Host response mechanisms in periodontal diseases

Unravelling the intricacies of Porphyromonas gingivalis: virulence factors, lifecycle dynamics and phytochemical interventions for periodontal disease management

Porphyromonas gingivalis is a gram-negative anaerobic bacterium recognized for its pivotal role in the pathogenesis of periodontal diseases. This review covers an overview of the virulence factors and lifecycle stages of P. gingivalis, with a specific focus on attachment and colonization, biofilm formation, growth and multiplication, dormancy survival and dissemination. Additionally, we explore the significance of inter-bacterial cross-feeding within biofilms. Furthermore, we discuss potential phytochemical-based strategies to target P. gingivalis, including the use of curcumin, apigenin, quercetin and resveratrol. Understanding the virulence factors and lifecycle stages of P. gingivalis, along with the promising phytochemical-based interventions, holds promise for advancing strategies in periodontal disease management and oral health promotion.

Effects of the DL76 Antagonist/Inverse Agonist of Histamine H3 Receptors on Experimental Periodontitis in Rats: Morphological Studies

BACKGROUND

Periodontitis preceded by gingivitis is the most common form of periodontal disease and occurs due to the interaction of microorganisms present in the complex bacterial aggregates of dental plaque biofilm and their metabolism products with periodontal tissues. Histamine is a heterocyclic biogenic amine acting via four types of receptors. Histamine H3 receptors act as presynaptic auto/heteroreceptors to regulate the release of histamine and other neurotransmitters.

AIM

Since the nervous system is able to regulate the progression of the inflammatory process and bone metabolism, the aim of this study was to investigate the effects of DL76, which acts as an antagonist/inverse agonist of H3 receptors, on the course of experimental periodontitis.

MATERIALS AND METHODS

This study was conducted in 24 mature male Wistar rats weighing 245-360 g, aged 6-8 weeks. A silk ligature was placed on the second maxillary molar of the right maxilla under general anesthesia. From the day of ligating, DL76 and 0.9% NaCl solutions were administered subcutaneously for 28 days in the experimental and control groups, respectively. After the experiment, histopathological, immunohistochemical and radiological examinations were performed.

RESULTS

Ligation led to the development of the inflammatory process with lymphocytic infiltration, increased epithelial RANKL and OPG expression as well as bone resorption. DL76 evoked a reduction in (1) lymphocytic infiltration, (2) RANKL and OPG expression as well as (3) bone resorption since the medians of the mesial and distal interdental spaces in the molars with induced periodontitis were 3.56-fold and 10-fold lower compared to the corresponding values in saline-treated animals with periodontitis.

CONCLUSION

DL76 is able to inhibit the progression of experimental periodontitis in rats, as demonstrated by a reduction in the inflammatory cell infiltration, a decrease in the RANKL/RANK OPG pathway expression and a reduction in the alveolar bone resorption.

Lung abscess caused by the anaerobic pathogen Tannerella forsythia

Odontogenic infections can spread to the respiratory tract. Despite the known role of Tannerella forsythia as the primary pathogen in periodontitis, the association between T. forsythia infection and risk of pneumonia or lung abscess remains unknown. In this report, we present a case of lung abscess caused by T. forsythia infection. The pathogen was detected by metagenomic next-generation sequencing (mNGS) in the bronchoalveolar lavage fluid of the patient. The clinical characteristics and possible mechanisms of the infection are discussed. T. forsythia is a conditional pathogen that can cause lung abscess in the presence of helper bacteria and reduced host immune status. The course of treatment should be personalized and might be longer than 3 months.

In Vivo Regulation of Active Matrix Metalloproteinase-8 (aMMP-8) in Periodontitis: From Transcriptomics to Real-Time Online Diagnostics and Treatment Monitoring

BACKGROUND

This study investigated in vivo regulation and levels of active matrix metalloproteinase-8 (aMMP-8), a major collagenolytic protease, in periodontitis.

METHODS

Twenty-seven adults with chronic periodontitis (CP) and 30 periodontally healthy controls (HC) were enrolled in immunohistochemistry and transcriptomics analytics in order to assess Treponema denticola (Td) dentilisin and MMP-8 immunoexpression, mRNA expression of MMP-8 and its regulators (IL-1β, MMP-2, MMP-7, TIMP-1). Furthermore, the periodontal anti-infective treatment effect was monitored by four different MMP-8 assays (aMMP-8-IFMA, aMMP-8-Oralyzer, MMP-8-activity [RFU/minute], and total MMP-8 by ELISA) among 12 CP (compared to 25 HC).

RESULTS

Immunohistochemistry revealed significantly more Td-dentilisin and MMP-8 immunoreactivities in CP vs. HC. Transcriptomics revealed significantly elevated IL-1β and MMP-7 RNA expressions, and MMP-2 RNA was slightly reduced. No significant differences were recorded in the relatively low or barely detectable levels of MMP-8 mRNAs. Periodontal treatment significantly decreased all MMP-8 assay levels accompanied by the assessed clinical indices (periodontal probing depths, bleeding-on-probing, and visual plaque levels). However, active but not total MMP-8 levels persisted higher in CP than in periodontally healthy controls.

CONCLUSION

In periodontal health, there are low aMMP-8 levels. The presence of Td-dentilisin in CP gingivae is associated with elevated aMMP-8 levels, potentially contributing to a higher risk of active periodontal tissue collagenolysis and progression of periodontitis. This can be detected by aMMP-8-specific assays and online/real-time aMMP-8 chair-side testing.

Polarized M2 macrophages induced by glycosylated nano-hydroxyapatites activate bone regeneration in periodontitis therapy

AIM

To investigate the association between periodontal macrophage polarization states and the alveolar bone levels, and to assess whether glycosylated nano-hydroxyapatites (GHANPs) could improve bone regeneration in periodontitis by inducing macrophage M2 polarization.

MATERIALS AND METHODS

The change of macrophage polarization state in inflammatory periodontal tissues (with bone loss) was examined using clinical gingival samples. The relationship between macrophage phenotype and bone level in periodontal bone loss and repair was evaluated using a mouse periodontitis model. The effect of GHANPs on macrophage polarization was assessed by the in vitro model of lipopolysaccharide (LPS)-stimulated inflammation. The polarization-related markers were detected by immunofluorescence staining, real-time polymerase chain reaction and enzyme-linked immunosorbent assay analysis. The therapeutic effect of GHANPs on alveolar bone loss was explored in experimental periodontitis by histological staining and micro-CT analysis.

RESULTS

A lower macrophage M2/M1 ratio was observed in periodontitis-affected human gingival tissues. The results of animal experiments demonstrated a positive correlation between a lower Arg-1/iNOS ratio and accelerated alveolar bone loss; also, the proportion of Arg-1-positive macrophages increased during bone repair and regeneration. The administration of GHANPs partially restored M2 macrophage polarization after LPS stimulation. GHANPs increased alveolar bone repair and regeneration in experimental periodontitis induced by ligation, potentially related to their macrophage M2 transition regulation.

CONCLUSIONS

The findings of this study indicate that the induction of macrophage M2 polarization can be considered a viable approach for enhancing inflammatory bone repair. Additionally, GHANPs show potential in the clinical treatment of periodontitis.

Investigating the diagnostic potential of IL-1β, IL-10, and IL-36γ in gingival crevicular fluid in patients with different periodontal conditions

BACKGROUND

The study aimed to analyze cytokine levels, including interleukin (IL)-1β, IL-10, and IL-36γ, to investigate the link between pro- and anti-inflammatory responses in periodontal conditions and assess their potential as diagnostic biomarkers for distinguishing between different types of periodontal conditions.

METHODS

80 systemically healthy non-smokers (25 periodontally healthy, 25 with gingivitis, 30 with periodontitis) were included. Clinical periodontal parameters were recorded, and gingival crevicular fluid (GCF) samples were obtained. Receiver operating characteristic (ROC) curve analysis was applied to determine the diagnostic value of cytokines.

RESULTS

IL-36γ had the highest sensitivity for diagnosing periodontitis, although its specificity for identifying those without periodontitis was relatively low. The combination of IL-1β and IL-36γ was the most effective in differentiating periodontitis from periodontal health. IL-10 was found to be an acceptable discriminator for distinguishing gingivitis from healthy conditions. However, its sensitivity and specificity for identifying gingivitis were lower. The combination of the three cytokines showed the highest ability to distinguish between periodontitis and gingivitis.

CONCLUSION

The levels of IL-1β, IL-10, and IL-36γ in GCF may provide insights into periodontal health and disease status. Further studies are needed to validate these results and explore the potential of these cytokines in periodontal disease management.

Trend in the Incidence of Severe Partial Edentulism among Adults Using the Korean National Health Insurance Service Claim Data, 2014-2018

PURPOSE

Missing teeth is one of the most important indicators of oral health behavior and the result of dental caries, periodontal disease, and injuries. This study examined a trend in the incidence of severe partial edentulism (SPE) using the Korean National Health Insurance Service (KNHIS) data.

