Oral Microorganisms Research Articles

Comparative evaluation of surface roughness and bacterial adhesion on two bioactive cements: an in-vitro study

BackgroundDental restorative materials are recognized as artificial niches that facilitate the adherence and accumulation of oral microorganisms. To mitigate oral diseases and extend the lifespan of restorations, it is advantageous to use dental materials that exhibit low susceptibility to bacterial adhesion.ObjectiveTo evaluate and compare bacterial adhesion on two bioactive restorative materials, a glass hybrid restorative, and an alkasite with a nanohybrid resin composite as a positive control. The secondary objectives were to compare the surface roughness (SR) of the materials and determine the correlation between the bacterial adhesion and the SR.Materials and methodsThe samples consisted of 33 polished discs of each material: Group A: Tetric® N-Ceram (nanohybrid resin composite), Group B: Equia Forte™ HT Fil (glass hybrid restorative) and Group C: Cention N® (alkasite). Streptococcus mutans cultures were inoculated and after 24-hours of incubation, bacterial adhesion was measured by measuring optical density (OD) and number of colony forming units (CFUs). After 96-hours incubation, the bacterial cell count was determined using scanning electron microscopy (SEM). SR was assessed using surface profilometer.ResultsAlkasite had significantly lower OD and CFUs (p < 0.001 and p = 0.015 respectively). According to the SEM analysis, the glass hybrid restorative had lower mean bacterial cell count with no significant difference between the groups. The nanohybrid composite had the smoothest surface that was significantly lower than the alkasite and glass hybrid restorative (p = 0.002). None of the groups demonstrated a correlation between bacterial adhesion and SR.ConclusionAlkasite impedes bacterial adhesion better than the glass hybrid restorative and nanohybrid composite, while smoother surfaces are achieved with the nanohybrid composite.

Inhibitory effects of chlorhexidine-loaded calcium carbonate nanoparticles against dental implant infections

This study aimed to design sustained released biodegradable calcium carbonate nanoparticles loaded with chlorhexidine (CHX-loaded NPs) and to investigate the early osteogenic differentiation and antimicrobial effects on the important bacteria involved in infections of dental implants. The microemulsion method was used to prepare the calcium carbonate nanoparticles loaded with chlorhexidine. The prepared nanoparticles were characterized using conventional methods. The release pattern determination and the biodegradation test were performed for the prepared nanoparticles. For the early osteogenic differentiation test of the prepared nanoparticles, alkaline phosphatase (ALP) activity was detected in human dental pulp stem cells (HDPSCs). The antimicrobial effects of the nanoparticles were evaluated against Escherichia coli, Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus, and Pseudomonas aeruginosa. The sizes of free calcium carbonate nanoparticles and CHX-loaded NPs were 105 ± 1.63 and 118 ± 1.47 nm and their zeta potentials were − 27 and − 36, respectively. A 50% degradation of nanoparticles was achieved after 100 days. These nanoparticles showed a two-stage sustained release pattern in vitro. Microscopic images revealed that the morphology of free calcium carbonate nanoparticles primarily took on a spherical calcite form, while CHX-loaded NPs predominantly exhibited a cauliflower-like vaterite polymorph. The nanoparticles increased the activity of ALP in cells in two weeks significantly (p < 0.05). Antimicrobial and antibiofilm results showed an efficient effect of the prepared nanoparticle against the studied bacteria. Calcium carbonate nanoparticles are an efficient multifunctional vector for chlorhexidine and can be used as a bioactive antibacterial agent against various oral microorganisms to prevent implant infections.

A Natural Approach to the Prevention and Treatment of Gingivitis and Periodontitis: A Review of Pomegranate’s Bioactive Properties

