oral microbiomes, conditions of impaired host immunity, age related illnesses, and hospitalized individuals. Many sources also contribute for its prevalence in the dental health care environment and the presence of drug resistant traits is also observed. Its association with oral cancers and oral squamous cell carcinoma is also evident.

CONCLUSIONS

The review calls for awareness on the emergence of A. baumannii in dental clinics and for the need for educational programs to monitor and control the sudden outbreaks of such virulent and resistant traits in the dental health care settings.

Redox biomarkers in saliva and nuclear abnormalities in jugal epithelial cells of individuals with type 2 diabetes mellitus and periodontitis

OBJECTIVE

To evaluate salivary redox biomarkers levels in individuals with periodontitis and type 2 diabetes mellitus (T2DM) and correlate with periodontal parameters and nuclear alterations in epithelial cells from jugal mucosa.

DESIGN

Sixty individuals were categorized into three groups: T2DM with periodontitis (DM, n = 20), non-T2DM with periodontitis (PE, n = 20), and non-T2DM with periodontal health (HC, n = 20). All participants underwent fasting blood glucose and glycated hemoglobin measurements. After a periodontal examination, samples of epithelial cells from the jugal mucosa and saliva were collected. DNA damage was assessed by counting nuclear abnormalities using cytological analysis. Biomarkers of oxidative stress were determined through biochemical methods. Significant differences among groups were assessed using Kruskal-Wallis, Mann-Whitney, and Chi-square tests at a 5% significance level. Data were analyzed using Spearman's correlation coefficient, linear regression, and logistic regression.

RESULTS

Frequencies of nuclear abnormalities, as well as levels of reduced glutathione and uric acid, were significantly higher in the DM group compared to the PE and HC groups (p < 0.05). Fasting glucose, glycated hemoglobin, nuclear abnormalities, reduced glutathione, and uric acid exhibited positive correlations with periodontal parameters (p < 0.05). Furthermore, reduced glutathione was associated with dental biofilm (OR = 1.027 [95% CI, 1.004-1.049]) and condensed chromatin (OR = 0.415 [95% CI, 0.196-0.878]).

CONCLUSIONS

Periodontitis and T2DM are correlated with nuclear abnormalities, as well as salivary reduced glutathione and uric acid levels. Moreover, a higher prevalence of teeth with dental biofilm increases the likelihood of elevated levels of reduced glutathione in saliva, while the presence of condensed chromatin decreases that likelihood.

Comparative analysis of antibodies to four major periodontal bacteria in respiratory diseases: a cohort study

OBJECTIVES

To make a descriptive comparison of antibodies to four major periodontal bacteria and their relation to the respiratory diseases asthma and bronchitis/emphysema, and to cancer incidence.

METHODS

The serum of a random sample of men with no history of cancer incidence (n=621) was analysed by the ELISA method for antibody levels of four periodontal bacteria; the anaerobes of the so-called red complex Tannerella forsythia (TF), Porphyromonas gingivalis (PG), and Treponema denticola (TD), and the facultative anaerobe Aggregatibacter actinomycetemcomitans (AA). The antibody readings were divided into quartiles and the distribution of cases of the relevant diseases as compared with the non-cases. Comparisons of the quartile distributions were by the Pearson χ2 test. Data and serum from the Oslo II study of Norwegian men from 2000 were used. The ELISA analyses were performed on thawed frozen serum. Cancer data from 17.5 years of follow-up were provided by the Norwegian Cancer Registry.

RESULTS

In all, 52 men had reported asthma and 23 men had bronchitis/emphysema at the health screening. Results on cancer incidence are given for all respiratory cancers, n=23, and bronchi and lung cancers separately, n=18. Stratified analyses were performed for the four endpoints showing significant association with low levels of TD antibodies for bronchitis; p=0.035. Both TF and TD were significant for low levels of antibodies among daily smokers; p=0.030 for TF and p<0.001 for TD in the analysis of the full study sample. For PG and AA, no such associations were observed. An association with respiratory cancers was not observed.

CONCLUSION

A low level of TD was associated with bronchitis/emphysema compared with the rest of the cohort. In the total study sample, low levels of antibodies to both TF and TD were associated with daily smoking.

Bacteriome analysis of Aggregatibacter actinomycetemcomitans-JP2 genotype-associated Grade C periodontitis in Moroccan adolescents

Background

Grade C (previously aggressive) periodontitis (GCP) in adolescents is prevalent in certain parts of Africa where it is associated with JP2 genotype, a highly virulent strain of Aggregatibacter actinomycetemcomitans. The aim of this study was to characterize the subgingival bacteriome in Moroccan subjects with GCP positive to A. actinomycetemcomitans JP2 genotype.

Methods

Subgingival plaque samples were collected from shallow and deep pockets of 8 subjects with GCP (17.2 ± 1.5 years) and from gingival sulci of 13 controls with no periodontitis (14.6 ± 1.1 years). Identification and genotyping of A. actinomycetemcomitans was performed using PCR analysis of the ltx operon, while bacteriome profiling was done by 16S rRNA gene sequencing (V1-V3 region). Groups were compared in terms of microbial diversity, abundances, and dysbiosis.

Results

The shallow and deep pocket sites from GCP cases had a significantly altered microbial composition compared to controls. Species associated with health included Haemophilus parainfluenzae, Lautropia mirabilis, Streptococcus spp., Gemella spp., and Rothia spp. While known periodontal pathogens, including Porphyromonas gingivalis, Tannerella forsythia, Treponema spp. and Fretibacterium spp., were significantly enriched in GCP, non-conventional taxa, including Pseudomonas oral taxon C61 and Enterobacter cloacae were more abundant and showed stronger association with the disease. Less significant differences in abundances of individual taxa were observed between shallow and deep pockets. Overall dysbiosis measured in terms of Subgingival Microbial Dysbiosis Index (SMDI) differentiated between GCP and no-periodontitis with 95% accuracy.

Conclusions

The results suggest that several periodontal pathogens involved in the adult-type periodontitis also play a role in JP2 genotype-associated GCP. The potential role of non-conventional taxa in the pathogenesis of GCP warrants further investigation.

Antibacterial efficacy of epigallocatechin-3-gallate cross-linked small intestinal submucosa guided bone regeneration membrane

The leading cause of guided bone regeneration (GBR) failure is infection. Herein, we developed a new GBR membrane with good mechanical and osteogenic properties by crosslinking the small intestinal submucosa (SIS) with epigallocatechin-3-gallate (EGCG). Meanwhile, EGCG is also a natural antibacterial agent. This study aimed to investigate the antibacterial efficacy of EGCG-crosslinked SIS (E-SIS) against Staphylococcus aureus and Escherichia coli through EGCG release, bacterial count, live/dead staining, scanning electron microscopy, growth curve, and biofilm formation tests. The results showed that E-SIS effectively inhibited bacteria's growth and adhesion, and its antibacterial activity against Staphylococcus aureus was stronger than that against Escherichia coli. 0.5% E-SIS had the most potent antibacterial activity. The antibacterial mechanism of E-SIS might be related to the release of EGCG and the surface properties of E-SIS. In conclusion, 0.5% E-SIS is a promising GBR membrane with good osteogenic and antibacterial properties.

Effects of hypochlorous acid mouthwash on salivary bacteria including Staphylococcus aureus in patients with periodontal disease: a randomized controlled trial

BACKGROUND

The effects of a low concentration of hypochlorous acid (HOCl) mouthwash on salivary bacteria remained unclear. We aimed to evaluate the antibacterial effects of 100 ppm HOCl mouthwash on salivary bacteria, including Staphylococcus aureus (S. aureus), in patients with periodontal disease (PD).

METHODS

Patients with PD were randomized into mouthwash-only (MW, n = 26) and mouthwash with periodontal flosser (MWPF, n = 27) groups. Patients without PD were selected for the control group (n = 30). S. aureus culture and saliva samples (before and after the intervention) were collected for bacterial DNA extraction. A real-time polymerase chain reaction assay and serial dilutions of S. aureus culture and saliva samples were used to measure the salivary bacteria total count (SBTC) and confirm the antibacterial effects of the mouthwash using S. aureus.

