Probiotics for periodontal health-Current molecular findings

Dysbiosis and interactions of the mycobiome and bacteriome in mucosal lesions of erosive and non-erosive oral lichen planus patients

Background

Oral lichen planus (OLP) is a common oral mucosal disease, clinically categorized into erosive OLP (EOLP) and non-erosive OLP (NEOLP) based on symptoms, but its pathogenic mechanism remains unclear. This study aims to explore the relationship between OLP and the oral microbiome.

Methods

We collected oral mucosal samples from 49 patients and 10 healthy individuals and conducted 16S rRNA and ITS gene sequencing to explore the oral fungal and bacterial communities.

Results

We observed significantly lower α diversity of fungi in the EOLP group, with Candida being significantly enriched as the main dominant genus. In the NEOLP group, Aspergillaceae were significantly enriched. The EOLP group showed significant enrichment of Aggregatibacter and Lactobacillus, but the relative abundance of Streptococcus was notably lower than in the other two groups. In the NEOLP group, two species including Prevotella intermedia were significantly enriched. The microbial co-occurrence and co-exclusion networks display distinct characteristics across the three groups, with Lactobacillus assuming a significant bridging role in the ELOP group.

Conclusions

Our study indicates that EOLP and NEOLP experience varying degrees of dysbiosis at both the fungal and bacterial levels. Therefore, the pathogenic mechanisms and interactive relationships of these microbiota associated with OLP merit further in-depth investigation.

Effects of sodium lauryl sulfate and postbiotic toothpaste on oral microecology

The diversity and delicate balance of the oral microbiome contribute to oral health, with its disruption leading to oral and systemic diseases. Toothpaste includes elements like traditional additives such as sodium lauryl sulfate (SLS) as well as novel postbiotics derived from probiotics, which are commonly employed for maintaining oral hygiene and a healthy oral cavity. However, the response of the oral microbiota to these treatments remains poorly understood. In this study, we systematically investigated the impact of SLS, and toothpaste containing postbiotics (hereafter, postbiotic toothpaste) across three systems: biofilms, animal models, and clinical populations. SLS was found to kill bacteria in both preformed biofilms (mature biofilms) and developing biofilms (immature biofilms), and disturbed the microbial community structure by increasing the number of pathogenic bacteria. SLS also destroyed periodontal tissue, promoted alveolar bone resorption, and enhanced the extent of inflammatory response level. The postbiotic toothpaste favored bacterial homeostasis and the normal development of the two types of biofilms in vitro, and attenuated periodontitis and gingivitis in vivo via modulation of oral microecology. Importantly, the postbiotic toothpaste mitigated the adverse effects of SLS when used in combination, both in vitro and in vivo. Overall, the findings of this study describe the impact of toothpaste components on oral microflora and stress the necessity for obtaining a comprehensive understanding of oral microbial ecology by considering multiple aspects.

Microbial diagnostics in periodontal diseases

Microbial analytical methods have been instrumental in elucidating the complex microbial etiology of periodontal diseases, by shaping our understanding of subgingival community dynamics. Certain pathobionts can orchestrate the establishment of dysbiotic communities that can subvert the host immune system, triggering inflammation and tissue destruction. Yet, diagnosis and management of periodontal conditions still rely on clinical and radiographic examinations, overlooking the well-established microbial etiology. This review summarizes the chronological emergence of periodontal etiological models and the co-evolution with technological advances in microbial detection. We additionally review the microbial analytical approaches currently accessible to clinicians, highlighting their value in broadening the periodontal assessment. The epidemiological importance of obtaining culture-based antimicrobial susceptibility profiles of periodontal taxa for antibiotic resistance surveillance is also underscored, together with clinically relevant analytical approaches to guide antibiotherapy choices, when necessary. Furthermore, the importance of 16S-based community and shotgun metagenomic profiling is discussed in outlining dysbiotic microbial signatures. Because dysbiosis precedes periodontal damage, biomarker identification offers early diagnostic possibilities to forestall disease relapses during maintenance. Altogether, this review highlights the underutilized potential of clinical microbiology in periodontology, spotlighting the clinical areas most conductive to its diagnostic implementation for enhancing prevention, treatment predictability, and addressing global antibiotic resistance.

