Current understanding of periodontal disease pathogenesis and targets for host-modulation therapy

Targeting the Neuropilin-1 receptor with Ovatodiolide and progress in using periodontal ligament organoids for COVID-19 research and therapy

The discovery of SARS-CoV-2 RNA in the periodontal tissues of patients who tested positive for COVID-19, 24 days post the initial symptom onset, indicates the oral cavity could serve as a viral reservoir. This research aims to investigate the antiviral capabilities of Ovatodiolide, introducing a novel periodontal ligament organoid model for the study of SARS-CoV-2. We have successfully established a reliable and expandable organoid culture from the human periodontal ligament, showcasing characteristics typical of epithelial stem cells. This organoid model enables us to delve into the lesser-known aspects of dental epithelial stem cell biology and their interactions with viruses and oral tissues. We conducted a series of in vitro and ex vivo studies to examine the inhibitory impacts of Ova on SARS-CoV-2. Our findings indicate that Ovatodiolide molecules can bind effectively to the NRP1 active domain. Our study identifies potential interaction sites for Ovatodiolide (OVA) within the b1 domain of the NRP1 receptor. We generated point mutations at this site, resulting in three variants: Y25A, T44A, and a double mutation Y25A/T44A. While these mutations did not alter the binding activity of the spike protein, they did impact the concentration of OVA required for inhibition. The inhibitory concentrations for these variants are 15 μM for Y25A, 15.2 μM for T44A, and 25 μM for the double mutant Y25A/T44A. In addition, in vitro inhibition experiments demonstrate that the EC50 of Ova against the main protease (Mpro) of the SARS-CoV-2 virus is 7.316 μM. Our in vitro studies and the use of the periodontal ligament organoid model highlight Ovatodiolide's potential as a small molecule therapeutic agent that impedes the virus's ability to bind to the Neuropilin-1 receptor on host cells. The research uncovers various pathways and biochemical strategies through which Ovatodiolide may function as an effective antiviral small molecule drug.

Genetic analysis of impaired healing responses after periodontal therapy in type 2 diabetes: Clinical and in vivo studies

OBJECTIVE

This study aims to investigate the mechanisms underlying the impaired healing response by diabetes after periodontal therapy.

BACKGROUND

Outcomes of periodontal therapy in patients with diabetes are impaired compared with those in patients without diabetes. However, the mechanisms underlying impaired healing response to periodontal therapy have not been sufficiently investigated.

MATERIALS AND METHODS

Zucker diabetic fatty (ZDF) and lean (ZL) rats underwent experimental periodontitis by ligating the mandibular molars for one week. The gingiva at the ligated sites was harvested one day after ligature removal, and gene expression was comprehensively analyzed using RNA-Seq. In patients with and without type 2 diabetes (T2D), the corresponding gene expression was quantified in the gingiva of the shallow sulcus and residual periodontal pocket after non-surgical periodontal therapy.

RESULTS

Ligation-induced bone resorption and its recovery after ligature removal were significantly impaired in the ZDF group than in the ZL group. The RNA-Seq analysis revealed 252 differentially expressed genes. Pathway analysis demonstrated the enrichment of downregulated genes involved in the peroxisome proliferator-activated receptor (PPAR) signaling pathway. PPARα and PPARγ were decreased in mRNA level and immunohistochemistry in the ZDF group than in the ZL group. In clinical, probing depth reduction was significantly less in the T2D group than control. Significantly downregulated expression of PPARα and PPARγ were detected in the residual periodontal pocket of the T2D group compared with those of the control group, but not in the shallow sulcus between the groups.

CONCLUSIONS

Downregulated PPAR subtypes expression may involve the impaired healing of periodontal tissues by diabetes.

Impact of the uninstructed use of a herbal, ayurvedic toothpaste on parameters of gingival health in periodontal aftercare patients: A randomized, double-blinded, two-arm parallel-group study

AIM

The aim of this study was to evaluate the impact of the uninstructed use of a toothpaste containing herbal ayurvedic ingredients on parameters of gingival health in a cohort of periodontal aftercare patients affected by gingival inflammation compared to the use of a standard, non-herbal toothpaste.

MATERIALS AND METHODS

The monocentric, randomized, double-blinded, two-arm parallel-group intervention was performed in a cohort of 88 periodontal aftercare patients with clinical signs of gingival inflammation. At baseline, bleeding on probing (BoP), gingival index (GI) and Quigley-Hein plaque index (QHI) were recorded. Subsequently, the study patients were randomly provided with a herbal ayurvedic toothpaste (n = 44) or a conventional, non-ayurvedic control toothpaste (n = 44) and without additional oral hygiene training instructed to use it 2× daily for the next 28 days. On day 28, BoP, GI and QHI were recorded again.

RESULTS

At baseline, there were no significant differences between both groups. On day 28, mean GI and BoP scores were significantly lower (p < 0.001) compared to baseline in both groups. Differences between the groups could not be verified. Mean QHI scores did not change significantly between day 0 and day 28 in both groups.

CONCLUSIONS

The impact of uninstructed toothbrushing with an ayurvedic toothpaste on the manifestation of gingival inflammation in periodontal aftercare patients is not significantly different to the use of a conventional, non-herbal toothpaste.

Role of Piezo1 in modulating the RANKL/OPG ratio in mouse osteoblast cells exposed to Porphyromonas gingivalis lipopolysaccharide and mechanical stress

AIMS

Excessive occlusal force with periodontitis leads to rapid alveolar bone resorption. However, the molecular mechanism by which inflammation and mechanical stress cause bone resorption remains unclear. We examined the role of Piezo1, a mechanosensitive ion channel expressed on osteoblasts, in the changes in the receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) ratio in mouse MC3T3-E1 osteoblast-like cells under Porphyromonas gingivalis lipopolysaccharide (P.g.-LPS) and mechanical stress.

METHODS

To investigate the effect of P.g.-LPS and mechanical stress on the RANKL/OPG ratio and Piezo1 expression, we stimulated MC3T3-E1 cells with P.g.-LPS. After 3 days in culture, shear stress, a form of mechanical stress, was applied to the cells using an orbital shaker. Subsequently, to investigate the role of Piezo1 in the change of RANKL/OPG ratio, we inhibited Piezo1 function by knockdown via Piezo1 siRNA transfection or by adding GsMTx4, a Piezo1 antagonist.

RESULTS

The RANKL/OPG ratio significantly increased in MC3T3-E1 cells cultured in a medium containing P.g.-LPS and undergoing mechanical stress compared to cells treated with P.g.-LPS or mechanical stress alone. However, the expression of Piezo1 was not increased by P.g.-LPS and mechanical stress. In addition, phosphorylation of MEK/ERK was induced in the cells under P.g.-LPS and mechanical stress. MC3T3-E1 cells treated with P.g.-LPS and mechanical stress when cocultured with RAW264.7 cells induced their differentiation into osteoclast-like cells. The increased RANKL/OPG ratio was suppressed by either Piezo1 knockdown or the addition of GsMTx4. Furthermore, GsMTx4 inhibited the phosphorylation of MEK/ERK.

CONCLUSION

These findings suggest that P.g.-LPS and Piezo1-mediated mechanical stress induce MEK/ERK phosphorylation and increase RANKL expression in osteoblasts. Consequently, this leads to the differentiation of osteoclast precursor cells into osteoclasts.

Early detection of cardiovascular risk markers through non-invasive ultrasound methodologies in periodontitis patients

Objectives

This narrative review aims to update the current evidence and offer insight into the new non-invasive ultrasound techniques used to early identify degenerative vascular changes in subjects with periodontitis and to investigate if these methodologies could be useful to identify subclinical cardiovascular disease (CVD) dysfunction in periodontitis patients and to monitor changes in CVD risk after periodontal treatment.

Methods

Studies examining the assessment of vascular endothelial function through the latest methodologies were analyzed. Systematic reviews, observational studies, and clinical trials in the English language were identified using PubMed, Web of Science, and Google Scholar databases with key search terms such as "periodontitis," "endothelial dysfunction (ED)," "arterial stiffness," and "periodontal therapy."

Results

Several mechanisms are involved in the association between periodontitis and CVD. The key players are periodontal bacteria and their toxins, which can enter the circulation and infiltrate blood vessel walls. The increase in proinflammatory molecules such as interleukins and chemokines, c-reactive protein, fibrinogen, and oxidative stress also plays a decisive role. In addition, an increase in parameters of ED, arterial stiffness, and atherosclerosis, such as carotid intima-media thickness, pulse wave velocity, and flow-mediated dilatation, has been shown in periodontal patients.

Conclusions

The literature today agrees on the association of periodontitis and CVD and the positive role of periodontal therapy on systemic inflammatory indices and cardiovascular outcomes. Hopefully, these non-invasive methodologies could be extended to periodontal patients to provide a comprehensive understanding of the CVD-periodontitis link from the perspective of a personalized medicine approach in periodontology.

