Porphyromonas Gingivalis Research Articles

Full-length structure and heme binding in the transcriptional regulator HcpR.

HcpR is a CRP-family transcriptional regulator found in many Gram-negative anaerobic bacteria. In the perio-pathogen Porphyromonas gingivalis, HcpR is crucial for the response to reactive nitrogen species such as nitric oxide (NO). Binding of NO to the heme group of HcpR leads to transcription of the redox enzyme Hcp. However, the molecular mechanisms of heme binding to HcpR remain unknown. In this study we present the 2.3Å structure of the P. gingivalis HcpR. Interdomain interactions present in the structure help to form a hydrophobic pocket in the N-terminal sensing domain. A comparison analysis with other CRP-family members reveals that the molecular mechanisms of HcpR-mediated regulation may be distinct from other family members. Using docking studies, we identify a putative heme binding site in the sensing domain. In vitro complementation and mutagenesis studies verify Met68 as an important residue in activation of HcpR. Finally, heme binding studies with purified forms of recombinant HcpR support Met68 and His149 residues as important for proper heme coordination in HcpR.

Impaired Periodontitis-Induced Cytokine Production by Peripheral Blood Monocytes and Myeloid Dendritic Cells in Patients with Rheumatoid Arthritis: A Case-Control Study.

Background: Immune cells from rheumatoid arthritis (RA) patients display a reduced in vitro response to Porphyromonas gingivalis (P. gingivalis), which may have functional immune consequences. The aim of this study was to characterize, by flow cytometry, the frequency/activity of monocytes and naturally occurring myeloid dendritic cells (mDCs) in peripheral blood samples from patients with periodontitis and patients with periodontitis and RA. Methods: The relative frequency of monocytes and mDCs in the whole blood, the frequency of these cells producing TNFα or IL-6 and the protein expression levels for each cytokine, before and after stimulation with lipopolysaccharide (LPS) from Escherichia coli plus interferon-γ (IFN-γ), were assessed by flow cytometry, in peripheral blood samples from 10 healthy individuals (HEALTHY), 10 patients with periodontitis (PERIO) and 17 patients with periodontitis and RA (PERIO+RA). Results: The frequency of monocytes and mDCs producing IL-6 or TNF-α and the expression of IL-6 and TNF-α in the PERIO group were generally higher. Within the PERIO+RA group, P. gingivalis and related antibodies were negatively correlated with the monocyte and mDC expression of IL-6. A subgroup of the PERIO+RA patients that displayed statistically significantly lower frequencies of monocytes producing IL-6 after activation presented statistically significantly higher peptidylarginine deiminase (PAD)2/4 activity, anti-arg-gingipain (RgpB) IgG levels, mean probing depth (PD), periodontal inflamed surface area (PISA) and bleeding on probing (BoP). Conclusions: In the patients with PERIO+RA, innate immune cells seemed to produce lower amounts of pro-inflammatory cytokines, which are correlated with worse periodontitis-related clinical and microbiological parameters.

PHD2 shRNA-Modified Bone Marrow Mesenchymal Stem Cells Facilitate Periodontal Bone Repair in Response to Inflammatory Condition.

To investigate whether bone marrow mesenchymal stem cells (BMMSCs) modulate periodontal bone repair through the hydroxylase domain-containing protein 2 (PHD2)/hypoxia- inducible factor-1 (HIF-1) signalling pathway in response to inflammatory conditions. Osteogenic differentiation of PHD2 shRNA-modified BMMSCs and the possible mechanism were explored in an inflammatory microenvironment stimulated by porphyromonas gingivalis lipopolysaccharide (Pg-LPS) in vitro. The effect of PHD2 gene-modified BMMSCs on periodontal bone loss was evaluated with experimental periodontitis. Pg-LPS stimulation greatly impaired the osteogenic differentiation of BMMSCs, whereas the silence of PHD2 significantly enhanced the osteogenesis of BMMSCs. More importantly, increased level of vascular endothelial growth factor (VEGF) was detected under Pg-LPS stimulation, which was verified to be associated with the augmented osteogenesis. In experimental periodontitis, PHD2-modified BMMSCs transplantation elevated osteogenic parameters and the expression of VEGF in periodontal tissue. This study highlighted that PHD2 gene silencing could be a feasible approach to combat inflammatory bone loss by rescuing the dysfunction of seed cells.