(1) Background: This systematic review explores the bioactive properties of Punica granatum (pomegranate) and its potential applications in the prevention and treatment of gingivitis, periodontitis, and other oral diseases. (2) Methods: A comprehensive literature search was conducted using PubMed and Google Scholar, focusing on pomegranate and oral diseases. Inclusion criteria included studies evaluating the effects of pomegranate on oral health, while exclusion criteria eliminated non-peer-reviewed and non-English articles. This review aims to assess the efficacy of pomegranate extracts as a natural alternative to synthetic pharmaceuticals in oral health care. A structured search strategy included key terms such as “pomegranate”, “oral health”, “gingivitis”, and “periodontitis”. A total of 125 relevant references were reviewed to identify the most pertinent findings. (3) Results: The results indicate that pomegranate extracts have demonstrated efficacy in reducing plaque, inhibiting harmful oral microorganisms, and promoting overall oral health. Furthermore, clinical studies highlight the potential of pomegranate-based products, such as mouthwashes and gels, as viable alternatives to conventional pharmaceuticals, particularly in resource-limited settings. However, the review also notes the need for further research, particularly in the form of clinical trials, to establish optimal formulations and long-term safety. (4) Conclusions: Pomegranate presents a promising, natural solution for preventing and treating gingivitis and periodontitis. Further studies should focus on long-term effects and clinical efficacy.

Oral Microbiota in Patients with Alzheimer’s Disease: A Systematic Review

Oral microorganisms have been found in the cerebral milieu, suggesting the involvement of oral microbiota in the onset and course of Alzheimer’s Disease (AD) through mechanisms such as amyloid-beta accumulation, tau phosphorylation and neuroinflammation. It is still uncertain whether and which oral bacteria are associated with AD. Therefore, the aim of this systematic review was to assess the current evidence for associations between oral microbiota and AD. A database search in Pubmed and Embase resulted in 623 hits. After removing duplicates, 437 papers remained. Of these, 13 papers passed the inclusion criteria and were included for quality/risk of bias assessment and data extraction. Analysis of these 13 studies revealed high heterogeneity in terms of sample size, age, study design and microbiological methods. Quality assessment using the MINORS criteria indicated reasonable to good quality across studies. As a result of the omission of two of the criteria, the quality results may have been biased. There is no conclusive evidence as to if and which oral microbiota are associated with AD since many conflicting results were reported. Although the overall quality of the studies was acceptable, the studies differed in study design and protocol. Further research is needed to clarify this association.

Sono-Catalytic Tooth Whitening and Oral Health Enhancement with Oxygen Vacancies-Enriched Mesoporous TiO2 Nanospheres: A Nondestructive Approach for Daily Tooth Care.

Tooth discoloration and the breeding of oral microorganisms pose threats to both one's aesthetic appearance and oral health. Clinical whitening agents based on H2O2 with high concentrations are effective in tooth whitening and bacterial elimination but may also cause enamel demineralization, gingival irritation, or cytotoxicity, necessitating professional supervision. Herein, leveraging sono-catalysis effects, a nondestructive and convenient tooth whitening strategy was developed, utilizing oxygen vacancies (OVs)-enriched mesoporous TiO2 nanospheres. The introduction of OVs leads to TiO2 bandgap narrowing, boosting the generation of reactive oxygen species (ROS) by TiO2 under ultrasound treatment. Additionally, through the chemocatalysis effect, the ROS yield can be further augmented by employing OVs-enriched TiO2 in conjunction with an extremely low concentration of H2O2 (1%) during ultrasound treatment. Hence, under ultrasound treatment simulating daily tooth brushing using an electronic toothbrush, the combination of OVs-enriched TiO2 and 1% H2O2 proves to be effective in whitening teeth stained by tea, coffee, and mix juice. Furthermore, the combination of OVs-enriched TiO2 and 1% H2O2 demonstrates potent bacterial-killing and biofilm-eradicating effects under ultrasound treatment within an extremely short duration (5 min). Additionally, given the mesoporous structure, curcumin, serving as an anti-inflammatory agent, can be efficiently loaded into OVs-enriched TiO2 and then controllably released through ultrasound treatment. The curcumin-loaded TiO2 facilitates the transition of macrophages to the anti-inflammatory M2 phenotype, potentially alleviating oral inflammation induced by bacterial infection without showing any biotoxicity. The OVs-enriched TiO2 based sono-catalysis tooth whitening procedure provides the convenience of whitening teeth during daily brushing without requiring professional supervision.

Role of Salivary Protease Enzymatic Activity in Saliva of Children with and without Early Childhood Caries: A Randomized Clinical Trial.