MATERIALS AND METHODS

Data of adults aged ≥20 years were obtained from the KNHIS for the 2014-2018 period. SPE was defined in dental information within a population with a treatment history of dental scaling as having 1 to 8 natural teeth. Crude incidence rates (CIRs) and age-standardized incidence rates (AIRs) with 95% confidence interval were calculated per 100000 persons. The Cochran Armitage trend (CAT) test and average annual percentage change were used to analyze SPE trends.

RESULTS

The CIRs among Korean adults were from 346.29 to 391.11 in 2014-2016 and from 391.11 to 354.09 in 2016-2018. The AIRs trend statistically increased by 4.31% from 346.29 to 376.80 and decreased by 4.72% from 376.80 to 342.10. The AIRs in men increased by 4.00% and decreased by 3.01%. The AIRs in women decreased by 2.18% and increased by 2.11% (CAT; p<0.01). The AIRs by region and income also showed trends of increase and decrease.

CONCLUSION

The study showed that the incidence trend of SPE increased and decreased from 2014 to 2018. This result would be able to aid in the planning of public oral health, and may also serve as fundamental data for verifying the impact of the public oral health policies implemented.

The Impact of Periodontal Disease on Preterm Birth and Preeclampsia

This review delves into the possible connection between periodontitis and negative pregnancy outcomes, such as preeclampsia and preterm birth. It highlights the potential influence of an unidentified microbial factor on preeclampsia and the effects of inflammatory responses on the rate of preterm births. Furthermore, it underscores the prevalent occurrence of oral ailments within the populace and their significant repercussions on quality of life. Hormonal fluctuations during pregnancy may exacerbate oral conditions such as pregnancy gingivitis and periodontitis, necessitating bespoke therapeutic approaches that take into account potential fetal ramifications. Periodontal disease, characterized by microbial attack and inflammatory response, results in tissue destruction and tooth loss. The oral cavity's susceptibility to bacterial colonization, which is primarily due to its role as a site for food intake, is highlighted. Furthermore, research indicates a correlation between inflammatory responses and factors such as prostaglandin E2 and IL-1β, and preterm birth. Therapeutic interventions are a focus of international research, with efforts being aimed at optimizing outcomes through larger studies involving pregnant women.

Mass spectrometry-based proteomics profiling of dogs with and without oral diseases: a systematic review

BACKGROUND

Understanding the distinct proteomics profiles in dogs' oral biofluids enhances diagnostic and therapeutic insights for canine oral diseases, fostering cross-species translational research in dentistry and medicine. This study aimed to conduct a systematic review to investigate the similarities and differences between the oral biofluids' proteomics profile of dogs with and without oral diseases.

METHODS

PubMed, Web of Science, and Scopus were searched with no restrictions on publication language or year to address the following focused question: "What is the proteome signature of healthy versus diseased (oral) dogs' biofluids?" Gene Ontology enrichment and the Kyoto Encyclopedia of Genes and Genomes pathway analyses of the most abundant proteins were performed. Moreover, protein-protein interaction analysis was conducted. The risk of bias (RoB) among the included studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Studies Reporting Prevalence Data.

RESULTS

In healthy dogs, the proteomic analysis identified 5,451 proteins, with 137 being the most abundant, predominantly associated with 'innate immune response'. Dogs with oral diseases displayed 6,470 proteins, with distinct associations: 'defense response to bacterium' (periodontal diseases), 'negative regulation of transcription' (dental calculus), and 'positive regulation of transcription' (oral tumors). Clustering revealed significant protein clusters in each case, emphasizing the diverse molecular profiles in health and oral diseases. Only six studies were provided to the JBI tool, as they encompassed case-control evaluations that compared healthy dogs to dogs with oral disease(s). All included studies were found to have low RoB (high quality).

CONCLUSION

Significant differences in the proteomics profiles of oral biofluids between dogs with and without oral diseases were found. The synergy of animal proteomics and bioinformatics offers a promising avenue for cross-species research, despite persistent challenges in result validation.

Periodontal and Systemic Diseases: A Descriptive Analysis of Awareness Among the General Saudi Population

Background Taking into account the limited availability of research data, this study aimed to determine the general Saudi population's awareness of the link between periodontal diseases and systemic diseases. Methodology A structured online questionnaire with eight awareness items, apart from demographic variables, was distributed through email, WhatsApp, and Telegram to a sample of 500 individuals. The data were analyzed using a simple descriptive statistical approach and interpreted as ratios for comparison. The awareness regarding systemic diseases associated with periodontal diseases was classified into the following four categories based on the Bloom cutoff points: high (>80%), average (60-79%), low (40-59%), and extremely low (<40%). Results A response rate of 68% was reached with the participation of 340 Saudi citizens residing in the Al Qassim region. Overall, 61.22% of research participants had an average awareness of the link between periodontal and systemic diseases. Almost two-thirds (>60%) of participants were aware that periodontal diseases and systemic diseases have an association and that individuals with systemic diseases need a periodontal checkup. A majority (85%) of participants opined that periodontal treatment has the potential to enhance overall health. Nonetheless, only a few participants (60%) were aware of the association between diabetes mellitus and periodontal diseases, and they had a limited awareness of the association with other systemic diseases. Conclusions Although the Saudi general population possesses average awareness about the relationship between periodontal diseases and systemic diseases, their awareness about different systemic diseases and conditions is extremely low, particularly regarding infertility, stroke, and metabolic diseases. The present research indicates a deficiency in the efforts by healthcare professionals, community service providers, and community administrators to educate the general public regarding the association between periodontal diseases and systemic diseases. This awareness is crucial for individuals to control these intricate, interconnected diseases.

Caspase-3 and gasdermin E mediate macrophage pyroptosis in periodontitis

BACKGROUND AND OBJECTIVES

Periodontitis is a chronic inflammatory disease linked to pyroptosis, an inflammatory cell death process. Macrophages are essential for maintaining microenvironment homeostasis, which is crucial for periodontal health. This study explores the mechanisms underlying the relationship between macrophage pyroptosis and periodontitis.

METHODS

Expression of the pyroptosis marker gasdermin E (GSDME) and the macrophage surface marker CD68 was examined by immunofluorescence double staining in healthy and periodontitis gingival tissues. In an in vitro pyroptosis model, RAW264.7 cells were irritated using Porphyromonas gingivalis-lipopolysaccharide (P. gingivalis-LPS) after treatment with either a nuclear factor kappa-B (NF-κB) agonist or inhibitor. The mRNA and protein levels of NF-κB, caspase-3, GSDME, and interleukin-1β (IL-1β) were evaluated through qRT-PCR, western blotting, and ELISA techniques.

RESULTS

GSDME and CD68 were heavily elevated in inflamed gingival tissues compared to healthy tissues and co-localized in the same region. Furthermore, exposure to P. gingivalis-LPS resulted in a significant upregulation of NF-κB, caspase-3, GSDME, and IL-1β at both the mRNA and protein levels in RAW264.7 cells. NF-κB agonist or inhibitor pretreatment enhanced or inhibited these effects.

CONCLUSIONS

GSDME-mediated macrophage pyroptosis is implicated in periodontitis. Based on in vitro experiments, P. gingivalis-LPS causes pyroptosis in RAW264.7 cells through the caspase-3/GSDME pathway. Furthermore, NF-κB regulates this pyroptotic pathway.

Transferrin receptor 2 mitigates periodontitis-driven alveolar bone loss

Periodontitis is associated with significant alveolar bone loss. Patients with iron overload suffer more frequently from periodontitis, however, the underlying mechanisms remain largely elusive. Here, we investigated the role of transferrin receptor 2 (Tfr2), one of the main regulators of iron homeostasis, in the pathogenesis of periodontitis and the dental phenotype under basal conditions in mice. As Tfr2 suppresses osteoclastogenesis, we hypothesized that deficiency of Tfr2 may exacerbate periodontitis-induced bone loss. Mice lacking Tfr2 (Tfr2-/- ) and wild-type (Tfr2+/+ ) littermates were challenged with experimental periodontitis. Mandibles and maxillae were collected for microcomputed tomography and histology analyses. Osteoclast cultures from Tfr2+/+ and Tfr2-/- mice were established and analyzed for differentiation efficiency, by performing messenger RNA expression and protein signaling pathways. After 8 days, Tfr2-deficient mice revealed a more severe course of periodontitis paralleled by higher immune cell infiltration and a higher histological inflammation index than Tfr2+/+ mice. Moreover, Tfr2-deficient mice lost more alveolar bone compared to Tfr2+/+ littermates, an effect that was only partially iron-dependent. Histological analysis revealed a higher number of osteoclasts in the alveolar bone of Tfr2-deficient mice. In line, Tfr2-deficient osteoclastic differentiation ex vivo was faster and more efficient as reflected by a higher number of osteoclasts, a higher expression of osteoclast markers, and an increased resorptive activity. Mechanistically, Tfr2-deficient osteoclasts showed a higher p38-MAPK signaling and inhibition of p38-MAPK signaling in Tfr2-deficient cells reverted osteoclast formation to Tfr2+/+ levels. Taken together, our data indicate that Tfr2 modulates the inflammatory response in periodontitis thereby mitigating effects on alveolar bone loss.