Comparative Antimicrobial Efficacy of Garlic and Guava Extracts on Oral Pathogens Using a Time Kill Assay: An In Vitro Study

Abstract Background: Periodontal disease is characterized by inflammation mediated by the host and related microbes, which leads to the loss of periodontal attachment and tooth loss. Due to an increase in bacterial resistance to antibiotics, there is a shift toward use of herbal medicines. Aim: The aim of the study is to compare the antimicrobial effect of aqueous garlic extract (AGE) and ethanolic guava extract (EGuE) on Tanerella forsythia and Porphyromonas gingivalis using the time kill assay Materials and Methods: AGE and EGuE are prepared. Ciprofloxacin was taken as the control. The MIC was performed for garlic, guava extract, and ciprofloxacin. P. gingivalis and T. forsythia were cultured, and the time kill assay was performed at 0 h, 5 min, 30 min, 1 h, and 2 h. Colonies were counted after 48–72 h for growth. Results: The minimal inhibitory concentration (MIC) results indicated that both EGuE and AGE exhibited superior antibacterial activity compared to ciprofloxacin, suggesting their potential as alternative or complementary antimicrobial agents. In a time kill assay, EGuE demonstrated a significant reduction in colony forming units (CFUs) at 30 min, 1 h, and 2 h, outperforming AGE and ciprofloxacin. Intragroup comparisons revealed that EGuE significantly reduced CFUs at 0 h and 5 min, while AGE showed no notable reduction over time. Conclusion: Overall, the study demonstrates the antimicrobial efficacy of EGuE and AGE against T. forsythia and P. gingivalis at higher concentrations. Hence, these extracts may serve as alternative antimicrobial agents against periodontal pathogens.

Antibacterial and cytotoxicity properties of a polyherbal mouthwash containing Achyranthes aspera and Trachyspermum ammi against selected periodontal pathogens

BackgroundChlorhexidine (CHX) is considered as a gold standard for its antibacterial efficacy and substantivity in chemical plaque control. However, some adverse effects are associated with its prolonged use. Herbal medicines like Achyranthes aspera and Trachyspermum ammi have been used in many clinical conditions, and they appear to be a valuable substitute next to CHX in the management of periodontal diseases. ObjectiveThis in vitro study was designed to assess and compare the antibacterial potential and cytotoxic effects of novel polyherbal mouthwash containing A. aspera and T. ammi with 0.2% CHX mouthwash against Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans. MethodsEthanolic extracts of A. aspera and T. ammi were prepared by the Soxhlet apparatus method and were subjected to preliminary phytochemical screening. The individual plant extracts and the plant extract mixture (PEM) of A. aspera and T. ammi in the ratio of 1:1, 2:1, 1:2 (w/v) were assessed for minimum inhibitory concentration (resazurin microtitre assay) and minimum bactericidal concentration (spread plating method) against selected periodontal pathogens in comparison to CHX. The polyherbal mouthwash was assessed for zone of inhibition (well diffusion method) and cytotoxicity (MTT assay) on adult human gingival fibroblasts. All the experiments were performed in triplicate. ResultsThe antibacterial activity was evident in the PEMs, and polyherbal mouthwash against tested periodontal pathogens and was comparable to CHX. The cytotoxicity assay findings confirmed that polyherbal mouthwash exhibited 82.1% of surviving cells which proved good biocompatibility. ConclusionA. aspera and T. ammi based mouthwash possess comparable antibacterial activity against periodontal pathogens when compared to CHX.