Early childhood caries (ECC) is one of the most prevalent diseases in children worldwide. Early childhood caries is driven by a dysbiotic state of oral microorganisms, mainly caused by a sugar-rich diet. Additionally, poor oral hygiene or insufficient dental plaque removal leads to the rapid progression of ECC. Early childhood caries leads not only to dental destruction and pain in children but also affects the quality of life of the caregivers.Additionally, upon neutrophil activation at inflammatory locations, these proteases are externalized in an active state, aiding in the control of inflammatory and immunological responses. Any enzyme that catalyzes proteolysis reactions is known as a protease. Proteases are produced by human glands or derived from microbes in the oral cavity. Additionally, the oropharyngeal mucosae and crevicular fluids are sources of protease. This study is aimed at the estimation and correlation of salivary protease enzymatic activity in the saliva of children with and without ECC. A total of 50 children were included in the study, which was divided into two groups: group I (caries-active) and group II (caries-free)-each consisting of 25 children. Unstimulated saliva samples were collected and subjected to a spectrophotometer for analysis. Salivary protease levels were estimated and correlated between caries-active and caries-free children. The correlation between caries score and salivary protease activity was statistically significant with a moderate correlation. The comparison of mean salivary protease activity between caries-active and caries-free groups was statistically significant. However, the comparison of salivary protease activity based on different age-groups was not statistically significant, whereas gender and caries scores in group A were statistically significant. In conclusion, there is a substantial correlation between salivary protease enzyme levels and the severity of dental caries, and an increase in salivary protease enzyme levels is linked to a considerable rise in caries severity. As a result, prevention may be possible with early detection. Thimmegowda U, Kuri PN, Dhamnekar P. Role of Salivary Protease Enzymatic Activity in Saliva of Children with and without Early Childhood Caries: A Randomized Clinical Trial. Int J Clin Pediatr Dent 2024;17(8):877-880.

Impact of microorganism virulence on endophthalmitis outcomes

AimsTo determine the impact of microorganism virulence on visual outcomes in endophthalmitis.MethodsRetrospective, multicentre cohort study of patients presenting with endophthalmitis between 2006 and 2021. A literature review was conducted to...

Biofilm mediated antibiotic resistant oral bacteria among Parkinson's patients

Aim: The aim of this study was to examine the oral microbe biofilm and antibiotic resistance in individuals with Parkinson's disease compared to those without the condition. Methodology: In this study, the oral bacteria of older patients with Parkinson's disease and those without the condition were examined for antibiotic resistance and biofilm formation. In this study, the microbiologists examined oral samples collected from 33 individual, out of which 18 sufferred from Parkinson's disease while the remaining 15 individuals were normal. This case involved the use of the Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) technology to identify six different species. Results: The analysis of oral samples showed the presence of six isolates viz. Staphylococcus epidermis, S. auricularis, S. simiae, Panebacillus thiaminolyticus, P. aeruginosa and Bacillus cereus. Out of these, P. thiaminolyticus was absent in the control group. The incidence of oral microorganisms was somewhat higher in Parkinson's disease patients than control individuals, however, there was no discernible variation in the oral bacterial strains found in the two research groups. The isolates underwent further analysis following Congo Red Agar and Tissue Culture Plate methods and showed positive result for biofilm formation. Each isolate found in the Parkinson's disease groups were found resistant to at least five antibiotics used. Interpretation: The ability to produce biofilm was present in approximately 83.3% of the isolates from the Parkinson's disease group and 80% of those from the control group. This study provides a deeper understanding of the relationship between biofilm-producing, antibiotic-resistant oral bacteria and Parkinson's disease, and also address the need for effective management of oral hygiene in Parkinson’s patients. Key words: Antibiotic resistance, Biofilm, Oral microbiota, Oral health, Parkinson’s disease

Evaluation of symbiotic relationships of oral microorganisms and their effect on the development of inflammatory changes of the oral mucosa in the complete absence of teeth

