The predominant cultivable microbiota of active and inactive lesions of destructive periodontal diseases

Efficacy of antimicrobial peptide P113 oral health care products on the reduction of oral bacteria number and dental plaque formation in a randomized clinical assessment

Background/purpose

Dental plaque is the main cause leading to the dental caries and periodontal diseases. The main purpose of this study was to test the efficacy of oral spray containing the antimicrobial peptide P-113 on the reduction of oral bacteria number and dental plaque formation in a randomized clinical assessment.

Materials and methods

This study was divided into two parts. In Part A, we investigated the user experiences with the P-113 containing oral spray. In part B, 14 subjects in the experimental group used the P-113-containing oral spray, while 14 subjects in the control group used a placebo without the P-113 in a 4-week clinical trial. Participants were asked to use the P-113-containing oral spray or placebo 3 times per day and 5 times per use. Moreover, 3 check-ups and 2 washouts were carried out to evaluate the DMFT score, dental plaque weight, dental plaque index, and gingival index.

Results

In part A, up to 91.8% of the subjects in the experimental group were satisfied with the use of the P-113-containing oral spray. In part B, based on our PacBio SMRT sequencing platform and DADA2 analysis, the numbers of Streptococcus and Porphyromonas in the experimental group were lower than those in the control group. In addition, decreased dental plaque weight, dental plaque index, and gingival index were all observed in the experimental group.

Conclusion

The P-113-containing oral spray has the potential to reduce the dental caries and periodontal disease-related bacteria and to control the dental plaque formation.

Comparison of Antimicrobial Efficacy of Ocimum sanctum (Tulsi) Extract and Chlorhexidine Against Tannerella forsythia: An In Vitro Study

CONTEXT

Periodontitis, a chronic inflammatory disease affecting the periodontium, is primarily caused by gram-negative anaerobic bacteria. Conventional periodontal therapy aims to eradicate pathogenic microflora through mechanical debridement, often supplemented with chemical agents. However, the use of these chemical adjuvants is frequently associated with adverse drug reactions and the development of antimicrobial resistance. Consequently, researchers are increasingly exploring herbal antibacterial agents, such as Ocimum sanctum (Tulsi), as viable alternatives due to their broad-spectrum antimicrobial properties and reduced side effect profile.

AIM

 This study aims to analyze the antibacterial efficacy of the ethanolic extract of O. sanctum (Tulsi) against Tannerella forsythia, a key bacterium of the red complex, using chlorhexidine as a reference standard. Traditionally, chlorhexidine has been utilized as an adjunct to nonsurgical therapy in the treatment of patients with periodontal disease.

MATERIALS AND METHODS

The cold extraction method was used to prepare the ethanolic extract of O. sanctum leaves. The resultant substance was mixed into five different concentrations (3.13%, 6.25%, 12.5%, 25%, and 50%) using dimethylformamide as the solvent. The antimicrobial activity of these varying concentrations was assessed against T. forsythia in culture plates employing the agar well diffusion method, with 0.2% chlorhexidine serving as the positive reference. The zone of inhibition of bacterial growth has been determined and compared with that of 0.2% chlorhexidine.

RESULTS

The ethanolic extract of O. sanctum exhibited highly statistically significant antibacterial activity against T. forsythia (p < 0.001). At a dosage of 25 mg/mL, the extract created a zone of inhibition measuring 17 mm, while at 50 mg/mL, the zone of inhibition increased to 25 mm. However, when compared to 0.2% chlorhexidine, which had a zone of inhibition of 32 mm, O. sanctum showed a slightly smaller inhibitory effect.

CONCLUSION

The extract of Tulsi showed notable antibacterial activity against T. forsythia, with the antibacterial impact observed at the 50 mg/mL dilution.

N6-methyladenosine-mediated overexpression of TREM-1 is associated with periodontal disease

Periodontitis, a prevalent inflammatory disease, involves the destruction of tooth-supporting tissues. N6-methyladenosine (m6A) is a type of post-transcriptional modification that significantly influences gene and protein expression. It is involved in the regulation of various diseases, including those with an inflammatory component. This study investigates the potential role of m6A-mediated TREM-1 expression in the development of periodontitis. Clinical features and TREM-1 expression were assessed in periodontitis patients and healthy controls. LPS-stimulated human gingival fibroblasts (HGFs) were used to investigate m6A levels, m6A regulator METTL3, TREM-1, and inflammatory gene expression. In silico functional analysis explored TREM-1 interactions and functionalities. Periodontitis patients showed significantly elevated TREM-1 expression at both mRNA and protein levels. Predicted m6A motifs were present within the TREM-1 transcript. LPS stimulation of HGFs increased m6A content, METTL3, and TREM-1 expression, suggesting a potential link between m6A modification and TREM-1 regulation. Bioinformatic analysis revealed TREM-1 interaction with genes associated with periodontitis and its association with inflammatory pathways. This study suggests a potential role for METTL3-mediated m6A modification in regulating TREM-1 expression in periodontitis. Further investigation is needed to solidify this link and translate findings into clinical applications for improved periodontal health.

Assessment of the Efficiency of Tulsi Extract as a Locally Administered Medication Agent and Its Comparison With Curcumin in the Treatment of Periodontal Pockets

INTRODUCTION

The use of locally administered medication (LAM) agents such as minocycline, metronidazole, and tetracycline as antimicrobials has drawbacks, including the development of microorganism resistance, exorbitant pricing, and limited accessibility. Thus, there is a need for safer and more affordable alternatives. Numerous natural therapies have been found to be superior in this situation. In this study, the efficacy of tulsi extract as a LAM agent was assessed and it was compared with curcumin, which is currently used for the treatment of periodontal pockets.

METHODS AND MATERIALS

There were three categories: each category had 30 sites. Category 1 sites underwent scaling along with root planing (SRP) solely, Category 2 sites received curcumin extract as LAM in the periodontal pocket in addition to SRP, and Category 3 sites received tulsi extract as LAM in the periodontal pocket in addition to SRP. The stent was used to ensure consistent and unbiased measurements on the 30th day after treatment. Clinical attachment level (CAL) and probing pocket depth (PPD) were measured at six points around each tooth.  Results: The reduction in values of periodontal parameters such as BAPNA (Nα-benzoyl-DL-arginine-p-nitroanilide) assays, modified sulcus bleeding index (mSBI), gingival index (GI), plaque index (PI), CAL, and PPD in sites within Category 1, Category 2, and Category 3 was statistically significant. The decrease in BAPNA assay results indicates that tulsi extract is more effective than curcumin gel at eradicating red-complex bacteria. Although not significantly different, the decrease in PI and GI was observed to be greater when curcumin jelly was used. This suggests that curcumin jelly has a stronger impact on reducing plaque, which in turn decreases gingival inflammation.

CONCLUSION

Based on the overall results of the study, it can be said that both tulsi and curcumin have similar effectiveness in reducing periodontal markers.

Preparation of Ocimum Sanctum-Based Hydrogel and Evaluation of Its Cytotoxicity: An In Vitro Study

INTRODUCTION

While traditional periodontal treatments like scaling and root planing, antibiotics, and surgical intervention remain the primary approaches, herbal medicine is continuously evolving as an alternative for the management of periodontal diseases. This study focused on the evaluation of the cytotoxicity of Ocimum sanctum (OS)-based hydrogel for its use in local drug delivery in periodontitis.

METHODS

OS-based hydrogel was prepared using 50 g of OS powder and 200 ml of ethanol, along with carboxymethyl cellulose gel and sorbitol. The prepared formulation was evaluated for its cytotoxicity by using the MTT assay, cell viability, cell morphology, and brine shrimp egg assessment.

RESULTS

Cell viability was assessed, and it was above 95% for the control and 85% for the OS hydrogel by the 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay. Brine shrimp egg assessment also showed a survival rate of 80% at low concentrations. The cell morphology test showed round and uniform cells growing in a monolayer shape.

CONCLUSION

The findings of this study confirmed that OS-based hydrogel is cytocompatible and, hence, can be used as a local drug delivery agent for periodontitis management, especially in resource-constrained settings where affordable and natural treatment options are highly valued.

The effect of antimicrobial photodynamic therapy on periodontal disease and glycemic control in patients with type 2 diabetes mellitus

OBJECTIVES

This study is aimed at determining the effect of concomitant antimicrobial photodynamic therapy (aPTD) on periodontal disease and glycaemic control in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Twenty-four patients with T2DM were enrolled in the study. Periodontal clinical parameters were assessed by measuring probing pocket depth (PPD), clinical attachment loss (CAL), gingival recession (GR), full-mouth bleeding score (FMBS), full-mouth plaque score (FMPS), and full-mouth sulcus bleeding score (FMSBS). Glycated haemoglobin A1c (HbA1c) was measured. To determine the presence of the following periodontal pathogenic bacteria, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, subgingival plaque samples were taken from two periodontal pockets per jaw with the greatest PPD using paper tips. Patients were randomly divided into the test and control group. In the test group, full-mouth disinfection was performed in combination with aPTD. In the control group, only full-mouth disinfection was performed.

RESULTS

The results showed an improvement in periodontal clinical parameters in both groups. The difference between the groups in favour of the test group was statistically significant for BOP. The HbA1c level decreased in both groups. The difference was not statistically significant. The results of the microbiological analysis suggest that the presence of periodontal pathogenic bacteria is lower with additional antimicrobial photodynamic therapy with statistically significant difference for T. forsythia.

CONCLUSIONS

Additional aPDT causes a significant reduction in BoP in the proportion of positive sites for periodontal pathogens.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT05816941.

CLINICAL RELEVANCE

aPTD is a noninvasive adjunctive therapy that can positively influence the periodontal treatment outcome.