The impact of arthritogenic viruses in oral tissues

Arthritis and periodontitis are inflammatory diseases that share several immunopathogenic features. The expansion in the study of virus-induced arthritis has shed light on how this condition could impact other parts of the human body, including the mouth. Viral arthritis is an inflammatory joint disease caused by several viruses, most notably the alphaviruses Chikungunya virus (CHIKV), Sindbis virus (SINV), Ross River virus (RRV), Mayaro virus (MAYV), and O'nyong'nyong virus (ONNV). These viruses can induce an upsurge of matrix metalloproteinases and immune-inflammatory mediators such as Interleukin-6 (IL6), IL-1β, tumor necrosis factor, chemokine ligand 2, and receptor activator of nuclear factor kappa-B ligand in the joint and serum of infected individuals. This can lead to the influx of inflammatory cells to the joints and associated muscles as well as osteoclast activation and differentiation, culminating in clinical signs of swelling, pain, and bone resorption. Moreover, several data indicate that these viral infections can affect other sites of the body, including the mouth. The human oral cavity is a rich and diverse microbial ecosystem, and viral infection can disrupt the balance of microbial species, causing local dysbiosis. Such events can result in oral mucosal damage and gingival bleeding, which are indicative of periodontitis. Additionally, infection by RRV, CHIKV, SINV, MAYV, or ONNV can trigger the formation of osteoclasts and upregulate pro-osteoclastogenic inflammatory mediators, interfering with osteoclast activation. As a result, these viruses may be linked to systemic conditions, including oral manifestations. Therefore, this review focuses on the involvement of alphavirus infections in joint and oral health, acting as potential agents associated with oral mucosal inflammation and alveolar bone loss. The findings of this review demonstrate how alphavirus infections could be linked to the comorbidity between arthritis and periodontitis and may provide a better understanding of potential therapeutic management for both conditions.

Periodontitis and the incidence of metabolic syndrome: An 8-year longitudinal study of an adult Japanese cohort

AIM

To examine the effect of periodontitis on the development of metabolic syndrome (MetS) and MetS components.

MATERIALS AND METHODS

This study included 4761 participants aged 30-74 years who underwent health examinations at both baseline and 8-year follow-up. The Japanese MetS criteria were used for diagnosis. The Community Periodontal Index was used to assess periodontal status. The association between periodontal status and MetS incidence was examined by Poisson regression analysis.

RESULTS

Multivariate analysis revealed that individuals with a ≥6 mm periodontal pocket had a significantly higher relative risk (RR) for MetS onset, as compared to individuals without deep periodontal pockets (adjusted RR 1.30, 95% confidence interval [CI]: 1.01-1.67). Compared to individuals without a deep periodontal pocket, individuals with a ≥6 mm periodontal pocket had significantly higher RRs for developing two components of MetS; the RRs were 1.25 (95% CI: 1.01-1.56) for abdominal obesity and 1.39 (95% CI: 1.03-1.86) for hyperglycaemia.

CONCLUSIONS

Individuals with periodontitis had a significantly higher risk of MetS onset, possibly due to the influence of periodontitis on abdominal obesity and hyperglycaemia.

Alcohol Consumption and the Diversity of the Oral Microbiome in Postmenopausal Women

BACKGROUND

Alcohol reduces neutrophil function and decreases salivary flow, which could affect the composition of the oral microbiome.

OBJECTIVE

We hypothesized that the α- and β-diversity of the oral microbiome and the relative abundance of bacterial taxa would differ by frequency and type of alcohol consumption.

METHODS

We used a food frequency questionnaire to assess the frequency of consumption of beer, wine, and liquor (drinks/week) in a sample of 1179 postmenopausal women in the Osteoporosis and Periodontal Disease Study. Women were categorized as nondrinkers, drinking <1 drink/wk, ≥1 to <7 drinks/wk, or ≥7 drinks/wk for total alcohol consumption and for beer, wine, and liquor consumption. The composition and diversity of the oral microbiome was assessed from subgingival plaque samples using 16S ribosomal RNA amplicon sequencing. Permutational multivariate analysis of variance (PERMANOVA) was used to examine β-diversity (between-sample diversity) in the microbiome between alcohol consumption categories. Analysis of covariance was used to examine the mean α-diversity (within-sample diversity), assessed by the Shannon index (species evenness), Chao1 index (species richness), and observed operational taxonomic unit (OTU) count and the mean relative abundance of 245 bacterial taxa across alcohol consumption categories.

RESULTS

Over half of the participants (67%) consumed alcohol, with 14% reporting ≥1 drink/d. The β-diversity across categories of total alcohol consumption, but not categories of alcohol type, was statistically significantly different (P for PERMANOVA = 0.016). Mean α-diversity measures were statistically significantly higher (P < 0.05) in the highest category of total alcohol and wine consumption compared to nondrinkers; no significant associations were found for beer or liquor consumption. The relative abundance of 1 OTU, Selenomonassp._oral_taxon_133, was significantly lower in the highest level of total alcohol consumption compared to nondrinkers after adjustment for multiple comparisons.

CONCLUSIONS

Alcohol consumption was associated with the diversity and composition of the subgingival microbiome.

Azithromycin with scaling and root planing versus scaling and root planing alone in the treatment of periodontitis: A randomized controlled trial

Background

The growing interest in the possibilities of macrophages modulation with therapeutic purposes promotes new approaches for periodontitis treatment.

Aim

The aim of this randomized controlled open clinical study was to evaluate the early clinical and immunological effects of the long-course azithromycin as an adjunct to scaling and root planing in periodontitis.

Methods

50 patients (with stage I-III, grade A/B periodontitis) and 22 periodontally healthy volunteers as the reference group were recruited. Following scaling and root planing (SRP), the patients were randomly assigned to one of two treatment modalities: SRP only (n = 25) and adjunct azithromycin (Az) treatment (n = 25). The patients were monitored at baseline, and 30 ± 5 days after therapy. Clinical attachment loss (CAL), periodontal probing depth (PPD) and bleeding on probing (BoP) were evaluated. Secondary outcome measures included mean changes in single-positive CD68 + and CD163 + macrophages (Mφs) density and ratio, evaluated by immunohistochemistry, and IL1-β, IL-6, IL-10, TGF-β levels, detected by ELISA.

Results

At 1 month both groups showed significant improvements of CAL, PPD and BoP, without significant added benefit in terms of CAL, PPD and BoP of Az. But Az increased the density of CD68 + and CD163 + Mφs (P < 0.0001), decreased the CD68+/CD163 + ratio (P = 0.043), decreased IL-1β (P < 0.01), IL-6 (P < 0.001) levels, and increased IL-10 (P < 0.0001) and TGF-β (P < 0.001) levels compared to SRP and periodontitis at baseline.

Conclusion

The long course of Az demonstrated modulation of CD68 + and CD163 + Mφs towards M2 polarization, which may play a significant role in achieving favorable long-term treatment outcomes. ClinicalTrials.gov.

Interleukin 1 beta and its association with the periodontal health of pregnant women

Objectives

In this study, we measured and compared serum and gingival crevicular fluid (GCF) levels of interleukin 1 beta (IL-1β) in pregnant women with periodontitis and pregnant women with a healthy periodontium. We also determined the prevalence of periodontitis among pregnant women attending Omdurman Midwifery Hospital.

Materials

This was a hospital-based clinical study and laboratory investigation using ELISA tests of 80 pregnant women in the third trimester conducted at the Omdurman Midwifery Hospital in Khartoum, Sudan. The study group consisted of 50 women while the control group consisted of 30 women.

Results

Independent samples t-tests were used to compare serum and GCF levels of IL-1β between the study and control groups. Pearson's correlation analysis was also used to compare gingival parameters and IL-1β levels in the GCF. For each comparison, the p-value was fixed at 0.05. The GCF in the research group showed a considerable increase in IL-1β levels. There was also a strong positive association between high IL-1β levels in the research group's GCF and probing pocket depth (PPD) and clinical attachment level (CAL) levels.

Conclusions

Our study provides further evidence that periodontitis, as measured by a PD ≥4 mm and a CAL ≥3 mm, is associated with an increased level of IL-1β in the GCF of pregnant women with active periodontal disease during pregnancy and may include the transient translocation of oral organisms to the utero-placental unit, inciting placental inflammation or oxidative stress early in pregnancy, ultimately resulting in placental damage and clinical manifestations.

Effects of enamel matrix derivative in nonsurgical periodontal therapy on pro-inflammatory profiles, microbial environment and clinical outcome: a randomized clinical trial

OBJECTIVES

This study aimed to evaluate the impact of enamel matrix derivative (EMD) application following subgingival instrumentation of residual pockets in periodontitis patients on inflammatory host response, microbiological composition, and clinical outcome.