Introduction. By fixing on the exposed surfaces of complete removable dentures and oral soft tissues, bacteria form a biofilm, thereby increasing their overall virulence and resistance. The microorganisms that make up the biofilm are often in a symbiotic relationship, which allows them to increase their pathogenic potential and cause the development of denture stomatitis. Accordingly, when a particular strain is present in the oral cavity, the risks of symbiosis are significantly increased. The aim of the study was to evaluate the effect of symbiotic relationships of oral bacteria on the development of inflammatory changes in the oral cavity in the absence of teeth. Materials and methods. Two groups of patients belonging to the elderly age according to WHO systematization (60–74 years) with complete absence of teeth (K08.1) were formed, differing in the presence of clinical manifestations of inflammation (82 men and 49 women). Biological material sampled from the oral cavity of patients was studied using the culture method and RT-PCR. To quantify the interaction between members of the microbiocenosis, we used the Jaccard similarity coefficient. Results. Coagulase-negative and coagulase-positive staphylococci, Neisseria, Candida spp., Enterobacterales and F. nucleatum were more frequently found in patients with complete absence of teeth. Expressed symbiotic relations between microorganisms of the Enterobacterales order, Lactobacillus, Neisseria and Corynebacterium genera, as well as S. salivarius, C. albicans, F. nucleatum were established. The nature of these relations depended on the presence of inflammatory changes in the oral mucosa and, in turn, influenced the development of the latter. Thus, in the absence of inflammation, Corynebacterium, Lactobacillus and S. salivarius showed stable synergism. In case of inflammation, the association between these bacteria was accompanied by the introduction of F. nucleatum and displacement of S. salivarius. Conclusion. Thus, conditionally pathogenic microorganisms, forming microbial associations with multidirectional symbiotic relations increase their virulence, which allows them to occupy free niches in the oral cavity and subsequently trigger the development of pathological process of inflammatory character of prosthetic bed tissues.

The comparative evaluation of cell viability, inflammatory response, and antimicrobial activity of calcium hydroxide-bovine dentin grain

Abstract Objectives Dentin tissue can act as a reservoir for bioactive molecules that create signals for cellular proliferation and differentiation to initiate tissue regeneration. Therefore, the aim of this study is to compare the cell viability, inflammatory response, and antimicrobial activity of bovine dentin grain-added calcium-hydroxide (CH-BDG) with different pulp-capping materials. Methods ProRoot MTA, Biodentine, Dycal, TheraCal-LC, and an experimental material, CH-BDG, were examined. Cell viability was determined via the WST-1 assay. The inflammatory response was analysed by the monocyte chemoattractant protein-1 (MCP-1/CCL2) and macrophage inflammatory protein-1α (MIP-1α/CCL3) levels. The antimicrobial activity was evaluated by agar-diffusion. Results The cell viability of CH-BDG was analogous with Biodentine and control at 24 h. The cell viability of CH-BDG decreased at 48 h, but the rate was higher than ProRoot MTA and Dycal (p&lt;0.05). For MCP-1 and MIP-1α values, there was no significant difference between the control and CH-BDG. The MCP-1 level of CH-BDG was lower compared to other pulp-capping materials (p&lt;0.05). The MIP-1α level of CH-BDG was lower compared to ProRoot MTA, Biodentine, and TheraCal-LC (p&lt;0.05). No inhibition zone was detected against oral microorganisms for CH-BDG. Conclusions The experimentally developed CH-BDG showed competing properties and additional advantages compared to the existing pulp-capping materials.

Enhanced Antimicrobial Properties of Polymeric Denture Materials Modified with Zein-Coated Inorganic Nanoparticles.

Polymeric denture materials can be susceptible to colonization by oral microorganisms. Zein-coated magnesium oxide nanoparticles (zMgO NPs) demonstrate antimicrobial activity. The aim of this study was to investigate the antimicrobial effect and adherence of different oral microorganisms on hybrid polymeric denture materials incorporated with zMgO NPs. Five types of polymeric denture materials were used. A total of 480 disc-shaped specimens were divided by material type (n=96/grp), then subdivided by zMgO NPs concentration: control with no nanoparticles and other groups with zMgO NPs concentrations of 0.3%, 0.5% and 1% by weight. Characterization of the polymeric denture materials incorporating zMgO NPs was done, and the antimicrobial activity of all groups was tested against four types of microorganisms: 1) Streptococcus mutans, 2) Staphylococcus aureus, 3) Enterococcus faecalis and 4) Candida albicans. The samples underwent an adherence test and an agar diffusion test. Experiments were done in triplicates. The characterization of the hybrid samples revealed variation in the molecular composition, as well as a uniform distribution of the zMgO NPs in the polymeric denture materials. All hybrid polymeric denture materials groups induced a statistically significant antimicrobial activity, while the control groups showed the least antimicrobial activity. The agar diffusion test revealed no release of the zMgO NPs from the hybrid samples, indicating the NPs did not seep out of the matrix. The zMgO NPs were effective in reducing the adherence of the tested microorganisms and enhancing the antimicrobial activity of the polymeric denture materials. This antimicrobial effect with the polymeric dentures could aid in resisting microbial issues such as denture stomatitis.