Antimicrobial adhesive self-healing hydrogels for efficient dental biofilm removal from periodontal tissue

ObjectivesOral biofilms, including pathogens such as Porphyromonas gingivalis, are involved in the initiation and progression of various periodontal diseases. However, the treatment of these diseases is hindered by the limited efficacy of many antimicrobial materials in removing biofilms under the harsh conditions of the oral cavity. Our objective is to develop a gel-type antimicrobial agent with optimal physicochemical properties, strong tissue adhesion, prolonged antimicrobial activity, and biocompatibility to serve as an adjunctive treatment for periodontal diseases. MethodsPhenylboronic acid-conjugated alginate (Alg–PBA) was synthesized using a carbodiimide coupling agent. Alg–PBA was then combined with tannic acid (TA) to create an Alg–PBA/TA hydrogel. The composition of the hydrogel was optimized to enhance its mechanical strength and tissue adhesiveness. Additionally, the hydrogel’s self-healing ability, erosion and release profile, biocompatibility, and antimicrobial activity against P. gingivalis were thoroughly characterized. ResultsThe Alg–PBA/TA hydrogels, with a final concentration of 5 wt% TA, exhibited both mechanical properties comparable to conventional Minocycline gel and strong tissue adhesiveness. In contrast, the Minocycline gel demonstrated negligible tissue adhesion. The Alg–PBA/TA hydrogel also retained its rheological properties under repeated 5 kPa stress owing to its self-healing capability, whereas the Minocycline gel showed irreversible changes in rheology after just one stress cycle. Additionally, Alg–PBA/TA hydrogels displayed a sustained erosion and TA release profile with minimal impact on the surrounding pH. Additionally, the hydrogels exhibited potent antimicrobial activity against P. gingivalis, effectively eliminating its biofilm without compromising the viability of MG-63 cells. SignificanceThe Alg–PBA/TA hydrogel demonstrates an optimal combination of mechanical strength, self-healing ability, tissue adhesiveness, excellent biocompatibility, and sustained antimicrobial activity against P. gingivalis. These attributes make it superior to conventional Minocycline gel. Thus, the Alg–PBA/TA hydrogel is a promising antiseptic candidate for adjunctive treatment of various periodontal diseases.

Association of Oral Microbiome with Periodontal Disease Progression: A Longitudinal Study

Periodontal disease, a prevalent oral health condition, is characterized by the inflammation and destruction of the supporting tissues around the teeth and poses significant challenges to global public health. Objectives: To examine the association between the oral microbiome and periodontal disease progression in a Pakistani population. Methods: A total of 350 patients aged ≥ 18 years, diagnosed with periodontal disease, were registered from August 2023 to February 2024. Participants were evaluated for periodontal health indicators, including probing depth and clinical attachment loss, and their oral microbiome profiles were analyzed using high-throughput sequencing of the 16S rRNA gene. Machine learning algorithms, including Random Forest and Support Vector Machines, were applied to predict disease progression based on microbial profiles. Results: Porphyromonas gingivalis and Tannerella forsythia were strongly associated with greater probing depths and clinical attachment loss (β = 0.45, p < 0.01), indicating their role in disease progression. Conversely, Streptococcus and Lactobacillus were linked to reduced disease severity (β = -0.30, p < 0.05). The oral microbiome exhibited high diversity, with Firmicutes (35%), Bacteroidetes (25%), Proteobacteria (20%), and Actinobacteria (15%) being the predominant species. The Random Forest model predicted disease progression with 85% accuracy (Area under the curve (AUC) = 0.87), emphasizing the predictive value of microbial profiles. Conclusions: It was concluded that the study confirms a strong link between specific oral microbiota and periodontal disease progression, emphasizing the importance of microbial analysis in predicting and managing periodontal health.

Microbiological aspects of dental health in children with osteogenesis imperfecta

Background. Oral microbiome actively affects the child’s health and is an available tool for diagnosing and predic­ting dental and systemic diseases. Studying the colonization of the oral cavity by cariogenic and periodontopathogenic bacteria, given the congenital, genetically determined decrease in the quality of collagen in children with osteogenesis imperfecta, is an urgent problem. The purpose of the study was to determine the level of cariogenic and periodontopathogenic microorganisms in the oral cavity of children with osteogenesis imperfecta. Materials and methods. Clinical studies were conducted with the participation of children aged 2 to 17 years diagnosed with osteogenesis imperfecta, in whom the level of contamination of the oral cavity with cariogenic bacteria Streptococcus mutans and Lactobacter spp. and periodontal pathogens Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Treponema denticola, Bacteroides forsythus, Prevotella intermedia was determined. Results. All children with osteogenesis imperfecta were found to have a borderline high level of Streptococcus mutans contamination and the presence of periodontal pathogens of the first order, mainly in the form of monocultures in preclinical concentration, which, against the background of low collagen quality, indicates a sufficiently high risk of developing ­caries and periodontal diseases.