The oral microbiota and periodontal health in orthodontic patients

The oral microbiota develops within the first 2 years of childhood and becomes distinct from the parents by 4 years-of-age. The oral microbiota plays an important role in the overall health/symbiosis of the individual. Deviations from the state of symbiosis leads to dysbiosis and an increased risk of pathogenicity. Deviations can occur not only from daily life activities but also from orthodontic interventions. Orthodontic appliances are formed from a variety of biomaterials. Once inserted, they serve as a breeding ground for microbial attachment, not only from new surface areas and crevices but also from material physicochemical interactions different than in the symbiotic state. Individuals undergoing orthodontic treatment show, compared with untreated people, qualitative and quantitative differences in activity within the oral microbiota, induced by increased retention of supra- and subgingival microbial plaque throughout the treatment period. These changes are at the root of the main undesirable effects, such as gingivitis, white spot lesions (WSL), and more severe caries lesions. Notably, the oral microbiota profile in the first weeks of orthodontic intervention might be a valuable indicator to predict and identify higher-risk individuals with respect to periodontal health and caries risk within an otherwise healthy population. Antimicrobial coatings have been used to dissuade microbes from adhering to the biomaterial; however, they disrupt the host microbiota, and several bacterial strains have become resistant. Smart biomaterials that can reduce the antimicrobial load preventing microbial adhesion to orthodontic appliances have shown promising results, but their complexity has kept many solutions from reaching the clinic. 3D printing technology provides opportunities for complex chemical syntheses to be performed uniformly, reducing the cost of producing smart biomaterials giving hope that they may reach the clinic in the near future. The purpose of this review is to emphasize the importance of the oral microbiota during orthodontic therapy and to use innovative technologies to better maintain its healthy balance during surgical procedures.

Nanoparticles in Periodontitis Therapy: A Review of the Current Situation

Periodontitis is a disease of inflammation that affects the tissues supporting the periodontium. It is triggered by an immunological reaction of the gums to plaque, which leads to the destruction of periodontal attachment structures. Periodontitis is one of the most commonly recognized dental disorders in the world and a major factor in the loss of adult teeth. Scaling and root planing remain crucial for managing patients with persistent periodontitis. Nevertheless, exclusive reliance on mechanical interventions like periodontal surgery, extractions, and root planning is insufficient to halt the progression of periodontitis. In response to the problem of bacterial resistance, some researchers are committed to finding alternative therapies to antibiotics. In addition, some scholars focus on finding new materials to provide a powerful microenvironment for periodontal tissue regeneration and promote osteogenic repair. Nanoparticles possess distinct therapeutic qualities, including exceptional antibacterial, anti-inflammatory, and antioxidant properties, immunomodulatory capacities, and the promotion of bone regeneration ability, which made them can be used for the treatment of periodontitis. However, there are many problems that limit the clinical translation of nanoparticles, such as toxic accumulation in cells, poor correlation between in vitro and in vivo, and poor animal-to-human transmissibility. In this paper, we review the present researches on nanoparticles in periodontitis treatment from the perspective of three main categories: inorganic nanoparticles, organic nanoparticles, and nanocomposites (including nanofibers, hydrogels, and membranes). The aim of this review is to provide a comprehensive and recent update on nanoparticles-based therapies for periodontitis. The conclusion section summarizes the opportunities and challenges in the design and clinical translation of nanoparticles for the treatment of periodontitis.

Investigating the role of a Tannerella forsythia HtrA protease in host protein degradation and inflammatory response

Introduction

Degradation of host proteins by bacterial proteases leads to the subversion of the host response and disruption of oral epithelial integrity, which is considered an essential factor in the progression of periodontitis. High-temperature requirement A (HtrA) protease, which is critical for bacterial survival and environmental adaptation, is found in several oral bacteria, including the periodontal pathogen Tannerella forsythia. This study investigated the proteolytic activity of HtrA from T. forsythia and its ability to modulate the host response.

Methods

HtrA of T. forsythia was identified bioinformatically and produced as a recombinant protein. T. forsythia mutants with depleted and restored HtrA production were constructed. The effect of T. forsythia wild-type, mutants and recombinant HtrA on the degradation of casein and E-cadherin was tested in vitro. Additionally, the responses of human gingival fibroblasts and U937 macrophages to the different HtrA-stimuli were investigated and compared to those triggered by the HtrA-deficient mutant.

Results

T. forsythia wild-type producing HtrA as well as the recombinant enzyme exhibited proteolytic activity towards casein and E-cadherin. No cytotoxic effect of either the wild-type, T. forsythia mutants or rHtrA on the viability of host cells was found. In hGFB and U937 macrophages, both T. forsythia species induced an inflammatory response of similar magnitude, as indicated by gene and protein expression of interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor α and monocyte chemoattractant protein (MCP)-1. Recombinant HtrA had no significant effect on the inflammatory response in hGFBs, whereas in U937 macrophages, it induced a transient inflammatory response at the early stage of infection.

Conclusion

HtrA of T. forsythia exhibit proteolytic activity towards the host adhesion molecule E-cadherin and has the potential to influence the host response. Its role in the progression of periodontitis needs further clarification.

Boric acid alleviates periodontal inflammation induced by IL-1β in human gingival fibroblasts

BACKGROUND

Boric acid (BA) has been found to have therapeutic effects on periodontal disease through beneficially affecting antibacterial, anti-viral, and anti-inflammatory actions.

METHODS

This study was conducted to determine the effect of BA on cell viability and on mRNA expressions of proinflammatory and anti-inflammatory cytokines and on oxidative stress enzymes induced by IL-1β (1 ng/mL) in Human Gingival Fibroblasts (HGF) cultured for 24 and 72 h in DMEM media. The BA concentrations added to the media were 0.09 %, 0.18 %, 0.37 %, and 0.75 %.

RESULTS

All of the BA concentrations increased the viability of cell cultured in DMEM media only, indicating that these concentrations were not toxic and actually beneficial to cell viability. The addition of 1 ng/m: of IL-1β decreased cell viability that was overcome by all concentrations of BA at both 24 and 72 h. The IL-1β addition to the media increased the expressions of the proinflammatory cytokines IL-1β, IL-6, IL-8, and IL-17; the anti-inflammatory cytokine IL-10; and the oxidative stress enzymes superoxide dismutase (SOD0 and glutathione peroxidase (GPX). The IL-1β induced increase mRNA expression of IL-1β was decreased at 24 h by the 0.37 % and 0.75 % BA additions to the media and decreased in a dose-dependent manner by all concentrations of BA at 72 h. The IL-1β induced increase in the expression of IL-6 was decreased in dose-dependent manner at 72 h by BA. All BA concentrations decreased the IL-1β induced expression of IL-8 at both 24 and 72 h. The induced increase in IL-17 by IL-1β was not significantly affected by the BA additions. The increase in the anti-inflammatory cytokine IL10 induced by IL-1β was increased further by all BA additions in dose dependent manner at both 24 and 72 h. The mRNA expressions of SOD and GPX increased by IL-1β were further increased by the 0.37 % and 0.75 % BA concentrations at 72 h.

CONCLUSIONS

These findings indicate that BA can significantly modulate the cytokines that are involved in inflammatory stress and reactive oxygen species action and thus could be an effective therapeutic agent in the treatment of periodontal disease.

Photobiomodulation of Gingival Cells Challenged with Viable Oral Microbes

The oral cavity, a unique ecosystem harboring diverse microorganisms, maintains health through a balanced microflora. Disruption may lead to disease, emphasizing the protective role of gingival epithelial cells (GECs) in preventing harm from pathogenic oral microbes. Shifting GECs' response from proinflammatory to antimicrobial could be a novel strategy for periodontitis. Photobiomodulation therapy (PBMT), a nonpharmacologic host modulatory approach, is considered an alternative to drugs. While the host cell response induced by a single type of pathogen-associated molecular patterns (PAMPs) was widely studied, this model does not address the cellular response to intact microbes that exhibit multiple PAMPs that might modulate the response. Inspired by this, we developed an in vitro model that simulates direct interactions between host cells and intact pathogens and evaluated the effect of PBMT on the response of human gingival keratinocytes (HGKs) to challenge viable oral microbes at both the cellular and molecular levels. Our data demonstrated that LED pretreatment on microbially challenged HGKs with specific continuous wavelengths (red: 615 nm; near-infrared: 880 nm) induced the production of various antimicrobial peptides, enhanced cell viability and proliferation, promoted reactive oxygen species scavenging, and down-modulated proinflammatory activity. The data also suggest a potential explanation regarding the superior efficacy of near-infrared light treatment compared with red light in enhancing antimicrobial activity and reducing cellular inflammation of HGKs. Taken together, the findings suggest that PBMT enhances the overall barrier function of gingival epithelium while minimizing inflammation-mediated breakdown of the underlying structures.

The association of composite dietary antioxidant index with periodontitis in NHANES 2009-2014

Background

To date, evidence is rare regarding whether and how dietary antioxidants are associated with the risk of periodontitis. This study aimed to investigate the association of composite dietary antioxidant index (CDAI) with periodontitis and tooth loss, using data from the National Health and Nutrition Examination Survey (2009-2014).

Methods

A cross-sectional analysis was conducted using data from 10,067 adults aged ≥30 years who underwent assessments of periodontal health and the 1st day dietary recall. Based on a crude model and three adjusted models, multivariate regressions were used to examine the relationship between CDAI and periodontitis-related measurements including probing pocket depth, clinical attachment loss and tooth loss. Subgroup analyses and the restricted cubic splines plots were applied to examine the association between CDAI ingredients and periodontitis.

Results

For the subjects with high CDAI scores, increased CDAI was associated with significant (P < 0.05) reduction of severe periodontitis (odd ratio = 0.663, 95% confidence interval: 0.491-0.896) and increased number of remaining teeth (weighted β[SE] = 1.167[0.211]). However, the protective effect of CDAI on periodontitis vanished (P > 0.05) in active smokers and former smokers. There were threshold levels for β-carotene, Vitamin A, C and E intakes where the risk of periodontitis significantly decreased (P < 0.05) above these levels.

Conclusion

Increased CDAI was associated with reduced risk of periodontitis and tooth loss for non-smokers. It was recommendable that proper dietary intakes of β-carotene, Vitamin A, C and E would be of benefit for preventive dental care and adjuvant therapies for periodontitis.

The effect of antireaction medications on the association between periodontitis and leprosy reactions: An important methodological issue in periodontal medicine

BACKGROUND

The treatment of leprosy reactions (LRs) involves thalidomide, corticosteroids, and other immunomodulatory medications. This study evaluated the effect of these treatments on the association between periodontitis and LRs, as well as factors associated with LRs.