RESULTS

No significant difference in demographic data was observed among the three groups. Before the intervention, the baseline SBTC of the MW and MWPF groups was significantly higher than that of the control group. After the mouthwash rinses, the SBTC data significantly changed in the MW and MWPF groups only (by 62.4% and 77.4%, respectively). After the base-2 log-transformation of the SBTC data, a similar trend was observed. Linear regression revealed that baseline SBTC and the MWPF intervention significantly affected SBTC reduction percentage by volume. After incubation with 10% (v/v) of mouthwash, the survival rates of 106 and 107 colony-forming units/mL of S. aureus were 0.51% ± 0.06% and 1.42% ± 0.37%, respectively.

CONCLUSIONS

These study results indicated that 100 ppm HOCl mouthwash treatment could effectively reduce SBTC in patients with PD and the abundance of S. aureus. It provides that the HOCl mouthwash can be an option for individuals to help control SBTC, especially in patients with PD.

TRIAL REGISTRATION

The study protocol was approved by the Institutional Review Board of Kaohsiung Medical University Hospital (KMUHIRB-F(I)-20200042) on 20/03/2020 and retrospectively registered at ClinicalTrial.gov (NCT05372835) on 13/05/2022.

Comparative proteomics of saliva of healthy and gingivitis individuals from Rio de Janeiro

PURPOSE

In this work, we identified human and bacterial proteomes in the saliva from volunteers with gingivitis or healthy.

EXPERIMENTAL DESIGN

The reported population consisted of 18 volunteers (six with gingivitis and 12 healthy controls). Proteomics characterization was performed using a quantitative mass spectrometry method.

RESULTS

A total of 74 human and 116 bacterial proteins were identified in saliva. The major functional category that was modified in the human proteome was the immune response, followed by transport and protease inhibition. In the bacterial proteome, most of the proteins identified were from the Fusobacteria phylum, followed by Chlamydiae and Spirochaetes.

CONCLUSIONS AND CLINICAL RELEVANCE

We observed statistically relevant differences in the data between the groups. The 15 most important human proteins affecting the variation between case and control groups included cystatin S, alpha amylase, lactotransferrin, and negative elongation factor E. We found that bacterial proteins from Porphyromonas gingivalis and Fusobacterium nucleatum subsp. nucleatum related to the red and orange complexes were closely correlated with the occurrence of periodontal diseases.

Prevalence of Enterococcus species in adults with periodontal health or with periodontitis: a systematic review

The aim of this study was to evaluate the prevalence of Enterococcus species in the mouth of adults with periodontal health and periodontitis. A systematic search was made in databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The search for articles was conducted in Medline/PubMed, Latin American and Caribbean Health Sciences Literature Database (LILACS), Cochrane Library, Scopus, Embase, Web of Science databases and in the System of Information on Grey Literature in Europe (SINGLE) and included articles published in English up to April 25th, 2021. Observational studies in humans with and without periodontitis were evaluated to identify the prevalence of Enterococcus species. Articles that met the inclusion criteria were analyzed and classified to determine the quality rating in good, fair, and poor. A new detailed checklist for quality assessment was developed based on the information required for applicable data extraction in reviews. The study design, sample size, demographic data, periodontal clinical parameters, microbial analysis method, biological sample, prevalence of Enterococcus spp., and correlations with periodontal clinical parameters were assessed. After screening and full-text reading, 8 articles met the inclusion criteria. All selected studies showed a significantly higher prevalence of Enterococcus spp. in patients with periodontitis compared with periodontally healthy patients. Thus, the present systematic review suggests that the prevalence of Enterococcus faecalis in the mouth of periodontitis individuals is higher than that of periodontally healthy individuals.

Antimicrobial resistance and virulence of subgingival staphylococci isolated from periodontal health and diseases

The dysbiotic biofilm of periodontitis may function as a reservoir for opportunistic human pathogens of clinical relevance. This study explored the virulence and antimicrobial susceptibility of staphylococci isolated from the subgingival biofilm of individuals with different periodontal conditions. Subgingival biofilm was obtained from 142 individuals with periodontal health, 101 with gingivitis and 302 with periodontitis, and cultivated on selective media. Isolated strains were identified by mass spectrometry. Antimicrobial susceptibility was determined by disk diffusion. The mecA and virulence genes were surveyed by PCR. Differences among groups regarding species, virulence and antimicrobial resistance were examined by Chi-square, Kruskal-Wallis or Mann-Whitney tests. The overall prevalence of subgingival staphylococci was 46%, especially in severe periodontitis (> 60%; p < 0.01). S. epidermidis (59%) and S. aureus (22%) were the predominant species across groups. S. condimenti, S. hominis, S. simulans and S. xylosus were identified only in periodontitis. High rates of resistance/reduced sensitivity were found for penicillin (60%), amoxicillin (55%) and azithromycin (37%), but multidrug resistance was observed in 12% of the isolates. Over 70% of the mecA + strains in periodontitis were isolated from severe disease. Higher detection rates of fnB + isolates were observed in periodontitis compared to health and gingivitis, whereas luxF/luxS-pvl + strains were associated with sites with deep pockets and attachment loss (p < 0.05). Penicillin-resistant staphylococci is highly prevalent in the subgingival biofilm regardless of the periodontal status. Strains carrying virulence genes related to tissue adhesion/invasion, inflammation and cytotoxicity support the pathogenic potential of these opportunists in the periodontal microenvironment.

Newly identified pathogens in periodontitis: evidence from an association and an elimination study

We assessed the level of evidence for the presence of new periodontal pathogens by (i) comparing the occurrence of non-classical periodontal taxa between healthy vs. periodontitis patients (Association study); (ii) assessing the modifications in the prevalence and levels of these species after treatments (Elimination study). In the Association study, we compared the prevalence and levels of 39 novel bacterial species between periodontally healthy and periodontitis patients. In the Elimination study, we analyzed samples from periodontitis patients assigned to receive scaling and root planing alone or with metronidazole+ amoxicillin TID/ 14 days. Levels of 79 bacterial species (39 novel and 40 classic) were assessed at baseline, 3 and 12 months post-therapy. All samples were analyzed using Checkerboard DNA-DNA hybridization. Out of the 39 novel species evaluated, eight were categorized as having strong and four as having moderate association with periodontitis. Our findings suggest strong evidence supporting Lancefieldella rimae, Cronobacter sakazakii, Pluralibacter gergoviae, Enterococcus faecalis, Eubacterium limosum, Filifactor alocis, Haemophilus influenzae, and Staphylococcus warneri, and moderate evidence supporting Escherichia coli, Fusobacterium necrophorum, Spiroplasma ixodetis, and Staphylococcus aureus as periodontal pathogens. These findings contribute to a better understanding of the etiology of periodontitis and may guide future diagnostic and interventional studies.

Bacteria in the oral cavity of individuals consuming intoxicating substances

Food habits and oral hygiene are critical attributes for physiochemical environment of the oral cavity. Consumption of intoxicating substances such as betel nut ('Tamul'), alcohol, smoking and chewing tobacco may strongly influence the oral ecosystem including commensal microbes. Therefore, a comparative assessment of microbes in the oral cavity between individuals consuming intoxicating substances and non-consumers may indicate the influence of these substances. Oral swabs were collected from consumers of intoxicating substances and non- consumers of Assam, India, microbes were isolated by culturing on Nutrient agar and identified by phylogenetic analysis of their 16S rRNA gene sequences. The risks of consumption of intoxicating substance on occurrence of microbes and health conditions were estimated using binary logistic regression. Mostly pathogens and opportunistic pathogens were found in the oral cavity of consumers and oral cancer patients which included Pseudomonas aeruginosa, Serratia marcescens, Rhodococcus antrifimi, Paenibacillus dendritiformis, Bacillus cereus, Staphylococcus carnosus, Klebsiella michiganensis and Pseudomonas cedrina. Enterobacter hormaechei was found in the oral cavity of cancer patients but not in other cases. Pseudomonas sp. were found to be widely distributed. The risk of occurrence of these organisms were found in between 0.01 and 2.963 odds and health conditions between 0.088 and 10.148 odds on exposure to different intoxicating substances. When exposed to microbes, the risk of varying health conditions ranged between 0.108 and 2.306 odds. Chewing tobacco showed a higher risk for oral cancer (10.148 odds). Prolonged exposure to intoxicating substances conduce a favorable environment for the pathogens and opportunistic pathogens to colonize in the oral cavity of individuals consuming intoxicating substances.

