Microbial etiological agents of destructive periodontal diseases

The periodontal stem/progenitor cell inflammatory-regenerative cross talk: A new perspective

Adult multipotent stem/progenitor cells, with remarkable regenerative potential, have been isolated from various components of the human periodontium. These multipotent stem/progenitor cells include the periodontal ligament stem/progenitor cells (PDLSCs), stem cells from the apical papilla (SCAP), the gingival mesenchymal stem/progenitor cells (G-MSCs), and the alveolar bone proper stem/progenitor cells (AB-MSCs). Whereas inflammation is regarded as the reason for tissue damage, it also remains a fundamental step of any early healing process. In performing their periodontal tissue regenerative/reparative activity, periodontal stem/progenitor cells interact with their surrounding inflammatory micro-environmental, through their expressed receptors, which could influence their fate and the outcome of any periodontal stem/progenitor cell-mediated reparative/regenerative activity. The present review discusses the current understanding about the interaction of periodontal stem/progenitor cells with their surrounding inflammatory micro-environment, elaborates on the inflammatory factors influencing their stemness, proliferation, migration/homing, differentiation, and immunomodulatory attributes, the possible underlying intracellular mechanisms, as well as their proposed relationship to the canonical and noncanonical Wnt pathways.

Past, Present, and Future of Regeneration Therapy in Oral and Periodontal Tissue: A Review

Chronic periodontitis is the most common disease which induces oral tissue destruction. The goal of periodontal treatment is to reduce inflammation and regenerate the defects. As the structure of periodontium is composed of four types of different tissue (cementum, alveolar bone periodontal ligament, and gingiva), the regeneration should allow different cell proliferation in the separated spaces. Guided tissue regeneration (GTR) and guided bone regeneration (GBR) were introduced to prevent epithelial growth into the alveolar bone space. In the past, non-absorbable membranes with basic functions such as space maintenance were used with bone graft materials. Due to several limitations of the non-absorbable membranes, membranes of the second and third generation equipped with controlled absorbability, and a functional layer releasing growth factors or antimicrobials were introduced. Moreover, tissue engineering using biomaterials enabled faster and more stable tissue regeneration. The scaffold with three-dimensional structures manufactured by computer-aided design and manufacturing (CAD/CAM) showed high biocompatibility, and promoted cell infiltration and revascularization. In the future, using the cell sheath, pre-vascularizing and bioprinting techniques will be applied to the membrane to mimic the original tissue itself. The aim of the review was not only to understand the past and the present trends of GTR and GBR, but also to be used as a guide for a proper future of regeneration therapy in the oral region.

Chlamydia pneumoniae is present in the dental plaque of periodontitis patients and stimulates an inflammatory response in gingival epithelial cells

Chlamydia pneumoniae is an airborne, Gram-negative, obligate intracellular bacterium which causes human respiratory infections and has been associated with atherosclerosis. Because individuals with periodontitis are at greater risk for atherosclerosis as well as respiratory infections, we in-vestigated the role of C. pneumoniae in inflammation and periodontal dis-ease. We found that C. pneumoniae was more frequently found in subgingival dental plaque obtained from periodontally diseased sites of the mouth versus healthy sites. The known periodontal pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were also found in the plaque. In addition, C. pneumoniae could efficiently invade human gingival epithelial cells (GECs) in vitro, causing translocation of NF-κB to the nucleus along with increased secretion of mature IL-1β cytokine. Supernatants collected from C. pneumoniae-infected GECs showed increased activation of caspase-1 protein, which was significantly reduced when nlrp3 gene expression was silenced using shRNA lentiviral vectors. Our results demonstrate that C. pneumoniae was found in higher levels in periodontitis patients compared to control pa-tients. Additionally, C. pneumoniae could infect GECs, leading to inflammation caused by activation of NF-κB and the NLRP3 inflammasome. We propose that the presence of C. pneumoniae in subgingival dental plaque may contribute to periodontal disease and could be used as a potential risk indicator of perio-dontal disease.

Recombinant fimbriae protein of Porphyromonas gingivalis induces an inflammatory response via the TLR4/NF‑κB signaling pathway in human peripheral blood mononuclear cells

Porphyromonas gingivalis (P. gingivalis) is a periodontal pathogen that may accumulate with other organisms in subgingival plaque biofilms and is associated with periodontal disease. P. gingivalis fimbriae (FimA) is a filamentous structure on the surface of bacteria that is closely associated with bacterial adhesion to and colonization of host tissues, and serves an essential role in biofilm formation. The present study aimed to construct P. gingivalis FimA prokaryotic expression plasmids, purify a FimA fusion protein and explore the effect of a recombinant FimA protein on the inflammatory response in human peripheral blood mononuclear cells (PBMCs). P. gingivalis FimA prokaryotic expression plasmids were constructed by gene cloning and recombination technology. SDS-PAGE was used to evaluate the purified recombinant FimA protein. The cell proliferation rate and inflammatory cytokine expression of PBMCs treated with the FimA fusion protein with or without transfection with toll-like receptor 4 (TLR4) small interfering (si)RNA were detected by CCK-8 assays and ELISAs, respectively. The expression levels of TLR4, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and myeloid differentiation primary response 88 (MyD88) in PBMCs were detected by western blot analysis and reverse transcription quantitative polymerase chain reaction. A FimA fusion protein with high purity was obtained. FimA fusion protein treatment significantly increased PBMC proliferation and promoted the release of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, matrix metalloproteinase (MMP)-8 and MMP-9 in PBMCs. TLR4 interference reversed the effects of the FimA fusion protein on PBMC proliferation and inflammatory cytokine release. The expression levels of TLR4, NF-κB and MyD88 in PBMCs were significantly increased following treatment with the FimA fusion protein, while the expression levels of these genes at the mRNA and protein levels decreased significantly in PBMCs following FimA fusion protein treatment and TLR4 interference. The FimA fusion protein increased PBMC proliferation and promoted the release of the inflammatory cytokines TNF-α, IL-6, MMP-8 and MMP-9 via the TLR4/NF-κB signaling pathway. FimA may serve as a promising therapeutic strategy for periodontal disease.

Exploring a temporal relationship between biofilm microbiota and inflammatory mediators during resolution of naturally occurring gingivitis

BACKGROUND

This study uses multiple, contemporary methodologies to expand our knowledge of the temporal relationship between host-microbial interactions and clinical signs of gingivitis.

METHODS

Subgingival plaque and crevicular fluid samples were collected from 31 systemically healthy adults with naturally occurring plaque-induced gingivitis. Professional prophylaxis was administered and participants were followed over 7 weeks. Microbial characterization was performed using a bead-based hybridization assay and cytokine analysis using bead-based flow cytometry.

RESULTS

The provision of sequential interventions, oral hygiene instruction, and subsequent professional prophylaxis brought about significant reduction of plaque and resolution of gingivitis at all post baseline time points (P < 0.0001). Candidate cytokines that increased significantly (95% level) were interleukin (IL)-1β, matrix metalloproteinases (MMP)-1, MMP-3, MMP-8, MMP-9, from baseline to week 2; regulated on activation, normal T cell expressed and secreted (RANTES) at week 4 and week 8; macrophage inflammatory protein (MIP)-1α and MIP-1β at week 8. Resolution of inflammation was accompanied by a shift in the microbiological flora toward those species associated with health.

CONCLUSIONS

This study provides further evidence of the dynamic relationships that exist between the overt clinical signs, the microbial biofilm, and the host response in gingivitis and upon resolution following clinical interventions. Understanding the interactions between the host immune system and subgingival microbial communities during the resolution of established gingivitis continues to evolve as additional knowledge is achieved through using new analytical technologies. The present study confirms a critical effect of oral hygiene measures on restoration of microbial eubiosis in subgingival communities, confirming the important role for home care and professional intervention in maintaining oral health.