The Effect of Oral Mucosal Disinfection with Povidone-Iodine in Oral and Maxillofacial Surgery.

This study enrolled 60 patients aged 28 to 76 years who were oral malignancy undergoing radical surgery for more than 3 hours to assess the disinfection effect of povidone-iodine in oral and maxillofacial surgery which is a clean-contaminated wound. The authors collected and compared the sample from oral mucosa and counted the colony-forming units before disinfection, after disinfection for 10 minutes, 1, 2, 3, and 4 hours. The results showed that the oral bacterial colony-forming units significantly decreased after disinfecting with povidone-iodine and the effect existed for 2 hours and the colony-forming units of 3 hours after disinfection showed statistically significant increase. In oral and maxillofacial surgery, povidone-iodine can effectively disinfect the mouth and maintain a certain period of time. Therefore, to reduce the number of oral mucosa microorganisms, it is recommended to disinfect the oral cavity again after 3 hours.

Application of Prebiotics and Probiotics to Improve Oral and Dental Health by Inhibiting Streptococcus mutans

Background: The most common method to combat microorganisms that cause tooth decay is the use of antibiotics. However, despite the benefits of antibiotics, their use has significant disadvantages, such as the increased resistance of microorganisms to these chemicals. Objectives: A promising and safer alternative is the use of probiotics and prebiotics, which can reduce or inhibit the growth of disease-causing oral microorganisms. Streptococcus salivarius is one such probiotic, while inulin and nisin are the prebiotics commonly recommended for this purpose. Methods: Several assays, including agar bilayer interference, agar well penetration, and microdilution, were used to assess the antibacterial activities of S. salivarius K12 and S. salivarius M18 probiotics, as well as those of the prebiotics nisin and inulin. Additionally, bile salt and low pH tolerance assessments were conducted for the probiotics, and the synthesis of bacteriocins by the probiotics was verified using proteolytic and enzymatic activity assays. Results: The minimum inhibitory concentration (MIC) assay revealed that Streptococcus mutans growth was inhibited by S. salivarius K12 and S. salivarius M18 at a concentration of 75%, and by nisin and inulin at 200 IU/mL. In the well penetration assay, S. salivarius K12 exhibited significantly better results compared to S. salivarius M18. Nisin had significantly greater inhibitory effects on S. mutans compared to inulin. A combination of all four components (S. salivarius K12, S. salivarius M18, nisin, and inulin) resulted in maximum antibacterial activity, indicating a synergistic effect. Based on the agar bilayer assay and the growth inhibition zone diameters, nisin showed the highest antibacterial activity against S. mutans, followed by S. salivarius K12, inulin, and S. salivarius M18. Enzymatic digestion and proteolytic activity assays confirmed the synthesis of bacteriocins by S. salivarius K12 and S. salivarius M18. Both probiotics demonstrated bile salt tolerance at a concentration of 0.3% and surviving rates of 36% and 33%, respectively, at pH 2. Conclusions: The most important finding of the current study is the synergistic effect between the highlighted prebiotics and probiotics, which may offer a novel and effective combination for preventing tooth decay.

Antimicrobial Potential of Strontium-Functionalized Titanium Against Bacteria Associated With Peri-Implantitis.