Bacterial Detection, Deformation, and Torque Loss on Dental Implants with Different Tapered Connections Compared with External Hexagon Connection after Thermomechanical Cycling

The relationship between bacterial infiltration and internal conical Implant-Abutment Interfaces (IAIs) with different conicities still requires investigations that can offer valuable information in the clinical understanding of peri-implant health. The present study aimed to verify the bacterial infiltration of two internal conical connections with an angulation of 11.5° and 16° with the external hexagonal connection as a comparative after thermomechanical cycling using saliva as a contaminant. Test (n = 10) and control (n = 3) groups were set up. Evaluations were made on torque loss, Scanning Electron Microscopy (SEM), and Micro Computerized Tomography (MicroCT) after performing 2 × 10⁶ mechanical cycles (120 N) and 600 thermal cycles (5°-55° C) with 2 mm lateral displacement. The contents of the IAI were collected for microbiological analysis. There was a difference (p < 0.05) in torque loss of the groups tested; groups from the 16° IAI obtained a lower percentage of torque loss. All groups presented contamination and the analysis of the results shows that the microbiological profile of the IAI differs qualitatively from the profile found in the saliva used for contamination. The mechanical loading affects the microbiological profile found in the IAIs (p < 0.05). In conclusion, the IAI environment may favor a microbiological profile different from that of saliva and the thermocycling condition may alter the microbial profile found in the IAI.

Periodontal disease severity is associated to pathogenic consortia comprising putative and candidate periodontal pathogens

BACKGROUND

Based on a holistic concept of polymicrobial etiology, we have hypothesized that putative and candidate periodontal pathogens are more frequently detected in consortia than alone in advanced forms of periodontal diseases (PD).

OBJECTIVE

To correlate specific consortia of periodontal pathogens with clinical periodontal status and severity of periodontitis.

METHODOLOGY

Subgingival biofilm was obtained from individuals with periodontal health (113, PH), gingivitis (91, G), and periodontitis (209, P). Genomic DNA was purified and the species Aggregatibacter actinomycetemcomitans (Aa), Aa JP2-like strain, Porphyromonas gingivalis (Pg), Dialister pneumosintes (Dp), and Filifactor alocis (Fa) were detected by PCR. Configural frequency and logistic regression analyses were performed to correlate microbial consortia and PD.

RESULTS

Aa + Pg in the presence of Dp (phi=0.240; χ2=11.9, p<0.01), as well as Aa JP2 + Dp + Fa (phi=0.186, χ2=4.6, p<0.05) were significantly more associated in advanced stages of P. The consortium Aa + Fa + Dp was strongly associated with deep pocketing and inflammation (p<0.001). The best predictors of disease severity (80% accuracy) included older age (OR 1.11 [95% CI 1.07 - 1.15], p<0.001), Black/African-American ancestry (OR 1.89 [95% CI 1.19 - 2.99], p=0.007), and high frequency of Aa + Pg + Dp (OR 3.04 [95% CI 1.49 - 6.22], p=0.002).

CONCLUSION

Specific microbial consortia of putative and novel periodontal pathogens, associated with demographic parameters, correlate with severe periodontitis, supporting the multifactorial nature of PD.

qPCR Detection and Quantification of Aggregatibacter actinomycetemcomitans and Other Periodontal Pathogens in Saliva and Gingival Crevicular Fluid among Periodontitis Patients

OBJECTIVE

The detection of special bacterial species in patients with periodontitis is considered useful for clinical diagnosis and treatment. The aim of this study was to investigate the presence of specific periopathogens and investigate whether there is a correlation between the results of different bacterial species in whole saliva and pooled subgingival plaque samples (healthy and diseased sites) from individuals with periodontitis and periodontally healthy subjects.

MATERIALS AND METHODS

In total, 52 patients were recruited and divided into two groups: non-periodontitis and periodontitis patients. For each group, the following periodontal pathogens were detected using real-time polymerase chain reaction: A. actinomycetemcomitans JP2 clone, A. actinomycetemcomitans non JP2 clone, Porphyromonasgingivalis, and total eubacteria.

RESULTS

Higher levels of the various studied bacteria were present in both saliva and plaque samples from the periodontitis group in comparison to non-periodontitis subjects. There were significant differences in P. gingivalis and A. actinomycetemcomitans JP2 clones in the saliva of periodontitis patient compared to the control group. Subgingival plaque of diseased sites presented a significant and strong positive correlation between A. actinomycetemcomitans and P. gingivalis. In saliva samples, there was a significant positive correlation between A. actinomycetemcomitans JP2 clone and P. gingivalis (p ≤ 0.002).

CONCLUSION

Quantifying and differentiating these periodontal species from subgingival plaque and saliva samples showed a good potential as diagnostic markers for periodontal disease. Regarding the prevalence of the studied bacteria, specifically A. actinomycetemcomitans JP2 clone, found in this work, and the high rate of susceptibility to periodontal species in Africa, future larger studies are recommended.

High Virulence and Multidrug Resistance of Escherichia coli Isolated in Periodontal Disease

Periodontal disease is caused by different gram-negative anaerobic bacteria; however, Escherichia coli has also been isolated from periodontitis and its role in periodontitis is less known. This study aimed to determine the variability in virulence genotype, antibiotic resistance phenotype, biofilm formation, phylogroups, and serotypes in different emerging periodontal strains of Escherichia coli, isolated from patients with periodontal disease and healthy controls. E. coli, virulence genes, and phylogroups, were identified by PCR, antibiotic susceptibility by the Kirby-Bauer method, biofilm formation was quantified using polystyrene microtiter plates, and serotypes were determined by serotyping. Although E. coli was not detected in the controls (n = 70), it was isolated in 14.7% (100/678) of the patients. Most of the strains (n = 81/100) were multidrug-resistance. The most frequent adhesion genes among the strains were fimH and iha, toxin genes were usp and hlyA, iron-acquisition genes were fyuA and irp2, and protectin genes were ompT, and KpsMT. Phylogroup B2 and serotype O25:H4 were the most predominant among the strains. These findings suggest that E. coli may be involved in periodontal disease due to its high virulence, multidrug-resistance, and a wide distribution of phylogroups and serotypes.

Oral-gut bacterial profiles discriminate between periodontal health and diseases

OBJECTIVE

This investigation explored oral-gut microbial signatures with potential to distinguish among periodontal conditions.

BACKGROUND DATA

The interplay between the oral and gut microbiomes may be a critical pathway linking periodontal diseases and systemic inflammatory disorders. The mechanisms by which oral microorganisms translocate to the gut and cause microbial dysbiosis, favoring an inflammatory state, are still unknown. As a first approach, characterization of oral-gut microbial profiles associated with periodontal health and diseases can provide insights on such mechanisms of etiology and pathogenesis.

METHODS

Fecal and saliva samples from individuals with periodontal health (PH, 8), gingivitis (GG, 17), and periodontitis (PD, 24) were analyzed for their microbial composition by 16S rRNA gene sequencing. Microbial taxa were compared and correlated to periodontal parameters. Multivariate discriminant analysis (MDA) was carried out to identify profiles related to health and disease.

RESULTS

Few significant differences in oral-gut taxa were detected among clinical groups, although increase in fecal Fusobacterium nucleatum ss vincentii and salivary Aggregatibacter actinomycetemcomitans, Parvimonas micra, and Fretibacterium sp. HMT358 were strongly correlated with deep pockets and inflammation (p < .01). Over 50% of the fecal microbiota comprised microorganisms shared between oral and gut sites, whereas oral taxa were detected in approximately 9%, particularly enriched in GG fecal samples (p = .04). Trends for lower fecal richness and higher salivary diversity in PD compared to PH were observed. MDA was able to classify correctly 82% of the patients into the clinical groups. Main classifiers of periodontitis were high BMI, older age, and enrichment of oral-fecal Leptotrichia sp. HMT4, Peptostreptococcus stomatis, Dialister invisus, and a novel Lautropia sp. HMTC89-like organism.

CONCLUSION

Within the limitations of an exploratory investigation, specific profiles of oral-gut taxa, including known and potential novel organisms, combined with social-demographic features were able to discriminate individuals with periodontal diseases in this study population.