METHODS

In this double-blinded randomized controlled trial, a total of 22 patients with generalized periodontitis stage III or IV presenting with ≥ 6 mm probing pocket depth (PPD) at re-evaluation after initial periodontal therapy were included. Participants were randomly allocated at a 1:1 ratio to subgingival instrumentation with (EMD +) or without (EMD-) non-surgical EMD application into the pocket. PPD, clinical attachment level (CAL), bleeding on probing (BoP), plaque index (PI), as well as a panel of pro-inflammatory cytokines and periodontal pathogen count in the gingival crevicular fluid (GCF) of the respective sites were evaluated at baseline (T0) and six months afterwards (T1).

RESULTS

Both treatment groups showed a significant PPD reduction (EMD + 1.33 ± 1.15 mm, p < 0.001; EMD- 1.32 ± 1.01 mm, p < 0.001) as well as CAL gain (EMD + 1.13 ± 1.58 mm, p < 0.001; EMD- 0.47 ± 1.06 mm, p = 0.005) from T0 to T1. While no intergroup differences for PPD reduction were observed, CAL gain was higher in EMD + sites compared to EMD- (p = 0.009). No essential effects on cytokine expression as well as bacterial count were detected.

CONCLUSIONS

Application of EMD as an adjunct to subgingival instrumentation of residual pockets yielded benefits regarding CAL gain; however, effects on PPD reduction, inflammatory cytokines, and bacterial count were negligible.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04449393), registration date 26/06/2020.

CLINICAL RELEVANCE

Based on the obtained results, additional non-surgical EMD application compared to subgingival instrumentation alone showed no clinically relevant effects on treatment outcome and underlying biological mechanisms.

Chronic periodontitis and risk of cerebro-cardiovascular diseases among older Koreans

BACKGROUND AND OBJECTIVE

There is a relative lack of evidence from observational studies of older populations investigating the association between chronic periodontitis and cerebro-cardiovascular diseases. Accordingly, we investigated the risk of cerebro-cardiovascular diseases according to the severity of chronic periodontitis among older adults.

METHODS

Data on older adults with chronic periodontitis were extracted from the Korea National Health Insurance Service-Senior Cohort Database using diagnosis codes and dental procedures. Participants were divided into two exposure groups. Among 46 737 participants eligible for inclusion, 21 905 (46.9%) had newly diagnosed mild chronic periodontitis, and 24 832 (53.1%) had newly diagnosed severe chronic periodontitis. To determine the risk of cerebro-cardiovascular diseases, including ischemic stroke, haemorrhagic stroke, and myocardial infarction, multivariable-adjusted Cox proportional hazards modelling was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) in this retrospective follow-up study.

RESULTS

A total of 3453 (7.4%) outcomes were identified during a mean follow-up of 6.1 years. Kaplan-Meier analysis revealed that disease-free probability was lower in the severe group than in the mild group (log-rank P < .001). In the multivariable-adjusted model, the HR for cerebro-cardiovascular diseases in the severe group (relative to the mild group) was 1.16 (95% CI: 1.09-1.25). In individual outcome analysis, ischemic stroke and myocardial infarction were associated with chronic periodontitis severity, but haemorrhagic stroke was not.

CONCLUSION

The severity of chronic periodontitis could be associated with the risk of cerebro-cardiovascular diseases in older adults.

Risk of Periodontal Diseases in Women With Polycystic Ovary Syndrome: An Overview

Polycystic ovary syndrome (PCOS) is the most prevalent condition seen in reproductive-aged women, which has a negative impact on their health system. There is a serious concern for women having PCOS that they may experience long-term metabolic conditions. PCOS also has a negative impact on periodontium components such as gingiva, periodontal ligament (PDL), and alveolar bone. It has been said that there may be a bidirectional link between PCOS and periodontal diseases. Moreover, PCOS and periodontal disorders both have common risk factors. Periodontal diseases are exacerbated by systemic low-grade inflammation, including obesity, constant immunological imbalance, and oxidative stress caused by PCOS. On the other hand, periodontal diseases can also increase the risk of causing PCOS. According to recent data, women with PCOS may be more likely to suffer from periodontal diseases. A PubMed and Google Scholar search was conducted for literature relating to PCOS and its relationship with different comorbidities which also included periodontal disorders. Analyses were performed, and data was synthesized and assembled in a presentable form. Therefore, the focus of this review will be on the relationship between PCOS and periodontal disorders, as well as the risk factors for both. However, in order to establish a more distinct and solid link, more studies with a large sample size need to be done.

Comparative analysis of antigen-presenting cells in gingival tissues in healthy and periodontitis patients

AIMS

Microbial flora of dental plaque trigger innate and adaptive immune responses. The function of antigen-presenting cells (APCs) is to bridge the innate and adaptive immune systems. The human immune system contains three main types of APCs: dendritic cells (DC) (Langerhans cells (LCs) and interstitial DCs, IDCs), macrophages and B lymphocytes. In this study, the distribution and density of all APCs in healthy and inflamed human gingival tissue were comparatively analysed.

METHODS

Research was conducted on gingival biopsy specimens obtained from 55 patients and classified in three groups: healthy gingiva (control group, n=10), moderate periodontal disease (PD) (n=21) and severe PD (n=24). For APCs' identification antibodies raised against CD_1a (for LCs), S₁₀₀ protein (for iDCs), CD₆₈ (for macrophages) and CD₂₀ (for B lymphocytes) were used.

RESULTS

Increased density of IDCs, macrophages and B lymphocytes in lamina propria and reduced density of LCs in the gingival epithelium were found in patients with periodontitis. Simultaneously, it was noticed an increased concentration of macrophages and B cells in the gingival epithelium in patients with PD. No statistically significant difference in the distribution and density of APC was found among patients with moderate and advanced periodontitis.

CONCLUSIONS

It was hypothesised that in the periodontitis the role of antigen presentation was largely taken from LCs by the DCs, macrophages and B cells. These APCs are thought to have less protective and tolerogenic potential than LCs and this is a significant reason for alveolar bone destruction in periodontitis.

aMMP-8 point-of-care - diagnostic methods and treatment modalities in periodontitis and peri-implantitis

INTRODUCTION

When collected in a standardized fashion, oral fluid analysis can refine the diagnosis of periodontal and peri-implant disease. In practice, dental professionals can perform active matrix metalloproteinase (aMMP-8) analysis chairside.

AREAS COVERED

Periodontal tissues are mainly made up of type I collagen, and collagen breakdown is one of the main events in periodontal and peri-implantitis destructive lesions. In addition to traditional measurements, their diagnosis can be refined with tests utilizing oral fluids. The active matrix metalloproteinase-8 (aMMP-8) is possible to be determined from the gingival crevicular fluid (GCF), peri-implant sulcus fluid (PISF), and other oral fluids such as mouth rinse and saliva. We also investigated the applicability of aMMP-8 chair-side test kits in the evaluation of oral health benefits of different adjunctive host-modulating periodontal therapies including fermented lingonberry mouthwash (FLJ) and antibacterial photodynamic therapy (aPDT).

EXPERT OPINION

The aMMP-8 levels can more reliably detect early activation of periodontal and peri-implant disease as compared to traditional diagnostic methods that assess the experienced health status or past disease, rather than the present or future pathology. Novel therapies like, fermented lingonberry juice as a mouthrinse or aPDT, are potential host-modulating adjunctive treatments to reduce the signs of oral inflammation and infection.

"Medicine food homology" plants promote periodontal health: antimicrobial, anti-inflammatory, and inhibition of bone resorption

"Medicine food homology" (MFH) is a term with a lengthy history. It refers to the fact that a lot of traditional natural products have both culinary and therapeutic benefits. The antibacterial, anti-inflammatory and anticancer effects of MFH plants and their secondary metabolites have been confirmed by numerous research. A bacterially generated inflammatory illness with a complicated pathophysiology, periodontitis causes the loss of the teeth's supporting tissues. Several MFH plants have recently been shown to have the ability to prevent and treat periodontitis, which is exhibited by blocking the disease's pathogens and the virulence factors that go along with them, lowering the host's inflammatory reactions and halting the loss of alveolar bone. To give a theoretical foundation for the creation of functional foods, oral care products and adjuvant therapies, this review has especially explored the potential medicinal benefit of MFH plants and their secondary metabolites in the prevention and treatment of periodontitis.

Macrophages induce gingival destruction via Piezo1-mediated MMPs-degrading collagens in periodontitis

Macrophages are an integral part of the innate immune response in periodontal tissue and play a crucial role in the progression of periodontitis. Here we reported that macrophages also provoke periodontitis-induced gingival destruction through Piezol-mediated collagen degradation. We discovered that the PIEZO1 expression was markedly elevated in patients with periodontitis through transcriptomic profiling. Moreover, Piezo1 promoted macrophage polarization toward the M1 type in response to lipopolysaccharide (LPS) and induced production of proinflammatory cytokines, which in turn stimulated production of matrix metalloproteinases (MMPs) leading to collagen degradation. Our study suggests that Piezol might be a potential therapeutic target for treating periodontitis-induced gingival destruction.