Optimal management of intrabony defects: current insights

Periodontitis is the most common condition, which causes bony defects. Intrabony defects thought not as common as the horizontal bone loss pose a risk of disease progression and thus should be managed optimally; however, it does not mean all the intrabony defects can be treated and all the mobile teeth saved! But, with the advent of new biomaterials prognosis of teeth can be improved. The objective of this article is to discuss old and new concepts toward the optimal management of intrabony defects.

Screening of Genetic Factor in the Interaction Between Periodontitis and Metabolic Traits Using Candidate Gene Association Study (CGAS)

Periodontitis has been reported to relate to metabolic syndrome traits such as obesity, blood pressure, and so on. However, the relation between periodontitis and metabolic syndrome remains unclear. The present study aimed to confirm common genetic factors between periodontitis and metabolic traits using Candidate gene association study (CGAS) in the Korean population. Based on the analysis of CGAS, this study performed linear regression analyses to examine the single-nucleotide polymorphisms (SNPs) between periodontitis and metabolic syndrome traits. Among the analyzed SNPs, 2649 SNPs in five genes (TENM2, LDLRAD4, SLC9C2, MFSD1, and A2BP1) showed a statistical significance at p < 0.05. Interestingly, A2BP1 and TENM2 were related to obesity. Also, elevated levels of LDLRAD4, SLC9C2, and MFSD1 were observed in the patients with high blood pressure. Taken together, the present study suggests that some of the SNPs are related to periodontitis. Therefore, if any of TENM2, A2BP1, LDLRAD4, SLC9C2, and MFSD1 is detected in the patients with periodontitis, obesity and blood pressure have to be treated simultaneously.

A cross-sectional study on the periodontal status and prevalence of red complex periodontal pathogens in a Japanese population

This large-scale study cross-sectionally examined the periodontal status and prevalence of "red complex" bacteria (Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) in Japanese adults. A total of 977 participants were enrolled in the study. Probing depth (PD), bleeding on probing (BOP), and bone crest level (BCL) were recorded, and the presence of red complex bacteria in the saliva was examined using polymerase chain reaction. The mean BCL value and the percentage of sites with a PD ≥4 mm or the presence of BOP were significantly higher in older participants. The detection rates of P. gingivalis, T. denticola, and T. forsythia were 46.3%, 76.4%, and 61.1%, respectively. The P. gingivalis detection rate significantly increased with age, while those of T. denticola and T. forsythia were comparably high for all age groups. A close correlation between P. gingivalis and the percentage of sites with PD ≥4 mm was indicated by nonlinear canonical correlation analysis. Current smokers exhibited a more advanced disease condition and a significantly higher P. gingivalis detection rate than non-smokers. In conclusion, periodontal condition worsens with age, and P. gingivalis appears to be the red complex bacterium most closely associated with periodontitis.

Evaluation of the antibacterial activity of a new ozonized olive oil against oral and periodontal pathogens

Background

In the present study, the antimicrobial properties of a new ozonized olive oil (O-zone gel) against oral and periodontal pathogens will be evaluated and compared with that of common CHX-based agents.

Material and Methods

O-zone gel was compared with two agents based on chlorhexidine digluconate (CHX): Corsodyl Dental Gel and Plak Gel. A. actinomycetemcomitans, P. intermedia and S. mutans, were selected and the antibacterial capability of the compounds was tested by using direct contact agar diffusion test (DCT) and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) evaluations. Differences between specific means were analyzed by a one-way analysis of variance (ANOVA). Group means were compared using a one-way ANOVA and Tukey’s test (P<0.05).

Results

O-zone gel reported inhibition zones which correspond to 33% and 43% of that achieved by the CHX agents. No inhibition of bacterial growth (MIC) on the Gram-positive strain by using O-zone gel was found and no antimicrobial effect (MBC) was observed by using O-zone gel on both Gram-negative and -positive strains.

Conclusions

The new ozonated oil was a relatively moderate antiseptic. Gram-negative bacteria proved to be more sensitive to ozonized olive oil than Gram-positive ones. The ozonized olive oil demonstrated a lower antibacterial activity if compared to the CHX-based agents tested.

Key words:Agar diffusion test, antibacterial activity, direct contact test, ozone, ozonized olive oil.

Interactions between the Aggregatibacter actinomycetemcomitans secretin HofQ and host cytokines indicate a link between natural competence and interleukin-8 uptake

Naturally competent bacteria acquire DNA from their surroundings to survive in nutrient-poor environments and incorporate DNA into their genomes as new genes for improved survival. The secretin HofQ from the oral pathogen Aggregatibacter actinomycetemcomitans has been associated with DNA uptake. Cytokine sequestering is a potential virulence mechanism in various bacteria and may modulate both host defense and bacterial physiology. The objective of this study was to elucidate a possible connection between natural competence and cytokine uptake in A. actinomycetemcomitans. The extramembranous domain of HofQ (emHofQ) was shown to interact with various cytokines, of which IL-8 exhibited the strongest interaction. The dissociation constant between emHofQ and IL-8 was 43 nM in static settings and 2.4 μM in dynamic settings. The moderate binding affinity is consistent with the hypothesis that emHofQ recognizes cytokines before transporting them into the cells. The interaction site was identified via crosslinking and mutational analysis. By structural comparison, relateda type I KH domain with a similar interaction site was detected in the Neisseria meningitidis secretin PilQ, which has been shown to participate in IL-8 uptake. Deletion of hofQ from the A. actinomycetemcomitans genome decreased the overall biofilm formation of this organism, abolished the response to cytokines, i.e., decreased eDNA levels in the presence of cytokines, and increased the susceptibility of the biofilm to tested β-lactams. Moreover, we showed that recombinant IL-8 interacted with DNA. These results can be used in further studies on the specific role of cytokine uptake in bacterial virulence without interfering with natural-competence-related DNA uptake.

Effects of periodontal disease on systemic health

About one in two adults in the United States has periodontal disease. Chronic periodontitis is an oral disease affecting the supporting structures of the teeth leading to progressive loss of the attachment apparatus and bone around teeth. It is characterized by gingival pocket formation and/or gingival recession. The disease is initiated by bacteria and their components like lipopolysaccharide and causes a heightened host inflammatory response. This cascade of inflammatory response ultimately leads to an increased osteoclastic activity and bone loss. Individuals with periodontitis have increased systemic levels of acute phase proteins, plasma antibody levels, coagulation factor, total white blood cell count, neutrophils, C reactive protein (CRP), and cytokines such as INF- gamma (Interferon gamma), TNF-α (Tumor necrosis Factor- Alpha), IL (Interleukin)-1β, IL-2 and IL-6. As periodontitis works on the same chronic inflammation model seen in systemic diseases, there is sufficient evidence to suggest a bi-directional link between the two. This article summarizes the established associations between periodontal disease and systemic health.

Microbiological Response to Periodontal Therapy: A Retrospective Study

BACKGROUND

Periodontitis is a multifactorial infection caused by a complex of pathogenic bacterial species that induce the destruction of periodontal structures.

OBJECTIVE

The aim of this study is to evaluate the presence and bacterial load of six periodontal pathogens bacteria, measured at initial visit and after osseous surgery in patients affected by chronic periodontitis and treated between 2005 and 2007.

METHODS

This cohort study was carried out on a sample of 38 consecutive patients affected by severe chronic periodontitis, diagnosed at baseline on the basis of probing depths equal to 6.68 ± 1.47 mm. On each subject, a microbiological test was performed before periodontal initial therapy and after osseous surgery (one year later). Five compromised teeth were chosen for each patient (the same teeth, before and after surgery), for a total of 190 teeth. Real-time PCR based analysis computed total bacterial load of the samples and quantified six periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum and Prevotella intermedia. Data collection was made consulting medical charts.