Triclosan antimicrobial activity against dental-caries-related bacteria

Triclosan (TCS) is a chlorinated diphenyl ether and a possible active agent against microorganisms. Due to its probability of reducing dental plaque accumulation, TCS can be added as a substance for oral hygiene. Aim: To evaluate the efficacy and antimicrobial capacity of TCS against Pseudomonas aeruginosa and Streptococcus mutans. Methods: This work evaluates the percentage of bacteria inhibition of P. aeruginosa (ATCC 27853) and S. mutans (ATCC 25175). TCS concentrations between 2 and 128 μg.mL-1 were tested. Results: An inhibitory potential of TCS was found against S. mutans. No percentage of inhibition was detected against P. aeruginosa (technical and biological triplicate). Conclusion: TCS, an antimicrobial agent used in dentifrices, can reduce S. mutans levels therefore these dentifrices should be indicated for patients with a high risk of caries. However, further study is needed, including antimicrobial analyses against other microbial conditions.

In Vitro Antimicrobial Potential of CAPE and Caffeamide Derivatives against Oral Microbes

Caffeic acid phenethyl ester (CAPE) is a natural component isolated from propolis and used in traditional medicine. We aimed to investigate the antimicrobial properties and action mechanism of CAPE and caffeamide derivatives (26G and 36M) against oral disease microbes. We resolved the minimum inhibitory and bactericidal concentrations of 26G and 36M and their stability at different temperatures and pH. We also evaluated their effect on biofilm formation and antibiotic resistance gene expression in methicillin-resistant Staphylococcus aureus (MRSA). Our results revealed that 26G and 36M showed the best anticancer and antimicrobial activities, respectively, compared with the other four caffeamide derivatives. Both 26G and 36M showed heat-dependent decreases in antimicrobial activity. The 36M derivative was stable irrespective of pH, whereas 26G was not stable under high pH conditions. Biofilm formation and antibiotic resistance-related gene expression were consistent with their respective phenotypes. This study provides evidence for the potential application of CAPE and caffeamide derivatives in dental medicine to cure or prevent oral diseases.

Role of Hydrogen Sulfide in Oral Disease

Oral diseases are among the most common human diseases yet less studied. These diseases affect both the physical, mental, and social health of the patients resulting in poor quality of life. They affect all ages, although severe stages are mostly observed in older individuals. Poor oral hygiene, genetics, and environmental factors contribute enormously to the development and progression of these diseases. Although there are available treatment options for these diseases, the recurrence of the diseases hinders their efficiency. Oral volatile sulfur compounds (VSCs) are highly produced in oral cavity as a result of bacteria activities. Together with bacteria components such as lipopolysaccharides, VSCs participate in the progression of oral diseases by regulating cellular activities and interfering with the immune response. Hydrogen sulfide (H2S) is a gaseous neurotransmitter primarily produced endogenously and is involved in the regulation of cellular activities. The gas is also among the VSCs produced by oral bacteria. In numerous diseases, H2S have been reported to have dual effects depending on the cell, concentration, and donor used. In oral diseases, high production and subsequent utilization of this gas have been reported. Also, this high production is associated with the progression of oral diseases. In this review, we will discuss the production of H2S in oral cavity, its interaction with cellular activities, and most importantly its role in oral diseases.

Antitumor and Protective Activity of TVLE against CdCl2-Induced Renal Damage in Rats

&lt;b&gt;Background and Objective:&lt;/b&gt; Cadmium is a heavy metal that has a wide range of applications in human existence. Cadmium may bind to the protein metallothionein and decrease kidney function once it enters the body. The purpose of this study was to investigate the renal protective activity of TVLE against CdCl&lt;sub&gt;2&lt;/sub&gt;-induced renal toxicity in rats. &lt;b&gt;Materials and Methods:&lt;/b&gt; TVLE was prepared and characterized using instrumental analysis and spectral data. Furthermore, the IC&lt;sub&gt;50&lt;/sub&gt; of TVLE against the Vero renal carcinoma cell line was calculated. Adult albino rats were used to assess the renal protective activity of TVLE (150 and 300 mg kg&lt;sup&gt;1&lt;/sup&gt; b.wt.) in CdCl&lt;sub&gt;2&lt;/sub&gt;-treated rats. &lt;b&gt;Results:&lt;/b&gt; IC&lt;sub&gt;50 &lt;/sub&gt;of TVLE against Vero cell line equals 148.25 μg mL&lt;sup&gt;1&lt;/sup&gt;. The daily oral administration of TVLE at concentrations of 150 and 300 mg kg&lt;sup&gt;1&lt;/sup&gt; b.wt. for 21 days to CdCl&lt;sub&gt;2&lt;/sub&gt;-treated rates resulted in a significant improvement in tumour volume and tumour weight, urea, creatinine, uric acid, TNF-α, NOx, TBARs, GSH, CAT, SOD, GPx and VEGF-C gene expression in CdCl&lt;sub&gt;2&lt;/sub&gt;-treated rats. Furthermore, TVLE almost normalized these effects in renal histoarchitecture. &lt;b&gt;Conclusion:&lt;/b&gt; The biochemical, histological and MRI examinations of the current study suggested that TVLE have renal protective activity against CdCl&lt;sub&gt;2&lt;/sub&gt;-induced renal toxicity in rats.

Potential Microbiological Risk Factors Associated With Periodontitis and Periodontal Health Disparities

Periodontitis disproportionately affects different racial and ethnic populations. In this study, we used qPCR to determine and compare oral microbial profiles in dental plaque samples from 191 periodontitis patients of different ethnic/racial backgrounds. We also obtained the periodontal parameters of these patients retrospectively using axiUm and performed statistical analysis using SAS 9.4. We found that in this patient cohort, neighborhood median incomes were significantly higher among Caucasians Americans (CAs) than among African Americans (AAs) and Hispanic Americans (HAs). Levels of total bacteria and Porphyromonas gingivalis, a keystone periodontal pathogen, were not evenly distributed among the three groups. We confirmed our previous findings that Streptococcus cristatus reduces P. gingivalis virulence potential and likely serves as a beneficial bacterium. We also showed the ratio of S. cristatus to P. gingivalis to be significantly higher in CAs than in HAs and AAs. Our results suggest that higher levels of P. gingivalis and lower ratios of S. cristatus to P. gingivalis may contribute to periodontal health disparities.

Recent progress in materials development and biological properties of GTR membranes for periodontal regeneration

Chronic periodontal is a very common infection that instigates the destruction of oral tissue, and for its treatment, it is necessary to minimize the infection and the defects regeneration. Periodontium consists of four types of tissues: (a) cementum, (b) periodontal ligament, (c) gingiva, and 4) alveolar bone. In separated cavities, regenerative process also allows various cell proliferations. Guided tissue regeneration (GTR) is a potential procedure that favors periodontal regrowth; however, some limitations (such as ineffective hemostatic property, poor mechanical property, and improper biodegradation) are also associated with it. This review mainly emphasizes on the following areas: (a) a summarized overview of the periodontium and its immunological situations, (b) recently utilized treatments for regeneration of distinctive periodontal tissues; (c) an overview of GTR membranes available commercially, and the latest developments on the characterization and processing of GTR membrane material; and 4) the function of the different non-polymeric/polymeric materials, which are acting as drug carriers, antibacterial agents, nanoparticles, and periodontal barrier membranes to prevent periodontal inflammation and to improve the strength of the GTR membrane.

Aerosol-generating dental procedures: a reappraisal of analysis methods and infection control measures

BACKGROUND

Dental aerosol-generating procedures (AGPs) have been associated with risk for transmitting infectious agents. However, existing infection control monitoring studies potentially underestimate the extent of contamination, due to methodological inadequacies. These studies employed settle plate methodology which only captures droplets that land on agar plates, but not those suspended in air. Furthermore, bacterial culture was used to determine the extent of contamination, without accounting for non-bacterial sources of contamination.

AIMS

This study sought to bridge these gaps by establishing a monitoring protocol involving active aerosol sampling and analysis of two dental AGPs, root canal treatment (RCT) and scaling.

METHODS

RCT and scaling were performed with standard aerosol mitigation precautions. Aerosols generated throughout each procedure were sampled using the air sampler device, while contamination of operatory fomites and personal protective equipment was sampled using surface swabs, before and post-treatment. The amount of contamination was quantified using bacterial culture and adenosine triphosphate (ATP) assay.

FINDINGS

RCT generated insignificant aerosol and splatter, supporting the infection control procedures' effectiveness. Conversely, scaling significantly increased the amount of aerosol and splatter. When comparing bacterial culture and ATP assay, the magnitude of contamination obtained with ATP assay was greater, suggesting that ATP assay may have detected additional contamination of human origin and bacteria that was not recovered by the culture conditions employed.

CONCLUSIONS

This monitoring protocol is feasible in the dental setting and determines the extent of contamination generated during AGPs. This could be adopted in future studies to overcome the limitations of the existing literature.