The Use of Lemongrass/Lemon Blend Essential Oil Nanoemulsions in Chewy Candy Formulations and Its Evaluation Against Streptococcus mutans and Porphyromonas gingivalis

Lemongrass (Lg) and lemon (Lm) essential oils (EOs) mainly contain citral and limonene, respectively, which are not limited to flavor for food but can also provide antibacterial activity. The information on the enrichment of these combined EOs in chewy candy products has never been documented yet. This study aimed to evaluate the physical-chemical properties and volatile compound of nanoemulsion formulations of Lg/Lm blend EOs as well as the physical-chemical properties, total plate count (TPC), and sensory acceptability of chewy candy formulated with nanoemulsions. Antibacterial evaluations against Streptococcus mutans and Porphyromonas gingivalis were performed for both nanoemulsion and chewy candy. Blending Lg and Lm EOs at ratios of Lg1.85 : Lm2.25 and Lg3.65 : Lm0.45 showed a broadly different constituent of the volatile compound than the ratio with the least amount of Lg (Lg0.05 : Lm4.05) but all the formulations possessed eugenol, β-Bisabolene, and caryophyllene oxide. The combination of Lg1.85 : Lm2.25 produced the nanoemulsion with the lowest particle size but lower zeta potential and emulsion stability. At this ratio, the significant inhibitory activity of the nanoemulsion was found to be 92.40% and 84.14% for S. mutans and P. gingivalis, respectively (p < 0.05). Its application in chewy candy formulation also resulted in the highest inhibitory activity against S. mutans (85%) and P. gingivalis (77.20%). Chewy candy formulated with Lg1.85 : Lm2.25 nanoemulsion was also found to have the lowest TPC of 3.72 log CFU/g. The overall acceptability of the chewy candy was around neutral (3.77) by panelists for its higher color score (4.73) and aroma (4.37) in average to the other samples. This study discovered the potential of Lg/Lm blend EOs nanoemulsion for enhancing the antibacterial effect and improving the texture and color of chewy candy.

A handheld electrochemical bacterial sensor based on multifunctional composite hydrogels and DNA biomimetic nanowalls for accurate detection of Porphyromonas gingivalis

Porphyromonas gingivalis (Pg) is not merely one of the important periodontal pathogens, but also exhibits a profound and intimate connection with various systemic diseases, such as cancer, cardiovascular disease, and Alzheimer’s disease. Hence, a handheld electrochemical bacterial sensor (Hebs) is developed for point-of-care testing of Pg in saliva based on an enhanced personal glucose meter platform. In the Hebs, a novel multifunctional composite hydrogel (MFCHgel) is prepared with outstanding conductivity, electrical activity, adhesion and modifiability. In particular, its superior adhesion effectively addresses the inherent issue of electrode-modified material being prone to detachment while ensuring excellent conductivity, which is extremely beneficial for the stability of biosensor. In addition, by assembling DNA biomimetic nanowalls (DBNWs), the surface negative charge and steric hindrance of Pg are enhanced significantly, leading to a remarkable improvement in the electrical impedance response of Pg. Based on their cooperation, the Hebs is capable of effectively detecting Pg within the range of 10 to 1 × 107 CFU/mL, with an impressive limit of detection as low as 6 CFU/mL. Significantly, Hebs exhibits remarkable accuracy in analyzing 40 clinical saliva samples and offers distinct advantages in terms of time consumption and portability as compared to the ELISA kit. This work successfully develops a Hebs for point-of-care testing of Pg, thereby presenting a novel perspective for the advancement of portable bacterial detection devices.

Involvement of PG1037 in the repair of 8-oxo-7,8-dihydroguanine caused by oxidative stress in Porphyromonas gingivalis.