METHODS

This case-control study was conducted on 283 individuals followed at a leprosy outpatient clinic in Brazil. The case group was comprised of 158 individuals presenting type 1 or type 2 LRs, and the control group of 125 leprosy individuals without reactions. A complete oral examination was performed to diagnose periodontitis, the independent variable. Antireaction medication used was collected from medical records, and participants were classified according to the use of prednisone and/or thalidomide, time of use, or non-use of medication. Socioeconomic-demographic, clinical, and lifestyle covariables were collected by interview. Unconditional logistic regression analysis by subgroups evaluated the effect of antireaction medication on the association between periodontitis and LRs, estimating the odds ratio with a 95% confidence interval (OR; 95% CI).

RESULTS

A relationship between periodontitis and LRs was observed only in the subgroup using the association prednisone and thalidomide: ORadjusted = 0.32; 95% CI = 0.11-0.95. Conversely, more severe periodontal clinical parameters were observed in cases versus controls. Several socioeconomic, health conditions, and lifestyle factors were associated with the presence of LRs.

CONCLUSIONS

Although periodontal disease indicators were worse among the cases, the findings showed a negative relationship between periodontitis and LRs in individuals receiving associated prednisone and thalidomide. These medications appear to influence the inflammatory cascade between diseases, modifying and masking the manifestations of periodontitis.

Impact of Inflammatory Markers and Senescence-Associated Secretory Phenotype in the Gingival Crevicular Fluid on the Outcomes of Periodontal Regeneration

The aim of this study was to test the molecular expression profile (senescence-associated secretory phenotype; SASP) in gingival crevicular fluid (GCF) prior to surgery in relation to the distribution of clinical success of periodontal regeneration. Forty consecutive patients presenting sites with residual probing pocket depth (PPD) ≥ 6 mm and intrabony defects ≥ 3 mm were treated through a minimally invasive surgical technique. Pre-operatively, GCF was sampled for inflammatory biomarker analysis related to SASP [interleukin (IL)-1β, IL-6, and IL-12; matrix-metalloproteinases (MMP)-8 and -9]. Better or worse responders were classified depending on the achievement of a composite outcome measure at 1-year [COM; PPD ≤ 4 mm and clinical attachment gain (CAL) gain ≥ 3 mm]. Correlation analyses and logistic regression models were performed. Periodontal regeneration led to significant improvements in mean clinical and radiographic parameters. Teeth achieving COM presented significantly lower amounts of SASP factors compared with non-successful teeth. Higher CAL gain, PPD reduction, and radiographic bone fill were negatively correlated with IL-1β and MMP-8 and -9 (p < 0.001), while IL-12 showed a direct relationship with CAL gain (p = 0.005) and PPD reduction (p = 0.038). Sites expressing higher SASP expression in the GCF before periodontal regeneration achieved worse clinical and radiographic outcomes.

Which types of bony changes in the maxillary sinus indicate chronic sinusitis?

OBJECTIVES

To determine which types of bone lesion (spicules, lobules, porous bone) in the maxillary sinus indicate sinusitis METHODS: Subadjacent dental disease is a cause of maxillary sinusitis; if a lesion type indicates sinusitis it should be more common above diseased posterior maxillary teeth than a lesion type that is not indicative of sinusitis. The study sample is a British Mediaeval human skeletal collection.

RESULTS

Porous bone lesions (chiefly new bone deposits) in maxillary sinuses are associated with subadjacent dental disease; spicules/lobules of bone in the sinus are not.

CONCLUSIONS

The results support the idea that porous lesions indicate sinusitis but the spicules/lobules may not. Spicules, lobules and porous lesions within the maxillary sinus should be analysed separately in biocultural studies; it would be prudent to regard only the porous lesions as indicative of sinusitis.

SIGNIFICANCE

Maxillary sinusitis is commonly used as a health indicator in palaeopathology, and spicular deposits are generally the most common type of alterations. By assuming that they are indicative of sinusitis we may have been greatly overestimating the prevalence of bony sinusitis in the past.

LIMITATIONS

These conclusions are provisional. Further work on larger, more diverse samples, together with more detailed anatomical studies on lesion location and structure is ongoing.

Elevated neutrophil extracellular trap levels in periodontitis: Implications for keratinization and barrier function in gingival epithelium

AIM

To explore the levels of neutrophil extracellular traps (NETs) in patients with periodontitis and examine their effects on keratinization, barrier function of human gingival keratinocytes (HGKs) and the associated mechanisms.

MATERIALS AND METHODS

Saliva, gingival crevicular fluid (GCF), clinical periodontal parameters and gingival specimens were collected from 10 healthy control subjects and 10 patients with stage II-IV periodontitis to measure the NET levels. Subsequently, mRNA and protein levels of keratinization and barrier indicators, as well as intracellular calcium and epithelial barrier permeability, were analysed in HGKs after NET stimulation.

RESULTS

The study showed that NET levels significantly elevated in patients with periodontitis, across multiple specimens including saliva, GCF and gingival tissues. Stimulation of HGKs with NETs resulted in a decrease in the expressions of involucrin, cytokeratin 10, zonula occludens 1 and E-cadherin, along with decreased intracellular calcium levels and increased epithelial barrier permeability. Furthermore, the inhibition of keratinization by NETs is ERK-KLF4-dependent.

CONCLUSIONS

This study indicates that NETs impair the barrier function of HGKs and suppress keratinization through ERK/KLF4 axis. These findings provide potential targets for therapeutic approaches in periodontitis to address impaired gingival keratinization.

The effect of dental material type and masticatory forces on periodontitis-derived subgingival microbiomes

Restorative dental materials can frequently extend below the gingival margin, serving as a potential haven for microbial colonization, and altering the local oral microbiome to ignite infection. However, the contribution of dental materials on driving changes of the composition of the subgingival microbiome is under-investigated. This study evaluated the microbiome-modulating properties of three biomaterials, namely resin dental composites (COM), antimicrobial piezoelectric composites (BTO), and hydroxyapatite (HA), using an optimized in vitro subgingival microbiome model derived from patients with periodontal disease. Dental materials were subjected to static or cyclic loading (mastication forces) during biofilm growth. Microbiome composition was assessed by 16S rRNA gene sequencing. Dysbiosis was measured in terms of subgingival microbial dysbiosis index (SMDI). Biomaterials subjected to cyclic masticatory loads were associated with enhanced biofilm viability except on the antibacterial composite. Biomaterials held static were associated with increased biofilm biomass, especially on HA surfaces. Overall, the microbiome richness (Chao index) was similar for all the biomaterials and loading conditions. However, the microbiome diversity (Shannon index) for the HA beams was significantly different than both composites. In addition, beta diversity analysis revealed significant differences between composites and HA biomaterials, and between both loading conditions (static and cyclic). Under static conditions, microbiomes formed over HA surfaces resulted in increased dysbiosis compared to composites through the enrichment of periopathogens, including Porphyromonas gingivalis, Porphyromonas endodontalis, and Fretibacterium spp., and depletion of commensals such as Granulicatella and Streptococcus spp. Interestingly, cyclic loading reversed the dysbiosis of microbiomes formed over HA (depletion of periopathogenes) but increased the dysbiosis of microbiomes formed over composites (enrichment of Porphyromonas gingivalis and Fusobacterim nucleatum). Comparison of species formed on both composites (control and antibacterial) showed some differences. Commercial composites enriched Selenomonas spp. and depleted Campylobacter concisus. Piezoelectric composites effectively controlled the microbiome viability without significantly impacting the species abundance. Findings of this work open new understandings of the effects of different biomaterials on the modulation of oral biofilms and the relationship with oral subgingival infections.

Cascade Reactions Catalyzed by Gold Hybrid Nanoparticles Generate CO Gas Against Periodontitis in Diabetes

The treatment of diabetic periodontitis poses a significant challenge due to the presence of local inflammation characterized by excessive glucose concentration, bacterial infection, and high oxidative stress. Herein, mesoporous silica nanoparticles (MSN) are embellished with gold nanoparticles (Au NPs) and loaded with manganese carbonyl to prepare a carbon monoxide (CO) enhanced multienzyme cooperative hybrid nanoplatform (MSN-Au@CO). The Glucose-like oxidase activity of Au NPs catalyzes the oxidation of glucose to hydrogen peroxide (H2O2) and gluconic acid，and then converts H2O2 to hydroxyl radicals (•OH) by peroxidase-like activity to destroy bacteria. Moreover, CO production in response to H2O2, together with Au NPs exhibited a synergistic anti-inflammatory effect in macrophages challenged by lipopolysaccharides. The underlying mechanism can be the induction of nuclear factor erythroid 2-related factor 2 to reduce reactive oxygen species, and inhibition of nuclear factor kappa-B signaling to diminish inflammatory response. Importantly, the antibacterial and anti-inflammation effects of MSN-Au@CO are validated in diabetic rats with ligature-induced periodontitis by showing decreased periodontal bone loss with good biocompatibility. To summarize, MSN-Au@CO is fabricate to utilize glucose-activated cascade reaction to eliminate bacteria, and synergize with gas therapy to regulate the immune microenvironment, offering a potential direction for the treatment of diabetic periodontitis.