The influence of smoking on oral neutrophils and matrix metalloproteinase-8 in periodontitis patients before and after nonsurgical treatment

Objective

To evaluate and compare the oral neutrophil numbers (ONN) in saliva, the level of matrix metalloproteinase-8 (MMP-8) in gingival crevicular fluid (GCF) and the periodontal parameters in smokers versus non-smokers with periodontitis, before and after nonsurgical periodontal treatment (NSPT).

Materials and method

40 chronic periodontitis patients including 20 smokers and 20 non-smokers were enrolled in this quasi-experimental study. All patients were received the NSPT included instructing oral hygiene, scaling and root planing. At baseline (T0) and after NSPT 1 month (T1) and 3 months (T3), all patients were assessed for salivary ONN, GCF MMP-8, and clinical parameters like plaque index (PlI), gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD) and clinical attachment loss (CAL). The differences between the two groups were analyzed using the independent sample t-test and the Mann-Whitney U test; and the differences between T0, T1 and T3 of each group were analyzed with paired-samples t-test and Wilcoxon signed-rank test. The level of significance was set at 0.05.

Results

The ONN was significantly less in smokers than in non-smokers although there was no significant difference in other parameters between the two groups at baseline (p > 0.05). All clinical periodontal parameters reduced significantly after 1 month and 3 months of NSPT in both groups (p < 0.01). PPD of non-smokers was significantly lower than those of smokers at T1 and T3. ONN and MMP-8 level showed a significant decrease in non-smoking subjects, while there was no significant difference in smoking ones after NSPT (T1 and T3). At 1 month after treatment, ONN tended to reduce in non-smokers whereas to increase in smokers significantly.

Conclusion

Smoking reduced ONN, impaired treatment effect in reducing PPD, and changed the MMP-8 level in gingival crevicular fluid to NSPT.

Trial registration

Identifier NCT04974502 in CLinicalTrials.gov.

Immunomodulatory nanotherapeutic approaches for periodontal tissue regeneration

Periodontitis is an infection-induced inflammatory disease characterized by progressive destruction of tooth supporting tissues, which, if left untreated, can result in tooth loss. The destruction of periodontal tissues is primarily caused by an imbalance between the host immune protection and immune destruction mechanisms. The ultimate goal of periodontal therapy is to eliminate inflammation and promote the repair and regeneration of both hard and soft tissues, so as to restore the physiological structure and function of periodontium. Advancement in nanotechnologies has enabled the development of nanomaterials with immunomodulatory properties for regenerative dentistry. This review discusses the immune mechanisms of the major effector cells in the innate and adaptive immune systems, the physicochemical and biological properties of nanomaterials, and the research advancements in immunomodulatory nanotherapeutic approaches for the management of periodontitis and the regeneration of periodontal tissues. The current challenges, and prospects for future applications of nanomaterials are then discussed so that researchers at the intersections of osteoimmunology, regenerative dentistry and materiobiology will continue to advance the development of nanomaterials for improved periodontal tissue regeneration.

Systematic Review on Protocols of Coenzyme Q10 Supplementation in Non-Surgical Periodontitis Therapy

This systematic review focuses on the different study protocols on CoQ10 as an adjunct in non-surgical periodontitis therapy. The study protocol was developed following PRISMA guidelines and was registered in PROSPERO (CRD42021156887). A sensitive search up to January 2022 considered MEDLINE via PubMed and Web of Science, Embase, Web of Science Core Collection via Web of Science, Google Scholar, Cochrane CENTRAL, WHO (ICTRP), ClinicalTrials.gov, and grey literature. Randomized controlled (SRP with/without placebo) clinical trials (RCTs) on all types of CoQ10 administration were included. The primary outcome was probing pocket depth (PPD). Secondary outcomes were bleeding on probing, clinical attachment loss, and gingival and plaque indices. Twelve RCTs with local and five with systemic CoQ10 administration were included. The study protocols were heterogeneous. Local CoQ10 administration was performed once or several times in a period up to 15 days. Systemic CoQ10 was applied twice or three times daily for six weeks up to four months. The reporting quality was low, including missing information about CoQ10 doses. Risk of bias was high or unclear. About half of the studies reported significant group differences for PPD. Until now, no statement on the effectiveness of CoQ10 in non-surgical periodontitis therapy is possible. Further high-quality RCTs are necessary and should consider the protocol recommendations of this review.

Calotropis procera latex protein reduces inflammation and bone loss in ligature-induced period ontitis in male rats

OBJECTIVE

Calotropis procera latex protein (CpLP) is a popular anti-inflammatory and therefore we aimed to study its effects on inflammatory bone loss.

DESIGN

Male Wistar rats were subjected to a ligature of molars. Groups of rats received intraperitoneally CpLP (0.3 mg/kg, 1 mg/kg, or 3 mg/kg) or saline (0.9% NaCl) one hour before ligature and then daily up to 11 days, compared to naïve. Gingiva was evaluated by myeloperoxidase activity and interleukin-1 beta (IL-1β) expression by ELISA. Bone resorption was evaluated in the region between the cement-enamel junction and the alveolar bone crest. The histology considered alveolar bone resorption and cementum integrity, leukocyte infiltration, and attachment level, followed by immunohistochemistry bone markers between 1^st and 2^nd molars. Systemically, the weight of the body and organs, and a leukogram were performed.

RESULTS

The periodontitis significantly increased myeloperoxidase activity and the IL-1β level. The increased bone resorption was histologically corroborated by periodontal destruction, leukocyte influx, and attachment loss, as well as the increasing receptor activator of the nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) ratio, and Tartrate-resistant acid phosphatase (TRAP)+ cells when compared to naïve. CpLP significantly reduced myeloperoxidase activity, level of IL-1β, alveolar bone resorption, periodontal destruction, leukocyte influx, and attachment loss. The CpLp also reduced the RANKL/OPG ratio and TRAP+ cells, when compared with the saline group, and did not affect the systemic parameters.

CONCLUSIONS

CpLP exhibited a periodontal protective effect by reducing inflammation and restricting osteoclastic alveolar bone resorption in this rat model.

Electroacupuncture regulates macrophage, neutrophil, and oral microbiota to alleviate alveolar bone loss and inflammation in experimental ligature-induced periodontitis

AIM

Electroacupuncture (EA) regulates distant body physiology through somatic sensory autonomic reflexes, balances the microbiome, and can promote the release of immune cells into bloodstream, thereby inhibiting severe systemic inflammation. This makes it possible to use EA as an integrated treatment for periodontitis.

MATERIALS AND METHODS

In this study, EA was applied to the ST36 acupoints in a ligature-induced periodontitis (LIP) mouse model. Then the effects of EA on periodontal myeloid cells, cytokines, and the microbiome were comprehensively analysed using flow cytometry, quantitative Polymerase Chain Reaction (PCR), and 16 S sequencing.

RESULTS

Results demonstrated that EA could significantly relieve periodontal bone resorption. EA also suppressed the infiltration of macrophages and neutrophils, reduced gene expression of the pro-inflammatory cytokines IL-1β, IL-6, IL-17 and TNF-α, and increased expression of the anti-inflammatory factors IL-4 and IL-10 in periodontal tissues. Moreover, composition of the periodontal microbiome was regulated by EA, finding that complex of microbiota, including supragingival Veillonella, subgingival Streptococcus, and subgingival Erysipelatoclostridium, were significantly reduced. Meanwhile, nitrate and nitrate-related activities of subgingival microbiota were reversed. Network analysis revealed close relationships among Veillonella, Streptococcus, and Bacteroides.

CONCLUSIONS

Our study indicates that EA can effectively alleviate inflammation and bone resorption in LIP mice, potentially via the regulation of myeloid cells, cytokines, and periodontal microbiome.

Exosomes derived from mesenchymal stem cells: Heralding a new treatment for periodontitis?

Periodontitis, as a complex inflammatory disorder, is characterized by continuous destruction of the teeth-supporting components, like alveolar bone and periodontal ligament, and affects a great percentage of individuals over the world. Also, this oral disease is linked with multiple serious illnesses, e.g., cardiovascular disorders, diabetes, and oral cancer; thus, exerting efficient therapy for periodontitis is necessary. Unfortunately, the current therapies for the disease (e.g., surgical and nonsurgical methods) have not reflected enough effectiveness against periodontitis. At present, mesenchymal stem cell (MSC)-based remedy has created new hope for curating different diseases; however, MSCs have no capability to engraft into the chosen tissue, and the tumorigenic influences of MSCs are still the main concern. Interestingly, documents have revealed that MSC-derived mediators, like exosomes, which their exploitation is more feasible than intact MSCs, can be an effective therapeutic candidate for periodontitis. Therefore, in this study, we will review evidence in conjunction with their possible curative impacts on periodontitis cases.