Green Alternatives as Antimicrobial Agents in Mitigating Periodontal Diseases: A Narrative Review

Periodontal diseases and dental caries are the most common infectious oral diseases impacting oral health globally. Oral cavity health is crucial for enhancing life quality since it serves as the entranceway to general health. The oral microbiome and oral infectious diseases are strongly correlated. Gram-negative anaerobic bacteria have been associated with periodontal diseases. Due to the shortcomings of several antimicrobial medications frequently applied in dentistry, the lack of resources in developing countries, the prevalence of oral inflammatory conditions, and the rise in bacterial antibiotic resistance, there is a need for reliable, efficient, and affordable alternative solutions for the prevention and treatment of periodontal diseases. Several accessible chemical agents can alter the oral microbiota, although these substances also have unfavorable symptoms such as vomiting, diarrhea, and tooth discoloration. Natural phytochemicals generated from plants that have historically been used as medicines are categorized as prospective alternatives due to the ongoing quest for substitute products. This review concentrated on phytochemicals or herbal extracts that impact periodontal diseases by decreasing the formation of dental biofilms and plaques, preventing the proliferation of oral pathogens, and inhibiting bacterial adhesion to surfaces. Investigations examining the effectiveness and safety of plant-based medicines have also been presented, including those conducted over the past decade.

Subgingival host-microbiome metatranscriptomic changes following scaling and root planing in grade II/III periodontitis

AIM

To assess the effects of scaling and root planing (SRP) on the dynamics of gene expression by the host and the microbiome in subgingival plaque samples.

MATERIALS AND METHODS

Fourteen periodontitis patients were closely monitored in the absence of periodontal treatment for 12 months. During this period, comprehensive periodontal examination and subgingival biofilm sample collection were performed bi-monthly. After 12 months, clinical attachment level (CAL) data were compiled and analysed using linear mixed models (LMM) fitted to longitudinal CAL measurements for each tooth site. LMM classified the sites as stable (S), progressing (P), or fluctuating (F). After the 12-month visit, subjects received SRP, and at 15 months they received comprehensive examination and supportive periodontal therapy. Those procedures were repeated at the 18-month visit, when patients were also sampled. Each patient contributed with one S, one P, and one F site collected at the 12- and 18-month visits. Samples were analysed using Dual RNA-Sequencing to capture host and bacterial transcriptomes simultaneously.

RESULTS

Microbiome and host response behaviour were specific to the site's progression classification (i.e., S, P, or F). Microbial profiles of pre- and post-treatment samples exhibited specific microbiome changes, with progressing sites showing the most significant changes. Among them, Porphyromonas gingivalis was reduced after treatment, while Fusobacterium nucleatum showed an increase in proportion. Transcriptome analysis of the host response showed that interleukin (IL)-17, TNF signalling pathways, and neutrophil extracellular trap formation were the primary immune response activities impacted by periodontal treatment.

CONCLUSIONS

SRP resulted in a significant "rewiring" of host and microbial activities in the progressing sites, while restructuring of the microbiome was minor in stable and fluctuating sites.

Virulence Factors of the Periodontal Pathogens: Tools to Evade the Host Immune Response and Promote Carcinogenesis

Periodontitis is the most common chronic, inflammatory oral disease that affects more than half of the population in the United States. The disease leads to destruction of the tooth-supporting tissue called periodontium, which ultimately results in tooth loss if uncured. The interaction between the periodontal microbiota and the host immune cells result in the induction of a non-protective host immune response that triggers host tissue destruction. Certain pathogens have been implicated periodontal disease formation that is triggered by a plethora of virulence factors. There is a collective evidence on the impact of periodontal disease progression on systemic health. Of particular interest, the role of the virulence factors of the periodontal pathogens in facilitating the evasion of the host immune cells and promotion of carcinogenesis has been the focus of many researchers. The aim of this review is to examine the influence of the periodontal pathogens Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P. gingivalis), and Fusobacterium nucleatum (F. nucleatum) in the modulation of the intracellular signaling pathways of the host cells in order to evade the host immune response and interfere with normal host cell death and the role of their virulence factors in this regard.

Host and bacterial factors linking periodontitis and rheumatoid arthritis

Observations from numerous clinical, epidemiological and serological studies link periodontitis with severity and progression of rheumatoid arthritis. The strong association is observed despite totally different aetiology of these two diseases, periodontitis being driven by dysbiotic microbial flora on the tooth surface below the gum line, while rheumatoid arthritis being the autoimmune disease powered by anti-citrullinated protein antibodies (ACPAs). Here we discuss genetic and environmental risk factors underlying development of both diseases with special emphasis on bacteria implicated in pathogenicity of periodontitis. Individual periodontal pathogens and their virulence factors are argued as potentially contributing to putative causative link between periodontal infection and initiation of a chain of events leading to breakdown of immunotolerance and development of ACPAs. In this respect peptidylarginine deiminase, an enzyme unique among prokaryotes for Porphyromonas gingivalis, is elaborated as a potential mechanistic link between this major periodontal pathogen and initiation of rheumatoid arthritis development.

Comparative evaluation of subgingival microbiome in healthy periodontium and gingivitis using next-generation sequencing technology: A case–control study

Background:

Human dental plaque is a complex microbial community containing millions of species. Gingivitis is a dysregulated immune-inflammatory response induced by dysbiotic plaque biofilm that interrupts symbiosis. The emergence of next-generation sequencing with 16S rRNA gene has greatly contributed in understanding the complexity of microbiota. However, studies focusing on microbiome in gingivitis are limited. The whole bacterial community is important in causing periodontal disease than a small number of periodontal pathogens. In this study, we attempted to profile the subgingival microbiome from individuals with healthy gingiva and in patients with gingivitis using next-generation sequencing technology.

Materials and Methods:

Subgingival plaque samples from 15 healthy periodontium (Group I) and 15 gingivitis (Group II) were collected and 16s rRNA sequencing was done in Illumina Solexa Sequencer. Data analysis using 16s metagenomics tool from BaseSpace onsite operational taxonomic units was assigned to each sequence using HOMD database. Individual variation in the microbiome of the subgingival samples between the two groups was also evaluated.

Results:

The comparison of top 20 species between Group I and Group II revealed no significant species group between them. Synergistetes was absent in Group I samples but found in Group II. At the genus level, HACEK group species were found in both the groups, while Dialister and Aneroglobus were found abundantly in the Group II.

Conclusion:

The presence of unique genera and species seen in Group II samples could point toward a dysbiotic shift that could be taking place in the subgingival environment leading to gingivitis.

Modulation of the Host Cell Transcriptome and Epigenome by Fusobacterium nucleatum

Fusobacterium nucleatum is a ubiquitous opportunistic pathogen with an emerging role as an oncomicrobe in colorectal cancer and other cancer settings. F. nucleatum can adhere to and invade host cells in a manner that varies across F. nucleatum strains and host cell phenotypes. Here, we performed pairwise cocultures between three F. nucleatum strains and two immortalized primary host cell types (human colonic epithelial [HCE] cells and human carotid artery endothelial [HCAE] cells) followed by transcriptome sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) to investigate transcriptional and epigenetic host cell responses. We observed that F. nucleatum-induced host cell transcriptional modulation involves strong upregulation of genes related to immune migration and inflammatory processes, such as TNF, CXCL8, CXCL1, and CCL20. Furthermore, we identified genes strongly upregulated in a cell line-specific manner. In HCE cells, overexpressed genes included UBD and DUOX2/DUOXA2, associated with p53 degradation-mediated proliferation and intestinal reactive oxygen species (ROS) production, respectively. In HCAE cells, overexpressed genes included EFNA1 and LIF, two genes commonly upregulated in colorectal cancer and associated with poor patient outcomes, and PTGS2 (COX2), a gene associated with the protective effect of aspirin in the colorectal cancer setting. Interestingly, we also observed downregulation of numerous histone modification genes upon F. nucleatum exposure. We used the ChIP-seq data to annotate chromatin states genome wide and found significant chromatin remodeling following F. nucleatum exposure in HCAE cells, with increased frequencies of active enhancer and low-signal/quiescent states. Thus, our results highlight increased inflammation and chemokine gene expression as conserved host cell responses to F. nucleatum exposure and extensive host cell epigenomic changes specific to host cell type. IMPORTANCE Fusobacterium nucleatum is a bacterium normally found in the healthy oral cavity but also has an emerging role in colorectal cancer and other cancer settings. The host-microbe interactions of F. nucleatum and its involvement in tumor initiation, progression, and treatment resistance are not fully understood. We explored host cell changes that occur in response to F. nucleatum. We identified key genes differentially expressed in response to various conditions of F. nucleatum exposure and determined that the conserved host cell response to F. nucleatum was dominated by increased inflammation and chemokine gene expression. Additionally, we found extensive host cell epigenomic changes as a novel aspect of host modulation associated with F. nucleatum exposure. These results extend our understanding of F. nucleatum as an emerging pathogen and highlight the importance of considering strain heterogeneity and host cell phenotypic variation when exploring pathogenic mechanisms of F. nucleatum.