Evaluation of Antimicrobial Susceptibility and Resistance Patterns of Treponema denticola Isolated From Periodontal Disease: An In Vitro Study

Background Periodontal disease poses a significant oral health challenge, involving inflammatory conditions impacting tooth-supporting structures. Treponema denticola, a "red complex" organism, plays a crucial role in periodontal pathogenesis, forming biofilms in subgingival environments and contributing to dysbiosis. Antimicrobial therapy is pivotal in managing periodontal disease, requiring a nuanced understanding of susceptibility patterns exhibited by key pathogens like T. denticola. Aims and objectives This study aims to investigate the antimicrobial susceptibility and resistance profiles of Treponema denticola, a prominent bacterium in periodontal disease, by examining its responses to various antimicrobial agents commonly used in periodontal therapy. Methodology Plaque samples were meticulously collected from individuals diagnosed with periodontal disease to ensure a diverse representation of the oral microbiome. All the samples were cultured, and red complex bacteria were isolated under anaerobic culture. Treponema denticola isolates were cultured from these samples under anaerobic conditions, and molecular techniques were employed for species identification. A comprehensive panel of antimicrobial agents was selected to assess the response of Treponema denticola. In vitro antimicrobial susceptibility testing (AST) was conducted using the antimicrobial gradient method, employing a hybrid approach combining elements of disk-diffusion and dilution methods. Results Treponema denticola had exhibited resistance to metronidazole, a commonly used antibiotic effective against anaerobic bacteria, emphasizing limitations in its applicability. However, the bacterium displayed sensitivity to tetracycline, imipenem, cefoperazone, chloramphenicol, clindamycin, and moxifloxacin, offering diverse therapeutic options. The antimicrobial gradient strip test provided detailed minimum inhibitory concentration (MIC) values, contributing to a nuanced understanding of susceptibility and resistance patterns. Conclusion This study significantly advances our understanding of Treponema denticola's antimicrobial susceptibility and resistance profiles in the context of periodontal disease. The findings underscore the importance of tailored treatment strategies and contribute to broader efforts in antimicrobial stewardship, aligning with global initiatives to combat antibiotic resistance. This research lays the foundation for more effective and personalized approaches to periodontal care, emphasizing the intricate microbial dynamics associated with periodontal health and disease.

Microbial- and host immune cell-derived extracellular vesicles in the pathogenesis and therapy of periodontitis: A narrative review

Periodontitis is a chronic inflammatory disease caused by dysbiotic biofilms and destructive host immune responses. Extracellular vesicles (EVs) are circulating nanoparticles released by microbes and host cells involved in cell-to-cell communication, found in body biofluids, such as saliva and gingival crevicular fluid (GCF). EVs are mainly involved in cell-to-cell communication, and may hold promise for diagnostic and therapeutic purposes. Periodontal research has examined the potential involvement of bacterial- and host-cell-derived EVs in disease pathogenesis, diagnosis, and therapy, but data remains scarce on immune cell- or microbial-derived EVs. In this narrative review, we first provide an overview of the role of microbial and host-derived EVs on disease pathogenesis. Recent studies reveal that Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans-derived outer membrane vesicles (OMVs) can activate inflammatory cytokine release in host cells, while M1 macrophage EVs may contribute to bone loss. Additionally, we summarised current in vitro and pre-clinical research on the utilisation of immune cell and microbial-derived EVs as potential therapeutic tools in the context of periodontal treatment. Studies indicate that EVs from M2 macrophages and dendritic cells promote bone regeneration in animal models. While bacterial EVs remain underexplored for periodontal therapy, preliminary research suggests that P. gingivalis OMVs hold promise as vaccine candidates. Finally, we acknowledge the current limitations present in the field of translating immune cell derived EVs and microbial derived EVs in periodontology. It is concluded that microbial and host immune cell-derived EVs have a role in periodontitis pathogenesis and hence may be useful for studying disease pathophysiology, and as diagnostic and treatment monitoring biomarkers.

Influence of Hypoxic Condition on Cytotoxicity, Cellular Migration, and Osteogenic Differentiation Potential of Aged Periodontal Ligament Cells

OBJECTIVE

 This study aimed to investigate and compare the influence of hypoxic conditions on cytotoxicity, cellular migration, and osteogenic differentiation of aged periodontal ligament (PDL) cells.

MATERIALS AND METHODS

 Isolated human PDL cells from aged and young subjects were cultured under hypoxic conditions, which were treated with hydrogen peroxide (H2O2) (0, 25, 50, 100, 200, and 500 µM). To assess cytotoxicity, lactate dehydrogenase release was determined by the optical density at 490 nm, and the percentage of cell death was calculated. An in vitro wound healing assay was performed over 24 to 48 hours for cellular migration determination. Osteogenic differentiation was determined by alizarin red staining and osteogenic gene expression, including the expression of runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), and osteopontin (OPN).

RESULTS

 There was a significant difference in the percentage of cell death with high hypoxic condition (200 and 500 µM) compared to low hypoxic conditions on both day 1 and 2. The highest cellular migration was depicted at 50 µM in both young and aged groups of the in vitro wound healing assay. Osteogenic gene expression of RUNX2 in the aged group was increased at 25 and 50 µM hypoxic condition at day 7, but the expression was gradually decreased after 14 days. On the contrary, the expression of ALP and OPN in the aged group was increased at day 14. Only OPN had been found to be statistically significantly different when compared with gene expression at day 7 and 14 (p < 0.05). The results showed no statistically significant differences when compared with the young and aged groups in all genes and all concentrations.

CONCLUSION

 The concentration of low hypoxic condition (25-50 µM) was proposed to promote cell viability, cellular migration, and osteogenic differentiation in aged PDL cells. We suggested that the potential of aged PDL cells for use in cell therapy for periodontal regeneration might possibly be similar to that of young PDL cells.

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.

Proteome-Wide Mendelian Randomisation Identifies Causal Links of Plasma Proteins With Periodontitis

OBJECTIVE

Periodontitis is a complex and multifactorial disease and it is challenging to decipher its underlying causes and mechanisms. This study attempted to explore potential circulating proteins in connection to periodontitis through proteome-wide Mendelian randomisation (MR).

METHODS

We analysed 1722 circulating proteins to identify prospective drug targets for tackling periodontitis, using the genomic dataset from the FinnGen study. Two-sample MR was conducted to evaluate the bidirectional relationship between circulating proteins and periodontitis risk. A dataset from the UK Biobank was used to validate the findings. Single-cell analysis was performed to assess the cellular expression of the identified proteins within gingival tissues.

RESULTS

MR analyses found that genetically predicted circulating levels of von Willebrand factor A domain-containing 1 (von Willebrand factor A domain containing 1 [VWA1], odds ratios: 0.94, 95% CI 0.92-0.97, P = 1.28 × 10-5) were inversely associated with periodontitis. In contrast, the level of growth differentiation factor 15 (growth differentiation factor 15 [GDF15], odds ratios: 1.05, 95% CI 1.02-1.07, P = 2.12 × 10-5) might be associated with an increased risk of periodontitis. Single-cell analysis indicated that VWA1 was primarily expressed in endothelial cells of healthy gingival tissues, while the main source of GDF15 was not derived from periodontal cells.

CONCLUSIONS

The present study suggests that certain plasma proteins like VWA1 and GDF15 may be potentially indicative of the risk and susceptibility to periodontitis. These proteins could possibly be the potential therapeutic targets for treating periodontitis, and further investigation is highly warranted.

Longitudinal analysis of microcirculatory parameters in gingival tissues after tooth extraction in patients with different risk profiles for wound healing disorders - a pilot study

OBJECTIVES

We aimed to establish a risk profile for intraoral wound healing disorders based on measurements of microcirculation in gingival tissues.

MATERIALS AND METHODS

Oxygen saturation (SO2) and blood flow in gingival tissues were measured with tissue spectrometry and laser doppler spectroscopy in 37 patients before/after tooth extractions. Patients were assigned to four groups: anamnestically and periodontally healthy patients (n = 7), anamnestically healthy but suffering from periodontitis (n = 10), anamnestically healthy but smoking and suffering from periodontitis (n = 10) and suffering from diabetes and periodontitis (n = 10). Measurements were performed at three different time points: Baseline measurement (T0), one day post extractionem (p.e.) (T1) and seven days p.e. (T2).

RESULTS

Baseline SO2 values were higher in control patients (p = .038). This effect was most evident in comparison to smokers suffering from periodontitis (p = .042), followed by diabetics suffering from periodontitis (p = .09). An opposite trend was seen for blood flow. Patients suffering from periodontitis demonstrated higher blood flow values (p = .012). Five patients, which belonged to the group of smokers suffering from periodontitis, showed clinically a delayed wound healing.

CONCLUSION

Differences in SO2 and blood flow of gingival tissue could be detected in different groups of patients with existing periodontitis compared to control patients.

CLINICAL RELEVANCE

Lower baseline SO2 values could be a warning signal for possible wound healing disorders after oral surgery.

Patent Mining on the Use of Antioxidant Phytochemicals in the Technological Development for the Prevention and Treatment of Periodontitis

Periodontal disease is an inflammatory condition characterized by an aberrant immune response against a dysbiotic dental biofilm, with oxidative stress performing an essential role in its pathogenesis. This paper presents a patent mining, performed in the Orbit Intelligence patent database, related to antioxidant phytochemicals in the technological developments that are working to prevent and treat periodontal disease. To access the documents, the descriptors "PERIODONTAL" and "ANTIOXIDANT" were typed in the title, abstract, and claim search fields. A total of 322 patents demonstrate the growing interest in researching natural antioxidants for scientific and technological purposes. The top ten countries regarding the number of family patents produced were the United States, the European Office, Japan, South Korea, China, India, Mexico, Denmark, Canada, and Great Britain. The most cited compounds were vitamin C, green tea, quercetin, melatonin, lycopene, resveratrol, and curcumin. These compounds have been used for the technological development of gels, membranes, dentifrices, chewing gum, orally disintegrating film, mouthwash, mouth spray, and mouth massage cream and exhibit the ability to neutralize free radicals and reduce oxidative stress, a critical factor in the development and progression of periodontal diseases. The patent documents have shown that using antioxidant compounds in conjunction with traditional periodontal treatments is a promising area of interest in periodontal therapy.