RESULTS

Pocket probing depth reduction after surgery was 4.50 ± 1.54 mm (p=0.0001). The mean number of sites with bleeding at baseline was 2.08 ± 1.17 and 0.58 ± 1.00 after surgery (p=0.001). The mean number of sites with suppuration at baseline was 0.26 ± 0.86 and 0 after surgery (p=0.02). Cell count of each pathogen and total cell count were significantly higher at baseline than after surgery. Almost all bacteria presented a mean percentage reduction equal to that of the total count, except for Aa and Pi, which seemed to show a greater resistance. The difference of bacterial load, both before and after surgery, between smokers and non-smokers was not statistically significant (p<0.05). A statistically significant correlation was detected between pocket probing depth variation and bleeding on probing variation before and after the surgery, controlling for age (r=0.6, p=0.001). No significant correlations were observed between pocket probing depth and bacterial loads, except for Pg (r=0.5, p=0.001), Tf (r=0.6, p=0.001) and Td (r=0.4, p=0.02).

CONCLUSIONS

Reduction of presence and bacterial load of the examined periodontal pathogens bacteria after osseous surgery, along with periodontal pocket reduction, appeared to be essential to achieve and maintain periodontal stability over years.

Antimicrobial photodynamic therapy alone or in combination with antibiotic local administration against biofilms of Fusobacterium nucleatum and Porphyromonas gingivalis

Antimicrobial photodynamic therapy (aPDT) kills several planktonic pathogens. However, the susceptibility of biofilm-derived anaerobic bacteria to aPDT is poorly characterized. Here, we evaluated the effect of Photodithazine (PDZ)-mediated aPDT on Fusobacterium nucleatum and Porphyromonas gingivalis biofilms. In addition, aPDT was tested with metronidazole (MTZ) to explore the potential antimicrobial effect of the treatment. The minimum inhibitory concentration (MIC) of MTZ was defined for each bacterial species. Single-species biofilms of each species were grown on polystyrene plates under anaerobic conditions for five days. aPDT was performed by applying PDZ at concentrations of 50, 75 and 100 mg/L, followed by exposure to 50 J/cm² LED light (660 nm) with or without MTZ. aPDT exhibited a significant reduction in bacterial viability at a PDZ concentration of 100 mg/L, with 1.12 log₁₀ and 2.66 log₁₀ reductions for F. nucleatum and P. gingivalis in biofilms, respectively. However, the antimicrobial effect against F. nucleatum was achieved only when aPDT was combined with MTZ at 100× MIC. Regarding P. gingivalis, the combination of PDZ-mediated aPDT at 100 mg/L with MTZ 100× MIC resulted in a 5 log₁₀ reduction in the bacterial population. The potential antimicrobial effects of aPDT in combination with MTZ for both single pathogenic biofilms were confirmed by live/dead staining. These results suggest that localized antibiotic administration may be an adjuvant to aPDT to control F. nucleatum and P. gingivalis biofilms.

Real-time PCR quantification of 9 periodontal pathogens in saliva samples from periodontally healthy Korean young adults

Purpose

Few studies have examined periodontal pathogens from saliva samples in periodontally healthy young adults. The purposes of this study were to determine the prevalence of periodontopathic bacteria and to quantify periodontal pathogens in saliva samples using real-time polymerase chain reaction (PCR) assays in periodontally healthy Korean young adults under 35 years of age.

Methods

Nine major periodontal pathogens were analyzed by real-time PCR in saliva from 94 periodontally healthy young adults. Quantification of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum, Campylobacter rectus, Peptostreptococcus anaerobius, and Eikenella corrodens was performed by DNA copy number measurement.

Results

F. nucleatum and E. corrodens were detected in all subjects; the numbers of positive samples were 87 (92.6%), 91 (96.8%), and 90 (95.7%) for P. gingivalis, P. anaerobius, and C. rectus, respectively. Other pathogens were also detected in periodontally healthy subjects. Analysis of DNA copy numbers revealed that the most abundant periodontal pathogen was F. nucleatum, which was significantly more prevalent than all other bacteria (P<0.001), followed by P. anaerobius, P. gingivalis, E. corrodens, C. rectus, and T. denticola. There was no significant difference in the prevalence of each bacterium between men and women. The DNA copy number of total bacteria was significantly higher in men than in women.

Conclusions

Major periodontal pathogens were prevalent in the saliva of periodontally healthy Korean young adults. Therefore, we suggest that the development of periodontal disease should not be overlooked in periodontally healthy young people, as it can arise due to periodontal pathogen imbalance and host susceptibility.

Development and in vitro evaluation of chitosan based system for local delivery of atorvastatin for treatment of periodontitis

In recent years, statin group drugs have been widely investigated in treatment of periodontal diseases due to their anti-inflammatory effect. The efficacy of statins can be enhanced by local administration into the periodontal pocket by appropriate delivery systems. The aim of our study was to develop a bioadhesive delivery system for local delivery of atorvastatin in treatment of periodontal disease. For this purpose, gel formulations were prepared using different types of chitosan (base and water soluble) and viscosity, bioadhesivity and syringeability of the gels as well as in vitro drug release properties were investigated vitro. Furthermore, anti-inflammatory effect of the formulations was studied in vitro using tumor necrosis factor (TNF)-alfa induced human gingival fibroblast (hGF) cells. Release of proinflammatory (IL-1β, IL-6, IL-8) and anti-inflammatory (TGF-β1, TGF-β2, TGF-β3, IL-10) cytokines were measured after incubating the hGF cells with the formulations. The viscosity of the formulations was found to be suitable for a local application into periodontal pocket. In presence of drug, bioadhesive property of the formulations was found to increase, and bioadhesion force was within the range, which would retain the delivery system at the application site, subsequently maintain drug levels at desired amount for longer period of time. The release of atorvastatin from the gels was found to be slower than that of the solution. The cytokine levels were found to decrease following application of the formulations, and anti-inflammatory effect was observed to enhance in presence of chitosan. No significant differences were found between base and water-soluble chitosan.

Litsea japonica Leaf Extract Suppresses Proinflammatory Cytokine Production in Periodontal Ligament Fibroblasts Stimulated with Oral Pathogenic Bacteria or Interleukin-1β

Periodontal disease, a chronic disease caused by bacterial infection, eventually progresses to severe inflammation and bone loss. Regulating excessive inflammation of inflamed periodontal tissues is critical in treating periodontal diseases. The periodontal ligament (PDL) is primarily a connective tissue attachment between the root and alveolar bone. PDL fibroblasts (PDLFs) produce pro-inflammatory cytokines in response to bacterial infection, which could further adversely affect the tissue and cause bone loss. In this study, we determined the ability of Litsea japonica leaf extract (LJLE) to inhibit pro-inflammatory cytokine production in PDLFs in response to various stimulants. First, we found that LJLE treatment reduced lipopolysaccharide (LPS)-induced pro-inflammatory cytokine (interleukin-6 and interleukin-8) mRNA and protein expression in PDLFs without cytotoxicity. Next, we observed the anti-inflammatory effect of LJLE in PDLFs after infection with various oral bacteria, including Fusobacterium nucleatum, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. These anti-inflammatory effects of LJLE were dose-dependent, and the extract was effective following both pretreatment and posttreatment. Moreover, we found that LJLE suppressed the effect of interleukin-1 beta-induced pro-inflammatory cytokine production in PDLFs. Taken together, these results indicate that LJLE has anti-inflammatory activity that could be exploited to prevent and treat human periodontitis by controlling inflammation.

Gene expression analysis of neuropeptides in oral mucosa during periodontal disease in non-human primates

BACKGROUND

Neuropeptides (NPs) are innate pivotal regulators of the immunoinflammatory response. Nevertheless, their role in the pathogenesis of periodontal disease remains unknown. Changes in gene expression of 10 NPs and 16 NP receptors (NPRs) coincident with the initiation, progression, and resolution of periodontitis were determined.

METHODS

The ligature-induced periodontitis model was used in rhesus monkeys (n = 18). Gingival tissue samples were taken at baseline (preligatures), at 2 weeks and at 1 month (initiation), and at 3 months (progression) postligation. Ligatures were removed and samples taken 2 months later (resolution). Total RNA was isolated from tissues and NP/NPR gene expression microarray analysis was performed. Gene expression changes were validated by quantitative polymerase chain reaction and immunohistochemistry.