Prevalence and antimicrobial susceptibility of Gram-negative bacilli in subgingival biofilm associated with periodontal diseases

BACKGROUND

This cross-sectional study aimed to determine the prevalence and antimicrobial susceptibility of Gram-negative bacilli (GNB) isolated from subgingival biofilm of individuals with different periodontal conditions.

METHODS

Subgingival biofilm was obtained from 362 individuals with periodontal health (PH) (n = 83), gingivitis (n = 74), and periodontitis (n = 205), cultivated in broth and selective media. Isolated strains were identified by mass spectrometry. Antimicrobial susceptibility was determined by the Clinical and Laboratory Standards Institute disk diffusion guidelines. Production of extended-spectrum beta-lactamase (ESBL) and carbapenemases were evaluated by double disk synergy test and spectrophotometric detection of imipenem hydrolysis, respectively. ESBL and carbapenemase encoding genes were surveyed by Polymerase chain reaction (PCR). Differences among groups were examined by Chi-square, Kruskal-Wallis or Mann-Whitney tests.

RESULTS

GNB were isolated from 36.2% of all subgingival biofilm samples, with a significantly greater prevalence and species diversity (P < 0.001) in patients with periodontitis (45.9%) compared with individuals with PH (24.1%) and gingivitis (22.9%). Pseudomonas aeruginosa (27.5%), Enterobacter cloacae (16.8%), and Enterobacter asburiae (10.7%) were the most predominant species. Resistance/reduced sensitivity to at least 1 antimicrobial was detected in 60% of the strains, but only 4.6% were multidrug resistant. Serratia marcescens, E. cloacae, and Enterobacter kobei presented high rates of intrinsic resistance (>40%) to amoxicillin-clavulanate and first/second-generations of cephalosporins. One strain of Klebsiella pneumoniae isolated from periodontitis was resistant to imipenem, but no ESBL encoding genes or ESBL phenotype was detected.

CONCLUSION

High prevalence and diversity of GNB, with low susceptibility to β-lactams are observed in the subgingival microbiota associated with periodontitis.

Presence of non-oral bacteria in the oral cavity

A homeostatic balance exists between the resident microbiota in the oral cavity and the host. Perturbations of the oral microbiota under particular conditions can contribute to the growth of non-oral pathogens that are hard to kill because of their higher resistance to antimicrobials, raising the probability of treatment failure and reinfection. The presence of these bacteria in the oral cavity has been proven to be associated with several oral diseases such as periodontitis, caries, and gingivitis, and systemic diseases of importance in clinical medicine such as cystic fibrosis, HIV, and rheumatoid arthritis. However, it is still controversial whether these species are merely transient members or unique to the oral cavity. Mutualistic and antagonistic interactions between the oral microbiota and non-oral pathogens can also occur, though the mechanisms used by these bacteria are not clear. Therefore, this review presents an overview of the current knowledge about the presence of non-oral bacteria in the oral cavity, their relationship with systemic and oral diseases, and their interactions with oral bacteria.

Antimicrobial susceptibility and virulence of Enterococcus spp. isolated from periodontitis-associated subgingival biofilm

BACKGROUND

This study evaluated the prevalence, virulence and antimicrobial susceptibility of enterococci isolated from the subgingival microbiota of patients with different periodontal status.

METHODS

Subgingival biofilm was obtained from individuals with periodontal health (PH) (n = 139), gingivitis (n = 103), and periodontitis (n = 305) and cultivated on selective media. Isolated strains were identified by mass spectrometry. Antimicrobial sensitivity was determined by disk diffusion, virulence genes by polymerase chain reaction, and the subgingival microbiota by checkerboard. Differences among groups were assessed by Kruskal-Wallis, Mann-Whitney, and Chi-square tests.

RESULTS

Enterococcus spp. were isolated from 7.4% of all samples; 53.7% were Enterococcus faecalis. They were more prevalent in periodontitis (9.8%) and gingivitis (7.8%) than PH (2.2%; P <0.05), but no differences among stages of disease severity were observed. High rates of low susceptibility/resistance (>64%) to at least one antimicrobial were observed. Predominant virulence factors included ace (64.3%), asa (39.3%), and esp (35.7%). Fusobacterium nucleatum was prevalent in the subgingival microbiota of enterococci+ individuals, whereas Dialister pneumosintes was found in low frequency in patients with bopD+ enterococci. Oral streptococci were prevalent (>70%) in patients carrying enterococci susceptible to doxycycline (P <0.05), usually bopD- and esp- (P <0.01).

CONCLUSIONS

E. faecalis is increased in periodontitis-associated biofilm. Oral enterococci carry virulence genes and express resistance to some antibiotics commonly used in dentistry, such as ciprofloxacin and erythromycin. Specific subgingival taxa are associated with oral enterococci, suggesting they may interact with species of the dysbiotic periodontitis biofilm, constituting a potential source of factors to tissue destruction, antibiotic resistance dissemination, and poor response to periodontal therapy.

Subgingival microbiota in overweight and obese young adults with no destructive periodontal disease

BACKGROUND

This study analyzed the levels of a specific group of periodontal health/disease-related oral bacteria in the subgingival biofilm of young adults with overweight (OW) and obesity (OB), and no destructive periodontal disease.

METHODS

Full-mouth periodontal assessment and subgingival biofilm sampling were performed in individuals with normal weight (NW) (BMI [body mass index] ≥18.5 to ≤24.9 kg/m² ; n = 29), OW (BMI ≥25 to ≤29.9 kg/m² ; n = 26), or OB (BMI ≥30 kg/m² ; n = 22). BMI, waist (WC) and hip (HC) circumferences, and waist-hip ratio (WHR) were established for every individual. Biofilm samples were analyzed by checkerboard. Spearman coefficient, linear, and logistic regression analyses were obtained.

RESULTS

Gingivitis was detected in 45% NW, 65% OW, and 73% OB individuals. NW patients presented significantly less calculus and supragingival biofilm than OB. OW, and OB individuals had significantly higher levels of Porphyromonas gingivalis and Tannerella forsythia than NW patients (P <0.05). Treponema denticola correlated with BMI (rho = 0.31), WC (rho = 0.28), and HC (rho = 0.29), P≤0.01. Linear regression analysis showed significant (P <0.05) positive associations between BMI, WC, HC, and WHR indicators and Prevotella spp., Lactobacillus spp., V. parvula, and A. actinomycetemcomitans (Aa); negative associations were found between Capnocytophaga spp., WC, and HC (β = -0.29 and β = -0.37, respectively; P <0.01). However, the interaction of Prevotella spp. and T. forsythia decreased the likelihood of an individual to be diagnosed as OW/OB (OR 0.183 [95% CI, 0.062-0.540]).

CONCLUSIONS

Few periodontal pathogens differed in levels between NW and OW/OB individuals without destructive periodontal disease. Moreover, Aa, T. denticola, and Prevotella spp. were associated with clinical parameters of obesity.

Omics and interspecies interaction

Interspecies interactions are key determinants in biofilm behavior, ecology, and architecture. The cellular responses of microorganisms to each other at transcriptional, proteomic, and metabolomic levels ultimately determine the characteristics of biofilm and the corresponding implications for health and disease. Advances in omics technologies have revolutionized our understanding of microbial community composition and their activities as a whole. Large-scale analyses of the complex interaction between the many microbial species residing within a biofilm, however, are currently still hampered by technical and bioinformatics challenges. Thus, studies of interspecies interactions have largely focused on the transcriptional and proteomic changes that occur during the contact of a few prominent species, such as Porphyromonas gingivalis, Streptococcus mutans, Candida albicans, and a few others, with selected partner species. Expansion of available tools is necessary to grow the revealing, albeit limited, insight these studies have provided into a profound understanding of the nature of individual microbial responses to the presence of others. This will allow us to answer important questions including: Which intermicrobial interactions orchestrate the myriad of cooperative, synergistic, antagonistic, manipulative, and other types of relationships and activities in the complex biofilm environment, and what are the implications for oral health and disease?

Did Omics change periodontal therapy?