In-vitro effects of novel periodontal scalers with a planar ultrasonic piezoelectric transducer on periodontal biofilm removal, dentine surface roughness, and periodontal ligament fibroblasts adhesion

OBJECTIVES

To compare ultrasonic scaler prototypes based on a planar piezoelectric transducer with different working frequencies featuring a titanium (Ti-20, Ti-28, and Ti-40) or stainless steel (SS-28) instrument, with a commercially available scaler (com-29) in terms of biofilm removal and reformation, dentine surface roughness and adhesion of periodontal fibroblasts.

MATERIALS AND METHODS

A periodontal multi-species biofilm was formed on specimens with dentine slices. Thereafter specimens were instrumented with scalers in a periodontal pocket model or left untreated (control). The remaining biofilms were quantified and allowed to reform on instrumented dentine slices. In addition, fibroblasts were seeded for attachment evaluation after 72 h of incubation. Dentine surface roughness was analyzed before and after instrumentation.

RESULTS

All tested instruments reduced the colony-forming unit (cfu) counts by about 3 to 4 log10 and the biofilm quantity (each p < 0.01 vs. control), but with no statistically significant difference between the instrumented groups. After 24-hour biofilm reformation, no differences in cfu counts were observed between any groups, but the biofilm quantity was about 50% in all instrumented groups compared to the control. The attachment of fibroblasts on instrumented dentine was significantly higher than on untreated dentine (p < 0.05), with the exception of Ti-20. The dentine surface roughness was not affected by any instrumentation.

CONCLUSIONS

The planar piezoelectric scaler prototypes are able to efficiently remove biofilm without dentine surface alterations, regardless of the operating frequency or instrument material.

CLINICAL RELEVANCE

Ultrasonic scalers based on a planar piezoelectric transducer might be an alternative to currently available ultrasonic scalers.

Association between antihyperlipidemic agents and the risk of chronic periodontitis in patients with hyperlipidemia: A population-based retrospective cohort study in Taiwan

BACKGROUND

The lipid-lowering and anti-inflammatory effects of statins and fibrates may ameliorate periodontitis. Patients with hyperlipidemia tend to have a worse periodontal status. This study assessed the association between the use of statins/fibrates and the incidence of chronic periodontitis in patients with hyperlipidemia in Taiwan.

METHODS

This retrospective cohort study enrolled patients newly diagnosed with hyperlipidemia between 2001 and 2012 from the 2000 Longitudinal Generation Tracking Database and followed them for 5 years. The study population was divided into four groups: statin monotherapy, fibrate monotherapy, combination therapy (both statins and fibrates), and control (neither statins nor fibrates). Each patient in the treatment group was matched at a ratio of 1:1 with a control. Chronic periodontitis risk was compared in the three study arms by using a Cox proportional hazard model.

RESULTS

Chronic periodontitis risk was reduced by 25.7% in the combination therapy group compared with the control group (adjusted hazard ratio [aHR], 0.743; 95% confidence interval (CI), 0.678-0.815). Low dose (<360 cumulative defined daily dose [cDDD]) and shorter duration (<2 years) of statin monotherapy seem to be associated with an increased risk of chronic periodontitis; high dose (≥720 cDDD/≥1080 cDDD) and longer duration (≥3 years) of statin/fibrate monotherapy may be correlated with a lower risk of periodontitis. Hydrophobic statin users had a lower chronic periodontitis risk than hydrophilic statin users.

CONCLUSION

Chronic periodontitis risk was lower in patients with hyperlipidemia on combination treatment with statins and fibrates, and the risk decreased when patients used statins or fibrates for >3 years.

Evaluation of Clinical Efficacy of 1.2% Rosuvastatin Hydrogel as an Adjunct to Scaling and Root Planing in Generalized Chronic Periodontitis

Background Periodontitis, characterized by chronic inflammation and tissue destruction, remains a significant public health concern. Conventional treatment like scaling and root planing (SRP) is effective but often augmented with adjunctive therapies to improve outcomes. Local drug delivery (LDD) systems containing pharmacological agents offer targeted treatment with reduced systemic side effects. Rosuvastatin (RSV), known for its anti-inflammatory and tissue regenerative properties, has shown promise in periodontal therapy. This prospective clinical trial assessed the effectiveness of 1.2% RSV hydrogel as an adjunct to SRP in managing generalized chronic periodontitis. Methods Thirty patients were grouped into Group A (SRP alone) and Group B (SRP + 1.2% RSV hydrogel). Clinical measurements, such as the modified sulcular bleeding index (mSBI), probing pocket depth (PPD), and clinical attachment level (CAL), were documented both at the beginning of the study and after three months. Statistical analysis was performed using SPSS software. A p-value of less than 0.05 was considered statistically significant. Results Participants in Group B showed significant improvements in mSBI (from 2.34 ± 0.59 to 1.01 ± 0.29), PPD (from 7.36 ± 1.12 mm to 4.63 ± 0.88 mm), and CAL (from 8.56 ± 1.22 mm to 5.90 ± 1.24 mm) compared to Group A at the three-month follow-up. The mean values of these parameters decreased significantly in both groups from baseline to three months. However, the reductions were more substantial in Group B, indicating the beneficial effect of RSV hydrogel adjunctive therapy. Conclusion The study demonstrates the efficacy of 1.2% RSV hydrogel employed as a localized drug in enhancing the outcomes of SRP for generalized chronic periodontitis. The adjunctive use of RSV hydrogel led to noteworthy enhancements in clinical parameters, highlighting its potential in periodontal therapy.

Ropinirole suppresses LPS-induced periodontal inflammation by inhibiting the NAT10 in an ac4C-dependent manner

BACKGROUND

Periodontitis is a chronic osteolytic inflammatory disease, where anti-inflammatory intervention is critical for restricting periodontal damage and regenerating alveolar bone. Ropinirole, a dopamine D2 receptor agonist, has previously shown therapeutic potential for periodontitis but the underlying mechanism is still unclear.

METHODS

Human gingival fibroblasts (HGFs) treated with LPS were considered to mimic periodontitis in vitro. The dosage of Ropinirole was selected through the cell viability of HGFs evaluation. The protective effects of Ropinirole on HGFs were evaluated by detecting cell viability, cell apoptosis, and pro-inflammatory factor levels. The molecular docking between NAT10 and Ropinirole was performed. The interaction relationship between NAT10 and KLF6 was verified by ac4C Acetylated RNA Immunoprecipitation followed by qPCR (acRIP-qPCR) and dual-luciferase reporter assay.

RESULTS

Ropinirole alleviates LPS-induced damage of HGFs by promoting cell viability, inhibiting cell apoptosis and the levels of IL-1β, IL-18, and TNF-α. Overexpression of NAT10 weakens the effects of Ropinirole on protecting HGFs. Meanwhile, NAT10-mediated ac4C RNA acetylation promotes KLF6 mRNA stability. Upregulation of KLF6 reversed the effects of NAT10 inhibition on HGFs.

CONCLUSIONS

Taken together, Ropinirole protected HGFs through inhibiting the NAT10 ac4C RNA acetylation to decrease the KLF6 mRNA stability from LPS injury. The discovery of this pharmacological and molecular mechanism of Ropinirole further strengthens its therapeutic potential for periodontitis.

Advances in periodontal biomarkers

Due to technologic advancements, periodontology has witnessed a boost in biomarker research over the past three decades. Indeed, with the aid of omics, our understanding of the healthy periodontium, pathogenesis of periodontal diseases, and healing after periodontal treatment has improved significantly. Yet, the traditional methods, periodontal probing and radiographies, remain the most common methods to diagnose periodontal disease and monitor treatment. Although these approaches can produce reliable diagnostic outcomes, they generally detect disease only after significant tissue degradation thus making treatment outcome highly uncertain. Accordingly, laboratories worldwide have collaborated with clinicians to design accurate, rapid and cost-effective biomarkers for periodontal disease diagnosis. Despite these efforts, biomarkers that can be widely used in early disease diagnosis and for treatment outcome prediction are far from daily use. The aim of this chapter is to give a general overview on periodontal health and diseases, and review recent advancements in periodontal biomarker research. A second aim will discuss the strengths and limitations of translating periodontal biomarker research to clinical practice. Genetic biomarkers of periodontitis are not discussed as the available confirmatory data is scarce.

Association between dental scaling and metabolic syndrome and lifestyle

PURPOSE

Periodontal disease is a risk factor for diabetes and metabolic syndrome, and non-surgical periodontal treatment has been shown to help maintain stable blood sugar in diabetic patients. Determining the level of preventive scaling in patients with metabolic syndrome will help manage the disease. The purpose of this study was to investigate the extent to which people with metabolic syndrome or bad lifestyle performed scaling and the association between preventive scaling and metabolic syndrome or lifestyle in a large population.

METHODS

This study was conducted on adults aged 20 years or older from January 2014 to December 2017 in the National Health Insurance System (NHIS) database. Among 558,067 people who underwent health checkups, 555,929 people were included. A total of 543,791 people were investigated for preventive scaling. Metabolic syndrome components were abdominal obesity, lower high density lipoprotein cholesterol (HDL)-C, high triglycerides, high blood pressure and hyperglycemia. Unhealthy lifestyle score was calculated by assigning 1 point each for current smokers, drinkers, and no performing regular exercise.