The PG1037 gene is part of the uvrA-PG1037-pcrA operon in Porphyromonas gingivalis. It encodes for a protein of unknown function upregulated under hydrogen peroxide (H2O2)-induced oxidative stress. Bioinformatic analysis shows that PG1037 has a zinc-finger motif, two peroxidase motifs, and one cytidylate kinase domain. The aim of this study is to characterize further the role of the PG1037 recombinant protein in the unique 8-oxoG repair system in P. gingivalis. PG1037 recombinant proteins with deletions in the zinc-finger or peroxidase motifs were created. Electrophoretic mobility shift assays were used to evaluate the ability of the recombinant proteins to bind 8-oxoG-containing oligonucleotides. Zinc binding, peroxidase, and Fenton reaction assays were used to assess the functional roles of the rPG1037 protein. A bacterial adenylate cyclase two-bride assay was used to identify the partner protein of PG1037 in the repair of 8-oxoG. The recombinant PG1037 (rPG1037) protein carrying an N-terminal His-tag demonstrated an ability to recognize and bind 8-oxoG-containing oligonucleotide. In contrast to the wild-type rPG1037 protein, the zinc-finger motif deletion resulted in the loss of zinc and 8-oxoG binding activities. A deletion of the peroxidase motif-1 showed a decrease in peroxidase activity. Using a bacterial adenylate cyclase two-hybrid system, there was no observed protein-protein interaction of PG1037 with UvrA (PG1036), PcrA (PG1038), or mismatch repair system proteins. Taken together, the results show that PG1037 is an important member of a novel mechanism that recognizes and repairs oxidative stress-induced DNA damage in P. gingivalis.

Oral and Gut Microbiota Dysbiosis Due to Periodontitis: Systemic Implications and Links to Gastrointestinal Cancer: A Narrative Review.

Periodontitis can disrupt oral and gut microbiota, leading to dysbiosis that affects overall systemic health. Besides the spread of periodontal pathogens by the hematogenous route, they can also be translocated into the gastrointestinal tract, possibly intervening in the neoplastic process in the gastrointestinal tract. This manuscript reviews the relationship between oral and gut microbiota due to periodontitis, discussing systemic health implications and potential links to gastrointestinal cancer. This article highlights the significance and effect of dysbiosis in the gut, emphasizing the importance of maintaining oral health to prevent systemic diseases. Lastly, it will go through therapeutic innovations such as probiotics and oral microbiota analysis tools for systemic disease detection. These findings will mark the integration of oral health management in clinical practice to lower systemic disease risk and improve overall patient outcomes. Aim of work: This manuscript aims to unravel the pathological interaction between oral and gut microbiota and their bidirectional effect on systemic diseases. Materials and methods: The review was performed using the MEDLINE and ScienceDirect databases. Reviewed articles were published in English between the year 2015 and 2024. The search used keywords such as ("oral microbiota" AND "periodontal disease") OR ("oral microbiota" AND "gastrointestinal cancer") OR ("Porphyromonas gingivalis" AND "periodontal disease") OR ("Helicobacter pylori" AND "gastric cancer") OR ("gut microbiome" AND "inflammatory bowel disease") OR ("oral microbiome" AND "systemic diseases"). Conclusions: The dysbiotic change in the oral cavity due to periodontitis is linked directly and indirectly to systemic diseases such as IBS, neurodegenerative diseases, muscle joint diseases, respiratory infections, and gastrointestinal cancer; this underscores the importance of maintaining oral hygiene for prophylaxis of oral diseases and the prevention of systemic diseases. A better understanding of the interconnections between oral health and systemic diseases will integrate oral health management to offer new prevention, diagnostic, and treatment opportunities to improve overall patient outcomes.

Efficacy of toothpaste containing Brazilian green propolis extracts with an optimal kaempferide/betuletol ratio for improving oral microbiota: A randomized, controlled, paired crossover study