The impact of smoking on periodontitis patients' GCF/serum cytokine profile both before and after periodontal therapy: a meta-analysis

BACKGROUND

Smoking is an established modifying factor for the host immune response of periodontitis patients. However, its exact influence remains unclear. We aimed to compare the cytokine profile of periodontitis patients with and without smoking habits both before and after periodontal therapy to preliminarily explore its influence on the host immune response to periodontitis.

METHODS

The protocol of the present meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the code CRD42021255656. Meta-analysis was performed for each cytokine if at least three studies were included. We synthesized the evidence to compare the cytokine profile of periodontitis with and without smoking both in gingival cervical fluid (GCF) and serum to explore the impact of smoking on periodontitis both locally and systemically. Moreover, we also compared the cytokine profile of the two groups of patients after periodontal therapy to explore the effect of smoking on the outcome of periodontal therapy.

RESULTS

Fifteen studies were included in this meta-analysis. We found that there was no significant difference between the two groups of patients in the baseline cytokine profile. However, after periodontal therapy, smoking periodontitis patients showed significantly higher IL-1β levels in their GCF than nonsmoking patients.

DISCUSSION

There was no significant difference between smoking and nonsmoking periodontitis patients in the baseline cytokine profile. However, after periodontal therapy, smoking periodontitis patients showed significantly higher IL-1β levels in their GCF than nonsmoking patients, which indicates that smoking may impair the response of periodontitis to periodontal treatment.

Efficacy confirmation of Scutellaria baicalensis Georgi in the treatment of periodontitis via topical administration and active ingredients screening

ETHNOPHARMACOLOGICAL RELEVANCE

Periodontal disease is a complex inflammatory disease that seriously affects peoples' lives. Scutellaria radix (SR) is traditionally used as a folk medicine to clear away heat and dampness, purge fire and detoxification. Although it has been extensively used as a medicinal plant to treat a variety of inflammatory illnesses, the efficacy and active ingredient for topical administration in the treatment of periodontitis is unknown.

AIM OF STUDY

The aim of this study was to screen and validate the active ingredients in SR for the prevention and treatment of periodontitis.

MATERIALS AND METHODS

A ligature-induced periodontitis in rats was used to investigate the efficacy of topical administration of SR for the treatment of periodontitis, and the active fraction was screened after separation of the aqueous extract of SR into fractions of different polarities using a lipopolysaccharide (LPS)-induced cell model. Chromatographic fingerprints were established for 18 batches of SR by high performance liquid chromatography. The potential active components were screened using spectral effect relationship analysis and the target cell extraction method.

RESULTS

SR has good efficacy in the topical treatment of periodontitis, according to animal experiments. Five active ingredients were screened out and their anti-inflammatory activity was confirmed in vitro.

CONCLUSION

The main active compounds in the treatment of periodontitis via topical administration of SR were found and this provides an experimental basis for further studies on the pharmacodynamic material basis of SR, as well as reference for the comprehensive evaluation of SR quality and the development of substitute resources.

Matrix Metalloproteinase-3 but Not Matrix Metalloproteinase-9, Implicated in the Manifestation of Chronic Periodontitis

Background

Periodontal disease is an inflammatory condition affecting the tooth's supporting tissues, resulting in gradual loss of periodontal ligament (PDL), alveolar bone, and gum resorption. Neutrophil and monocyte/macrophage, destructive proteases like matrix metalloproteinase (MMP)-3 and MMP-9 play pivotal roles in such lesions in periodontitis. Therefore, this study aims to compare the level of MMP-3 and MMP-9 gene expression in patients with or without periodontitis in an Iranian population.

Methods

This cross-sectional study was carried out on 22 chronic periodontitis patients and 17 healthy control subjects referred to the department of periodontology, Mashhad Dental School. In both groups, the gingival tissue was removed during surgery and transferred to the Molecular Biology Laboratory for MMP-3 and MMP-9 gene expression evaluation. The qRT-PCR, TaqMan method was used for gene expression assessments.

Results

The average age of periodontitis patients was 33± 5 years, and in controls, 34.7± 6 with no significant differences. The mean MMP-3 expression in periodontitis patients was 146.67±38.7, and in controls, 63.4±9.1. The difference was statistically significant (P=0.04). The mean expression of MMP-9 in periodontitis patients and controls were 103.8± 21.66 and 87.57± 16.05, respectively. Although the target gene expression in patients was higher, the difference was insignificant. Furthermore, there was not any significant correlation between age or gender with the expression of MMP3 or MMP9.

Conclusion

The study demonstrated that the MMP3 seems to have a destructive impact on the gingival tissue in chronic periodontitis, but not MMP9.

Mechanisms of Porphyromonas gingivalis to translocate over the oral mucosa and other tissue barriers

Introduction

The oral pathogen Porphyromonas gingivalis is not only associated with periodontitis but also with systemic diseases elsewhere in the body. The mechanisms by which P. gingivalis travels from the oral cavity to other organs in the body are largely unknown. This review describes the four putative mechanisms supported by experimental evidence, which enable translocation of P. gingivalis over the oral mucosa, endothelial barriers and subsequent dissemination into the bloodstream.

Mechanisms

The first mechanism: proteolytic enzymes secreted by P. gingivalis degrade adhesion molecules between tissue cells, and the extracellular matrix. This weakens the structural integrity of the mucosa and allows P. gingivalis to penetrate the tissue. The second is transcytosis: bacteria actively enter tissue cells and transfer to the next layer or the extracellular space. By travelling from cell to cell, P. gingivalis reaches deeper structures. Thirdly, professional phagocytes take up P. gingivalis and travel to the bloodstream where P. gingivalis is released. Lastly, P. gingivalis can adhere to the hyphae forming Candida albicans. These hyphae can penetrate the mucosal tissue, which may allow P. gingivalis to reach deeper structures.

Conclusion

More research could elucidate targets to inhibit P. gingivalis dissemination and prevent the onset of various systemic diseases.

Heparan Sulfate Glycosaminoglycan Is Predicted to Stabilize Inflammatory Infiltrate Formation and RANKL/OPG Ratio in Severe Periodontitis in Humans

Since chronically inflamed periodontal tissue exhibits extracellular matrix (ECM) degradation, the possible alternative to standard periodontitis treatment is to restore ECM by supplementing its components, including heparan sulfate glycosaminoglycan (HS GAG). Supplementation of the degraded ECM with synthetic derivatives of HS GAGs has been shown to be effective for periodontal tissue regeneration in experimental animal models of periodontitis. However, the potential of HS GAG supplementation for the treatment of periodontal disease in humans is still unknown. Here, we used a statistical model to investigate the role of HS GAG on inflammatory infiltrate formation and alveolar bone resorption in humans with severe periodontitis. The model was based on data from immunofluorescence staining (IF) of human gingiva samples, and reconstruction of a subset of HS GAG -related proteins from STRING reactome database. According to predictions, increased expression of native HS GAG might stabilize the accumulation of gingival inflammatory infiltrate (represented by the general inflammatory cell marker CD45) and alveolar bone resorption (represented by Receptor Activator of Nuclear ΚΒ ligand (RANKL) and osteoprotegerin (OPG) ratio) but could not restore them to healthy tissue levels. Therefore, supplementation of native HS GAG may be of limited benefits for the treatment of sever periodontitis in humans.

Neutrophil N1 and N2 Subsets and Their Possible Association with Periodontitis: A Scoping Review

Periodontitis is a chronic non-communicable disease caused by dysbiotic changes that affect the subgingival microbiota. During periodontitis, neutrophils play a central role in the initial recognition of bacteria, and their number increases with the appearance of the first signs of periodontal inflammation. Recent evidence has led to the proposition that neutrophils can also functionally polarize, determining selective activity patterns related to different diseases. Two well-defined neutrophil phenotypes have been described, the pro-inflammatory N1 subset and the suppressor N2 subset. To date, it has not been established whether these different neutrophil subtypes play a role in the pathogenesis of periodontitis. Thus, this scoping review aimed to determine whether there was evidence to suggest that the neutrophils present in periodontal tissues can be associated with certain phenotypes. The research question, population, concept, and context sought to identify original articles, in humans, that detected the presence of neutrophils in the periodontal tissues of people affected by periodontitis. Based on the search strategy, we found 3658 studies. After removing the papers with abstracts not related to the outcome measures and eligibility criteria, 16 articles were included for qualitative analysis. Several studies identified the presence of different neutrophil subsets, specifically, the naive, pro- and para-inflammatory, hyper-reactive and hyper-active, and high- and low-responder phenotypes. The existing evidence demonstrates the presence of pro-inflammatory, hyper-reactive and high-responder neutrophils in periodontal tissues affected with periodontitis. There is no evidence demonstrating the presence of the N1 or N2 phenotypes in periodontal tissues during periodontitis. However, the existence of pro-inflammatory phenotypes, which increase NETosis and degranulation, and increase the production of pro-inflammatory cytokines, could be suggestive of the N1 phenotypes.