RESULTS

When multiple logistic regression analysis was performed after adjusting for age, sex, income, body mass index (BMI), smoking, drinking and regular exercise, the Odds ratios (OR) and 95% confidence intervals (CI) of the group with 5 metabolic syndrome components were 0.741 (0.710, 0.773) (p<0.0001). After adjustment for age, sex, income, BMI, smoking, drinking, regular exercise, diabetes, hypertension and dyslipidemia, the OR (95% CI) of the group with unhealthy lifestyle score = 3 was 0.612 (0.586, 0.640) (p<0.0001).

CONCLUSIONS

The more metabolic syndrome components, and the higher unhealthy lifestyle score, the less scaling was performed.

A Mendelian randomization study on the association of bone mineral density with periodontitis

OBJECTIVE

Observational studies indicated that individuals with osteoporosis could be at an increased risk of periodontitis. This study aimed to investigate whether there is a causal association of bone mineral density (BMD) with periodontitis using Mendelian randomization (MR).

MATERIALS AND METHODS

Summary statistics were sourced from genome-wide association study on BMD measured at different skeletal sites, including estimated heel BMD (eBMD, N = 426,824), forearm BMD (FA-BMD, N = 8143), femoral neck BMD (FN-BMD, N = 32,735), and lumbar spine BMD (LS-BMD, N = 28,498). Genetic variants of periodontitis (N = 45,563) and loose teeth (N = 461,031) were used as outcome surrogates. Inverse variance weighted meta-analysis (IVW) was adopted as main analyses. Other sensitivity MR approaches were used to boost power and account for pleiotropy.

RESULTS

IVW results suggested no evidence for a causal association of any phenotypes of BMD with periodontitis (eBMD, odds ratio [OR] = 0.984, 95% confidence interval [CI] = 0.885-1.083; FA-BMD, OR = 1.028, 95%CI = 0.864-1.193; FN-BMD, OR = 1.033, 95%CI = 0.896-1.169; LS-BMD, OR = 0.991, 95%CI =0.878-1.103; all P > 0.65). Such null associations were consistent through other sensitivity MR approaches. Similarly, no significant causal effects of BMD on loose teeth were found.

CONCLUSIONS

Within the limitation of the study, our MR estimates suggested that a decreased BMD is unlikely to substantially increase the risk of periodontitis.

J-shaped association between systemic immune-inflammation index and periodontitis: Results from NHANES 2009-2014

BACKGROUND

To examine the relationship between the systemic immune-inflammation index (SII) and periodontitis and to investigate possible effect modifiers.

METHODS

Data used in the present cross-sectional study are from the National Health and Nutrition Examination Survey (NHANES) 2009-2014 (N = 10,301). The SII was calculated using the following formula: (neutrophils count × platelet count)/lymphocytes count. The category of periodontitis was defined by the Centers for Disease Control and Prevention and American Academy of Periodontology (CDC/AAP) classification. We employed natural cubic spline and multivariable logistic regression analyses to evaluate the associations of the SII with periodontitis.

RESULTS

The associations between SII and periodontal health followed a J-shape (p < 0.001). The risk of periodontitis tended to reduce with the increment of log2(SII) in participants with log2(SII) ≤ 8.66 (odds radio [OR] = 0.83; 95% CI: 0.69-0.999), especially among non-Hispanic Whites (OR = 0.70; 95% CI: 0.52-0.95), and increased with the increment of log2(SII) in participants with log2(SII) > 8.66 (OR = 1.19; 95% CI: 1.02-1.38). A similar trend was also observed between the SII and the number of sites with probing pocket depth (PPD) ≥4 mm and clinical attachment loss (CAL) ≥ 3 or 5 mm. Furthermore, we found a significantly stronger correlation between lymphocytes and either neutrophils or platelets in individuals with log2(SII) > 8.66, as opposed to those with log2(SII) ≤ 8.66.

CONCLUSIONS

There is a J-shaped association between SII and periodontitis in US adults, with an inflection point of log2(SII) at 8.66, which may provide potential adjunctive treatment strategies for periodontitis with different immune response states. Further prospective trials are still required to confirm our findings.

Oral streptococci: modulators of health and disease

Streptococci are primary colonizers of the oral cavity where they are ubiquitously present and an integral part of the commensal oral biofilm microflora. The role oral streptococci play in the interaction with the host is ambivalent. On the one hand, they function as gatekeepers of homeostasis and are a prerequisite for the maintenance of oral health - they shape the oral microbiota, modulate the immune system to enable bacterial survival, and antagonize pathogenic species. On the other hand, also recognized pathogens, such as oral Streptococcus mutans and Streptococcus sobrinus, which trigger the onset of dental caries belong to the genus Streptococcus. In the context of periodontitis, oral streptococci as excellent initial biofilm formers have an accessory function, enabling late biofilm colonizers to inhabit gingival pockets and cause disease. The pathogenic potential of oral streptococci fully unfolds when their dissemination into the bloodstream occurs; streptococcal infection can cause extra-oral diseases, such as infective endocarditis and hemorrhagic stroke. In this review, the taxonomic diversity of oral streptococci, their role and prevalence in the oral cavity and their contribution to oral health and disease will be discussed, focusing on the virulence factors these species employ for interactions at the host interface.

Nel-like Molecule Type 1 Combined with Gold Nanoparticles Modulates Macrophage Polarization, Osteoclastogenesis, and Oral Microbiota in Periodontitis

The disruption of host-microbe homeostasis and uncontrolled inflammatory response have been considered as vital causes for developing periodontitis, subsequently leading to an imbalance between the bone and immune system and the collapse of bone homeostasis. Consequently, strategies to modulate the immune response and bone metabolization have become a promising approach to prevent and treat periodontitis. In this study, we investigated the cooperative effects of Nel-like molecule type 1 (Nell-1) and gold nanoparticles (AuNPs) on macrophage polarization, osteoclast differentiation, and the corresponding functions in an experimental model of periodontitis in rats. Nell-1-combined AuNPs in in vitro studies were found to reduce the production of inflammatory factors (TNF-α, p < 0.0001; IL-6, p = 0.0012), modulate the ratio of M2/M1 macrophages by inducing macrophage polarization into the M2 phenotype, and inhibit cell fusion, maturation, and activity of osteoclasts. Furthermore, the local application of Nell-1-combined AuNPs in in vivo studies resulted in alleviation of damages to the periodontal and bone tissues, modulation of macrophage polarization and the activity of osteoclasts, and alteration of the periodontal microbiota, in which the relative abundance of the probiotic Bifidobacterium increased (p < 0.05). These findings reveal that Nell-1-combined AuNPs could be a promising drug candidate for the prevention and treatment of periodontitis. However, Nell-1-combined AuNPs did not show organ toxicity or impair the integrity of intestinal epithelium but alter the gut microbiota, leading to the dysbiosis of gut microbiota. The adverse impact of changes in gut microbiota needs to be further investigated. Nonetheless, this study provides a novel perspective and direction for the biological safety assessment of biomaterials in oral clinical applications.

Periodontitis and Inflammatory Bowel Disease: A Review

The complex relationship between periodontitis (PD) and inflammatory bowel disease (IBD) has received significant attention in recent studies. Emerging evidence suggests that the oral-gut axis plays a pivotal role in their interaction. This review provides a comprehensive, up-to-date analysis of original research from 2003 to 2023 on the PD-IBD relationship and aims to be a reference for future research. Relevant literature was sourced from the PubMed database using the keywords "periodontitis" and "inflammatory bowel disease". Additionally, a manual library search and a review of bibliographies were conducted. Of the 297 articles retrieved, 27 studies were chosen for final review. Out of these, 21 studies (78%), including both in vitro and in vivo research, indicated an association between PD and IBD. While many studies confirm a bi-directional relationship, others refute it or deem it clinically irrelevant. There is a need for more accessible studies, such as randomized trials, which also investigate the factors that could influence the outcomes to clarify the exact molecular mechanisms and clinical implications of this complex relationship.

Efficacy of Laser-Assisted Periodontal Therapy vs Conventional Scaling and Root Planing

Background

This study compares the effectiveness of laser-assisted periodontal therapy (LAPT) to conventional scaling and root planing (SRP) in the treatment of periodontal disease.

Materials and Methods

Patients with periodontal disease were divided into two groups. One group received LAPT, while the other group underwent conventional SRP. The periodontal parameters, including pocket depth (PD) and clinical attachment level (CAL), were measured before and after the treatments. The data were statistically analyzed using appropriate methods.

Results

After the treatments, the LAPT group showed a mean reduction in PD of 2.5 mm, while the conventional SRP group had a mean reduction of 2.0 mm. Additionally, the laser group demonstrated a mean improvement in CAL of 1.8 mm, whereas the conventional group showed an improvement of 1.3 mm. These differences were statistically significant (P < 0.05).

Conclusion

The findings of this study suggest that LAPT may be more effective in reducing PD and improving CAL compared with conventional SRP in the treatment of periodontal disease.

Poor Glycemic Control Increases Dental Risk in a Sri Lankan Population

Introduction: The aim of our study was to investigate the impact of diabetes-related factors on the dental disease outcomes of diabetes patients in Trincomalee, Sri Lanka. Materials and Methods: Dental data were collected from 80 type-2-diabetic individuals. A dental risk score was calculated based on the frequency of dental outcomes observed and categorized as low risk (≤3 dental outcomes) and high risk (>3 dental outcomes). Results: In this cohort of men and women with type 2 diabetes, there was a high frequency of periodontal related outcomes, including missing teeth (70%), gingival recessions (40%), tooth mobility (41%), and bleeding (20%). Thirty-nine (39%) of participants had high dental risk, while forty-nine (61%) had low risk. Conclusions: After controlling for age, participants with higher capillary blood glucose levels had 3-fold greater odds of a high dental risk score (OR = 2.93, 95%CI = 1.13, 7.61). We found that poor glycemic control indicated by elevated capillary blood glucose was associated with increased dental risk.