The Associations of Periodontopathic Bacteria and Oral Candida with Periodontal Inflamed Surface Area in Older Adults Receiving Supportive Periodontal Therapy

The periodontal inflamed surface area (PISA) has been proposed for assessment of the total periodontal inflammatory status in people with periodontitis. This study was performed to investigate the associations of periodontopathic bacteria and candida with PISA in older people. We enrolled 100 patients aged ≥ 60 years who visited Hiroshima University Hospital. PISA and periodontal epithelial surface area (PESA) were calculated in each patient. Oral rinse samples were collected for DNA extraction. Periodontopathic bacteria and candida were detected by polymerase chain reaction. The mean values of PISA and PESA were significantly greater in T.forsythia-positive patients than in T.forsythia-negative patients. T.forsythia/C. albicans double-positive patients exhibited significantly greater PISA values than did non-double-positive patients. Additionally, PISA values were significantly greater in T. forsythia//T. denticola/C. albicans triple-positive patients than in T. forsythia//T. denticola/C. albicans non-triple-positive patients (p = 0.02). Propensity score-matching was performed between periodontopathic bacteria-positive and -negative patients using propensity scores generated from clinical factors. Importantly, T.forsythia/T. denticola double-positive patients exhibited significantly greater PISA values than non-double-positive patients among 72 propensity score-matched patients. Our preliminary results highlight the importance of the presence of T.forsythia and T. denticola for periodontal inflammation severity in older Japanese people.

Dental chews positively shift the oral microbiota of adult dogs

Microbiota plays a prominent role in periodontal disease, but the canine oral microbiota and how dental chews may affect these populations have been poorly studied. We aimed to determine the differences in oral microbiota of adult dogs consuming dental chews compared with control dogs consuming only a diet. Twelve adult female beagle dogs (mean age = 5.31 ± 1.08 yr) were used in a replicated 4 × 4 Latin square design consisting of 28-d periods. Treatments (n = 12/group) included: diet only (CT); diet + Bones & Chews Dental Treats (BC; Chewy, Inc., Dania Beach, FL); diet + Dr. Lyon's Grain-Free Dental Treats (DL; Dr. Lyon's, LLC, Dania Beach, FL); and diet + Greenies Dental Treats (GR; Mars Petcare US, Franklin, TN). Each day, one chew was provided 4 h after mealtime. On day 27, breath samples were analyzed for total volatile sulfur compound concentrations using a Halimeter. On day 0 of each period, teeth were cleaned by a veterinary dentist blinded to treatments. Teeth were scored for plaque, calculus, and gingivitis by the same veterinary dentist on day 28 of each period. After scoring, salivary (SAL), subgingival (SUB), and supragingival (SUP) samples were collected for microbiota analysis using Illumina MiSeq. All data were analyzed using SAS (version 9.4) using the Mixed Models procedure, with P < 0.05 considered significant. All dogs consuming chews had lower calculus coverage and thickness, pocket depth and bleeding, plaque thickness, and halitosis compared with CT. In all sites of collection, CT dogs had a higher relative abundance of one or more potentially pathogenic bacteria (Porphyromonas, Anaerovorax, Desulfomicrobium, Tannerella, and Treponema) and lower relative abundance of one or more genera associated with oral health (Neisseria, Corynebacterium, Capnocytophaga, Actinomyces, Lautropia, Bergeyella, and Moraxella) than those fed chews. DL reduced Porphyromonas in SUP and SUB samples. DL and GR reduced Treponema in SUP samples. DL increased Corynebacterium in all sites of collection. BC increased Corynebacterium in SAL samples. DL and GR increased Neisseria in SAL samples. DL increased Actinomyces in the SUB sample. GR increased Actinomyces in SAL samples. Our results suggest that the dental chews tested in this study may aid in reducing periodontal disease risk in dogs by beneficially shifting the microbiota inhabiting plaque and saliva of a dog's oral cavity. These shifts occurred over a short period of time and were correlated with improved oral health scores.

Microbiota populations in supragingival plaque, subgingival plaque, and saliva habitats of adult dogs

Background

Oral diseases are common in dogs, with microbiota playing a prominent role in the disease process. Oral cavity habitats harbor unique microbiota populations that have relevance to health and disease. Despite their importance, the canine oral cavity microbial habitats have been poorly studied. The objectives of this study were to (1) characterize the oral microbiota of different habitats of dogs and (2) correlate oral health scores with bacterial taxa and identify what sites may be good options for understanding the role of microbiota in oral diseases. We used next-generation sequencing to characterize the salivary (SAL), subgingival (SUB), and supragingival (SUP) microbial habitats of 26 healthy adult female Beagle dogs (4.0 ± 1.2 year old) and identify taxa associated with periodontal disease indices.

Results

Bacterial species richness was highest for SAL, moderate for SUB, and lowest for SUP samples (p < 0.001). Unweighted and weighted principal coordinates plots showed clustering by habitat, with SAL and SUP samples being the most different from one another. Bacteroidetes, Proteobacteria, Firmicutes, Fusobacteria, Actinobacteria, and Spirochaetes were the predominant phyla in all habitats. Paludibacter, Filifactor, Peptostreptococcus, Fusibacter, Anaerovorax, Fusobacterium, Leptotrichia, Desulfomicrobium, and TG5 were enriched in SUB samples, while Actinomyces, Corynebacterium, Leucobacter, Euzebya, Capnocytophaga, Bergeyella, Lautropia, Lampropedia, Desulfobulbus, Enhydrobacter, and Moraxella were enriched in SUP samples. Prevotella, SHD-231, Helcococcus, Treponema, and Acholeplasma were enriched in SAL samples. p-75-a5, Arcobacter, and Pasteurella were diminished in SUB samples. Porphyromonas, Peptococcus, Parvimonas, and Campylobacter were diminished in SUP samples, while Tannerella, Proteocalla, Schwartzia, and Neisseria were diminished in SAL samples. Actinomyces, Corynebacterium, Capnocytophaga, Leptotrichia, and Neisseria were associated with higher oral health scores (worsened health) in plaque samples.

Conclusions

Our results demonstrate the differences that exist among canine salivary, subgingival plaque and supragingival plaque habitats. Salivary samples do not require sedation and are easy to collect, but do not accurately represent the plaque populations that are most important to oral disease. Plaque Actinomyces, Corynebacterium, Capnocytophaga, Leptotrichia, and Neisseria were associated with higher (worse) oral health scores. Future studies analyzing samples from progressive disease stages are needed to validate these results and understand the role of bacteria in periodontal disease development.

Subgingival microbiome is associated with alveolar bone loss measured 5 years later in postmenopausal women

BACKGROUND

The aim of this study was to quantify the association between subgingival microbiota and periodontal disease progression in older women, for which limited published data exist.

METHODS

A total of 1016 postmenopausal women, aged 53 to 81 years, completed baseline (1997 to 2001) and 5-year (2002 to 2006) dental exams that included probing depth, clinical attachment level, gingival bleeding, and radiographic alveolar crestal height (ACH). Baseline microbiota were measured in subgingival plaque using 16S rRNA sequencing. Associations between 52 microbiota we previously found statistically significantly associated with clinical periodontal disease at baseline, were examined with disease progression. The traditional Socransky microbiota complexes also were evaluated. Side-by-side radiograph comparisons were used to define progression as ≥2 teeth with ≥1 mm ACH loss or ≥1 new tooth loss to periodontitis. The association between baseline centered log(2) ratio transformed microbial relative abundances and 5-year periodontal disease progression was measured with generalized linear models.

RESULTS

Of 36 microbiota we previously showed were elevated in moderate/severe disease at baseline, 24 had statistically significantly higher baseline mean relative abundance in progressing compared with non-progressing women (P < .05, all); which included all Socransky red bacteria (P. gingivalis, T. forsythia, T. denticola). Of 16 microbiota elevated in none/mild disease at baseline, five had statistically significantly lower baseline abundance in non-progressing compared with progressing women (P < 0.05, all), including one Socransky yellow bacteria (S. oralis). When adjusted for baseline age, socioeconomic status, and self-rated general health status, odds ratios for 5-year progression ranged from 1.18 to 1.51 (per 1-standard deviation increment in relative abundance) for microbiota statistically significantly (P < 0.05) positively associated with progression, and from 0.77 to 0.82 for those statistically significantly (P < 0.05) inversely associated with progression. These associations were similar when stratified on baseline levels of pocket depth, gingival bleeding, ACH, and smoking status.

CONCLUSIONS

These prospective results affirm clearly that subgingival microbiota are measurably elevated several years prior to progression of alveolar bone loss, and include antecedent elevations in previously undocumented taxa additional to known Socransky pathogenic complexes.

Role of NLRP3 inflammasome in COVID-19 and periodontitis: Possible protective effect of melatonin

Daily new information emerges regarding the COVID-19, infection of SARS-CoV-2, which is considered a global pandemic. Angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) are required to complete the viral invasion pathway and are present in the oral mucosa, gingiva and periodontal pocket. Thus, increasing the likelihood of periodontitis and gingivitis caused by COVID-19. The cytokine storm during COVID-19 similarly arises during periodontal inflammation. Studies have reported that NOD-Like Receptor family pyrin domain-containing 3 (NLRP3) inflammasome is significant in the cytokine storm. Recently, the course of the COVID-19 has been related to the melatonin levels in both COVID-19 and periodontal diseases. It is known that melatonin prevents the activation of NLRP3 inflammasome. In light of these findings, we think that melatonin treatment during COVID-19 or periodontal diseases may prevent the damage seen in periodontal tissues by preventing the activation of NLRP3 inflammasome.