The starting point for defining effective treatment protocols is a clear understanding of the etiology and pathogenesis of a condition. In periodontal diseases, this understanding has been hindered by a number of factors, such as the difficulty in differentiating primary pathogens from nonpathogens in complex biofilm structures. The introduction of DNA sequencing technologies, including taxonomic and functional analyses, has allowed the oral microbiome to be investigated in much greater breadth and depth. This article aims to compile the results of studies, using next-generation sequencing techniques to evaluate the periodontal microbiome, in an attempt to determine how far the knowledge provided by these studies has brought us in terms of influencing the way we treat periodontitis. The taxonomic data provided, to date, by published association and elimination studies using next-generation sequencing confirm previous knowledge on the role of classic periodontal pathogens in the pathobiology of disease and include new species/genera. Conversely, species and genera already considered as host-compatible and others less explored were associated with periodontal health as their levels were elevated in healthy individuals and increased after therapy. Functional and transcriptomic analyses also demonstrated that periodontal biofilms are taxonomically diverse, functionally congruent, and highly cooperative. Very few interventional studies to date have examined the effects of treatment on the periodontal microbiome, and such studies are heterogeneous in terms of design, sample size, sampling method, treatment provided, and duration of follow-up. Hence, it is still difficult to draw meaningful conclusions from them. Thus, although OMICS knowledge has not yet changed the way we treat patients in daily practice, the information provided by these studies opens new avenues for future research in this field. As new pathogens and beneficial species become identified, future randomized clinical trials could monitor these species/genera more comprehensively. In addition, the metatranscriptomic data, although still embryonic, suggest that the interplay between the host and the oral microbiome may be our best opportunity to implement personalized periodontal treatments. Therapeutic schemes targeting particular bacterial protein products in subjects with specific genetic profiles, for example, may be the futuristic view of enhanced periodontal therapy.

Analysis of Porphyromonas gingivalis fimA genotypes in severe periodontitis patients

The aim of this study was to i) evaluate the prevalence of P. gingivalis and the genotypes fim A I, Ib, II, III, IV, and V in Brazilian patients with periodontitis stage III and IV, grades B and C, ii) compare periodontitis grades B and C with regard to the prevalence of P. gingivalis and fim A genotypes, and iii) correlate the presence of these pathogens with clinical periodontal variables. Two samples of subgingival biofilm were collected from the interproximal sites with the greatest clinical attachment loss (CAL) of each patient (grade B = 38; grade C = 54) and submitted to polymerase chain reaction (PCR) for the identification of P. gingivalis and fim A genotypes. The collected periodontal clinical parameters included gingival index, plaque index, probing depth (PD), bleeding on probing (BoP) and CAL. P. gingivalis was present in 61.96% of the samples, but more prevalent in patients with grade C periodontitis (p = 0.048) and higher CAL (p < 0.001), PD (p < 0.001), and BoP (p = 0.01) values, and at sites with high CAL values (p = 0.01). The fim A II genotype was more prevalent in patients with greater mean PD (p = 0.04) and a higher proportion of bleeding sites (p = 0.006). Thus, in this sample of Brazilian periodontitis patients, the presence of P. gingivalis was associated with grade C periodontitis and periodontal destruction, while the fim A II genotype was associated with increased PD and BoP, supporting the notion that P. gingivalis fim A II is an important virulence factor in periodontal tissues.

N-(3-oxododecanoyl)-homoserine lactone regulates osteoblast apoptosis and differentiation by mediating intracellular calcium

Pseudomonas aeruginosa (P. aeruginosa) is associated with periapical periodontitis. The lesions are characterized by a disorder in osteoblast metabolism. Quorum sensing molecular N-(3-oxododecanoyl)-homoserine lactone (AHL) is secreted by P. aeruginosa and governs the expression of numerous virulence factors. AHL can trigger intracellular calcium ([Ca²⁺]_i) fluctuations in many host cells. However, it is unclear whether AHL can regulate osteoblast metabolism by affecting [Ca²⁺]_i changes or its spatial correlation. We explored AHL-induced apoptosis and differentiation in pre-osteoblastic MC3T3-E1 cells and evaluated [Ca²⁺]_i mobilization using several extraction methods. The spatial distribution pattern of [Ca²⁺]_i among cells was investigated by Moran's I, an index of spatial autocorrelation. We found that 30 μM and 50 μM AHL triggered opposing osteoblast fates. At 50 μM, AHL inhibited osteoblast differentiation by promoting mitochondrial-dependent apoptosis and negatively regulating osteogenic marker genes, including Runx2, Osterix, bone sialoprotein (Bsp), and osteocalcin (OCN). In contrast, prolonged treatment with 30 μM AHL promoted osteoblast differentiation concomitantly with cell apoptosis. The elevation of [Ca²⁺]_i levels in osteoblasts treated with 50 μM AHL was spatially autocorrelated, while no such phenomenon was observed in 30 μM AHL-treated osteoblasts. The blocking of cell-to-cell spatial autocorrelation in the osteoblasts provoked by 50 μM AHL significantly inhibited apoptosis and partially restored differentiation. Our observations suggest that AHL affects the fate of osteoblasts (apoptosis and differentiation) by affecting the spatial correlation of [Ca²⁺]_i changes. Thus, AHL acts as a double-edged sword for osteoblast function.

Evaluation of the Microbiological Profile of Alveolar Residual Screws and Cleft-Adjacent Teeth in Individuals With Complete Unilateral Fissures

OBJECTIVE

To evaluate the microbiota profile of residual alveolar slits and teeth adjacent to the cleft in fissured individuals.

DESIGNS

This study used a cross-sectional design.

PARTICIPANTS

Twenty individuals, aged 14 to 24 years, who had a residual fissure in the maxillary alveolar ridge region were selected.

MAIN OUTCOME MEASURES

Three sites per individual were selected for microbiological collection (the site of the residual cleft and the 2 nearest teeth). The samples were analyzed using the Checkerboard DNA-DNA hybridization technique for 73 species of bacteria.

RESULTS

All the species analyzed were found in the 2 niches (slits and teeth). The bacterial species present in the largest number in the residual cracks were Prevotella melaninogenica, Prevotella nigrescens, and Streptococcus mitis. With regard to the bacterial profiles in the mesial and distal faces, the most prevalent species were P nigrescens, Veillonella parvula, and Fusobacterium nucleatum sp vicentii. The analysis of all the collected samples demonstrated very similar profiles for the mesial and distal faces, with these 2 sites even presenting the same species in greater frequencies. Higher counts of 20 bacterial species (Wilcoxon test) were observed in the dental niche, in relation to the fissure, particularly, P nigrescens, V parvula, F nucleatum sp vicentii, and Neisseria mucosa.

CONCLUSION

Some species were significantly more prevalent in the residual alveolar fissures and in adjacent teeth. The comparison between the profiles of the 2 niches demonstrated large differences in the most frequent species in the teeth, and no qualitative differences with regard to specific pathogens.

Phytochemical Composition and In Vitro Biological Activity of Iris spp. (Iridaceae): A New Source of Bioactive Constituents for the Inhibition of Oral Bacterial Biofilms

The inhibition and eradication of oral biofilms is increasingly focused on the use of plant extracts as mouthwashes and toothpastes adjuvants. Here, we report on the chemical composition and the antibiofilm activity of 15 methanolic extracts of Iris species against both mono-(Pseudomonas aeruginosa, Staphylococcus aureus) and multi-species oral biofilms (Streptococcus gordonii, Veillonella parvula, Fusobacterium nucleatum subsp. nucleatum, and Actinomyces naeslundii). The phytochemical profiles of Iris pallida s.l., Iris versicolor L., Iris lactea Pall., Iris carthaliniae Fomin, and Iris germanica were determined by ultra-high performance liquid chromatography-high-resolution tandem mass spectroscopy (UHPLC-HRMS/MS) analysis, and a total of 180 compounds were identified among Iris species with (iso)flavonoid dominancy. I. pallida, I. versicolor, and I. germanica inhibited both the quorum sensing and adhesion during biofilm formation in a concentration-dependent manner. However, the extracts were less active against maturated biofilms. Of the five tested species, Iris pallida s.l. was the most effective at both inhibiting biofilm formation and disrupting existing biofilms, and the leaf extract exhibited the strongest inhibitory effect compared to the root and rhizome extracts. The cytotoxicity of the extracts was excluded in human fibroblasts. The inhibition of bacterial adhesion significantly correlated with myristic acid content, and quorum sensing inhibition correlated with the 7-β-hydroxystigmast-4-en-3-one content. These findings could be useful for establishing an effective tool for the control of oral biofilms and thus dental diseases.