To explore the antimicrobial potential of strontium (Sr)-functionalized wafers against multiple bacteria associated with per-implant infections, in both mono- and multispecies biofilms. The bactericidal and bacteriostatic effect of silicon wafers functionalized with a strontium titanium oxygen coating (Sr-Ti-O) or covered only with Ti (controls) against several bacteria, either grown as a mono-species or multispecies biofilms, was assessed using a bacterial viability assay and a plate counting method. Mono-species biofilms were assessed after 2 and 24 h, while the antimicrobial effect on multispecies biofilms was assessed at Days 1, 3, and 6. The impact of Sr functionalization on the total percentage ofPorphyromonas gingivalis in the multispecies biofilm, using qPCR, and gingipain activity was also assessed. Sr-functionalized wafers, compared to controls, were associated with statistically significant less viable cells in both mono- and multispecies tests. The number of colony forming units (CFUs) within the biofilm was significantly less in Sr-functionalized wafers, compared to control wafers, for Staphylococcus aureus at all time points of evaluation and forEscherichia coli at Day 1. Gingipain activity was less in Sr-functionalized wafers, compared to control wafers, and the qPCR showed that P. gingivalis remained below detection levels at Sr-functionalized wafers, while it consisted of 15% of the total biofilm on control wafers at Day 6. Sr functionalization displayed promising antimicrobial potential, possessing bactericidal and bacteriostatic ability against bacteria associated with peri-implantitis grown either as mono-species or mixed in a multispecies consortium with several common oral microorganisms.

Oral microbiome and its relationship with oral cancer.

As the initial point for digestion, the balance of oral microorganisms plays an important role in maintaining local and systemic health. Oral dysbiosis, or an imbalance in the oral microbial community, may lead to the onset of various diseases. The presence or abnormal increase of microbes in the oral cavity has attracted significant attention due to its complicated relationship with oral cancer. Oral cancer can remodel microbial profiles by creating a more beneficial microenvironment for its progression. On the other hand, altered microbial profiles can promote tumorigenesis by evoking a complex inflammatory response and affecting host immunity. This review analyzes the oncogenic potential of oral microbiome alterations as a driver and biomarker. Additionally, a potentially therapeutic strategy via the reversal of the oral microbiome dysbiosis in oral cancers has been discussed.

Alterations in the Salivary Microbiome and Metabolism in Patients With Carotid Atherosclerosis from Rural Northeast China.

Periodontitis and atherosclerosis are both chronic inflammatory diseases with a high prevalence. Increasing evidence supports the independent association between severe periodontitis and atherosclerotic cardiovascular disease, in which oral microorganisms may play an important role. We aimed to evaluate the characteristic changes of salivary microbiome and metabolome in patients with carotid atherosclerosis (CAS) and periodontitis. The subjects were obtained from a cross-sectional study that included 1933 participants aged 40 years or older from rural northeast China. The study enrolled 48 subjects with CAS and 48 controls without CAS matched by sex, age, body mass index, and prevalence of hypertension, diabetes, and dyslipidemia. We performed full-length 16S rDNA gene sequencing and untargeted metabolomics of saliva samples from 96 subjects. We found that CAS was closely associated with an increased abundance of Streptococcus, Lactobacillus, and Cutibacterium. Furthermore, patients with CAS had higher prevalence of severe periodontitis than the control group. Notably, periodontal pathogens such as Tannerella and Anaeroglobus were not only associated with periodontitis but also enriched in patients with CAS, whereas periodontal health-associated Neisseria was more abundant in those without CAS. We also identified 2 lipid metabolism pathways, including glycerophospholipid and sphingolipid metabolism, as associated with CAS. The levels of trimethylamine N-oxide and inflammatory mediator leukotriene D4 were significantly higher in patients with CAS, whereas the levels of carnosine were significantly lower, than those in controls. Additionally, serum levels of inflammatory marker high-sensitivity C-reactive protein were significantly increased in CAS and positively correlated with the abundance of Anaeroglobus and leukotriene D4 in saliva. Our study suggests that characteristic changes in salivary microbiota and metabolites are closely related to CAS, and periodontitis and associated microorganisms may be involved in the initiation and progression of CAS.

The oral-gut microbiome axis in health and disease.

The human body hosts trillions of microorganisms throughout many diverse habitats with different physico-chemical characteristics. Among them, the oral cavity and the gut harbour some of the most dense and diverse microbial communities. Although these two sites are physiologically distinct, they are directly connected and can influence each other in several ways. For example, oral microorganisms can reach and colonize the gastrointestinal tract, particularly in the context of gut dysbiosis. However, the mechanisms of colonization and the role that the oral microbiome plays in causing or exacerbating diseases in other organs have not yet been fully elucidated. Here, we describe recent advances in our understanding of how the oral and intestinal microbiota interplay in relation to their impact on human health and disease.