RESULTS

Unexpectedly, the expression of pro-inflammatory NPs/NPRs did not change during periodontitis or with resolution. However, increased expression of the anti-inflammatory NPs adrenomedullin (ADM) and galanin (GAL), and the NPRs calcitonin receptor-like (CALCRL) and receptor activity-modifying protein-2 and -3 (RAMP2 and RAMP3) were observed during initiation and progression of disease. The expression of the same NPs/NPRs exhibited a significant positive correlation with both molecular (interleukin-1ß, matrix mettaloproteinase-9, and receptor activator of nuclear factor-kappa B ligand) and clinical measures of gingival inflammation and tissue destruction.

CONCLUSION

Initiation and progression of periodontitis involve significant overexpression of ADM, GAL, CALCRL, RAMP2, and RAMP3. These anti-inflammatory NPs/NPRs could play a role in the unresolved infection and inflammation that normally drives tissue destruction in periodontitis. Both ADM and GAL potentially are new candidates to consider as biomolecules associated with periodontal disease activity.

Extracellular Matrix Membrane Induces Cementoblastic/Osteogenic Properties of Human Periodontal Ligament Stem Cells

Objective: Periodontitis affects nearly 90% of adults over the age of 70, resulting to periodontal tissue infection, destruction, and ultimately tooth loss. Guided tissue regeneration (GTR) is a method widely used to treat severe periodontal disease, and involves placement of an occlusive barrier to facilitate regeneration of the damaged area by periodontal ligament stem cells (PDLSCs). In this study, we evaluate natural extracellular matrix (ECM) as a scaffold material to provide a suitable microenvironment to support the proliferation, differentiation, and tissue-regenerating properties of PDLSCs. Design: The viability, proliferation, apoptosis, and migration of PDLSCs cultured on ECM membrane, that was isolated from porcine urinary bladders, were compared with those cultured on type I collagen membrane, a commonly used scaffold in GTR. To evaluate the effects of ECM vs. type I collagen on the tissue-regenerating properties of PDLSCs, the bio-attachment and cementoblastic/osteogenic differentiation of PDLSCs were evaluated. Results: Incubation of PDLSCs with ECM resulted in increased viability, proliferation, and reduced apoptosis, compared with type I collagen treated PDLSCs. Co-culture with ECM membrane also increased the migration and bio-attachment of PDLSCs. Incubation of PDLSCs with ECM membrane increased expression of the cementoblastic/osteogenic differentiation markers BSP, RUNX2, ALP, OPN, OCN, and periostin. Conclusion: ECM membrane enhances the proliferation and regenerative properties of PDLSCs, indicating that ECM membrane can serve as a suitable scaffold in the application of GTR to treat periodontal disease.

Randomised clinical trial: Efficacy of strategies to provide oral hygiene activities to nursing home residents with dementia who resist mouth care

OBJECTIVES

The purpose of this study was to test the efficacy of MOUTh (Managing Oral Hygiene Using Threat Reduction), a nonpharmacologic, relationship-based intervention vs. control on 2 primary outcomes for nursing home (NH) residents with dementia who resisted mouth care: (i) reduction in the occurrence and intensity of care-resistant behaviours (CRBs) and (ii) improvement in oral health. Two secondary outcomes were also examined: (i) the duration of mouth care and (ii) the completion of oral hygiene activities.

BACKGROUND

Persons with dementia who exhibit CRBs are at risk for inadequate mouth care and subsequent systemic illnesses.

MATERIALS AND METHODS

The study used a randomised repeated measures design. Recruitment occurred in 9 nursing homes that varied in size, ownership, reimbursement patterns and location. One hundred and one nursing home residents with dementia were randomised at the individual level to experimental (n = 55) or control groups (n = 46). One hundred participants provided data for the analyses.

RESULTS

Compared to the control group, persons in the experimental group had twice the odds of allowing mouth care and completing oral hygiene activities; they also allowed longer duration of mouth care (d = 0.56), but showed only small reductions in the intensity of CRBs (d = 0.16) and small differential improvements in oral health (d = 0.18).

CONCLUSION

The data suggest that this intervention facilitates mouth care among persons with dementia. The management of refusal behaviour may be a clinically more realistic approach than reducing or eradicating refusals.

Identification of a specific domain of Porphyromonas gingivalis Hgp44 responsible for adhesion to Treponema denticola

Interaction between two periodontal pathogens, Porphyromonas gingivalis and Treponema denticola, contributes to plaque biofilm formation. Porphyromonas gingivalis forms aggregates with T. denticola through its adhesion/hemagglutinin domain (Hgp44). In this study, we investigated the specific domain of P. gingivalis Hgp44 responsible for adhesion to T. denticola using expression vectors harboring P. gingivalis Hgp44 DNA sequences encoding amino acid residues 1-419. Six plasmids harboring fragments in this region were generated by PCR amplification and self-ligation, and recombinant proteins r-Hgp44 (residues 1-419), r-Hgp441 (residues 1-124), r-Hgp442 (1-199), r-Hgp443 (1-316), r-Hgp444 (199-419), r-Hgp445 (124-198) and r-Hgp446 (199-316) were produced, as confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. r-Hgp44, r-Hgp443 and r-Hgp446 showed greater adhesion to T. denticola sonicates than the control, as determined by enzyme-linked immunosorbent assay. r-Hgp446 reduced the coaggregation of P. gingivalis and T. denticola. Scanning electron and confocal laser scanning microscopy analyses revealed that r-Hgp446 reduced dual-species biofilm formation. Our results indicate that residues 199-316 of P. gingivalis Hgp44 are mainly responsible for adhesion to T. denticola; inhibiting this domain could potentially disrupt periodontopathic biofilm formation and maturation.

An early report: a modified porphyrin-linked metronidazole targeting intracellular Porphyromonas gingivalis in cultured oral epithelial cells

Porphyromonas gingivalis (P. gingivalis) has a strong association with the pathogenesis of periodontal disease. Recurrence of periodontal disease following therapy is attributed to numerous factors, and of growing interest is the potential problem of intracellular bacteria that are able to persist and multiply within the host cell, thereby facilitating relapse of infection. The effect of antibiotic therapy in controlling P. gingivalis is questionable. Accordingly, while metronidazole is very effective against anaerobic extracellular P. gingivalis by disrupting the DNA of anaerobic microbial cells, this antibiotic does not effectively penetrate into mammalian cells to inhibit intracellular bacteria. Therefore in the present study, a modified porphyrin-linked metronidazole adducts, developed in our laboratory, was used to kill intracellular P. gingivalis. A series of experiments were performed, including cytotoxicity assays and cellular uptake of adducts by flow cytometry coupled with live cell imaging analysis, P. gingivalis invasion and elimination assays, and the analysis of colocalization of P. gingivalis and porphyrin-linked metronidazole by confocal laser scanning microscopy. Findings indicated that P. gingivalis and porphyrin-linked metronidazole were colocalized in the cytoplasm, and this compound was able to kill P. gingivalis intracellular with a sufficient culture time. This is a novel antimicrobial approach in the elimination of P. gingivalis from the oral cavity.

Localized In Situ Nanoemulgel Drug Delivery System of Quercetin for Periodontitis: Development and Computational Simulations

This study was aimed at formulating a bioabsorbable, controlled-release, nanoemulgel of Quercetin, a potent antimicrobial and anti-inflammatory agent for the treatment of periodontitis that could improve its solubility and bioavailability. Screening of components was carried out based on the solubility studies. Nanoemulsion containing cinnamon oil as the oil phase, tween 80 and Carbitol® as the surfactant-cosurfactant mixture (Smix) and water as the aqueous phase containing 125 µg/200 µL of Quercetin was prepared by using spontaneous emulsification method. Nanoemulgel was prepared using 23% w/v poloxamer 407 as gel base. Comprehensive evaluation of the formulated nanoemulgel was carried out, and the optimized formulation was studied for drug release using Franz vertical diffusion cells. The formulated nanoemulgelexhibited a remarkable release of 92.4% of Quercetin at the end of 6 h, as compared to that of pure Quercetin-loaded gel (<3% release). The viscosity of the prepared nanoemulgel was found to be 30,647 ± 0.32 cPs at 37 °C. Also, molecular dynamics (MD) simulation was utilized to understand the gelation process and role of each component in the formulation. The present study revealed that the developed nanoemulgel of Quercetin could be a potential delivery system for clinical testing in periodontitis.