Limosilactobacillus reuteri supernatant attenuates inflammatory responses of human gingival fibroblasts to LPS but not to elevated glucose levels

AIM

We investigated the in vitro effect of Limosilactobacillus reuteri DSM 17938 supernatant on the inflammatory response of human gingival fibroblasts (HGF) challenged by lipopolysaccharide (LPS) or elevated glucose levels.

METHODS

HGF were exposed to LPS (1 μg/mL), glucose (5, 12 mM or 25 mM), and dilutions of supernatant prepared from L. reuteri DSM 17938 (0.5 × 107, 1.0 × 107, 2.5 × 107, and 5.0 × 107 CFU/mL). After 24 h cell viability and levels of cytokines (IL-1β, IL-6 and IL-8) and TLR-2 were determined.

RESULTS

None of the tested L. reuteri (DSM 17938) supernatant concentrations reduced the viability of HGF. Supernatant concentrations (2.5 × 107 and 5 × 107 CFU/mL) significantly (p < .05) decreased the production of IL-1β, IL-6, IL-8, and TLR-2 in the presence of LPS. In contrast, inflammatory markers were not reduced by L. reuteri supernatant in the presence of glucose. Glucose concentrations of 12 mM and 24 mM still lead to an elevated production of the investigated biochemical mediators.

CONCLUSION

While L. reuteri (DSM 17938) supernatant attenuates the inflammatory response of HGF to LPS in a dose-dependent manner, elevated glucose levels suppress this action. These in vitro results support the overall anti-inflammatory efficacy of L. reuteri supplementation in plaque-associated periodontal inflammations.

Oral Biofilm Composition, Dissemination to Keratinocytes, and Inflammatory Attenuation Depend on Probiotic and Synbiotic Strain Specificity

Several inflammatory diseases are characterized by a disruption in the equilibrium between the host and its microbiome. Due to the increase in resistance, the use of antibiotics for the widespread, nonspecific killing of microorganisms is at risk. Pro-microbial approaches focused on stimulating or introducing beneficial species antagonistic toward pathobionts may be a viable alternative for restoring the host-microbiome equilibrium. Unfortunately, not all potential probiotic or synbiotic species and even subspecies (to strain level) are equally effective for the designated pathology, leading to conflicting accounts of their efficacy. To assess the extent of these species- and strain-specific effects, 13 probiotic candidates were evaluated for their probiotic and synbiotic potential with glycerol on in vitro oral biofilms, dissemination from biofilms to keratinocytes, and anti-inflammatory activity. Species- and strain-specific effects and efficacies were observed in how they functioned as probiotics or synbiotics by influencing oral pathobionts and commensals within biofilms and affected the dissemination of pathobionts to keratinocytes, ranging from ineffective strains to strains that reduced pathobionts by 3 + log. In addition, a minority of the candidates exhibited the ability to mitigate the inflammatory response of LPS-stimulated monocytes. For a comprehensive assessment of probiotic therapy for oral health, a judicious selection of fully characterized probiotic strains that are specifically tailored to the designated pathology is required. This approach aims to challenge the prevailing perception of probiotics, shifting the focus away from "form over function." Rather than using unproven, hypothetical probiotic strains from known genera or species, one should choose strains that are actually functional in resolving the desired pathology before labelling them probiotics.

Preventive and Therapeutic Potential of Streptococcus cristatus CA119 in Experimental Periodontitis in Rats

Periodontitis is an inflammatory condition of the oral cavity caused by a mixed infection of various bacteria, which not only severely affects the alveolar bone and connective tissues but also displays potential correlations with distal intestinal inflammation. In this study, we aimed to elucidate the therapeutic effects of Streptococcus cristatus CA119 on experimental periodontitis in rats and its impact on intestinal morphology. The results demonstrate that CA119 is capable of colonizing the oral cavity and exerting antagonistic effects on Porphyromonas gingivalis and Fusobacterium nucleatum, thus leading to a significant reduction in the oral pathogen load. Following CA119 intervention, there was a significant alleviation of weight loss in rats induced by periodontitis (P < 0.001). CA119 also regulated the expression of IL-6 (P < 0.05), IL-1β (P < 0.001), IL-18 (P < 0.001), COX-2 (P < 0.001), iNOS (P < 0.001), and MCP-1 (P < 0.01) in the gingival tissue. Additionally, CA119 reduced oxidative stress levels in rats and enhanced their antioxidant capacity. Microcomputed tomography (micro-CT) and histological analysis revealed that CA119 significantly reduced alveolar bone loss and reversed the downregulation of OPG/RANKL (P < 0.001). Furthermore, CA119 exhibited a significant protective effect against intestinal inflammation induced by periodontal disease and improved the colonic morphology in rats. In conclusion, this study demonstrates the role of CA119 as a potential oral probiotic in the prevention and treatment of experimental periodontitis, underscoring the potential of probiotics as a complementary approach to traditional periodontal care.