Ethnopharmacological relevancePropolis is a resinous substance collected by honeybees from various plant sources and has been used in traditional folk medicine for centuries. Propolis has various biological properties, including antibacterial, antiviral, anti-inflammatory, and anti-tumor properties. The use of propolis in oral health care is attributable to its antimicrobial and anti-inflammatory effects. However, limited evidence exists on the in vivo efficacy of propolis against periodontal pathogens. Aim of the studyWe aimed to evaluate the efficacy of Brazilian green propolis (BGP)-containing toothpaste for improving the oral environment and define its antibacterial compounds. Materials and methodsOverall, 48 student volunteers aged 18–40 years (24 females and 24 males) were randomly categorized into the BGP and placebo groups. The BGP and placebo groups received toothpaste with and without BGP, respectively. After a baseline assessment, the plaque index (PI) score, gingival index (GI) score, and proportion of periodontal pathogens on the tongue surface were analyzed at 0, 1, and 2 weeks. Antibacterial compounds were identified using liquid-liquid partitioning, high-performance liquid chromatography purification, and nuclear magnetic resonance methods. ResultsThe concentration of BGP in the toothpaste was set at 0.0347 w/v%. Compared with the placebo group, the BGP group demonstrated a reduction in the PI score (p < 0.05) but not in the GI score, as well as a reduction in Porphyromonas gingivalis (Pg)/Total bacteria (Tb), Fusobacterium nucleatum (Fn)/Tb, and Aggregatibacter actinomycetemcomitans (Aa)/Tb (p < 0.05) but not in Streptococcus salivalius/Tb. Effect sizes for Pg, Fn and Aa were 0.360, 0.556, and 0.164, respectively. The antibacterial compounds of the BGP-containing toothpaste included a mixture of kaempferide/betuletol. ConclusionsWe confirmed the efficacy of propolis toothpaste with an optimal kaempferide/betuletol ratio for improving oral microbiota, thereby suggesting that BGP toothpaste is clinically useful in maintaining oral health and preventing periodontal disease.

Mangostanin hyaluronic acid hydrogel as an effective biocompatible alternative to chlorhexidine

Periodontal disease (PD) prevention and treatment products typically demonstrate excellent antibacterial activity, but recent studies have raised concerns about their toxicity on oral tissues. Therefore, finding a biocompatible alternative that retains antimicrobial properties is imperative. In this study, a chemically modified hyaluronic acid (HA) hydrogel containing mangostanin (MGTN) was developed. Native HA was chemically modified, incorporating amino and aldehyde groups in different batches of HA, allowing spontaneous crosslinking and gelation when combined at room temperature. MGTN at different concentrations was incorporated before gelation. The structure, swelling characteristics MGTN release, rheological parameters, and in vitro degradation performance of the loaded hydrogel were first evaluated in the study. Then, antimicrobial properties were tested on Porphyromonas gingivalis and its biocompatibility in 3D-engineered human gingiva. HA hydrogel was very stable and showed a sustained release for MGTN for at least 7 days. MGTN-loaded HA hydrogel showed equivalent antimicrobial activity compared to a commercial gel of HA containing 0.2 % chlorhexidine (CHX). In contrast, while MGTN HA hydrogel was biocompatible, CHX gel showed high cytotoxicity, causing cell death and tissue damage. Modified HA hydrogel allows controlled release of MGTN, resulting in a highly biocompatible hydrogel with antibacterial properties. This hydrogel is a suitable alternative therapy to prevent and treat PD.

"Photo-Thermo-Electric" Dental Implant for Anti-Infection and Enhanced Osteoimmunomodulation.

The dental implant market has experienced explosive growth, owing to the widespread acceptance of implants as the core of oral rehabilitation. Clinically, achieving simultaneous anti-infective effects and rapid osseointegration is a crucial but challenging task for implants. The demand for implants with long-term broad-spectrum antibacterial and immune-osteogenic properties is growing. Existing methods are limited by a lack of safety, efficiency, short-lasting anti-infective ability, and inadequate consideration of the immunomodulatory effects on osteogenesis. Herein, a ZnO/black TiO2-x heterojunction surface structure was designed as a near-infrared (NIR) light-responsive nanofilm immobilized on a titanium (Ti) implant surface. This nanofilm introduces abundant oxygen vacancies and heterojunctions, which enhance the photothermal and photoelectric abilities of Ti implants under NIR illumination by narrowing the band gap and improving interfacial charge transfer. The "photo-thermo-electric" implant exhibits excellent broad-spectrum antibacterial efficacy against three dental pathogenic bacteria (Porphyromonas gingivalis, Fusobacterium nucleatum, and Staphylococcus aureus, >99.4%) by destroying the bacterial membrane and increasing the production of intracellular reactive oxygen species. Additionally, the implant can effectively eliminate mature multispecies biofilms and kill bacteria inside the biofilms under NIR irradiation. Meanwhile, this implant can also induce the pro-regenerative transformation of macrophages and promote osteoblast proliferation and differentiation. Moreover, in vivo results confirmed the superior antibacterial and osteoimmunomodulatory properties of this dental implant. RNA sequencing revealed that the underlying osteogenic mechanisms involve activation of the Wnt/β-catenin signaling pathway and bone development. Overall, this versatile "photo-thermo-electric" platform endows implants with anti-infection and bone integration performance simultaneously, which holds great potential for dental implants.