Insulin resistance predicts the risk of gingival/periodontal inflammation

OBJECTIVES

Evaluate whether insulin resistance (IR) predicts the risk of oral inflammation, assessed as the number of sites with bleeding on probing (BOP) and number of teeth with probing pocket depths (PPD) ≥ 4 mm and BOP.

METHODS

Data on 870 overweight/obese diabetes free adults, aged 40-65 years from the San Juan Overweight Adults Longitudinal Study over a three-year period, was analyzed. Baseline IR, assessed using the Homeostasis Model Assessment of IR (HOMA-IR) index, was divided into tertiles. BOP was assessed at buccal and lingual sites, and PPD at six sites per tooth. Negative binomial regression was used to estimate the risk ratios (RRs) for oral inflammation adjusted for baseline age, gender, smoking status, alcohol intake, education, physical activity, waist circumference, mean plaque index, and baseline number of sites with BOP, or number of teeth with PPD≥4 mm and BOP. The potential impact of tertiles of serum TNF-α and adiponectin on the IR-oral inflammation association was also assessed in a subsample of 597 participants.

RESULTS

Participants in the highest HOMA-IR tertile at baseline had significantly higher numbers of sites with BOP [RR = 1.19, 95% confidence interval (CI): 1.03-1.36] and number of teeth with PPD ≥ 4 mm and BOP (RR = 1.39, 95% CI: 1.09-1.78) at follow-up, compared with individuals in the lower two HOMA-IR tertiles. Neither TNF-α nor adiponectin confounded the associations.

CONCLUSION

IR significantly predicts gingival/periodontal inflammation in this population.

Caries and Periodontitis: Contesting the Conventional Wisdom on Their Aetiology

We review the literature on the oral microbiome and the role of the microbiota in the development of dental caries and periodontitis. While most research has been focused on identifying one or more specific determinants of these diseases, the results have provided limited predictive value and have not been able to explain the variation in the distribution of these diseases observed in epidemiological or clinical studies. Drawing on existing knowledge about the nature of the oral microbiota, we suggest that a stochastic model based on the Weiner process provides simple and parsimonious explanations for the pathogenesis of both caries and periodontitis, making few assumptions, and providing explanations for phenomena that have hitherto proved difficult, or have required complex arguments, to explain. These diseases occur as the result of the dental hard tissues and periodontal tissues integrating the random "noise" caused by normal metabolic activities of commensal microorganisms in the dental biofilm. The processes that result in the progression and regression of caries and periodontitis may be considered as "natural," rather than pathological, even if, when left unchecked over long periods of time, they can result in the development of pathologies. The likelihood of progression or regression can be influenced by other determinants, but these processes will nevertheless occur in the absence of such influences. The distributional characteristics of the model approximate the findings of epidemiological studies indicating that, for both caries and periodontitis, there will be few sites affected in the early period after the eruption of the permanent dentition, but in those older there is an almost linear relationship with increasing age; furthermore, the longer a site survives without being affected, the less likely that it will be affected. We discuss the clinical and public health importance of these findings.

In vitro effect of Porphyromonas gingivalis combined with influenza A virus on respiratory epithelial cells

OBJECTIVE

Respiratory epithelial cells are the first natural barrier against bacteria and viruses; hence, the interactions among epithelial cells, bacteria, and viruses are associated with disease occurrence and development. The effect of co-infection by P. gingivalis and influenza A virus (IAV) on respiratory epithelial cells remains unknown. The aim of this study was to analyze in vitro cell viability and apoptosis rates in respiratory epithelial A549 cells infected with P. gingivalis or IAV alone, or a combination of both pathogens.

DESIGN

A549 cells were first divided into a control group, a P. gingivalis group, an IAV group, and a P. gingivalis + IAV group, to examine cell viability and apoptosis rates, the levels of microtubule associated protein 1 light chain 3 B (LC3-II), microtubule associated protein 1 light chain 3A (LC3-I), and sequestosome 1 (P62), and the formation of autophagosomes. The autophagy inhibitor, 3-methyladenine (3MA), was used to assess autophagy and apoptosis in A549 cells infected with P. gingivalis or IAV.

RESULTS

An MTT assay revealed that cell viability was significantly lower in the IAV group than in the P. gingivalis + IAV group (P < 0.05). Flow cytometry indicated that the apoptosis rate was significantly higher in the IAV group than in the P. gingivalis + IAV group (P < 0.05). The fluorescence levels of GFP-LC3 increased significantly, the LC3-II/LC3-I ratio was significantly higher, and the P62 protein levels were statistically lower in the P. gingivalis + IAV group compared with the IAV group (all P < 0.05). Western blotting revealed that the LC3- II/LC3-I ratio was significantly lower, and caspase-3 levels were significantly higher in the 3MA + P. gingivalis + IAV group compared to the P. gingivalis + IAV group (all P < 0.05).

CONCLUSION

In vitro studies showed that infection by P. gingivalis combined with IAV temporarily inhibited apoptosis in respiratory epithelial cells, and this may be related to the initiation of autophagy.

A Chemically Modified Curcumin (CMC 2.24) Inhibits Nuclear Factor κB Activation and Inflammatory Bone Loss in Murine Models of LPS-Induced Experimental Periodontitis and Diabetes-Associated Natural Periodontitis

The purpose of this study was to assess the effect of a novel chemically modified curcumin (CMC 2.24) on NF-κB and MAPK signaling and inflammatory cytokine production in two experimental models of periodontal disease in rats. Experimental model I: Periodontitis was induced by repeated injections of LPS into the gingiva (3×/week, 3 weeks); control rats received vehicle injections. CMC 2.24, or the vehicle, was administered by daily oral gavage for 4 weeks. Experimental model II: Diabetes was induced in adult male rats by streptozotocin injection; periodontal breakdown then results as a complication of uncontrolled hyperglycemia. Non-diabetic rats served as controls. CMC 2.24, or the vehicle, was administered by oral gavage daily for 3 weeks to the diabetics. Hemimaxillae and gingival tissues were harvested, and bone loss was assessed radiographically. Gingival tissues were pooled according to the experimental conditions and processed for the analysis of matrix metalloproteinases (MMPs) and bone-resorptive cytokines. Activation of p38 MAPK and NF-κB signaling pathways was assessed by western blot. Both LPS and diabetes induced an inflammatory process in the gingival tissues associated with excessive alveolar bone resorption and increased activation of p65 (NF-κB) and p38 MAPK. In both models, the administration of CMC 2.24 produced a marked reduction of inflammatory cytokines and MMPs in the gingival tissues, decreased bone loss, and decreased activation of p65 (NF-κB) and p38 MAPK. Inhibition of these cell signaling pathways by this novel tri-ketonic curcuminoid (natural curcumin is di-ketonic) may play a role in its therapeutic efficacy in locally and systemically associated periodontitis.

Expression of protease-activated receptors 1 and 2 in individuals with healthy gingiva and chronic periodontitis

Background

Protease-activated receptors (PAR-1 and PAR-2) are found to be immensely exhibited in the periodontal tissues. These receptors are involved in the inflammatory and repair processes. Activation of PARs is mainly by the bacterial and endogenous enzymes. The aim of the study was to determine the role of PAR-1 and PAR-2 in initiating periodontal inflammation and to immunolocalize these receptors in the gingival tissues of healthy and chronic periodontitis individuals.