Alterations and correlations in dental plaque microbial communities and metabolome characteristics in patients with caries, periodontitis, and comorbid diseases

BACKGROUNDS

The pathogenic microorganisms and clinical manifestations of caries and periodontitis are different, caries and periodontitis are usually discussed separately, and the relationship between them is ignored. Clinically, patients prone to dental caries generally have a healthier periodontal status, whereas patients with periodontitis generally have a lower incidence of dental caries. The relationship between dental caries and periodontitis remains unclear.

OBJECTIVES

This study aimed to explain the clinical phenomenon of antagonism between dental caries and periodontitis by exploring the ecological chain and bacterial interactions in dental caries, periodontitis, and other comorbid diseases.

METHODS

The dental plaque microbiomes of 30 patients with oral diseases (10 each with caries, periodontitis, and comorbid diseases) were sequenced and analysed using 16 S rRNA gene sequencing. The Kyoto Encyclopaedia of Genes and Genomes (KEGG) database was used for a differential functional analysis of dental plaque microbial communities in caries, periodontitis, and comorbid diseases.

RESULTS

The coinfection group had the greatest bacterial richness in dental plaque. The principal coordinate analysis showed that caries and periodontitis were separate from each other, and comorbid diseases were located at the overlap of caries and periodontitis, with most of them being periodontitis. Simultaneously, we compared the microbiomes with significant differences among the three groups and the correlations between the microbiome samples. In addition, KEGG pathway analysis revealed significant differences in functional changes among the three groups.

CONCLUSIONS

This study revealed the composition of the dental plaque microbial communities in caries, periodontitis, and comorbidities and the differences among the three. Additionally, we identified a possible antagonism between periodontitis and caries. We identified a new treatment strategy for the prediction and diagnosis of caries and periodontitis.

Role of probiotics in managing various human diseases, from oral pathology to cancer and gastrointestinal diseases

The imbalance of microbial composition and diversity in favor of pathogenic microorganisms combined with a loss of beneficial gut microbiota taxa results from factors such as age, diet, antimicrobial administration for different infections, other underlying medical conditions, etc. Probiotics are known for their capacity to improve health by stimulating the indigenous gut microbiota, enhancing host immunity resistance to infection, helping digestion, and carrying out various other functions. Concurrently, the metabolites produced by these microorganisms, termed postbiotics, which include compounds like bacteriocins, lactic acid, and hydrogen peroxide, contribute to inhibiting a wide range of pathogenic bacteria. This review presents an update on using probiotics in managing and treating various human diseases, including complications that may emerge during or after a COVID-19 infection.

Periodontal disease in down syndrome: Predisposing factors and potential non-surgical therapeutic approaches

BACKGROUND

Periodontal diseases (PDs) have been documented to be significantly more prevalent and severe in patients with Down syndrome (DS). Different immunological and microbiological factors contributed to predisposing these patients to progressive and recurrent PDs.

AIM

The aim of this review was to investigate the altered immunological responses and oral microbiota disorders as well as focus on adjunctive non-surgical methods for the treatment of PDs and its applicability in patients with DS.

MATERIAL AND METHODS

A literature review was conducted addressing the following topics: (1) the altered immunological responses, (2) orofacial disorders related to DS patients, (3) oral microbiota changing, and (4) adjunctive non-surgical treatment and its efficacy in patients with DS.

RESULTS

Due to the early onset of PDs in children with DS, the need for prompt and effective treatment in these patients is essential.

DISCUSSION AND CONCLUSION

So, investigating underlying factors may open a new window to better understand the pathology of PDs in DS people and thus, find better strategies for treatment in such group. Although non-surgical treatments such as photodynamic therapy and probiotic consumption represented acceptable outcomes in different examined patients without DS, data about the application of these convenience and no need for local anesthesia methods in patients with DS is limited.