Characterization of ecotin homologs from Campylobacter rectus and Campylobacter showae

Ecotin, first described in Escherichia coli, is a potent inhibitor of a broad range of serine proteases including those typically released by the innate immune system such as neutrophil elastase (NE). Here we describe the identification of ecotin orthologs in various Campylobacter species, including Campylobacter rectus and Campylobacter showae residing in the oral cavity and implicated in the development and progression of periodontal disease in humans. To investigate the function of these ecotins in vitro, the orthologs from C. rectus and C. showae were recombinantly expressed and purified from E. coli. Using CmeA degradation/protection assays, fluorescence resonance energy transfer and NE activity assays, we found that ecotins from C. rectus and C. showae inhibit NE, factor Xa and trypsin, but not the Campylobacter jejuni serine protease HtrA or its ortholog in E. coli, DegP. To further evaluate ecotin function in vivo, an E. coli ecotin-deficient mutant was complemented with the C. rectus and C. showae homologs. Using a neutrophil killing assay, we demonstrate that the low survival rate of the E. coli ecotin-deficient mutant can be rescued upon expression of ecotins from C. rectus and C. showae. In addition, the C. rectus and C. showae ecotins partially compensate for loss of N-glycosylation and increased protease susceptibility in the related pathogen, Campylobacter jejuni, thus implicating a similar role for these proteins in the native host to cope with the protease-rich environment of the oral cavity.

Mitigation of the Toxic Effects of Periodontal Pathogens by Candidate Probiotics in Oral Keratinocytes, and in an Invertebrate Model

The larvae of the wax moth Galleria mellonella and human oral keratinocytes were used to investigate the protective activity of the candidate oral probiotics Lactobacillus rhamnosus GG (LHR), Lactobacillus reuteri (LR), and Streptococcus salivarius K-12 (SS) against the periodontal pathogens Fusobacterium nucleatum (FN), Porphyromonas gingivalis (PG), and Aggregatibacter actinomycetemcomitans (AA). Probiotics were delivered to the larvae (i) concomitantly with the pathogen in the same larval pro-leg; (ii) concomitantly with the pathogen in different pro-legs, and (iii) before inoculation with the pathogen in different pro-legs. Probiotics were delivered as viable cells, cell lysates or cell supernatants to the oral keratinocytes concomitantly with the pathogen. The periodontal pathogens killed at least 50% of larvae within 24 h although PG and FN were significantly more virulent than AA in the order FN > PG > AA and were also significantly lethal to mammalian cells. The candidate probiotics, however, were not lethal to the larvae or human oral keratinocytes at doses up to 10⁷ cells/larvae. Wax worm survival rates increased up to 60% for some probiotic/pathogen combinations compared with control larvae inoculated with pathogens only. SS was the most effective probiotic against FN challenge and LHR the least, in simultaneous administration and pre-treatment, SS and LR were generally the most protective against all pathogens (up to 60% survival). For P. gingivalis, LR > LHR > SS, and for A. actinomycetemcomitans SS > LHR and LR. Administering the candidate probiotics to human oral keratinocytes significantly decreased the toxic effects of the periodontal pathogens. In summary, the periodontal pathogens were variably lethal to G. mellonella and human oral keratinocytes and the candidate probiotics had measurable protective effects, which were greatest when administrated simultaneously with the periodontal pathogens, suggesting protective effects based on bacterial interaction, and providing a basis for mechanistic studies.

Evaluation and Comparison of Antibacterial Efficacy of Herbal Extracts in Combination with Antibiotics on Periodontal pathobionts: An in vitro Microbiological Study

BACKGROUND

In the past few decades focus of research has been toward herbal medicines because of growing bacterial resistance and side effects of antimicrobial agents. The extract derived from the plants may increase the efficacy of antibiotics when used in combination against pathogenic bacteria. In the current study, the synergistic antibacterial efficacy of plant extracts in combination with antibiotics has been assessed on selected periodontal pathogens.

METHODS

Ethanolic extracts were prepared from Salvadora persica (Miswak) and Cinnamomum zeylanicum (Ceylon cinnamon), by the soxhalate method. Plaque samples were collected from clinical periodontitis patients to isolate and grow the periodontal pathobionts under favorable conditions. Susceptibility of bacteria to the extracts was assessed by gauging the diameter of the inhibition zones. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of plant extracts were determined against each bacterium. Synergistic activity of plants extract in combination with antibiotics against the bacteria was also assessed by measuring the diameter of the inhibition zones.

RESULTS

Ethanolic extract of both the plants showed an inhibitory effect on the proliferation and growth of all four strains of periodontal pathobionts. Maximum antibacterial activity was exhibited by C. zeylanicum against Tannerella forsythia (MIC = 1.56 ± 0.24 mg/mL, MBC = 6.25 ± 0.68 mg/mL), whereas among all the studied groups the minimum activity was reported by C. zeylanicum against Aggregatibacter actinomycetemcomitans the (MIC = 12.5 ± 3.25 mg/mL, MBC = 75 ± 8.23 mg/mL). Combination of herbal extracts with different antibiotics revealed a synergistic antibacterial effect. The best synergism was exhibited by S. persica with metronidazole against A. actinomycetemcomitans (27 ± 1.78).

CONCLUSIONS

Current in vitro study showed variable antibacterial activity by experimented herbal extracts against periodontal pathobionts. The synergistic test showed significant antibacterial activity when plant extracts were combined with antibiotics.

Porphyromonas gingivalis and digestive system cancers

Porphyromonas gingivalis (P. gingivalis) is an anaerobic gram-negative bacterium that colonizes in the epithelium and has been strongly associated with periodontal disease. Recently, various degrees of associations between P. gingivalis and digestive system cancers, including oral squamous cell carcinoma in the oral cavity, oesophageal squamous carcinoma in the digestive tract, and pancreatic cancer in pancreatic tissues, have been displayed in multiple clinical and experimental studies. Since P. gingivalis has a strong association with periodontal diseases, not only the relationships between P. gingivalis and digestive system tumours but also the effects induced by periodontal diseases on cancers are well-illustrated in this review. In addition, the prevention and possible treatments for these digestive system tumours induced by P. gingivalis infection are also included in this review. At the end, we also highlighted the possible mechanisms of cancers caused by P. gingivalis. One important carcinogenic effect of P. gingivalis is inhibiting the apoptosis of epithelial cells, which also plays an intrinsic role in protecting cancerous cells. Some signalling pathways activated by P. gingivalis are involved in cell apoptosis, tumourigenesis, immune evasion and cell invasion of tumour cells. In addition, metabolism of potentially carcinogenic substances caused by P. gingivalis is also one of the connections between this bacterium and cancers.

Differences in the subgingival microbial population of chronic periodontitis in subjects with and without type 2 diabetes mellitus-a systematic review

OBJECTIVES

The purpose of this systematic review was to evaluate the available evidence in the literature in regard to the subgingival microbial population of chronic periodontitis in subjects with type 2 diabetes mellitus (T2DM+PD) compared to non-diabetic subjects (NDM+PD).

MATERIALS AND METHODS

A literature search was conducted at Ovid MEDLINE and EMBASE database from 1980 to 2016, supplemented by hand searching as needed. Studies presenting with at least one of the primary outcomes (presence of any subgingival microorganisms, proportion and/or the amount of any subgingival plaque bacteria in T2DM+PD versus NDM+PD) were included. Screening, data extraction and quality assessment were conducted independently and in duplicate.

RESULTS

From 611 citations, 19 full-text papers were screened and 11 articles were included for critical appraisal by both reviewers. Some evidence of a difference in the microbial profile between chronic PD subjects with and without T2DM was identified. The strength of evidence is strongest in Tannerella forthysia (T .forsythia) which was reported to be less frequent in the diabetic (T2DM+PD) group in five of the studies, followed by a weaker strength of evidence for other periodontal pathogens such as Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), which were also found less frequent in the diabetic (T2DM+PD) group .

CONCLUSION

Only few studies have compared T2DM+PD with NDM+PD. It is therefore strongly recommended that further studies which include four distinct groups of participants (NDM+PD, T2DM+PD, NDM+NPD, T2DM+NPD) instead of using intra-subject comparisons between healthy and diseased sites of the same subjects.

CLINICAL RELEVANCE

Differences in bacterial populations of T2DM+PD in comparison to NDM+PD subjects may indicate the need of different protocols for the treatment of the diabetic patients with periodontal disease.

Targeting the HUβ Protein Prevents Porphyromonas gingivalis from Entering into Preexisting Biofilms

The oral cavity is home to a wide variety of bacterial species, both commensal, such as various streptococcal species, and pathogenic, such as Porphyromonas gingivalis, one of the main etiological agents of periodontal disease. Our understanding of how these bacteria ultimately cause disease is highly dependent upon understanding how they coexist and interact with one another in biofilm communities and the mechanisms by which biofilms are formed. Our research has demonstrated that the DNABII family of DNA-binding proteins are important components of the extracellular DNA (eDNA)-dependent matrix of bacterial biofilms and that sequestering these proteins via protein-specific antibodies results in the collapse of the biofilm structure and release of the resident bacteria. While the high degree of similarity among the DNABII family of proteins has allowed antibodies derived against specific DNABII proteins to disrupt biofilms formed by a wide range of bacterial pathogens, the DNABII proteins of P. gingivalis have proven to be antigenically distinct, allowing us to determine if we can use anti-P. gingivalis HUβ antibodies to specifically target this species for removal from a mixed-species biofilm. Importantly, despite forming homotypic biofilms in vitro, P. gingivalis must enter preexisting biofilms in vivo in order to persist within the oral cavity. The data presented here indicate that antibodies derived against the P. gingivalis DNABII protein, HUβ, reduce by half the amount of P. gingivalis organisms entering into preexisting biofilm formed by four oral streptococcal species. These results support our efforts to develop methods for preventing and treating periodontal disease.IMPORTANCE Periodontitis is one of the most prevalent chronic infections, affecting 40 to 50% of the population of the United States. The root cause of periodontitis is the presence of bacterial biofilms within the gingival space, with Porphyromonas gingivalis being strongly associated with the development of the disease. Periodontitis also increases the risk of secondary conditions and infections such as atherosclerosis and infective endocarditis caused by oral streptococci. To induce periodontitis, P. gingivalis needs to incorporate into preformed biofilms, with oral streptococci being important binding partners. Our research demonstrates that targeting DNABII proteins with an antibody disperses oral streptococcus biofilm and prevents P. gingivalis entry into oral streptococcus biofilm. These results suggest potential therapeutic treatments for endocarditis caused by streptococci as well as periodontitis.