Do patients with aggressive and chronic periodontitis exhibit specific differences in the subgingival microbial composition? A systematic review

BACKGROUND

The 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions grouped the diseases previously recognized as chronic (CP) or aggressive (AgP) periodontitis under a single category named periodontitis. The rationale for this decision was the lack of specific patterns of immune-inflammatory response or microbial profiles associated with CP or AgP. However, no previous studies have compiled the results of all studies comparing subgingival microbial data between these clinical conditions. Thus, this systematic review aimed to answer the following focused question: "Do patients with AgP periodontitis present differences in the subgingival microbiota when compared with patients with CP?"

METHODS

A systematic review was conducted according to the PRISMA statement. The MEDLINE, EMBASE, and Cochrane databases were searched up to June 2019 for studies of any design (except case reports, case series, and reviews) comparing subgingival microbial data from patients with CP and AgP.

RESULTS

A total of 488 articles were identified and 56 were included. Thirteen studies found Aggregatibacter actinomycetemcomitans elevated in AgP in comparison with CP, while Fusobacterium nucleatum, Parvimonas micra, and Campylobacter rectus were elevated in AgP in a few studies. None of these species were elevated in CP. However, the number of studies not showing statistically significant differences between CP and AgP was always higher than that of studies showing differences.

CONCLUSION

These results suggested an association of A. actinomycetemcomitans with AgP, but neither this species nor the other species studied to date were unique to or could differentiate between CP and AgP (PROSPERO #CRD42016039385).

Triclosan toothpaste as an adjunct therapy to plaque control in children from periodontitis families: a crossover clinical trial

OBJECTIVES

Studies have demonstrated that children from aggressive periodontitis (AgP) parents presented precocious alterations in their periodontal condition, and the use of chemical agents in association to plaque control could be useful to control these alterations. This study aimed to evaluate the effect of Triclosan toothpaste to modulate the clinical and subgingival condition in children from AgP parents.

METHODS

Fifteen children from AgP parents and 15 from periodontally healthy parents were included in this crossover placebo study. Children were randomly allocated into triclosan or placebo therapy, using selected toothpaste for 45 days. After 15 days of wash-out, groups were crossed, changing the used toothpaste. Clinical examination and saliva, crevicular gingival fluid (GCF), and subgingival biofilm collection were performed at baseline and 45 days of each phase. GCF cytokines' levels were analyzed by Luminex/MAGpix platform and subgingival and salivary periodontal pathogens' levels by qPCR.

RESULTS

At baseline, AgP group presented higher plaque index (PI), gingival index (GI), and bleeding on probing (BoP), higher Aggregatibacter actinomycetemcomitans (Aa) abundance in saliva and subgingival biofilm, and lower levels of INF-ɣ, IL-4, and IL-17 in GCF. Placebo therapy only reduced PI in both groups. Triclosan toothpaste reduced PI and GI in both groups. Triclosan promoted reduction of BoP and probing depth (PD), Aa salivary, and IL-1β levels in AgP group. In health group, triclosan reduced INF-ɣ and IL-4 concentration.

CONCLUSION

Triclosan toothpaste demonstrated to be more effective than placebo toothpaste to control the periodontal condition in children from AgP parents, by reducing the BoP, PD, salivary Aa, and IL-1β.

CLINICAL RELEVANCE

Triclosan toothpaste can improve oral conditions in higher-risk population for AgP.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov with the identifier NCT03642353.

Proteomic analysis of whole saliva in chronic periodontitis

Periodontitis is a chronic inflammatory disease resulting from a dysbiosis of the dental biofilm and a dysregulated host response in susceptible individuals. It is characterized by periodontal attachment destruction, bone resorption and eventual tooth loss. Salivary biomarkers have been sought to predict and prevent periodontitis. This comparative study analyzed the salivary proteome of individuals with chronic periodontitis (CP) and periodontal health (PH) and correlated specific proteins with clinical parameters of disease by using mass spectrometry. Stimulated whole saliva was obtained 10 PH and 30 CP patients and pooled into 5 healthy control samples and 15 CP samples. After precipitation with TCA, samples were digested enzymatically with trypsin and analyzed by a LTQ Orbitrap Velos equipped with a nanoelectrospray ion source. A wide range of salivary proteins of various functions was significantly reduced in CP individuals, whereas salivary acidic proline-rich phosphoprotein, submaxillary gland androgen-regulated protein, histatin-1, fatty acid binding protein, thioredoxin and cystatin-SA were predominant in diseased patients and correlated significantly with signs of periodontal attachment loss and inflammation. In conclusion, few specific salivary proteins were associated with CP. These findings may contribute to the identification of disease indicators or signatures for the improvement of periodontal diagnosis. SIGNIFICANCE: Periodontitis is a chronic inflammatory disease that results in periodontal attachment destruction, bone resorption and eventual tooth loss. Salivary biomarkers have been sought to predict periodontitis. The analysis of the salivary proteome of individuals with chronic periodontitis indicated that several proteins of various functions were significantly reduced in these individuals, except for salivary acidic proline-rich phosphoprotein, submaxillary gland androgen-regulated protein, histatin, fatty acid binding protein, thioredoxin and cystatin. Differences in salivary proteome profiles between periodontal health and periodontitis may contribute to the identification of disease indicators and to the improvement of periodontal diagnosis and treatment.

A Potential Role of Phospholipase 2 Group IIA (PLA2-IIA) in P. gingivalis-Induced Oral Dysbiosis

Porphyromonas gingivalis is an oral pathogen with the ability to induce oral dysbiosis and periodontal disease. Nevertheless, the mechanisms by which P. gingivalis could abrogate the host-microbe symbiotic relationship leading to oral dysbiosis remain unclear. We have recently demonstrated that P. gingivalis specifically increased the antimicrobial properties of oral epithelial cells, through a strong induction of the expression of PLA₂-IIA in a mechanism that involves activation of the Notch-1 receptor. Moreover, gingival expression of PLA₂-IIA was significantly increased during initiation and progression of periodontal disease in non-human primates and interestingly, those PLA₂-IIA expression changes were concurrent with oral dysbiosis. In this chapter, we present an innovative hypothesis of a potential mechanism involved in P. gingivalis-induced oral dysbiosis and inflammation based on our previous observations and a robust body of literature that supports the antimicrobial and proinflammatory properties of PLA₂-IIA as well as its role in other chronic inflammatory diseases.

Calibrated interdental brushing for the prevention of periodontal pathogens infection in young adults - a randomized controlled clinical trial

Periodontal disease is clearly correlated with systemic disease. The presence of periodontal pathogens in interdental spaces in young, healthy adults is a strong indicator of the need to introduce daily interdental prophylaxis. Twenty-five subjects (aged 18–35 years), diagnosticated clinically as periodontally healthy, were enrolled in this study. One hundred interdental sites were included. Among these sites, 50 “test” sites were cleaned daily with calibrated interdental brushes (IDBs), whereas the other 50 sites were not cleaned and considered “controls”. The interdental biofilm at these interdental sites was collected at the beginning of the study (basal) and at 1 week, 2 weeks, 3 weeks, 4 weeks, and 3 months. Real-time polymerase chain reaction (PCR) methodology was used to quantify (i) 19 periodontal bacteria, including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, and (ii) total bacteria. In the test sites, the quantity of total bacteria decreased over time with the use of IDBs. The bacteria from the red and orange Socransky complexes, which are associated with periodontal disease, significantly decreased in the test sites but not in the control sites. Bacteria from the yellow, and purple Socransky complexes, which are associated with periodontal health, increased significantly in both groups whereas bacteria from the blue Socransky complex increased significantly only in the test sites. Furthermore, at basal, 66% of test sites and 68% of control sites bled during interdental brushing. These percentages decreased by 85% in 3 months for the test sites and by 27% in the control sites. In conclusion, the daily use of calibrated IDBs can reduce periodontal pathogens, reestablish symbiotic microbiota and, decrease interdental inflammation in interdental sites of healthy young adults.

Gingival crevicular fluid periostin levels in chronic periodontitis patients following nonsurgical periodontal treatment with low-level laser therapy

Objective:

Periostin is a matricellular protein highly expressed in periosteum, periodontal ligament and is essential for tissue integrity and maturation. It plays a role in collagen fibrillogenesis and is downregulated in periodontal disease. Biostimulation utilizing low-level laser therapy (LLLT) influences periodontal ligament fibroblast proliferation. This study was conducted with the objective of estimating periostin levels in chronic periodontitis (CP) patients following LLLT as an adjunct to root surface debridement (RSD).