Stem cell microencapsulation maintains stemness in inflammatory microenvironment

Maintaining the stemness of the transplanted stem cell spheroids in an inflammatory microenvironment is challenging but important in regenerative medicine. Direct delivery of stem cells to repair periodontal defects may yield suboptimal effects due to the complexity of the periodontal inflammatory environment. Herein, stem cell spheroid is encapsulated by interfacial assembly of metal-phenolic network (MPN) nanofilm to form a stem cell microsphere capsule. Specifically, periodontal ligament stem cells (PDLSCs) spheroid was coated with Fe^III/tannic acid coordination network to obtain spheroid@[Fe^III-TA] microcapsules. The formed biodegradable MPN biointerface acted as a cytoprotective barrier and exhibited antioxidative, antibacterial and anti-inflammatory activities, effectively remodeling the inflammatory microenvironment and maintaining the stemness of PDLSCs. The stem cell microencapsulation proposed in this study can be applied to multiple stem cells with various functional metal ion/polyphenol coordination, providing a simple yet efficient delivery strategy for stem cell stemness maintenance in an inflammatory environment toward a better therapeutic outcome.

Electrospun Nanofibers for Periodontal Treatment: A Recent Progress

Periodontitis is a major threat to oral health, prompting scientists to continuously study new treatment techniques. The nanofibrous membrane prepared via electrospinning has a large specific surface area and high porosity. On the one hand, electrospun nanofibers can improve the absorption capacity of proteins and promote the expression of specific genes. On the other hand, they can improve cell adhesion properties and prevent fibroblasts from passing through the barrier membrane. Therefore, electrospinning has unique advantages in periodontal treatment. At present, many oral nanofibrous membranes with antibacterial, anti-inflammatory, and tissue regeneration properties have been prepared for periodontal treatment. First, this paper introduces the electrospinning process. Then, the commonly used polymers of electrospun nanofibrous membranes for treating periodontitis are summarized. Finally, different types of nanofibrous membranes prepared via electrospinning for periodontal treatment are presented, and the future evolution of electrospinning to treat periodontitis is described.

Erythropoietin Activates Autophagy to Regulate Apoptosis and Angiogenesis of Periodontal Ligament Stem Cells via the Akt/ERK1/2/BAD Signaling Pathway under Inflammatory Microenvironment

Background. Angiogenic tissue engineering is a vital problem waiting to be settled for periodontal regeneration. Erythropoietin, a multieffect cytokine, has been reported as a protective factor for cell fate. According to our previous study, erythropoietin has a significantly angiogenic effect on periodontal ligament stem cells. To further explore its potential effects and mechanism, we studied biological behaviors of periodontal ligament stem cells under inflammatory microenvironment induced by different concentrations (0, 10, 20, 50, and 100 ng/mL) of tumor necrosis factor-α (TNF-α) and examined how different concentrations (0, 5, 10, 20, and 50 IU/mL) of erythropoietin changed biological behaviors of periodontal ligament stem cells. Materials and Methods. Cell Counting Kit-8 was used for cell proliferation assay. Annexin V-PI-FITC was used for cell apoptosis through flow cytometry. Matrigel plug was adopted to measure the angiogenic capacity in vitro. RNA sequencing was used to detect the downstream signaling pathway. Quantitative real-time polymerase chain reaction was conducted to examine mRNA expression level. Western blot and immunofluorescence were applied to testify the protein expression level. Results. Periodontal ligament stem cells upregulated apoptosis and suppressed autophagy and angiogenesis under inflammatory microenvironment. Erythropoietin could activate autophagy to rescue apoptosis and angiogenesis levels of periodontal ligament stem cells through the Akt/Erk1/2/BAD signaling pathway under inflammatory microenvironment. Conclusions. Erythropoietin could protect periodontal ligament stem cells from inflammatory microenvironment, which provided a novel theory for periodontal regeneration.

Cross-sectional study on the association of periodontitis with arterial hypertension in the Hamburg City Health Study

Aim

Aim of this study was to investigate the association between periodontitis and arterial hypertension, both of which show correlations with classical cardiovascular risk factors and inflammatory activity.

Materials and methods

A cross-sectional analysis of data from a large population-based health survey (the Hamburg City Health Study, HCHS) including 5934 participants with complete periodontal examination and blood pressure data, of whom 5735 had medical records regarding anti-hypertensive medication, was performed. Probing depths, gingival recessions, bleeding on probing (BOP), dental plaque, and decayed-missing-filled teeth (DMFT) indices were recorded as measures of oral health. Clinical attachment loss (CAL) per tooth was calculated and periodontitis was staged into three groups (no/mild, moderate, severe). Arterial hypertension was diagnosed based on the participants’ medication history and systolic and diastolic blood pressure values. Logistic regression models were constructed accounting for a set of potential confounders (age, sex, smoking, body mass index (BMI), diabetes, educational level, alcohol intake) and high sensitivity-C-reactive protein (hsCRP).

Results

The odds of arterial hypertension increased significantly along with periodontitis severity (OR for severe periodontitis: 2.19; 95% CI 1.85–2.59; p < 0.001; OR for moderate periodontitis: 1.65; 95% CI 1.45–1.87; p < 0.001). Participants with moderate or severe periodontitis also had significantly higher age- and sex-adjusted odds of arterial hypertension, which was slightly weakened when additionally adjusted for BMI, diabetes, smoking, educational level, and alcohol intake (OR for severe PD: 1.28, 95% CI 1.04–1.59, p = 0.02; OR for moderate PD: 1.30, 95% CI 1.11–1.52, p = 0.001). The fraction of participants with undertreated hypertension (untreated and poorly controlled hypertension) was considerably larger in participants with severe periodontitis than in those with no/mild periodontitis (50.1% vs. 37.4% for no/mild periodontitis).

Conclusions

The study shows an association between periodontitis and arterial hypertension that is independent of age, sex, diabetes, BMI, smoking, educational level, and alcohol intake. In addition, undertreatment of hypertension was more common in people with severe periodontitis compared with periodontally more healthy people.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00811-y.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

New Approach to Addison Disease: Oral Manifestations Due to Endocrine Dysfunction and Comorbidity Burden

This review highlights oral anomalies with major clinical impact in Addison disease (AD), including dental health and dermatologic features, through a dual perspective: pigmentation issues and AD comorbidities with oral manifestations. Affecting 92% of AD patients, cutaneomucosal hyperpigmentation is synchronous with or precedes general manifestations by up to a decade, underlying melanocytic infiltration of the basal epidermal layer; melanophages in the superficial dermis; and, rarely, acanthosis, perivascular lymphocytic infiltrate, and hyperkeratosis. Intraoral pigmentation might be the only sign of AD; thus, early recognition is mandatory, and biopsy is helpful in selected cases. The buccal area is the most affected location; other sites are palatine arches, lips, gums, and tongue. Pigmented oral lesions are patchy or diffuse; mostly asymptomatic; and occasionally accompanied by pain, itchiness, and burn-like lesions. Pigmented lingual patches are isolated or multiple, located on dorsal and lateral areas; fungiform pigmented papillae are also reported in AD individuals. Dermoscopy examination is particularly indicated for fungal etiology; yet, it is not routinely performed. AD’s comorbidity burden includes the cluster of autoimmune polyglandular syndrome (APS) type 1 underlying AIRE gene malfunction. Chronic cutaneomucosal candidiasis (CMC), including oral CMC, represents the first sign of APS1 in 70–80% of cases, displaying autoantibodies against interleukin (IL)-17A, IL-17F ± IL-22, and probably a high mucosal concentration of interferon (IFN)-γ. CMC is prone to systemic candidiasis, representing a procarcinogenic status due to Th17 cell anomalies. In APS1, the first cause of mortality is infections (24%), followed by oral and esophageal cancers (15%). Autoimmune hypoparathyroidism (HyP) is the earliest endocrine element in APS1; a combination of CMC by the age of 5 years and dental enamel hypoplasia (the most frequent dental complication of pediatric HyP) by the age of 15 is an indication for HyP assessment. Children with HyP might experience short dental roots, enamel opacities, hypodontia, and eruption dysfunctions. Copresence of APS-related type 1 diabetes mellitus (DM) enhances the risk of CMC, as well as periodontal disease (PD). Anemia-related mucosal pallor is related to DM, hypothyroidism, hypogonadism, corresponding gastroenterological diseases (Crohn’s disease also presents oral ulceration (OU), mucogingivitis, and a 2–3 times higher risk of PD; Biermer anemia might cause hyperpigmentation by itself), and rheumatologic diseases (lupus induces OU, honeycomb plaques, keratotic plaques, angular cheilitis, buccal petechial lesions, and PD). In more than half of the patients, associated vitiligo involves depigmentation of oral mucosa at different levels (palatal, gingival, alveolar, buccal mucosa, and lips). Celiac disease may manifest xerostomia, dry lips, OU, sialadenitis, recurrent aphthous stomatitis and dental enamel defects in children, a higher prevalence of caries and dentin sensitivity, and gingival bleeding. Oral pigmented lesions might provide a useful index of suspicion for AD in apparently healthy individuals, and thus an adrenocorticotropic hormone (ACTH) stimulation is useful. The spectrum of autoimmune AD comorbidities massively complicates the overall picture of oral manifestations.