Materials and Methods

A total of 50 patients were selected for this study, of which 25 were healthy controls and 25 were chronic periodontitis patients. Gingival tissues were excised from the marginal gingiva and interdental papilla under local anesthesia (xylocaine with 2% adrenaline) during crown lengthening procedure or during periodontal therapy depending on the respective groups. Immunohistochemical analyses of PARs were done by staining the samples with hematoxylin and eosin and with primary and secondary antibody for PAR-1 and PAR-2.

Results

The Hematoxylin and Eosin staining showed more inflammatory changes in the periodontitis group compared to healthy gingiva. In chronic periodontitis, PAR-1-positive cells were seen in the basal layer with a weak expression and were showing negative expression in the superficial layer. In consideration of PAR-2, there was a very strong expression up to the superficial layer of the epithelium, compared to PAR-1. On comparing the intensity of staining in the connective tissue of chronic periodontitis sample, there was an increased expression of PAR-2 compared with PAR-1. A low positive expression of PAR-1 and PAR-2 was observed in the epithelium and connective tissue of the healthy tissues.

Conclusion

The results clearly demonstrated the role of PAR-1 and 2 in periodontal inflammation.

The effects of a desiccant agent in the treatment of chronic periodontitis: a randomized, controlled clinical trial

OBJECTIVE

Chemotherapeutic agents have been widely used as adjuncts for the treatment of chronic periodontitis (CP). This study investigated and compared a desiccant agent as an adjunct to scaling and root planing (SRP) versus SRP alone for the treatment of CP.

MATERIALS AND METHODS

Thirty-six patients with CP were studied. Using a split-mouth design, the maxillary right and left quadrants were randomly assigned to SRP plus desiccant (Hybenx® EPIEN Medical, Inc. St. Paul, MN, USA) or SRP alone. Patients were examined on a regular basis for clinical, microbiological, and inflammatory mediator changes over a 1-year period. Clinical attachment level (CAL) was the primary outcome variable. In addition, the red complex bacteria and gingival crevicular fluid (GCF) inflammatory mediators were monitored.

RESULTS

Compared to baseline, both treatments demonstrated an improvement in periodontal parameters. Compared to SRP alone, SRP plus desiccant yielded a significant improvement in probing depth (PD) (SRP: 2.23 ± 0.31 mm vs. desiccant: 3.25 ± 0.57 mm, p < 0.05), CAL (SRP: 3.16 ± 0.29 mm vs. desiccant: 4.21 ± 0.34 mm, p < 0.05 mm) and bleeding on probing (BOP) (SRP: 4.56 ± 1.5% vs. desiccant: 34.23 ± 4.2%, p < 0.001) at 12 months. Similarly, in the SRP plus desiccant group, the bacteria of the red complex were significantly reduced (p < 0.05); and the level of inflammatory mediators was significantly reduced (p < 0.003) compared to SRP alone.

CONCLUSIONS

SRP plus the desiccant resulted in a greater reduction in clinical, microbial and inflammatory mediators compared to SRP alone.

CLINICAL RELEVANCE

Desiccant, when combined to SRP, was demonstrated as a significant approach to control the levels of certain periodontal pathogens, inflammatory mediators in patients with CP.

Effective professional intraoral tooth brushing instruction using the modified plaque score: a randomized clinical trial

Purpose

The purpose of this study was to evaluate the efficacy of the modified plaque score (MPS) for assessing the oral hygiene status of periodontitis patients.

Methods

A total of 116 patients were included in this study. After evaluation of the Löe and Silness gingival index (GI), Silness and Löe plaque index (PlI), O'Leary plaque control record (PCR), and MPS, patients were randomly assigned to either a conventional tooth brushing instruction (C-TBI) group (n=56) or a professional intraoral tooth brushing instruction (P-TBI) group (n=60). The MPS and clinical parameters were re-evaluated after scaling and a series of root planing. The convergent validity of MPS with the PlI and PCR was assessed. The measurement time for MPS and PCR was compared according to the proficiency of the examiner.

Results

After root planing, the GI, PlI, PCR, and MPS improved from their respective baseline values in both groups. Three different plaque indices including the MPS, showed significant differences between the C-TBI group and the P-TBI group after root planing. The MPS showed significant concurrence with the PCR and PlI. The mean time for PCR measurement was 2.76±0.71 times longer than that for MPS measurement after 2 weeks of training.

Conclusions

MPS seems to be a practical plaque scoring system compared with the PlI and PCR. These findings suggest that repetitive plaque control combined with an easily applicable plaque index (MPS) may facilitate more effective oral hygiene education and improved periodontal health.

Identification and functional characterization of type II toxin/antitoxin systems in Aggregatibacter actinomycetemcomitans

Type II toxin/antitoxin (TA) systems contribute to the formation of persister cells and biofilm formation for many organisms. Aggregatibacter actinomycetemcomitans thrives in the complex oral microbial community subjected to continual environmental flux. Little is known regarding the presence and function of type II TA systems in this organism or their contribution to adaptation and persistence in the biofilm. We identified 11 TA systems that are conserved across all seven serotypes of A. actinomycetemcomitans and represent the RelBE, MazEF and HipAB families of type II TA systems. The systems selectively responded to various environmental conditions that exist in the oral cavity. Two putative RelBE‐like TA systems, D11S_1194‐1195 and D11S_1718‐1719 were induced in response to low pH and deletion of D11S_1718‐1719 significantly reduced metabolic activity of stationary phase A. actinomycetemcomitans cells upon prolonged exposure to acidic conditions. The deletion mutant also exhibited reduced biofilm biomass when cultured under acidic conditions. The D11S_1194 and D11S_1718 toxin proteins inhibited in vitro translation of dihydrofolate reductase (DHFR) and degraded ribosome‐associated, but not free, MS2 virus RNA. In contrast, the corresponding antitoxins (D11S_1195 and D11S_1719), or equimolar mixtures of toxin and antitoxin, had no effect on DHFR production or RNA degradation. Together, these results suggest that D11S_1194‐1195 and D11S_1718‐1719 are RelBE‐like type II TA systems that are activated under acidic conditions and may function to cleave ribosome‐associated mRNA to inhibit translation in A. actinomycetemcomitans. In vivo, these systems may facilitate A. actinomycetemcomitans adaptation and persistence in acidic local environments in the dental biofilm.

Anti-oral common pathogenic bacterial active acetylenic acids from Thesium chinense Turcz

Discovery of agents for oral infectious diseases is always encouraged in natural products chemistry. A bioassay-guided isolation led to the isolation of two new acetylenic acids (1, 2) along with seven known ones (3-9) from the ethanol extract of Thesium chinense Turcz, a commonly used oral anti-bacterial and anti-inflammatory herb. Their structures were elucidated on the basis of spectroscopic and chemical evidence. Exocarpic acid (3) demonstrated the most promising activity against three tested oral pathogenic bacterial strains, Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mutans, with minimum inhibitory concentration values of 0.86, 3.43, and 13.70 μg/mL, respectively. Compounds 1, 2, 4, 5 and 7 also showed potential activities against periodontal bacteria (P. gingivalis, F. nucleatum).

The association between coeliac disease and periodontitis: Results from NHANES 2009-2012

AIM

To investigate whether coeliac disease (CD) was associated with periodontitis among a nationally representative sample of US adults.

MATERIALS AND METHODS

The National Health and Nutrition Examination Survey (NHANES) 2009-2012 enrolled 6,661 subjects with full-mouth periodontal examination and serological testing for antitissue transglutaminase (tTg) and antiendomysial (EMA) antibodies. CD was defined as (i) self-reported physician diagnosis while on a gluten-free diet; or (ii) tTg levels >10.0 U/ml and positive EMA results. Positive serology without self-reported diagnosis was defined as undiagnosed CD (UdxCD). Periodontitis was defined according to the CDC/AAP definition. Multivariable linear and logistic models were used to regress the mean probing depth (PD) or attachment loss (AL) outcomes across CD categories (none, diagnosed and undiagnosed).