Materials and Methods:

Thirty periodontally healthy participants (Group I) and sixty CP participants were recruited. Based on the therapeutic intervention, CP patients were allocated to either RSD (Group II) or to RSD with LLLT (Group III) group. Clinical parameters and gingival crevicular fluid (GCF) periostin levels were assessed at the baseline and at the 3^rd month.

Results:

Periostin levels were significantly lower in CP patients when compared to healthy individuals at the baseline (P < 0.01). Following nonsurgical periodontal treatment (NSPT), periostin levels significantly increased in both Group II and III, when compared to baseline values (P < 0.001). Comparison of mean periostin levels between both the treatment groups showed a significant increase in LLLT group than RSD at the 3^rd month (P < 0.05).

Conclusion:

Within the limitations of the present study, LLLT application was found to have additional benefits over RSD with respect to clinical periodontal parameters and GCF periostin levels. Moreover, periostin may be used as a possible biomarker to evaluate the outcome following NSPT.

Antimicrobial effects of various platelet rich concentrates-vibes from in-vitro studies-a systematic review

Aim

The aim of the current review was to outline the existing information related to antimicrobial properties of various platelet concentrates, as experimented in various in-vitro studies.

Background

One of the most interesting recent landmarks in the field of biological therapy has been the discovery that platelets, in addition to being capable of releasing hundreds of proteins and growth factors, can also release immunomodulatory agents with antimicrobial activity. Several international research groups have reported antimicrobial activities in both human platelets and other types of platelet rich plasma preparations.

Review Result

This review was carried-out pursuing a systematic approach. An electronic search was conducted on MEDLINE and GOOGLE SCHOLAR databases using suitable search terminologies. It included preclinical studies which assessed the antimicrobial activity of Autologous Platelet Concentrates(APC).Ten in-vitro studies and one animal study, which investigated APC effects on various microorganisms, were included. Almost in all the included in-vitro studies, it was found that complete breakdown of microbial load could not be achieved by any of the APC preparations but there occurred a reduction in the growth of microorganisms. Thus APCs displayed a bacteriostatic rather than bacteriocidal activity.The only animal study included in this review which had both in-vitro and in-vivo evaluation, also showed reduction of infection caused by different microorganisms.

Conclusion

Although the precise mechanism of synergy with microbial pathogens needs further validation, platelet concentrates proved to have antimicrobial properties.

The Effect of Er,Cr:YSGG and Diode Laser Applications on Dental Implant Surfaces Contaminated with Acinetobacter Baumannii and Pseudomonas Aeruginosa

Treatment of peri-implantitis through several implant surface decontamination techniques have been reported, however, some of them can negatively alter the implant surface or enhance more bacterial resistance. The aim of this in vitro study was to evaluate implant surface decontamination by means of Er,Cr:YSGG and diode lasers. Fifty micro-textured (MTX) dental implants were contaminated with Acinetobacter baumannii (n = 25) and with Pseudomonas aeruginosa (n = 25). All implants were then divided into five groups for the decontamination procedure. In group I (GI), decontamination was done with an Er,Cr:YSGG laser (2780 nm), while in group II (GII) decontamination was performed using photodynamic therapy (a 650 nm diode laser). In Group III (GIII) decontamination was performed with photodynamic therapy (an 808 nm diode laser), and in group IV (GIV) decontamination was performed with 0.12% chlorhexidine. Group V (GV) was the control group with no decontamination. After decontamination, colony forming units (CFU) were counted and implants were prepared for SEM analysis. A significant difference (p < 0.001) was observed for GI compared to the other groups, and also for GIV compared to both GII and GIII. The Er,Cr:YSGG laser (GI) showed the best results in decontaminating the implant surface. Chlorhexidine (GIV), proved to be better in decontaminating the implant surface than photodynamic therapy GII and diode laser GIII. No significant difference was found between group GII and GIII. The SEM analysis showed no significant change in the implant surface topography. The results of this study suggest that the Er,Cr:YSGG laser can be considered as an effective technique for reducing bacteria contamination on implant surfaces.

Acinetobacter baumannii orofacial cellulitis: report of 2 cases

Acinetobacter baumannii infection of skin and soft tissues is uncommon and usually associated with trauma. The present report describes 2 pediatric cases of cellulitis in the orofacial region, caused by A. baumannii infection with a fatal outcome. A 12-year-old male patient, diagnosed with acute promyelocytic leukemia, presented with an ulcerated lesion on the lip suggestive of local trauma. The condition progressed to cellulitis, epithelial necrosis, and nonspecific vesicles and blisters. The second case occurred in a 10-year-old male patient with a diagnosis of Burkitt lymphoma. The patient's condition progressed to World Health Organization Grade IV mucositis and cellulitis. In both cases, hemoculture was positive for multidrug-resistant A. baumannii. In conclusion, A. baumannii should be considered a potentially multidrug-resistant pathogen in the presence of skin and soft tissue cellulitis. Ulcerated oral lesions may place hospitalized pediatric patients at risk for A. baumannii infection.

Subgingival microbiome in Chinese patients with generalized aggressive periodontitis compared to healthy controls

OBJECTIVE

The aim of the study was to profile the subgingival microbiome of Chinese adults with generalized aggressive periodontitis (GAgP) using human oral microbe identification microarray (HOMIM), and to compare the results with matched periodontal healthy controls.

DESIGN

15 subjects with GAgP and 15 age- and gender- matched periodontal healthy controls were included. Subgingival plaque samples were collected from the deepest pockets of patients with GAgP and matched sites in controls and then analyzed by 16S rRNA-based microarrays. Student's paired t-test was used to compare clinical parameters and mean number of bacterial taxa detected between the two groups. Fisher's exact probability test and Wilcoxon Rank Sum were used to compare bacterial species between all samples. A multiple linear regression model was used for correlations among age, gender and bacterial with clinical parameters.

RESULTS

From a total sum of 379 strains tested, 171 bacterial strains were detected from subgingival plaques of the GAgP patients, more than the 157 strains detected in control group. Mean number of subgingival bacterial taxa detected in GAgP group was 68 (SD = 21.06) while in control group was 45 (SD = 21.60). 47 bacterial taxa were detected more frequently in GAgP group while 12 taxa were more prevalent in control group. The significantly more prevalent and abundant taxa of bacteria in GAgP group included Filifactor alocis, Desulfobulbus sp., Fretibacterium sp., Porphyromonas gingivalis, Tannerella forsythia, Porphyromon as endodontalis, Peptostreptococcaceae spp., Parvimonas micra, Eubacterium nodatum and Eubacterium saphenum. Meanwhile the more abundant taxa in control group were Streptococcus spp. and Pseudomonas aeruginosa.

CONCLUSIONS

There are more taxa of bacteria in subgingival plaques of Chinese patients with GAgP than in healthy controls. F. alocis, Desulfobulbus sp., Fretibacterium sp., P. gingivalis and T. forsythia are strongly associated with GAgP. High-throughout microbiological results may help dentists have a better understanding of subgingival microbiome of GAgP.

Novel Bioactive and Therapeutic Dental Polymeric Materials to Inhibit Periodontal Pathogens and Biofilms

Periodontitis is a common infectious disease characterized by loss of tooth-supporting structures, which eventually leads to tooth loss. The heavy burden of periodontal disease and its negative consequence on the patient's quality of life indicate a strong need for developing effective therapies. According to the World Health Organization, 10⁻15% of the global population suffers from severe periodontitis. Advances in understanding the etiology, epidemiology and microbiology of periodontal pocket flora have called for antibacterial therapeutic strategies for periodontitis treatment. Currently, antimicrobial strategies combining with polymer science have attracted tremendous interest in the last decade. This review focuses on the state of the art of antibacterial polymer application against periodontal pathogens and biofilms. The first part focuses on the different polymeric materials serving as antibacterial agents, drug carriers and periodontal barrier membranes to inhibit periodontal pathogens. The second part reviews cutting-edge research on the synthesis and evaluation of a new generation of bioactive dental polymers for Class-V restorations with therapeutic effects. They possess antibacterial, acid-reduction, protein-repellent, and remineralization capabilities. In addition, the antibacterial photodynamic therapy with polymeric materials against periodontal pathogens and biofilms is also briefly described in the third part. These novel bioactive and therapeutic polymeric materials and treatment methods have great potential to inhibit periodontitis and protect tooth structures.