Influence of periodontal microbial homeostasis on neurodegenerative diseases and its therapeutic perspectives

The oral cavity is the second largest reservoir of microorganisms in the human body, containing more than 700 species. Periodontal microorganisms are an important part of oral microorganisms. Plaque biofilm, the initiator of periodontal disease, contains an abundance of oral microorganisms. The special complex anatomy of the periodontium allows for a higher abundance of the periodontal microbiota. There are growing evidences show that the periodontal microbiota is not only closely associated with oral diseases, but also plays an important role in mouth-brain interactions. Dysbiosis of the periodontal microbiota may facilitate the progression of neurodegenerative diseases including Alzheimer disease, Parkinson disease, and multiple sclerosis. Here, this paper reviews the bidirectional role of periodontal microbiota between the oral cavity and the brain, that is, the bridge effect of periodontal microbiota involved in the interaction between the two diseases, enumerates the epidemiological and biological evidences that dysregulation of the periodontal microbiota induces and exacerbates neurodegenerative diseases, and analyzes their possible mechanisms. The positive implications of periodontal microbial homeostasis in the prevention and treatment of neurodegenerative diseases are described with the aim of providing new ideas and insights into the pathogenesis and therapeutic approaches for neurodegenerative diseases.

A pilot study on oral microbiome in electronic cigarettes consumers versus traditional cigarettes smokers.

Oral microorganisms are closely related to oral health, the occurrence of some oral diseases is associated with changes in the oral microbiota, and many studies have demonstrated that traditional smoking can affect the oral microbial community. However, due to the short time since the emergence of e-cigarettes, fewer studies are comparing oral microorganisms for users of e-cigarettes versus cigarettes. We collected saliva from 40 non-smokers (NS), 46 traditional cigarette smokers (TS), and 27 e-cigarette consumers (EC), aged between 18 and 35 years. We performed 16S rRNA gene sequencing on the saliva samples collected to study the effects of e-cigarettes versus traditional cigarettes on the oral microbiome. The results showed that compared with the NS group, the alpha diversity of oral flora in saliva was altered in the TS group, with no significant change in the e-cigarette group. Compared with the NS and EC groups, the relative abundance of Actinomyces and Prevotella was increased in the TS group. However, compared with the NS and TS groups, the relative abundance of Veillonella was increased, and the relative abundance of Porphyromonas and Peptostreptococcus was decreased in the EC group. These results showed that both e-cigarettes and traditional cigarettes could alter the structure and composition of oral microbiota. The use of traditional cigarettes promotes the growth of some anaerobic bacteria, which may contribute to dental decay and bad breath over time. E-cigarettes have a different effect on the structure and composition of the oral microbial community compared to conventional cigarettes. In order to better understand the effects of e-cigarettes and traditional cigarettes on users' mouths, future studies will investigate the relationship between diseases such as dental caries and periodontitis and changes in oral microbial species levels.

Persistent luminescence encoding for rapid and accurate oral-derived bacteria identification

The dysbiosis of oral microbiota contributes to diseases such as periodontitis and certain cancers by triggering the host inflammatory response. Developing methods for the immediate and sensitive identification of oral microorganism is crucial for the rapid diagnosis and early interventions of associated diseases. Traditional methods for microbial detection primarily include the plate culturing, polymerase chain reaction and enzyme-linked immunosorbent assay, which are either time-consuming or laborious. Herein, we reported a persistent luminescence-encoded multiple-channel optical sensing array and achieved the rapid and accurate identification of oral-derived microorganisms. Our results demonstrate that electrostatic attractions and hydrophobic-hydrophobic interactions dominate the binding of the persistent luminescent nanoprobes to oral microorganisms and the microbial identification process can be finished within 30 min. Specifically, a total of 7 oral-derived microorganisms demonstrate their own response patterns and were differentiated by linear discriminant analysis (LDA) with the accuracy up to 100% both in the solution and artificial saliva samples. Moreover, the persistent luminescence encoded array sensor could also discern the microorganism mixtures with the accuracy up to 100%. The proposed persistent luminescence encoding sensor arrays in this work might offer new ideas for rapid and accurate oral-derived microorganism detection, and provide new ways for disease diagnosis associated with microbial metabolism.