RESULTS

The prevalence of moderate/severe periodontitis and diagnosed/undiagnosed CD was 40% and 0.74%, respectively. Mean AL was lower among those with CD although results were not statistically significant (p = .67). The odds of periodontitis among individuals with diagnosed and undiagnosed CD were: 0.5(0.22, 1.16) and 0.62(0.1, 3.75), respectively. Mean PD levels among those without CD or with diagnosed or undiagnosed CD were 1.49 ± 0.02, 1.36 ± 0.11 and 1.31 ± 0.11 (p = .03).

CONCLUSION

CD is associated with modestly lower levels of mean PD but was not associated with mean AL or periodontitis. Larger studies are necessary to enhance precision and strengthen conclusions.

Acute septic arthritis of the knee: A rare case report of infection with Parvimonas micra after an intra-articular corticosteroid injection for osteoarthritis

Acute bacterial mono-articular septic arthritis affects most commonly the lower extremity joints in adult population and most commonly caused by Staphylococcus aureus. Various risk factors determine susceptibility to infection including host immunity, medical co-morbidity and joint structural abnormality and other organisms may be involved. Parvimonas micra (P. micra) is among the rare organisms that may be associated with atypical septic arthritis and primarily affects the native knee joint. Only 3 case reports in the literature have reported on pyogenic pyogenic joint infection caused by this organism. We hereby present our experience with a case of knee septic arthritis caused by P. micra in a patient with knee osteoarthritis following a recent intra-articular injection with corticosteroids. In susceptible patients, Intra-articular corticosteroid injection and crystal induced arthritis may propose a potential risk of contracting infection with P. micra.

The Anti-inflammatory Effects of Glycerol-supplemented Probiotic Lactobacillus reuteri on Infected Epithelial cells In vitro

Background:

One of the most interesting effects of probiotics is their ability to modulate the immune system through the induction of cytokines and to enhance the host immune response.

Aims:

The purpose of this study was to evaluate the anti-inflammatory effect of glycerol-supplemented Lactobacillus reuteri on the transcription level of interleukin (IL)-8 and human-beta-defensin (hBD)-2 expressed by epithelial cells after exposure to bacteria.

Materials and Methods:

The confluent-cultured HaCat cell line (10⁵ cells/mL) was exposed to Streptococcus mutans ATCC-25175 and Porphyromonas gingivalis ATCC-33277 (10⁷ colony-forming units [CFU]/mL) for 24 h and challenged with probiotic L. reuteri ATCC-55730 (10⁷ CFU/mL) supplemented with glycerol. Subsequently, the transcription levels of IL-8 and hBD-2 in HaCat cells were analyzed using reverse-transcription polymerase chain reaction (RT-PCR). In addition, cell viability was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. All the obtained data were statistically analyzed using the one-way analysis of variance test, with P < 0.05 set as the level of significance.

Results:

The MTT assays confirmed no cytotoxic effects of glycerol-supplemented L. reuteri on HaCat cells (viability >90%). mRNA expression of IL-8 and hBD-2 increased after exposure to both bacteria. The presence of glycerol-supplemented L. reuteri significantly reduced the expression of IL-8 and hBD-2 on HaCat cells (P < 0.05).

Conclusion:

Glycerol-supplemented L. reuteri reduced the expression of IL-8 and hBD-2, and the results may be proof of principle for a probiotic approach to combating inflammation. However, further studies are needed to validate this probiotic effect.

Clinical and Microbiological Evaluation of the Periodontal Status of Children with Unilateral Complete Cleft Lip and Palate

Objective

To compare periodontal conditions in children with and without cleft.

Design

Clinical examinations and microbiological analysis of 57 selected children, including 30 with unilateral complete cleft lip and palate (experimental group) and 27 without clefts (control group).

Setting

Hospital of Rehabilitation of Craniofacial Anomalies (HRCA) in Bauru, Sao Paulo, Brazil.

Patients, Participants

All children examined were healthy and between the ages of 5 and 6 years.

Results

The mean plaque index (PI) in the experimental group was higher (1.82 ± 0.3) than in the control group (1.63 ± 0.38), although this difference was not statistically significant. The mean gingival index (GI) in the experimental group (1.82 ± 0.38) was found to be significantly higher (p < .05) than that of the control group (0.79 ± 0.33). The cleft area in the experimental group, with a mean PI of 2.04 ± 0.58 and mean GI of 1.11 ± 0.26, compared with the posterior area, with a mean PI of 1.74 ± 0.37 and mean GI of 1.04 ± 0.26, showed a statistically significant difference only in the PI. Most of the children in both experimental and control groups presented a moderate PI degree (73.33% and 81.48%, respectively) and a high prevalence of mild gingivitis (53.33% and 70.37%, respectively). Analysis of the organisms showed that Prevotella nigrescens was detected in 16.67% of the experimental group and 11.11% of the control, whereas Porphyromonas gingivalis and Treponema denticola were not detected.

Conclusion

Children with clefts showed greater gingival inflammation, despite the same amount of plaque and prevalence of microorganisms.

Microbial colonization of the periodontal pocket and its significance for periodontal therapy

The aim of this paper was to evaluate strategies for periodontal therapy from the perspective of periodontal disease being a consequence of microbial colonization of the periodontal pocket environment. In classic bacterial infections the diversity of the microbiota decreases as the disease develops. In most cases of periodontitis, however, the diversity of the flora increases. Most incriminating bacteria are thought to harm tissues significantly only if present in high numbers over prolonged periods of time. Clinical trials have repeatedly demonstrated that scaling and root planing, a procedure that aims to remove subgingival bacterial deposits by scraping on the tooth surface within the periodontal pocket, is effective. At present, for the therapy of any form of periodontal disease, there exists no protocol with proven superiority, in terms of efficiency or effectiveness, over scaling and root planing plus systemic amoxicillin and metronidazole. Some exponents advocate rationing these drugs for patients with a specific microbial profile. However, the evidence for any benefit of bacteriology-assisted clinical protocols is unsatisfactory. Treated sites are subject to recolonization with a microbiota similar to that present before therapy. The degree and speed of recolonization depends on the treatment protocol, the distribution patterns of periodontal microorganisms elsewhere in the oral cavity and the quality of the patient's oral hygiene. To limit the use of antibiotics and to avoid accumulation of harmful effects by repeated therapy, further efforts must be made to optimize procedures addressing the microbial colonization and recolonization of the periodontal pocket.

Prevalence of Periodontal Destruction and Putative Periodontal Pathogens in the Same Lebanese Family

AIM

Periodontal diseases are associated with microorganisms rich in Gram-negative species. Several studies have indicated the presence of few a periodontopathic microorganisms in the same family. A parent with severe adult periodontitis, who is infected with bacteria associated with periodontal disease, may function as a source of infection. Their children may be at a greater risk to become colonized with bacteria. The purpose of this investigation was (1) to explore the presence of three bacteria, such as Porphyromonas gingivalis (PG), Prevotella intermedia (PI), and Aggregatibacter actinomycetemcomitans (AA) in the same Lebanese family and (2) to study the clinical destruction in the same family and their relations as members of this family due to the presence of PG.

MATERIALS AND METHODS

A total of 10 families were screened; only 5 (13 females and 5 males) were selected for this study, and at least one member of the family had untreated periodontal disease, chronic or aggressive. Every participant signed an informed consent form. A total of 18 available deoxyribonucleic acid (DNA) samples were taken to analyze the presence of three periodontal bacteria.

STATISTICS

Multiple logistic regression was used for the exact methods.

RESULTS

All 18 patients showed a positive result for PI. Also, PG. was recognized in 15 patients while AA was not detected in any of the subjects. All couples suffered from periodontitis, chronic or aggressive forms, five children suffered from gingivitis, three children had no clinical manifestation, and only one suffered from localized aggressive periodontitis. The statistical analysis showed with each 1 year of increase in age, the odds of having periodontal disease multiply by 1.39, i.e., age as a risk factor for periodontal disease due to the presence of PG and sharing the same plate.

CONCLUSION

This investigation demonstrates a high prevalence of periodontal microorganisms in children and young adults of Lebanese periodontitis parents and a microbiological similarity between the children and their mothers. All these factors could be a high risk of developing periodontal disease in the future.