ARMCX3 regulates ROS signaling, affects neural differentiation and inflammatory microenvironment in dental pulp stem cells

BackgroundThe neural differentiation of dental pulp stem cells (DPSCs) exhibits great potential in the treatment of dental pulp repair and neurodegenerative diseases. However, the precise molecular mechanisms underlying this process remain unclear. This study was designed to reveal the roles and regulatory mechanisms of the armadillo repeat-containing X-linked 3 (ARMCX3) in neural differentiation and inflammatory microenvironment in human DPSCs (hDPSCs). MethodsWe treated hDPSCs with porphyromonas gingivalis lipopolysaccharide (Pg-LPS) to simulate the inflammatory microenvironment. Then the lentiviral vectors were introduced to construct stable cell lines with ARMCX3 knockdown or overexpression. The expression of neural-specific markers, ARMCX3 and inflammation factors were estimated by immunofluorescence (IF), quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) assays. Additionally, we used IF assays and specific kits to investigate the regulatory role of ARMCX3 on reactive oxygen species (ROS) signaling. Moreover, a ROS inhibitor was utilized to verify whether ROS inhibition reversed the effects of ARMCX3 in Pg-LPS-treated hDPSCs. ResultsThis work illustrated that Pg-LPS treatment significantly enhanced ARMCX3 expression and inflammatory response, and inhibited neural differentiation in hDPSCs. ARMCX3 knockdown effectively accelerated neural differentiation and controlled inflammatory cytokines at a lower level in hDPSCs in the presence of Pg-LPS. Additionally, knockdown of ARMCX3 notably reduced ROS production and ROS inhibition effectively eliminated the roles of ARMCX3 overexpression in hDPSCs. Besides, all results were proved to be statistically significant. ConclusionThis investigation proved that ARMCX3 affected neural differentiation and inflammation microenvironment in hDPSCs at least partly by mediating ROS signal. These findings provided a new perspective on the mechanism of neural differentiation of hDPSCs and help to better explore the therapeutic schedule of pulpitis and neurodegenerative diseases.

COMPARISON OF MALACHITE GREEN AND METHYLENE BLUE DYES IN NON-SURGICAL PERIODONTAL TREATMENT IN PATIENTS LIVING WITH HIV/AIDS AND UNDERGOING IMMUNE RECONSTITUTION

The aim of this study was to evaluate the effect of photodynamic therapy (PDT) on non-surgical periodontal treatment in patients failing highly active antiretroviral therapy (HAART). comparing methylene blue (MB) (0.01%) and malachite green (MG) (0.01%) dyes as a therapeutic protocol, measuring the following periodontal clinical parameters: clinical probing depth (CPD), gingival recession (GR), clinical attachment level (CAL), full-mouth plaque index (PI), and full-mouth bleeding index (BI), using polymerase chain reaction (PCR) for identification of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Tannerella forsythia (Tf) pathogens. The study was approved by the Research Ethics Committee. Forty-four patients were evaluated, 15 (34.1%) female and 29 (65.9%) male. The mean age was 46 years. In the evaluation of GR, there was a significant difference in the non-resistant group in which MB was used. Resistant patients treated with MG or MB showed significant differences in the decrease of Pg bacteria. PDT associated with MB promoted improvements in CPD and decrease of Aa and Pg bacteria, being an effective therapeutic protocol.