Gene Correlation Network Analysis to Identify Biomarkers of Peri-Implantitis

Background and Objectives: The histopathological and clinical conditions for transforming peri-implant mucositis into peri-implantitis (PI) are not fully clarified. We aim to uncover molecular mechanisms and new potential biomarkers of PI. Materials and Methods: Raw GSE33774 and GSE57631 datasets were obtained from the Gene Expression Omnibus (GEO) database. The linear models for microarray data (LIMMA) package in R software completes differentially expressed genes (DEGs). We conducted a weighted gene co-expression network analysis (WGCNA) on the top 25% of altered genes and identified the key modules associated with the clinical features of PI. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using the R software. We constructed a protein–protein interaction (PPI) network through the STRING database. After that we used Cytohubba plug-ins of Cytoscape to screen out the potential hub genes, which were subsequently verified via receiver operating characteristic (ROC) curves in another dataset, GSE178351, and revalidation of genes through the DisGeNET database. Results: We discovered 632 DEGs (570 upregulated genes and 62 downregulated genes). A total of eight modules were screened by WGCNA, among which the turquoise module was most correlated with PI. The Cytohubba plug-ins were used for filtering hub genes, which are highly linked with PI development, from the candidate genes in the protein–protein interaction (PPI) network. Conclusions: We found five key genes from PI using WGCNA. Among them, ICAM1, CXCL1, and JUN are worthy of further study of new target genes, providing the theoretical basis for further exploration of the occurrence and development mechanism of PI.

Drug-Loaded Chitosan Scaffolds for Periodontal Tissue Regeneration

Chitosan is a natural anionic polysaccharide with a changeable architecture and an abundance of functional groups; in addition, it can be converted into various shapes and sizes, making it appropriate for a variety of applications. This article examined and summarized current developments in chitosan-based materials, with a focus on the modification of chitosan, and presented an abundance of information about the fabrication and use of chitosan-derived products in periodontal regeneration. Numerous preparation and modification techniques for enhancing chitosan performance, as well as the uses of chitosan and its metabolites, were reviewed critically and discussed in depth in this study. Chitosan-based products may be formed into different shapes and sizes, considering fibers, nanostructures, gels, membranes, and hydrogels. Various drug-loaded chitosan devices were discussed regarding periodontal regeneration.

LiCl-induced immunomodulatory periodontal regeneration via the activation of the Wnt/β-catenin signaling pathway

Background

Growing evidence suggests that excessive inflammation hampers the regenerative capacity of periodontal ligament cells (PDLCs) and that activation of the Wnt/β‐catenin pathway is crucial in suppressing immune dysregulation.

Objective

This study aimed to establish the role of the Wnt/β‐catenin in regulating the immune microenvironment and its subsequent impact on periodontal regeneration.

Methods

Lithium chloride (LiCl, Wnt activator) was administered daily into the standard periodontal defects created in 12‐week‐old Lewis rats. Harvested at 1‐week and 2‐week post‐surgery, samples were then subjected to histological and immunohistochemical evaluation of macrophage distribution and phenotype (pro‐inflammatory M1 and anti‐inflammatory M2). A murine macrophage cell line, RAW 264.7, was stimulated with LiCl to activate Wnt/β‐catenin. Following treatment with the conditioned medium derived from the LiCl‐activated macrophages, the expression of bone‐ and cementum‐related markers of the PDLCs was determined. The involvement of Wnt/β‐catenin in the immunoregulation and autophagic activity was further investigated with the addition of cardamonin, a commercially available Wnt inhibitor.

Results

A significantly increased number of macrophages were detected around the defects during early healing upon receiving the Wnt/β‐catenin signaling cue. The defect sites in week 2 exhibited fewer M1 and more M2 macrophages along with an enhanced regeneration of alveolar bone and cementum in the Wnt/β‐catenin activation group. LiCl‐induced immunomodulatory effect was accompanied with the activation Wnt/β‐catenin signaling, which was suppressed in the presence of Wnt inhibitor. Exposure to LiCl could induce autophagy in a dose‐dependent manner, thus maintaining macrophages in a regulatory state. The expression level of bone‐ and cementum‐related markers was significantly elevated in PDLCs stimulated with LiCl‐activated macrophages.

Conclusion

The application of Wnt activator LiCl facilitates the recruitment of macrophages to defect sites and regulates their phenotypic switching in favor of periodontal regeneration. Suppression of Wnt/β‐catenin pathway could attenuate the LiCl‐induced immunomodulatory effect. Taken together, the Wnt/β‐catenin pathway may be targeted for therapeutic interventions in periodontal diseases.

Impact of periodontal status on the oral mucositis in patients receiving high-dose chemotherapy

OBJECTIVES

Oral mucositis (OM) is a frequent complication of cancer treatments. Oral mucositis and periodontal disease have a common inflammatory pattern. The purpose of this study was to evaluate the OM and its association with periodontal status in patients with hematologic malignancies who undergo high-dose chemotherapy.

MATERIALS AND METHODS

Fifty-five patients who received high-dose chemotherapy were included in the study. Full-mouth periodontal clinical measurements including plaque index (PI), gingival index (GI), clinical attachment level (CAL), and probing depth (PD) values were recorded before the condition chemotherapy regime. OM monitoring was initiated 1 day after the chemotherapy and maintained for 20 days.

RESULTS

Twenty-two of patients (40%) were observed oral mucositis after high-dose chemotherapy. Patients with mucositis had significantly higher GI scores than those who did not have mucositis (p < 0.05). There was a significantly moderate positive correlation between the grade of mucositis and GI scores (p < 0.05). In patients with periodontitis, the incidence of grade 1-2 mucositis was significantly higher than in the healthy group (p < 0.05). In individuals with periodontitis and gingivitis, the healing duration of mucositis was significantly longer than the healthy group (p < 0.05).

CONCLUSIONS

The results of this study showed that the severity grades of oral mucositis may increase in patients with gingival inflammation. The results also suggest that periodontal diseases may have a significant impact on the duration of oral mucositis.

CLINICAL RELEVANCE

The current study contributes to our understanding of the importance of oral health status in reducing the occurrence, severity, and duration of OM in hematological cancer patients treated with high-dose chemotherapy.

Morphological Changes in the Oral Mucous Membrane in Viral Hepatitis C Patients: A Cross-Sectional Study

Background: The objective was to reveal the most typical changes in oral mucosa in HCV patients and compare them with those in HCV negative patients. Methods: The study involved 96 HCV patients and 100 patients without HCV who applied to a dental clinic. The content of cytokines IL-2, IL-4, IL-10 and ɤ-INF in the oral fluid was determined by ELISA. Buccal mucosa and gums biopsies passed histological examination. An immunohistochemical study of mucous membrane biopsies was performed using monoclonal mouse antibodies to CD3+ and CD20+. Results: The HCV patients group included 96 (63.5% males), and the non-HCV group included 100 subjects (62.0% males) with lesions of the oral mucous membrane. The lesions of lips and oral mucosa were more frequent in HCV than in the non-HCV group—e.g., erosion (13.5% vs. 1%), cracks in the mouth corners (42.7% vs. 0%), changes in the oral mucosa surface (89.6% vs. 3.0%), hemorrhages (78.1% vs. 0%), etc. The pro-inflammatory IL-2 level was higher and anti-inflammatory IL-4 level was lower in HCV patients compared with those in the non-HCV group. Conclusions: Morphological changes developed in the microvasculature both worsen the tissue trophism and accelerate the healing with differentiation into coarse-fibrous connective tissue. Immunohistochemical findings indicated a decrease in local humoral immune response.

Peridontitis as a Risk Factor for Attention Deficit Hyperactivity Disorder: Possible Neuro-inflammatory Mechanisms

Periodontitis is a condition caused mostly by the creation of a biofilm by the bacterium P. gingivalis, which releases toxins and damages the tooth structure. Recent research studies have reported association between dental health and neuropsychiatric illnesses. Neuroinflammation triggered by the first systemic inflammation caused by the bacterium present in the oral cavities is a plausible explanation for such a relationship. Substantial amount of evidence supports the role of neuroinflammation and dysfunction of the dopaminergic system in the pathology of ADHD (Attention deficit hyperactivity disorders). Recent epidemiological, microbiological and inflammatory findings strengthen that, periodontal bacteria, which cause systemic inflammation can contribute to neuroinflammation and finally ADHD. Although both diseases are characterized by inflammation, the specific pathways and crosslink's between periodontitis and ADHD remain unknown. Here, the authors describe the inflammatory elements of periodontitis, how this dental illness causes systemic inflammation, and how this systemic inflammation contributes to deteriorating neuroinflammation in the evolution of ADHD. Therefore, the aim of this review is to present possible links and mechanisms that could confirm the evidence of this association.