CLINICAL SIGNIFICANCE

This article shows that vertical transmission of microorganisms is a possible risk factor for developing periodontal disease in the offspring.

[Research progress on the type Ⅸ secretion system of Porphyromonas gingivalis]

In recent years, the study found that Porphyromonas gingivalis type Ⅸ secretion system (T9SS) is a novel protein secretion system, also known as Por secretion system (PorSS). Unlike the eight protein secretion systems found in the past, the system is a polyprotein complex found only in Bacteroides. The secreted proteins have both N- and C-terminus, where the former includes Sec-dependent type Ⅰ signals peptide, and the latter contains conserved domains (C-terminal conserved domain, CTD). Porphyromonas gingivalis T9SS includes proteins such as intima, outer membrane, cytoplasm, and cell cycle, including at least 34 proteins containing CTD. Porphyromonas gingivalis T9SS is involved in regulating associated virulence factors including gingivin, fimbriae, lipopolysaccharide, HBP35, CPG70 protein and peptidyl-arginine deiminase. These CTD-containing virulence proteins are localized by T9SS and then released to the extracellular domain, thereby destroying periodontal tissue. Therefore, this review summarizes the research progress on the T9SS of Porphyromonas gingivalis.

Advanced Scaffolds for Dental Pulp and Periodontal Regeneration

No current therapy promotes root canal disinfection and regeneration of the pulp-dentin complex in cases of pulp necrosis. Antibiotic pastes used to eradicate canal infection negatively affect stem cell survival. Three-dimensional easy-to-fit antibiotic-eluting nanofibers, combined with injectable scaffolds, enriched or not with stem cells and/or growth factors, may increase the likelihood of achieving predictable dental pulp regeneration. Periodontitis is an aggressive disease that impairs the integrity of tooth-supporting structures and may lead to tooth loss. The latest advances in membrane biomodification to endow needed functionalities and technologies to engineer patient-specific membranes/constructs to amplify periodontal regeneration are presented.

Hemin binding by Porphyromonas gingivalis strains is dependent on the presence of A-LPS

Porphyromonas gingivalis is a Gram-negative black pigmenting anaerobe that is unable to synthesize heme [Fe(II)-protoporphyrin IX] or hemin [Fe(III)-protoporphyrin IX-Cl], which are important growth/virulence factors, and must therefore derive them from the host. Porphyromonas gingivalis expresses several proteinaceous hemin-binding sites, which are important in the binding/transport of heme/hemin from the host. It also synthesizes several virulence factors, namely cysteine-proteases Arg- and Lys-gingipains and two lipopolysaccharides (LPS), O-LPS and A-LPS. The gingipains are required for the production of the black pigment, μ-oxo-bisheme {[Fe(III)PPIX]2 O}, which is derived from hemoglobin and deposited on the bacterial cell-surface leading to the characteristic black colonies when grown on blood agar. In this study we investigated the role of LPS in the deposition of μ-oxo-bisheme on the cell-surface. A P. gingivalis mutant defective in the biosynthesis of Arg-gingipains, namely rgpA/rgpB, produces brown colonies on blood agar and mutants defective in Lys-gingipain (kgp) and LPS biosynthesis namely porR, waaL, wzy, and pg0129 (α-1, 3-mannosyltransferase) produce non-pigmented colonies. However, only those mutants lacking A-LPS showed reduced hemin-binding when cells in suspension were incubated with hemin. Using native, de-O-phosphorylated and de-lipidated LPS from P. gingivalis W50 and porR strains, we demonstrated that hemin-binding to O-polysaccharide (PS) and to the lipid A moiety of LPS was reduced compared with hemin-binding to A-PS. We conclude that A-LPS in the outer-membrane of P. gingivalis serves as a scaffold/anchor for the retention of μ-oxo-bisheme on the cell surface and pigmentation is dependent on the presence of A-LPS.

The Infectious Basis of ACPA-Positive Rheumatoid Arthritis

Rheumatoid arthritis (RA) is associated with HLA-DRB1 shared epitope (HLA-DRB1SE) and anti-citrullinated protein autoantibodies (ACPAs). ACPAs precedes the onset of clinical and subclinical RA. There are strong data for three infectious agents as autoimmunity triggers in RA, namely Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans causes of periodontal disease (PD), and Epstein-Barr virus (EBV). P. gingivalis expresses arginine gingipains, that cleave proteins at the arginine residues, and peptidyl arginine deiminase (PPAD), which citrullinates arginine residues of proteins, thus forming neoantigens that lead to ACPA production. Peripheral blood plasmablasts from ACPA+RA patients produce ACPAs the majority of which react against P. gingivalis. A. actinocycetemcomitans produces leukotoxin A, a toxin that forms pores in the neutrophil membranes and leads to citrullination and release of citrullinated autoantigens in the gums. EBV can infect B cells and epithelial cells and resides as latent infection in resting B cells. Abs against citrullinated peptides derived from EBV nuclear antigen appear years before RA and cross-react with human citrullinated fibrin. Citrullinated proteins are potential arthritogenic autoantigens in RA. The conversion of arginine to citrulline increases the peptide binding affinity to HLA-DRB1SE. Also, citrullinated fibrinogen induces arthritis in HLA-DRB1*0401 transgenic mice, and transfer of their splenic T cells causes arthritis to recipient mice.

Latino Acculturation and Periodontitis Status Among Mexican-Origin Adults in the United States: NHANES 2009-2012

This study examined the association between Latino acculturation indicators (language and citizenship/nativity status) and periodontitis using data from the National Health and Nutrition Examination Survey (NHANES) 2009-2012. Descriptive statistics and logistic regression analyses were performed and all analyses were adjusted for the complex survey design. Results showed that 63.2% of participants had periodontitis: 9.4% mild, 37.9% moderate, and 16% severe. Language was significantly associated with periodontitis after adjusting for age, educational level, gender, usual source of care, flossing, smoking, and glycohemoglobin level (P = .02). Dental public and private health efforts should implement culturally tailored oral health promotion education efforts for this population.

Angiopoietin-like protein 2 regulates Porphyromonas gingivalis lipopolysaccharide-induced inflammatory response in human gingival epithelial cells

Angiopoietin-like protein 2 (ANGPTL2) maintains tissue homeostasis by inducing inflammation and angiogenesis. It is produced in infiltrating immune cells or resident cells, such as adipocytes, vascular endothelial cells, and tumor cells. We hypothesized that ANGPTL2 might play an important role as a unique mediator in both systemic and periodontal disease. We demonstrated an increased ANGPTL2 concentration in gingival crevicular fluid from chronic periodontitis patients. Porphyromonas gingivalis lipopolysaccharide (LPS) treatment strongly induced ANGPTL2 mRNA and protein levels in Ca9-22 human gingival epithelial cells. Recombinant human ANGPTL2 increased interleukin 1β (IL-1β), IL-8, and tumor necrosis factor-α (TNF-α) mRNA and protein levels in Ca9-22 cells. Small-interfering (si)RNA-mediated ANGPTL2 knockdown in Ca9-22 cells reduced IL-1β, IL-8 and TNF-α mRNA and protein levels compared with control siRNA (p<0.01) in P. gingivalis LPS-stimulated Ca9-22 cells. Antibodies against integrin α5β1, an ANGPTL receptor, blocked induction of these inflammatory cytokines in P. gingivalis LPS-treated Ca9-22 cells, suggesting that secreted ANGPTL induces inflammatory cytokines in gingival epithelial cells via an autocrine loop. The classic sequential cascade of P. gingivalis LPS → inflammatory cytokine induction is well established. However, in the current study, we reveal a novel cascade comprising sequential P. gingivalis LPS → ANGPTL2 → integrin α5β1 → inflammatory cytokine induction, which might be responsible for inducing potent periodontal disorganization activity in gingival epithelial cells. Via this pathway, ANGPTL2 functions in the pathogenesis of periodontitis and contributes to prolonging chronic inflammation in patients with systemic disease.