IL-39 and IL-35 gingival crevicular fluid levels in diabetic patients with generalized periodontitis

OBJECTIVES

This research was performed to investigate if there is a role for IL-39 in immunopathogenesis of both systemically healthy and diabetic periodontitis patients. Additionally, to explore if we can consider IL-39 and IL-35 as biomarkers for periodontitis activity.

MATERIALS AND METHODS

A total of 38 periodontitis patients and 19 control volunteers were included in our study. The periodontitis patients were divided equally into (Group I), 19 patients with stage III grade C periodontitis with diabetes mellitus and (Group II), 19 patients with stage III grade B periodontitis and systemically healthy. Gingival crevicular fluid levels of each interleukin were measured pre- and postoperatively for all periodontitis patients as well as control subjects using ELISA.

RESULTS

Our study results showed that the highest level for IL-39 was in diabetic periodontitis patients that decreased significantly postoperatively. However, the highest level for IL-35 was revealed in control group while the lowest value was registered in diabetic periodontitis patients and statistically increased after periodontal treatment.

CONCLUSIONS

Based on the results of our research, both investigated biomarkers may have a potent role in pathogenesis of periodontitis.

CLINICAL RELEVANCE

We could consider both interleukins as accurate diagnostic markers for periodontitis patients, regardless of diabetes mellitus association, as well as promising markers that can aid in the prevention and treatment of periodontitis patients worldwide.

New insights into nanotherapeutics for periodontitis: a triple concerto of antimicrobial activity, immunomodulation and periodontium regeneration

Periodontitis is a chronic inflammatory disease caused by the local microbiome and the host immune response, resulting in periodontal structure damage and even tooth loss. Scaling and root planning combined with antibiotics are the conventional means of nonsurgical treatment of periodontitis, but they are insufficient to fully heal periodontitis due to intractable bacterial attachment and drug resistance. Novel and effective therapeutic options in clinical drug therapy remain scarce. Nanotherapeutics achieve stable cell targeting, oral retention and smart release by great flexibility in changing the chemical composition or physical characteristics of nanoparticles. Meanwhile, the protectiveness and high surface area to volume ratio of nanoparticles enable high drug loading, ensuring a remarkable therapeutic efficacy. Currently, the combination of advanced nanoparticles and novel therapeutic strategies is the most active research area in periodontitis treatment. In this review, we first introduce the pathogenesis of periodontitis, and then summarize the state-of-the-art nanotherapeutic strategies based on the triple concerto of antibacterial activity, immunomodulation and periodontium regeneration, particularly focusing on the therapeutic mechanism and ingenious design of nanomedicines. Finally, the challenges and prospects of nano therapy for periodontitis are discussed from the perspective of current treatment problems and future development trends.

Association between periodontal diseases and chronic obstructive pulmonary disease: Evidence from sequential cross-sectional and prospective cohort studies based on UK Biobank

AIM

To investigate the association between periodontal diseases, airflow limitation and incident chronic obstructive pulmonary disease (COPD) in a large-scale prospective UK Biobank cohort.

MATERIALS AND METHODS

Our approach comprised a cross-sectional study and a prospective cohort. Periodontal diseases were determined based on the participants' self-reported dental symptoms, including painful gums, bleeding gums and loose teeth. Logistic regression and Cox proportional hazards models were used to evaluate the association of periodontal diseases with airflow limitation and incident COPD in the cross-sectional study and the prospective cohort, respectively.

RESULTS

The cross-sectional study involved 495,610 participants. Multivariable analysis found that periodontal diseases were significantly associated with airflow limitation (odds ratio = 1.036, 95% confidence interval [CI]: 1.015-1.059). The cohort study included 379,266 participants with a median follow-up period of 12.68 years. An elevated risk of incident COPD was associated with the presence of periodontal diseases (hazard ratio: 1.248, 95% CI: 1.174-1.326). The effect was consistent among subgroups, including baseline age (≤65 or >65 years), sex, smoking status and diabetes mellitus.

CONCLUSIONS

Periodontal diseases are associated with airflow limitation and elevated COPD incidence. Maintaining good periodontal health in patients with chronic bronchitis and emphysema may help prevent the onset of COPD.

Current concepts in the pathogenesis of periodontitis: from symbiosis to dysbiosis

The primary etiological agent for the initiation and progression of periodontal disease is the dental plaque biofilm which is an organized aggregation of microorganisms residing within a complex intercellular matrix. The non-specific plaque hypothesis was the first attempt to explain the role of the dental biofilm in the pathogenesis of periodontal diseases. However, the introduction of sophisticated diagnostic and laboratory assays has led to the realisation that the development of periodontitis requires more than a mere increase in the biomass of dental plaque. Indeed, multispecies biofilms exhibit complex interactions between the bacteria and the host. In addition, not all resident microorganisms within the biofilm are pathogenic, since beneficial bacteria exist that serve to maintain a symbiotic relationship between the plaque microbiome and the host’s immune-inflammatory response, preventing the emergence of pathogenic microorganisms and the development of dysbiosis. This review aims to highlight the development and structure of the dental plaque biofilm and to explore current literature on the transition from a healthy (symbiotic) to a diseased (dysbiotic) biofilm in periodontitis and the associated immune-inflammatory responses that drive periodontal tissue destruction and form mechanistic pathways that impact other systemic non-communicable diseases.

Melatonin supports nonsurgical periodontal treatment in patients with Type 2 diabetes mellitus and periodontitis: A randomized clinical trial

BACKGROUND

Diabetes mellitus (DM)-associated hyperinflammatory host response significantly provokes periodontal tissue destruction. In this context, the support of nonsurgical periodontal therapy in diabetics with host modulation agents is a current field of study. This clinical study aims to investigate the clinical efficacy of melatonin supplementation and discuss its possible biological mechanisms in nonsurgical periodontal treatment in patients with DM and periodontitis through some fundamental markers.

METHODS

In this randomized controlled and single-blind study, 27 of 55 diabetic patients with periodontitis (stage III/IV and grade C) underwent full-mouth scaling and root planing (fmSRP) alone and 28 patients underwent melatonin administration (6 mg daily, 30 days) in addition to fmSRP (full-mouth scaling and root planing plus melatonin, fmSRP-mel). The potential therapeutic contribution of melatonin was evaluated clinically and biochemically (gingival crevicular fluid RANKL, OPG, MMP-8, and serum IL-1β levels) at 3rd and 6th months.

RESULTS

Melatonin (tablet, 6 mg daily, 30 days) did not cause any local or systemic side effects. fmSRP alone resulted in significant reduction in serum IL-1β levels, pocket depths, gingival inflammation, and gingival crevicular fluid RANKL and MMP-8 levels (p < 0.05). Moreover, melatonin supplementation resulted in a more significant decrease in bleeding and pocket depth scores at probing, especially at 3 months (p < 0.05). Furthermore, RANKL and MMP-8 levels were significantly lower at 3 months and IL-1β levels at 6 months compared to the control group (p < 0.05). However, OPG levels were not affected significantly by the treatments (p > 0.05).

CONCLUSION

Melatonin, as a host modulation agent, significantly increases the clinical efficacy of fmSRP. The reduction in periodontal inflammation and pocket depths may be a result of marked suppression of RANKL-associated osteoclastogenesis and extracellular matrix damage by melatonin.

Microbial biomarkers as a predictor of periodontal treatment response: A systematic review

To evaluate the prognostic accuracy of microbial biomarkers and their associations with the response to active periodontal treatment (APT) and supportive periodontal therapy (SPT). Microbial dysbiosis plays a crucial role in the disease processes of periodontitis. Biomarkers based on microbial composition may offer additional prognostic value, supplementing the limitations of current clinical parameters. While these microbial biomarkers have been clinically evaluated, there is a lack of consensus regarding their prognostic accuracy. A structured search strategy was applied to MEDLINE (PubMed), Cochrane Library, and Embase on 1/11/2022 to identify relevant publications. Prospective clinical studies involving either APT or SPT, with at least 3-month follow-up were included. There were no restrictions on the type of microbial compositional analysis. 1918 unique records were retrieved, and 13 studies (comprising 943 adult patients) were included. Heterogeneity of the studies precluded a meta-analysis, and none of the included studies had performed the sequence analysis of the periodontal microbiome. Seven and six studies reported on response to APT and SPT, respectively. The prognostic accuracy of the microbial biomarkers for APT and SPT was examined in only two and four studies, respectively. Microbial biomarkers had limited predictive accuracy for APT and inconsistent associations for different species across studies. For SPT, elevated abundance of periodontal pathogens at the start of SPT was predictive of subsequent periodontal progression. Similarly, persistent high pathogen loads were consistently associated with progressive periodontitis, defined as an increased pocket probing depth or clinical attachment loss. While there was insufficient evidence to support the clinical use of microbial biomarkers as prognostic tools for active periodontal treatment outcomes, biomarkers that quantify periodontal pathogen loads may offer prognostic value for predicting progressive periodontitis in the subsequent supportive periodontal therapy phase. Additional research will be required to translate information regarding subgingival biofilm composition and phenotype into clinically relevant prognostic tools.

CCL2 is a key regulator and therapeutic target for periodontitis

AIM

Our previous study revealed that the C-C motif chemokine receptor 2 (CCR2) is a promising target for periodontitis prevention and treatment. However, CCR2 is a receptor with multiple C-C motif chemokine ligands (CCLs), including CCL2, CCL7, CCL8, CCL13 and CCL16, and which of these ligands plays a key role in periodontitis remains unclear. The aim of the present study was to explore the key functional ligand of CCR2 in periodontitis and to evaluate the potential of the functional ligand as a therapeutic target for periodontitis.