Metatranscriptome of the Oral Microbiome in Health and Disease

The last few decades have witnessed an increasing interest in studying the human microbiome and its role in health and disease. The focus of those studies was mainly the characterization of changes in the composition of the microbial communities under different conditions. As a result of those studies, we now know that imbalance in the composition of the microbiome, also referred to as microbial dysbiosis, is directly linked to developing certain conditions. Dysbiosis of the oral microbiome is a prime example of how this imbalance leads to disease in the case of periodontal disease. However, there is considerable overlap in the phylogenetic profiles of microbial communities associated with active and inactive lesions, suggesting that the difference in periodontal status of those sites may not be explained solely by differences in the subgingival microbial composition. These findings suggest that differences in functional activities may be the essential elements that define the dysbiotic process. Researchers have recently begun to study gene expression of the oral microbiome in situ with the goal of identifying changes in functional activities that could explain the transition from health to disease. These initial results suggest that, rather than a specific composition, a better understanding of oral dysbiosis can be obtained from the study of functional activities of the microbial community. In this review, we give a summary of these initial studies, which have opened a new door to our understanding of the dynamics of the oral community during the dysbiotic process in the oral cavity.

Efficacy of Acacia arabica gum as an adjunct to scaling and root planing in the treatment of chronic periodontitis: A randomized controlled clinical trial

Aim

The aim of the present study was to explore the adjunctive use of Acacia arabica gel in the treatment of chronic periodontitis.

Methods

Single centre, randomised, triple blind, controlled trial on mild to moderate chronic periodontitis patients; Group I (SRP + Acacia arabica, n = 40) and Group II (SRP + placebo, n = 40); were analysed for clinical improvements in periodontal pocket depth (PPD) and clinical attachment levels (CAL) at baseline, 15 and 90 days on application of gels. Gingival index and plaque index were assessed as secondary parameters.

Results

Statistically significant PPD reduction (p < .05) and CAL gain (p < .05) was observed with use of Acacia arabica gel. The reduction in sites with moderate PPD was observed more among Group I than Group II and the difference was statistically significant (p = .001). Secondary outcome variables; Plaque Index and Gingival Index showed better resolution with Acacia arabica gel.

Conclusion

Acacia arabica leads to better clinical outcomes in patients with mild to moderate chronic periodontitis with effective antiplaque and anti-gingivitis action. It may be recommended adjunct to SRP for maintenance in patients with mild to moderate chronic periodontitis.

Porphyromonas gingivalis Capsule-Mediated Coaggregation as a Virulence Factor in Mixed Infection With Fusobacterium nucleatum

BACKGROUND

Porphyromonas gingivalis (Pg) capsule enables evasion from phagocytosis, invasion of keratinocytes, and bacterial survival. In mixed infection, the capsule also participates in coaggregation, which may lead to characteristic virulence not present in the monoinfection. The aim of this study is to evaluate the role of Pg capsule as a virulence factor in coaggregated mixed infection with Fusobacterium nucleatum (Fn).

METHODS

Mixed infections containing Fn and non-capsulated or capsulated strains of Pg were compared with the same infection with lactose as coaggregation inhibitor. Murine experimental periodontitis was used to assess disease severity. Primary polymorphonuclear leukocytes and keratinocytes were used to examine phagocytosis and bacterial invasion, respectively.

RESULTS

Mixed infection with capsulated Pg augmented alveolar bone loss compared with that of mixed infection with non-capsulated Pg. Addition of lactose led to attenuation of bone loss in the capsulated mixed infection and to intensification of bone loss in the non-capsulated mixed infection. In the latter mixed infection, Fn evaded phagocytosis, whereas in the capsulated mixed infection Pg displayed a greater capacity for invasion of keratinocytes.

CONCLUSIONS

Pg capsule was found to serve as a unique virulence factor in mixed infection with Fn. Capsule-dependent coaggregation led to augmented invasion of Pg and may be responsible for the severity of disease after mixed infection with Fn.

Restriction Fragment Length Polymorphism Analysis of the Fimbrillin Locus, fimA, of Porphyromonas gingivalis

With hybridization probes derived from the fimbrial locus of Porphyromonas gingivalis strain 381, fimA381' restriction fragment length polymorphisms (RFLPs) were examined at the fimbrillin locus in 39 human and animal strains of this species. The 39 strains were subdivided into nine RFLP groups (I-IX) after genomic digests were probed with the internal coding sequence of the fimA381 gene. Thirty-three strains showed one or more AluI fragments of moderate-to-high homology (≥77%) with the internal coding sequence of fimA381. These strains were distributed into the first seven RFLP groups, based solely on the size of the major hybridizing AluI fragment. Five human strains (RFLP Group VIII) had only one Alu I fragment that hybridized very poorly with this probe. One animal strain did not have homology at all (RFLP Group IX). When all AluI fragments that hybridized with fimA381 were analyzed, RFLP groups I-VIII were further differentiated into 25 distinct RFLP patterns. Hybridizations were also performed with the internal coding sequence of fimA381 to probe PstI genomic digests of selected strains that appeared to have lesser homology with fimA381. These hybridizations were performed to determine the level and location of the region of poor homology within the fimA genes of these strains. The results suggested that fimbrial coding sequences are more commonly conserved between these strains in the 5'-region of the fimA locus (≥92% sequence homology). However, the five human strains of RFLP Group VIII had only one PstI fragment that hybridized very poorly with a probe derived from fimA381 coding sequence, and this sequence homology (only > 66%) was located in the central or 3'-end of the fimA gene. The 5'-region of the fimA allele in Group VIII strains did not have any detectable sequence homology. In contrast, the Group VIII strains were highly homologous with the sequences flanking the fimA381 gene. This indicates that these strains do possess a fimA allele at the same chromosomal location as fimA381.

Strain-Specific Impact of Fusobacterium nucleatum on Neutrophil Function

BACKGROUND

Neutrophil function is critical for initiation and progression of infecto-inflammatory diseases. Key quorum-sensing plaque bacteria, such as Fusobacterium nucleatum, act as bridging species between early and late colonizer pathogens, such as Porphyromonas gingivalis, as the biofilm ages and periodontal inflammation increases. This study is designed to determine impact of different F. nucleatum strains on neutrophil function.

METHODS

Cells of human promyelocytic leukemia cell line-60 were differentiated into neutrophil-like cells and cultured with F. nucleatum strains of subspecies (ssp.) nucleatum ATCC 25586, ssp. polymorphum ATCC 10953, and ssp. vincentii ATCC 49256. Neutrophil phagocytosis of F. nucleatum strains and neutrophil apoptosis were analyzed by flow cytometry. Superoxide generation was measured by cytochrome C reduction in the presence and absence of N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) (1 μM) stimulation. Proinflammatory cytokine release was determined after 2, 6, and 24 hours of culture in the presence/absence of different F. nucleatum strains. Expression of Toll-like receptor (TLR)2, TLR4, and nuclear factor (NF)-kappa B mRNA levels were analyzed using real-time quantitative polymerase chain reaction. Each experiment was repeated at least three times in triplicate. Data were analyzed using analysis of variance followed by post hoc Bonferroni correction.

RESULTS

All strains of F. nucleatum significantly increased phagocytic capacity of neutrophils. Neutrophil phagocytosis of F. nucleatum ssp. polymorphum was significantly greater than that of F. nucleatum ssp. vincentii and ssp. nucleatum (P <0.001). F. nucleatum ssp. nucleatum and ssp. polymorphum significantly blocked fMLP-induced superoxide generation (P <0.001). Although F. nucleatum vincentii also reduced superoxide generation (25%), the impact was not as strong as that of ssp. nucleatum (83%) and ssp. polymorphum (100%). All F. nucleatum strains stimulated significant increase in neutrophil apoptosis compared with control (P <0.001) and significantly increased expression of NF-κB mRNA in neutrophils (P <0.05). Levels of interleukin-8 and tumor necrosis factor-α produced by neutrophils were significantly increased in all F. nucleatum groups compared with control (P <0.001).

CONCLUSIONS

These findings suggest that different strains of F. nucleatum impact neutrophil function in different ways. Two of three subspecies blocked neutrophil superoxide generation in response to a secondary stimulus, preventing oxidative killing by neutrophils. The direct role of bridging species in pathogenesis of periodontitis may be greater than previously suspected in which they create a favorable environment for pathogenic transition of the dental ecosystem.

Selective photoantisepsis

BACKGROUND AND OBJECTIVE

Selective killing of pathogens by laser is possible due to the difference in absorption of photon energy by pathogens and host tissues. The optical properties of pathogenic microorganisms are used along with the known optical properties of soft tissues in calculations of the laser-induced thermal response of pathogen colonies embedded in a tissue model. The objective is to define the laser parameters that optimize pathogen destruction and depth of the bactericidal effect.

MATERIALS AND METHODS

The virtual periodontium is a computational model of the optical and time-dependent thermal properties of infected periodontal tissues. The model simulates the periodontal procedure: Laser Sulcular Debridement.¹ Virtual pathogen colonies are placed at different depths in the virtual periodontium to determine the depth for effective bactericidal effects given various laser parameters (wavelength, peak power, pulse duration, scan rate, fluence rate) and differences in pathogen sensitivities.