Green engineering of MgO nanoparticles: Assessment of their antioxidant and antibacterial activity against dental pathogens

Green engineering antibacterial nanoparticles have been synthesized using environmentally friendly plant extracts as nucleation agents due to their sustainability, biocompatibility and cost-effectiveness compared to conventional chemical methods. In this study, magnesium oxide nanoparticles (MgO NPs) were synthesized using the marine plant Avicennia marina as a reducing agent. The green synthesized MgO NPs were characterized for their structural, optical, morphological, and thermal properties using XRD, UV–Vis, TGA-DTA, SEM, and TEM characterization techniques. Our biomedical studies revealed that MgO NPs hold significant promise, demonstrating potent antibacterial and antioxidant properties. In the DPPH assay, MgO NPs antioxidant activity effectively neutralized free radicals. Furthermore, their antimicrobial activity was tested against dental bacterial pathogens, showing strong inhibitory effects on Streptococcus mutans, Streptococcus mitis, Porphyromonas gingivalis, and Streptococcus salivarius microorganisms. These findings underscore the potential of MgO NPs for a range of applications, particularly in the fields of dentistry and antioxidant research.

A study on the impact of gargling with compound Scutellaria baicalensis Georgi on oral health and microflora changes in fixed orthodontic patients: An experimental study.

To investigate the effect of Scutellaria baicalensis Georgi gargle on oral health and changes in oral bacteria among orthodontic patients. About 110 cases of oral fixed orthodontic patients were screened from January 2020 to June 2022 at Taizhou Hospital in Zhejiang Province. They were randomly divided into the experimental group (receiving compound S. baicalensis Georgi gargle once a day) and the control group (receiving 0.9% NS gargle once a day), with 55 cases in each group. Gingival samples were collected from both groups before and 3 months after the orthodontic surgery for bacterial culture, and the differences between the 2 groups of patients in Plaque Index (PLI), gingival bleeding index (sBl), and periodontal depth (PD) before and after the operation were compared. Results: The detection levels of PLI, PD, and sBI in the experimental group were lower than those in the control group (P < .05) 3 months after orthodontic surgery (P < .05); after orthodontic correction for 3 months, there was a significant difference in coccus, bacillus, Campylobacter, Clostridium, Helicobacter, and filamentous bacteria between the experimental group and the control group (P < .05); and Porphyromonas gingivalis, Fusobacterium nucleatum, Bacteroides forsythus (B.f), and Agglomerata actinomycetes in the 2 groups were statistically significant after 3 months of orthodontic treatment (P < .05). In fixed orthodontic treatment, S. baicalensis Georgi gargle can effectively inhibit oral pathogens and maintain periodontal health.

Analysis of the microbial community diversity in various regions of the healthy oral cavity

BackgroundMicrobiomics offers new methods for conducting epidemiological surveys of oral microbiota in large populations. Compared to curette sampling, swab sampling is more convenient and less technically sensitive, making it more suitable for such surveys. To verify the feasibility of using swabs for buccal mucosa sampling in large-scale studies, we collected samples from the buccal mucosa and tooth surfaces of healthy individuals using both swabs and curettes. Microbiomics was employed to analyze and compare microbial abundance and diversity between these two methods.MethodsFour sites were assessed: the buccal mucosa on both sides and the buccal surfaces of the left and right mandibular first molars. Two sampling methods, swab and curette, were used to collect bacterial communities from healthy individuals. Specifically, buccal mucosa samples (n = 10) and tooth surface samples (n = 20) were analyzed using 16 S rDNA gene sequencing. Bacterial signals were detected through fluorescence in situ hybridization (FISH), targeting the bacterial 16 S rDNA gene. Metastats analysis and Wilcoxon test were used.ResultsA total of 383 OTUs were detected in the 30 samples, which belonged to 1 kingdom (bacteria), 11 phyla, 23 classes, 40 orders, 75 families, 143 genus, and 312 species. Among them, 223 OTUs were found on both the buccal mucosa and tooth surfaces. The statistics suggest that although there were no significant differences in colony composition, there were differences in the abundance and distribution of colonies on the dental and buccal mucosal surfaces. When detecting oral disease-causing pathogens such as Enterococcus faecalis and Porphyromonas gingivalis, the efficiency of detection is higher when using curette sampling. Compared to right tooth sampling with a curette, the swab sampling group had higher levels of Firmicutes, while Fusobacteria and Bacteroidetes were more prevalent in the curette tissues.ConclusionsIn oral health individuals, there is no difference in the bacterial composition of the oral buccal mucosa and the dental surface, differing only in abundance. Thus, the buccal mucosa can act as a substitute for the teeth in epidemiological investigations exploring the bacterial composition of the oral cavity.