MATERIALS AND METHODS

The expression levels and clinical relevance of CCR2, CCL2, CCL7, CCL8, CCL13 and CCL16 were studied using human samples. The role of CCL2 in periodontitis was evaluated by using CCL2 knockout mice and overexpressing CCL2 in the periodontium. The effect of local administration of bindarit in periodontitis was evaluated by preventive and therapeutic medication in a mouse periodontitis model. Microcomputed tomography, haematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, bead-based immunoassays and flow cytometry were used for histomorphology, molecular biology and cytology analysis.

RESULTS

Among different ligands of CCR2, only CCL2 was significantly up-regulated in periodontitis gingival tissues and was positively correlated with the severity of periodontitis. Mice lacking CCL2 showed milder inflammation and less bone resorption than wild-type mice, which was accompanied by a reduction in monocyte/macrophage recruitment. Adeno-associated virus-2 vectors overexpressing CCL2 in Ccl2-/- mice gingiva reversed the attenuation of periodontitis in a CCR2-dependent manner. In ligation-induced experimental periodontitis, preventive or therapeutic administration of bindarit, a CCL2 synthesis inhibitor, significantly inhibited the production of CCL2, decreased the osteoclast number and bone loss and reduced the expression levels of proinflammatory cytokines TNF-α, IL-6 and IL-1β.

CONCLUSIONS

CCL2 is a pivotal chemokine that binds to CCR2 during the progression of periodontitis, and targeting CCL2 may be a feasible option for controlling periodontitis.

Salivary Biomarkers in Periodontitis: A Scoping Review

Periodontal disease is a prevalent and potentially impactful oral health condition, ranging from gingivitis to severe periodontitis. Early detection and precise management are crucial in modern dentistry due to its prevalence and potential systemic health implications. Traditional clinical assessments and radiographic imaging have been the primary diagnostic tools. However, recent advances in oral diagnostics have introduced the concept of non-invasive, easily accessible salivary biomarkers. This review explores the evolving landscape of salivary biomarkers associated with periodontal disease, offering a comprehensive analysis of recent studies. It delves into the key findings, clinical significance, and potential impact of these biomarkers in revolutionizing periodontal disease diagnostics and treatment monitoring. The study emphasizes their diagnostic and prognostic capabilities, including their ability to assess disease severity, correlate with clinical parameters, aid in early detection, and enhance personalized treatment planning. As the field of oral diagnostics continues to advance, understanding the role of salivary biomarkers in periodontal disease management holds the promise of improving precision and effectiveness in oral healthcare. This review underscores the potential for salivary biomarkers to become integral components of routine periodontal care, offering a minimally invasive and patient-centered approach to oral health management.

MicroRNA-155 (miR-155) as an accurate biomarker of periodontal status and coronary heart disease severity: a case-control study

BACKGROUND

Increasing evidence supports associations between periodontal disease and coronary heart disease (CHD). This case-control study evaluated whether inflammatory regulator, microRNA-155 (miR-155), could be utilised as a biomarker of periodontitis and/or CHD.

METHODS

Of 120 participants, 30 patients had clinically healthy periodontium (controls, C), 30 patients had generalized periodontitis (P), 30 patients had CHD and clinically healthy periodontium (AS-C); and 30 patients had CHD with generalized periodontitis (AS-P). Patient demographic and periodontal characteristics (plaque index, bleeding on probing, probing pocket depth and clinical attachment loss), were collected. Patient whole blood and saliva levels of miR-155 and pro-inflammatory cytokine (interleukin-1β), were quantified by quantitative real time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). One-way ANOVA with post-hoc Tukey test was used to determine differences among the four groups. Chi Square test was used for participant gender comparisons. Pearson correlation tests and multiple linear regression analyses were used to assess associations between the demographic and clinical variables analysed, versus IL-1β and miR-155 levels. miR-155 and IL-1β accuracy in differentiating healthy versus other patient groups were analysed using receiver operating characteristic (ROC) curves, by calculating area under the curve (AUC) values and sensitivity and specificity cut-off points using Youden's index. Statistical tests of sensitivity and specificity were conducted using the McNemar test.

RESULTS

Whole blood miR-155 levels were elevated in periodontitis/non-periodontitis patients with CHD (AS-P, AS-C), and periodontitis patients alone (P) (p < 0.001). Receiver operating characteristic (ROC) and area under the curve (AUC) analyses confirmed miR-155 accuracy in discriminating P, AS-C and AS-P groups (AUC 0.6861-0.9944, p < 0.0001-0.05), coupled with high sensitivity (76.7-100.0%), specificity (53.3-96.7%) and cut-off points (> 0.955- > 2.915 a.u.; p < 0.0001). miR-155 levels further distinguished between CHD (AS-C, AS-P) and periodontitis (P) patients (AUC ≥ 0.8378, sensitivity ≥ 88.7%, specificity ≥ 73.3%, cut-off > 2.82 a.u; p < 0.0001), and between AS-C and AS-P patients (AUC 0.7578, sensitivity 80.0%, specificity 50.0%, cut-off > 7.065 a.u; p < 0.001). Subsequent analyses identified positive correlations between miR-155 and the various patient demographics, salivary interleukin-1β and periodontal parameters assessed.

CONCLUSIONS

This study advocates miR-155 as an accurate diagnostic/prognostic biomarker of periodontitis and/or CHD severity, thereby improving detection and treatment for both conditions.

Non-Invasive Physical Plasma Reduces the Inflammatory Response in Microbially Prestimulated Human Gingival Fibroblasts

Non-invasive physical plasma (NIPP), an electrically conductive gas, is playing an increasingly important role in medicine due to its antimicrobial and regenerative properties. However, NIPP is not yet well established in dentistry, although it has promising potential, especially for periodontological applications. The aim of the present study was to investigate the effect of NIPP on a commercially available human gingival fibroblast (HGF) cell line and primary HGFs in the presence of periodontitis-associated bacteria. First, primary HGFs from eight patients were characterised by immunofluorescence, and cell numbers were examined by an automatic cell counter over 5 days. Then, HGFs that were preincubated with Fusobacterium nucleatum (F.n.) were treated with NIPP. Afterwards, the IL-6 and IL-8 levels in the cell supernatants were determined by ELISA. In HGFs, F.n. caused a significant increase in IL-6 and IL-8, and this F.n.-induced upregulation of both cytokines was counteracted by NIPP, suggesting a beneficial effect of physical plasma on periodontal cells in a microbial environment. The application of NIPP in periodontal therapy could therefore represent a novel and promising strategy and deserves further investigation.

Butyrate Inhibits Dendritic Cell Activation and Alleviates Periodontitis

Dendritic cells (DCs) can mediate inflammation-related bone resorption that is crucial in the development of periodontitis. Butyrate is a critical by-product of microbes with antibacterial and anti-inflammatory properties. Here, we found that butyrate inhibited the activation of lipopolysaccharide (LPS)-induced DCs and generation of inflammatory cytokines by DCs. Moreover, butyrate regulated glycolysis in LPS-induced DCs via the G-protein-coupled receptor/hypoxia-inducible factor-1α pathway. In addition, butyrate inhibited the maturation of CD11c+MHC-II+ DCs in vivo, suppressing local inflammatory infiltration and ultimately alleviating bone resorption in a periodontitis model. Our results imply that butyrate suppresses the activation of LPS-induced DCs by modulating their metabolism, highlighting its potential as a therapeutic agent for inflammatory diseases.

CGRP-Loaded Porous Microspheres Protect BMSCs for Alveolar Bone Regeneration in the Periodontitis Microenvironment

Periodontitis is a prevalent dental disease marked by progressive destruction of tooth-supporting tissues, and the recovery of bone defects after periodontitis remains challenging. Although stem cell-based therapy is a promising treatment for periodontal tissue regeneration, the function of mesenchymal stem cells is constantly impaired by the inflammatory microenvironment, leading to compromised treatment outcomes. Herein, calcitonin gene-related peptide (CGRP)-loaded porous microspheres (PMs) are prepared to protect bone marrow mesenchymal stem cells (BMSCs) against inflammatory mediators in periodontitis. The released CGRP can effectively ameliorate the inflammation-induced dysfunction of BMSCs, which may involve suppressing the ROS (reactive oxygen species)/NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3)/Caspase-1 (CASP1) pathway. Moreover, the porous architecture of PMs provides effective cell-carrying capacity and physical protection for BMSCs during transplantation. In vivo experiments demonstrate that CGRP/BMSC-loaded PMs can effectively inhibit inflammation and improve osteogenic activity, resulting in better periodontal bone regeneration. This study focuses on the protection of stem cell function in the inflammatory microenvironment, which is important for stem cell-mediated tissue regeneration and repair under inflammatory conditions.

Deciphering genetic causality between inflammatory bowel disease and periodontitis through bi-directional two-sample Mendelian randomization

Inflammatory bowel disease (IBD) and periodontitis are reported to be closely associated; however, whether there is a causal association between them remains unclear. To explore the existence of this causality, this study applied a bidirectional two-sample Mendelian randomization (MR). The genetic variants were obtained from the summary statistics of genome-wide association studies of IBD, including its subtypes CD and UC, and periodontitis. 175, 148, 113, and six single-nucleotide polymorphisms were selected as instrumental variables for IBD, CD, UC, and periodontitis, respectively. In MR analysis, random-effects inverse-variance weighted was used as the primary method, and weighted median and MR Egger regression were applied as the complementary method. A series of sensitivity analyses were also conducted to ensure the reliability of the results. None of these analyses found a significant effect of genetically proxied IBD and its subtypes on periodontitis, and vice versa. Subsequent sensitivity analyses did not detect any horizontal pleiotropy and heterogeneity. Caution should be exerted when it comes to clinical relevance and further studies are needed to clarify the relationship between IBD and periodontitis.