RESULTS

Accumulated background heat from multiple passes increases the depth of the bactericidal effect. In visible and near-IR wavelengths the large difference in absorption between normal soft tissue and Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi) results in selective destruction. Diode laser (810 nm) efficacy and depth of the bactericidal effect are variable and dependent on hemin availability. Both pulsed-Nd:YAG and the 810 nm diode lasers achieve a 2-3 mm deep damage zone for pigmented Pg and Pi in soft tissue without surface damage (selective photoantisepsis). The model predicts no selectivity for the Er:YAG laser (2,940 nm). Depth of the bactericidal effect is highly dependent on pathogen absorption coefficient. Highly sensitive pathogens may be destroyed as deep as 5-6 mm in soft tissue. Short pulse durations enable confinement of the thermal event to the target. Temporal selectivity is achieved by adjusting pulse duration based on target size.

CONCLUSION

The scatter-limited phototherapy model of the infected periodontium is applied to develop a proper dosimetry for selective photoantisepsis. Dosimetry planning is essential to the development of a new treatment modality. Lasers Surg. Med. 48:763-773, 2016. © 2016 Wiley Periodicals, Inc.

Detection and comparison of Selenomonas sputigena in subgingival biofilms in chronic and aggressive periodontitis patients

Background:

With the advent of DNA-based culture-independent techniques, a constantly growing number of Selenomonas phylotypes have been detected in patients with destructive periodontal diseases. However, the prevalence levels that have been determined in different studies vary considerably.

Aim:

The present study was undertaken to detect and compare the presence of Selenomonas sputigena in the subgingival plaque samples from generalized aggressive periodontitis (GAP), chronic generalized periodontitis, and periodontally healthy patients using conventional polymerase chain reaction (PCR) technique.

Materials and Methods:

A total of 90 patients were categorized as periodontally healthy individuals (Group I, n = 30), chronic generalized periodontitis (Group II, n = 30), and GAP (Group III, n = 30). The clinical parameters were recorded and subgingival plaque samples were collected. These were then subjected to conventional PCR analysis.

Statistical Analysis Used:

Kruskal–Wallis ANOVA test was used for multiple group comparisons followed by Mann–Whitney U-test for pairwise comparison.

Results:

On comparison between three groups, all the clinical parameters were found to be statistically highly significant. Comparing Groups I-II and I-III, the difference in detection was found to be statistically highly significant whereas in Groups II-III, it was statistically nonsignificant. On comparison of S. sputigena detected and undetected patients to clinical parameters in various study groups, the difference was found to be nonsignificant.

Conclusion:

S. sputigena was found to be significantly associated with chronic and aggressive periodontitis. Although the difference in its detection frequency in both groups was statistically nonsignificant when compared clinically, S. sputigena was more closely associated with the GAP.

Comparative Evaluation of Ciprofloxacin Levels in GCF and Plasma of Chronic Periodontitis Patients: Quasi Experimental Study

INTRODUCTION

For any antimicrobial approach to be successful in periodontal therapy, it is important that the antimicrobial agent targets the sub-gingival biofilm by attaining sufficient concentration at the sub-gingival site.

AIM

The purpose of the present study was to determine and compare the concentrations of ciprofloxacin present in Gingival Crevicular Fluid (GCF) and plasma after its systemic administration.

MATERIALS AND METHODS

A total of 20 subjects, in the age group of 30-60 years satisfying the inclusion and exclusion criteria, were chosen from the outpatient Department of Periodontology, Government Dental College and Hospital, Hyderabad and consent was obtained. Subjects were put on oral ciprofloxacin therapy (Baycip, Bayer Corporation) of 500mg twice daily doses for five days to establish steady state tissue levels of the agent. GCF and serum samples were collected at the 72(nd) hour after the first dose of ciprofloxacin and were compared using unpaired t test.

RESULTS

The mean gingival index value of the subjects was 1.8 ± 0.59 and the mean probing depth of the subjects taken in the study was 5.724 ± 0.47mm. The results of this study showed that ciprofloxacin concentrations were significantly higher (p<0.001) in GCF than in plasma.

CONCLUSION

Results from the present study and those from the earlier studies clearly indicate the ciprofloxacin's ability to reach and concentrate in infected periodontal sites via GCF. This property of ciprofloxacin may be useful for eradication of periodontal pathogens, thus improving the outcome of periodontal therapy.

Association Between High Serum Total Cholesterol and Periodontitis: National Health and Nutrition Examination Survey 2011 to 2012 Study of American Adults

BACKGROUND

Clinical studies have suggested that lipids increase activity of white blood cells. The objective of this study is to examine whether high serum total cholesterol (STC) is associated with periodontitis.

METHODS

A total of 1,061 participants from the 2011 to 2012 National Health and Nutrition Examination Survey who underwent both periodontal examination and laboratory test for STC was included. To examine effects of high STC on periodontitis, odds ratios were calculated, adjusting for age, sex, education, income, smoking status, diabetes, body mass index, and calcium levels.

RESULTS

Statistically significant associations were observed between borderline as well as high STC and periodontitis. Study participants with STC between 200 and 239 mg/dL (borderline) were 1.67 times (95% confidence interval [CI]: 1.13 to 2.47) as likely to have periodontitis as those with normal levels (≤199 mg/dL), and those with STC ≥240 mg/dL (high) were 2.22 times (95% CI: 1.27 to 3.87) as likely to have periodontitis as those with normal levels.

CONCLUSIONS

Positive significant association was observed between STC and periodontitis. Results of the present study provide insight into potential risk factors for periodontitis. High STC levels could be a potential risk factor for the disease; however, further studies need to be conducted to understand the actual relationship between STC levels and periodontitis and to establish causality and directional association.

Association of clinical parameters with periodontal bacterial haemolytic activity

AIMS

To determine whether haemolytic activity of subgingival bacteria is associated with periodontitis clinical parameters and to identify which bacteria produce the haemolysins.

MATERIALS AND METHODS

Subgingival plaque samples from 22 untreated chronic periodontitis patients were investigated by culture and identified with matrix assisted laser desorption/ionisation time-of-flight mass spectrometry.

RESULTS

Total aerobic and anaerobic bacterial viable counts, percentage distribution of α- and β-haemolytic bacteria were significantly elevated in diseased sites in relation to healthy sites (p < 0.001). Periodontal pathogens were more frequently detected at diseased sites: Porphyromonas gingivalis, Tannerella forsythia, Treponema sp., Prevotella sp., Parvimonas micra, Fusobacterium sp., Campylobacter sp., Capnocytophaga sp., and Selenomonas sp. Haemolytic unidentifiable species and Gram-positive anaerobes such as Slackia exigua, Solobacterium moorei, and Bulledia extructa were also more frequently detected at diseased sites. In diseased sites, the presence of different haemolytic characteristics was more strongly correlated with clinical measures of disease than the mere absence or presence of specific species. The strongest correlation with probing pocket depth was observed for overall β-haemolytic toxicity (r = 0.73, p < 0.001).

CONCLUSION

A strong association was observed between subgingival bacterial haemolytic activity and clinical parameters in patients with chronic periodontitis. Further investigations are warranted to delineate the role of haemolysins in the pathogenesis of periodontitis.

Natural antigenic differences in the functionally equivalent extracellular DNABII proteins of bacterial biofilms provide a means for targeted biofilm therapeutics

Bacteria that persist in the oral cavity exist within complex biofilm communities. A hallmark of biofilms is the presence of an extracellular polymeric substance (EPS), which consists of polysaccharides, extracellular DNA (eDNA), and proteins, including the DNABII family of proteins. The removal of DNABII proteins from a biofilm results in the loss of structural integrity of the eDNA and the collapse of the biofilm structure. We examined the role of DNABII proteins in the biofilm structure of the periodontal pathogen Porphyromonas gingivalis and the oral commensal Streptococcus gordonii. Co-aggregation with oral streptococci is thought to facilitate the establishment of P. gingivalis within the biofilm community. We demonstrate that DNABII proteins are present in the EPS of both S. gordonii and P. gingivalis biofilms, and that these biofilms can be disrupted through the addition of antisera derived against their respective DNABII proteins. We provide evidence that both eDNA and DNABII proteins are limiting in S. gordonii but not in P. gingivalis biofilms. In addition, these proteins are capable of complementing one another functionally. We also found that whereas antisera derived against most DNABII proteins are capable of binding a wide variety of DNABII proteins, the P. gingivalis DNABII proteins are antigenically distinct. The presence of DNABII proteins in the EPS of these biofilms and the antigenic uniqueness of the P. gingivalis proteins provide an opportunity to develop therapies that are targeted to remove P. gingivalis and biofilms that contain P. gingivalis from the oral cavity.

Non-Inflammatory Destructive Periodontal Disease

BACKGROUND

Non-Inflammatory Destructive Periodontal Disease (NIDPD), is a severe destructive periodontal disease, that is characterized by the attachment loss and alveolar bone loss, without signs of the gingival inflammation, and the periodontal pocket development.

OBJECTIVE

Despite the fact that various cases of NIDPD have been reported; their etiology and disease evolution is still indefinite, and therefore, are open for discussion.

METHOD

An NIDPD case was studied in order to demonstrate features of the disease, and discuss the possible etiology and treatment.

RESULTS

In this clinical case, the etiology of NIDPD seems to be an association of endogenous opportunist bacteria with anatomical aspects, occlusion pattern, emotional stress and mouth breathing condition.

CONCLUSION

In spite of all cases described in the literature are comparable and may have similar etiology as related in this clinical case, additional research is needed to identify and clarify the role of the etiologic factors which determine the disease.

Levels of Candidate Periodontal Pathogens in Subgingival Biofilm

In recent years, several new periodontal taxa have been associated with the etiology of periodontitis. A recent systematic review provides further support for the pathogenic role of 17 species/phylotypes. Thus, the aim of this study was to assess the prevalence and levels of these species in subjects with generalized chronic periodontitis (GChP; n = 30), generalized aggressive periodontitis (GAgP; n = 30), and periodontal health (PH; n = 30). All subjects underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analyzed for their content of 20 bacterial species/phylotypes through the RNA-oligonucleotide quantification technique. Subjects from the GChP and GAgP groups presented the highest mean values for all clinical parameters in comparison with the PH group (P < 0.05). Subjects with GChP and GAgP showed significantly higher mean levels of Bacteroidetes sp. human oral taxon (HOT) 274, Fretibacterium sp. HOT 360, and TM7 sp. HOT 356 phylotypes, as well as higher mean levels of Filifactor alocis, Fretibacterium fastidiosum, Porphyromonas gingivalis, Tannerella forsythia, and Selenomonas sputigena species than PH subjects (P < 0.05). GAgP subjects presented higher mean levels of TM7 sp. HOT 356 and F. alocis than GChP subjects (P < 0.05). A significantly higher mean prevalence of Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, and Fretibacterium sp. HOT 362 was found in subjects with GChP and GAgP than in PH subjects. Mean levels of P. gingivalis (r = 0.68), T. forsythia (r = 0.62), F. alocis (r = 0.51, P = 0.001), and Fretibacterium sp. HOT 360 (r = 0.41) were correlated with pocket depth (P < 0.001). In conclusion, Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, Fretibacterium sp. HOT 362, and TM7 sp. HOT 356 phylotypes, in addition to F. alocis, F. fastidiosum, and S. sputigena, seem to be associated with periodontitis, and their role in periodontal pathogenesis should be further investigated.

Antimicrobial efficacy of Tulsi leaf (Ocimum sanctum) extract on periodontal pathogens: An in vitro study

BACKGROUND

Periodontitis is an infection of the periodontal complex with severe forms of disease associated with specific bacteria colonizing the subgingival area. Widespread use of drugs has resulted in the emergence of side effects, uncommon infections, and resistance. Plant medicine like Tulsi has been used in many clinical conditions, and it appears to be a suitable alternative to manage conditions affecting the oral cavity. Hence, the objective was to assess the in vitro antimicrobial activity of Tulsi leaves extract (Ocimum sanctum) on periodontal pathogens with doxycycline as standard, as doxycycline has been used as an adjunct to nonsurgical therapy in periodontitis patients.

MATERIALS AND METHODS

Ethanolic extract of Tulsi was prepared by cold extraction method. Extract was diluted with an inert solvent, dimethyl formamide, to obtain five different concentrations (0.5%, 1%, 2%, 5%, and 10%). Doxycycline was used as a positive control and dimethyl formamide, as a negative control. The extract and controls were subjected to the microbiological investigation against Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Porphyromonas gingivalis. Agar well diffusion method was employed to determine the concentration at which Tulsi gave an inhibition zone, similar to doxycycline. Data were analyzed using one-way analysis of variance and Tukey post-hoc test was used for inter- and intra-group comparisons.

RESULTS

At 5% and 10% concentrations, Tulsi extracts demonstrated antimicrobial activity against A. actinomycetemcomitans, similar to doxycycline with similar inhibition zones (P > 0.05). P. gingivalis and P. intermedia, however, exhibited resistance to Tulsi extract that showed significantly smaller inhibition zones (P < 0.05).

CONCLUSIONS

Tulsi demonstrated effective antimicrobial property against A. actinomycetemcomitans, suggesting its possible use as an effective and affordable "adjunct" along with the standard care in the management of periodontal conditions. However, further research assessing the toxicity, durability, and other assessments followed by clinical trials is necessary to explore the potential of Tulsi in combating oral conditions.

Involvement of the Type IX Secretion System in Capnocytophaga ochracea Gliding Motility and Biofilm Formation

Capnocytophaga ochracea is a Gram-negative, rod-shaped bacterium that demonstrates gliding motility when cultured on solid agar surfaces. C. ochracea possesses the ability to form biofilms; however, factors involved in biofilm formation by this bacterium are unclear. A type IX secretion system (T9SS) in Flavobacterium johnsoniae was shown to be involved in the transport of proteins (e.g., several adhesins) to the cell surface. Genes orthologous to those encoding T9SS proteins in F. johnsoniae have been identified in the genome of C. ochracea; therefore, the T9SS may be involved in biofilm formation by C. ochracea. Here we constructed three ortholog-deficient C. ochracea mutants lacking sprB (which encodes a gliding motility adhesin) or gldK or sprT (which encode T9SS proteins in F. johnsoniae). Gliding motility was lost in each mutant, suggesting that, in C. ochracea, the proteins encoded by sprB, gldK, and sprT are necessary for gliding motility, and SprB is transported to the cell surface by the T9SS. For the ΔgldK, ΔsprT, and ΔsprB strains, the amounts of crystal violet-associated biofilm, relative to wild-type values, were 49%, 34%, and 65%, respectively, at 48 h. Confocal laser scanning and scanning electron microscopy revealed that the biofilms formed by wild-type C. ochracea were denser and bacterial cells were closer together than in those formed by the mutant strains. Together, these results indicate that proteins exported by the T9SS are key elements of the gliding motility and biofilm formation of C. ochracea.

Evaluation of antimicrobial action of Carie Care™ and Papacarie Duo™ on Aggregatibacter actinomycetemcomitans a major periodontal pathogen using polymerase chain reaction

Background:

In the present scenario, we are made available with chemomechanical caries removal system containing a natural proteolytic enzyme for the ease in the excavation of infected dentine. The additive action for these agents is providing antimicrobial and anti-inflammatory properties.

Aim:

This study was undertaken for assessing the action of Carie Care™ and Papacarie Duo™ on Aggregatibacter actinomycetemcomitans.

Materials and Methods:

The samples were collected for cultivation of the periodontal pathogen from the clinical periodontal pockets using sterile paper points. The samples cultured under suitable conditions were analyzed with quantitative polymerase chain reaction targeting 16s r-DNA. The samples were divided into three groups namely, Group A: Control, Group B: With Papacarie Duo, Group C: With Carie Care. The pathogen inoculums plugs were inserted in the petri dishes containing chemically defined medium and the experimental gels at different concentrations and were incubated under optimal conditions. The inhibition of growth of the pathogen was studied visually.

Results:

There was visual inhibition of growth for Group B and C and also exhibited a dose-dependent effect also.

Conclusion:

Based on the results of the present study, Carie Care™ gel demonstrated better antimicrobial action against A. actinomycetemcomitans which is a major periodontal disease causing pathogen.

Functional signatures of oral dysbiosis during periodontitis progression revealed by microbial metatranscriptome analysis

BACKGROUND

Periodontitis is a polymicrobial biofilm-induced inflammatory disease that affects 743 million people worldwide. The current model to explain periodontitis progression proposes that changes in the relative abundance of members of the oral microbiome lead to dysbiosis in the host-microbiome crosstalk and then to inflammation and bone loss. Using combined metagenome/metatranscriptome analysis of the subgingival microbiome in progressing and non-progressing sites, we have characterized the distinct molecular signatures of periodontitis progression.

METHODS

Metatranscriptome analysis was conducted on samples from subgingival biofilms from progressing and stable sites from periodontitis patients. Community-wide expression profiles were obtained using Next Generation Sequencing (Illumina). Sequences were aligned using 'bowtie2' against a constructed oral microbiome database. Differential expression analysis was performed using the non-parametric algorithm implemented on the R package 'NOISeqBio'. We summarized global functional activities of the oral microbial community by set enrichment analysis based on the Gene Ontology (GO) orthology.

RESULTS

Gene ontology enrichment analysis showed an over-representation in the baseline of active sites of terms related to cell motility, lipid A and peptidoglycan biosynthesis, and transport of iron, potassium, and amino acids. Periodontal pathogens (Tannerella forsythia and Porphyromonas gingivalis) upregulated different TonB-dependent receptors, peptidases, proteases, aerotolerance genes, iron transport genes, hemolysins, and CRISPR-associated genes. Surprisingly, organisms that have not been usually associated with the disease (Streptococcus oralis, Streptococcus mutans, Streptococcus intermedius, Streptococcus mitis, Veillonella parvula, and Pseudomonas fluorenscens) were highly active transcribing putative virulence factors. We detected patterns of activities associated with progression of clinical traits. Among those we found that the profiles of expression of cobalamin biosynthesis, proteolysis, and potassium transport were associated with the evolution towards disease.

CONCLUSIONS

We identified metabolic changes in the microbial community associated with the initial stages of dysbiosis. Regardless of the overall composition of the community, certain metabolic signatures are consistent with disease progression. Our results suggest that the whole community, and not just a handful of oral pathogens, is responsible for an increase in virulence that leads to progression.

TRIAL REGISTRATION

NCT01489839, 6 December 2011.

Identification of subgingival periodontal pathogens and association with the severity of periodontitis in patients with chronic kidney diseases: a cross-sectional study

BACKGROUND

The aim of our study was to assess the subgingival profile of 9 periodontal pathogens, by means of real-time PCR, in a group of predialysis chronic kidney disease patients with and without periodontal disease and to identify the risk factors associated with periodontal disease in these patients.

MATERIAL AND METHODS

This is a single centre cross-sectional cohort study performed on 70 CKD patients. Patients received a full-mouth periodontal examination and the following parameters were assessed: periodontal pocket depth (PPD), clinical attachment level, bleeding on probing, and plaque index; subgingival biofilm samples were collected from the deepest periodontal pocket of each quadrant and were pooled in one transporting unit. Clinical data were drawn from the medical file of the patients.

RESULTS

T. denticola (P = 0.001), T. forsythia (P < 0.001), and P. micros (P = 0.003) are significantly associated with periodontal disease in CKD subjects but in a multivariate model only age and T. forsythia remain independent risk factors for periodontal disease in patients with CKD.

CONCLUSIONS

In our cohort, age and T. forsythia are independently associated with periodontitis in CKD patients. Within the limits of this study, CKD was not significantly associated with a particular subgingival periodontal pathogens profile in periodontitis patients.

Quantification of Selenomonas sputigena in Chronic Periodontitis in Smokers Using 16S rDNA Based PCR Analysis

BACKGROUND AND AIM

Selenomonas species have been associated with chronic periodontitis and have been implicated in converting periodontal health to disease. Scanty literature is available in Indian population. Hence, the objective of the study was to detect the prevalence of Selenomonas sputigena in healthy and chronic periodontitis by polymerase chain reaction (PCR) in Indian population and to check whether smoking affects the subgingival microflora of this organism in chronic periodontitis.

MATERIALS AND METHODS

A total of 60 subjects with severe chronic periodontitis with or without smoking and periodontal healthy subjects underwent clinical and microbiological assessment. A deep subgingival plaque sample was collected and genomic DNA was extracted from each sample and analysed for detection of Selnomonas sputigena using PCR. The frequency and quantification of bacteria were also estimated.

RESULTS

All groups differed statistically significant in the frequency of detection of Selenomonas sputigena. On comparison of patients with chronic periodontitis in smokers and non-smokers, there was no statistically significant difference. When the results were quantified, statistically non-significant results were seen among all groups. Plaque index, gingival index, probing pocket depth and clinical attachment level were statistically non-significant in chronic periodontitis with smokers and non-smokers.

CONCLUSION

Prevalence of Selenomonas sputigena showed significant differences with respect to the frequency of detection when comparing the disease group to the healthy population. But no significant difference was seen when the results were quantified. Smoking has no influence on number of Selenomonas sputigena. This study highlights presence as well as quantity of the organism is very important in elucidating its role in causation and progression of the disease.

Association between Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis in subgingival plaque and clinical parameters, in Argentine patients with aggressive periodontitis

BACKGROUND

Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) have been associated with aggressive (AgP) and chronic periodontitis.

OBJECTIVE

The aim of this study was to evaluate the levels of Aa and Pg in gingival crevicular fluid (GCF) of patients with AgP and its relation with clinical parameters.

DESIGN

Sixteen females and fourteen males with clinical diagnosis of AgP aged 17-23 years and their match's controls, were included in this study. Clinical recording concerning probing pocket depth, clinical attachment level, plaque index and gingival bleeding index were performed at baseline, 30 and 60 days after baseline. After clinical examination GCF samples were analyzed for Aa and Pg with a real-time polymerase chain reaction technique. Patients group was treated with a combined of mechanical and oral antibiotic therapy (doxycycline 100 mg/day, during 21 days). A multivariate analysis was used to determine the relationship between Aa and Pg counts with clinical parameters.

RESULTS

GCF from all subjects was positive for Aa and PG. In controls Pg concentration was higher than Aa (Pg: 42,420 ± 3,034 copies/ml; Aa: 66.6 ± 5.4 copies/ml p < 0.001) while in patients both microbes showed the same concentration (Aa: 559,878 ± 39,698 Pg: 572,321 ± 58,752). A significant and positive correlation was observed between counts of Aa and Pg (R square: 0.7965, p < 0.0001). Female showed more counts/ml. Aa might be closely associated with clinical parameters while Pg did not. At 30 and 60 days Aa counts in patients were similar to controls while Pg counts were equal to baseline. However, in spite of Pg presence a clinical improvement was observed in all patients.

CONCLUSIONS

In our population the presence of Aa may be associated with AgP while Pg may be in GCF as an opportunistic pathogen which might caused disease when the ecological balance was favorable.

A Filifactor alocis-centered co-occurrence group associates with periodontitis across different oral habitats

Periodontitis is a highly prevalent polymicrobial disease worldwide, yet the synergistic pattern of the multiple oral pathogens involved is still poorly characterized. Here, saliva, supragingival and subgingival plaque samples from periodontitis patients and periodontally healthy volunteers were collected and profiled with 16S rRNA gene pyrosequencing. Different oral habitats harbored significantly different microbiota, and segregation of microbiota composition between periodontitis and health was observed as well. Two-step redundancy analysis identified twenty-one OTUs, including Porphyromonas gingivalis, Tannerella forsythia and Filifactor alocis, as potential pathogens that were significantly associated with periodontitis and with two periodontitis diagnostic parameters (pocket depth and attachment loss) in both saliva and supragingival plaque habitats. Interestingly, pairwise correlation analysis among the 21 OTUs revealed that Filifactor alocis was positively correlated with seven other putative pathogens (R > 0.6, P < 0.05), forming a co-occurrence group that was remarkably enriched in all three habitats of periodontitis patients. This bacterial cluster showed a higher diagnostic value for periodontitis than did any individual potential pathogens, especially in saliva. Thus, our study identified a potential synergistic ecological pattern involving eight co-infecting pathogens across various oral habitats, providing a new framework for understanding the etiology of periodontitis and developing new diagnoses and therapies.

Bacterial profile of aggressive periodontitis in Morocco: a cross-sectional study

Background

Aggressive periodontitis (AgP) is one of the most severe forms of periodontal diseases. In Morocco, Aggregatibacter actinomycetemcomitans has been strongly associated with AgP, however limited knowledge is available about the implication of other periodontal pathogens in this entity. Therefore, the main aim of this study was to evaluate the composition of the subgingival microbiota in Moroccan patients with AgP.

Methods

Subgingival plaque samples were collected from 50 aggressive, 13 localized and 37 generalized periodontitis patients. Samples from 20 chronic periodontitis (ChP) patients were taken as controls. Samples collected from the four deepest periodontal pockets in each patient were pooled in pre-reduced transport fluid and examined by culture.

Results

A. actinomycetemcomitans was significantly more frequent (p = 0.004) in generalised AgP compared to ChP, and Porphyromonas gingivalis was less prevalent in localized AgP, when compared with generalized AgP (p = 0.040) or ChP (p = 0.016). Prevotella intermedia, Fusobacterium nucleatum and Tannerella forsythia were also frequently detected in all groups. Mean proportions of A. actinomycetemcomitans were significantly higher in AgP groups, when compared to ChP, and generalized AgP patients harbored significantly higher proportions of P. gingivalis and T. forsythia, when compared to localized AgP or ChP.

Conclusions

A. actinomycetemcomitans, P. gingivalis, T. forsythia, P. intermedia and F. nucleatum were frequently detected in this Moroccan population with AgP. Differences in frequency of detection, counts and proportions of A. actinomycetemcomitans, P. gingivalis and T. forsythia suggests the presence of distinct microbiological profiles for localized AgP, generalized AgP and ChP patients.

Subgingival microbiome in smokers and non-smokers in Korean chronic periodontitis patients

Smoking is a major environmental factor associated with periodontal diseases. However, we still have a very limited understanding of the relationship between smoking and subgingival microflora in the global population. Here, we investigated the composition of subgingival bacterial communities from the pooled plaque samples of smokers and non-smokers, 134 samples in each group, in Korean patients with moderate chronic periodontitis using 16S rRNA gene-based pyrosequencing. A total of 17,927 reads were analyzed and classified into 12 phyla, 126 genera, and 394 species. Differences in bacterial communities between smokers and non-smokers were examined at all phylogenetic levels. The genera Fusobacterium, Fretibacterium, Streptococcus, Veillonella, Corynebacterium, TM7, and Filifactor were abundant in smokers. On the other hand, Prevotella, Campylobacter, Aggregatibacter, Veillonellaceae GQ422718, Haemophilus, and Prevotellaceae were less abundant in smokers. Among species-level taxa occupying > 1% of whole subgingival microbiome of smokers, higher abundance (≥ 2.0-fold compared to non-smokers) of seven species or operational taxonomic units (OTUs) was found: Fusobacterium nucleatum, Neisseria sicca, Neisseria oralis, Corynebacterium matruchotii, Veillonella dispar, Filifactor alocis, and Fretibacterium AY349371. On the other hand, lower abundance of 11 species or OTUs was found in smokers: Neisseria elongata, six Prevotella species or OTUs, Fusobacterium canifelinum, Aggregatibacter AM420165, Selenomonas OTU, and Veillonellaceae GU470897. Species richness and evenness were similar between the groups whereas diversity was greater in smokers than non-smokers. Collectively, the results of the present study indicate that differences exist in the subgingival bacterial community between smoker and non-smoker patients with chronic moderate periodontitis in Korea, suggesting that cigarette smoking considerably affects subgingival bacterial ecology.

Effects of ozone nano-bubble water on periodontopathic bacteria and oral cells - in vitro studies

The aims of the present study were to evaluate the bactericidal activity of a new antiseptic agent, ozone nano-bubble water (NBW3), against periodontopathogenic bacteria and to assess the cytotoxicity of NBW3 against human oral cells. The bactericidal activities of NBW3 against representative periodontopathogenic bacteria, Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) were evaluated using in vitro time-kill assays. The cytotoxicity of NBW3 was evaluated using three-dimensional human buccal and gingival tissue models. The numbers of colony forming units (CFUs)/mL of P. gingivalis and A. actinomycetemcomitans exposed to NBW3 dropped to below the lower limit of detection (<10 CFUs mL^-1) after only 0.5 min of exposure. There were only minor decreases in the viability of oral tissue cells after 24 h of exposure to NBW3. These results suggest that NBW3 possesses potent bactericidal activity against representative periodontopathogenic bacteria and is not cytotoxic to cells of human oral tissues. The use of NBW3 as an adjunct to periodontal therapy would be promising.