Mutanolysin-Digested Peptidoglycan of Lactobacillus reuteri Promotes the Inhibition of Porphyromonas gingivalis Lipopolysaccharide-Induced Inflammatory Responses through the Regulation of Signaling Cascades via TLR4 Suppression

Periodontitis is an oral infectious disease caused by various pathogenic bacteria, such as Porphyromonas gingivalis. Although probiotics and their cellular components have demonstrated positive effects on periodontitis, the beneficial impact of peptidoglycan (PGN) from probiotic Lactobacillus remains unclear. Therefore, our study sought to investigate the inhibitory effect of PGN isolated from L. reuteri (LrPGN) on P. gingivalis-induced inflammatory responses. Pretreatment with LrPGN significantly inhibited the production of interleukin (IL)-1β, IL-6, and CCL20 in RAW 264.7 cells induced by P. gingivalis lipopolysaccharide (LPS). LrPGN reduced the phosphorylation of PI3K/Akt and MAPKs, as well as NF-κB activation, which were induced by P. gingivalis LPS. Furthermore, LrPGN dose-dependently reduced the expression of Toll-like receptor 4 (TLR4), indicating that LrPGN inhibits periodontal inflammation by regulating cellular signaling cascades through TLR4 suppression. Notably, LrPGN exhibited stronger inhibition of P. gingivalis LPS-induced production of inflammatory mediators compared to insoluble LrPGN and proteinase K-treated LrPGN. Moreover, MDP, a minimal bioactive PGN motif, also dose-dependently inhibited P. gingivalis LPS-induced inflammatory mediators, suggesting that MDP-like molecules present in the LrPGN structure may play a crucial role in the inhibition of inflammatory responses. Collectively, these findings suggest that LrPGN can mitigate periodontal inflammation and could be a useful agent for the prevention and treatment of periodontitis.

A 10-year Scientometric Study of the Emerging Patterns and Spatial-Temporal Trends of Probiotics in Dentistry

AIM

To perform a bibliometric analysis of the scientific production related to the use of probiotics in oral health.

MATERIALS AND METHODS

A retrospective, descriptive, observational study with a scientometric approach was conducted. Metadata from scientific articles were retrieved from the Web of Science (WoS) Core Collection and analyzed using Medical Subject Headings (MeSH) and Emtree terms. The search strategy included the terms related to probiotics and oral health, and articles published between 2013 and 2022 were analyzed. Different scientometric indicators were used to analyze the production, impact, and network collaboration.

RESULTS

A total of 485 articles were retrieved from 241 sources, with an average annual growth rate of 10.72%. The manuscripts received an average citation per doc of 15.2. Authors collaborated on an average of 5.76 coauthors per paper. The number of articles published increased progressively from 2013 to 2022. The year 2022 had the highest number of articles published (90), while in 2013 only 36 articles were published. There was a progressive decrease in the average number of citations per article, from 32.44 in 2013 to 2.41 in 2022.

CONCLUSION

The production of articles on probiotics in dentistry has grown steadily, with an annual growth rate of 10.72%. The most productive countries were the United States, Italy, and China. The importance of international scientific collaborations and the need for more research in this field is emphasized.

CLINICAL SIGNIFICANCE

The findings of this study may help researchers identify areas that require further study and lead to more rapid and efficient advances in the use of probiotics to improve oral health. Its clinical importance lies in its value and ability to inform and guide future research to advance this field of science. How to cite this article: Mayta-Tovalino F, Espinoza-Carhuancho F, Alvitez-Temoche D, et al. A 10-year Scientometric Study of the Emerging Patterns and Spatial-Temporal Trends of Probiotics in Dentistry. J Contemp Dent Pract 2023;24(12):981-986.

EVIDENCE SUPPORTS SHORT-TERM CLINICAL BENEFITS OF ADJUNCTIVE ORAL PROBIOTICS FOLLOWING SCALING AND ROOT PLANING TREATMENT

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Hu D, Zhong T, Dai Q. Clinical efficacy of probiotics as an adjunctive therapy to scaling and root planning in the management of periodontitis: a systematic review and meta-analysis of randomized controlled trails. J Evid Based Dent Pract. 2021;21(2):101547. doi:10.1016/j.jebdp.2021.101547.

SOURCE OF FUNDING

Self-funded.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data.

Mechanism and application of Lactobacillus in type 2 diabetes-associated periodontitis

Type 2 diabetes mellitus (T2DM) accelerates the progression of periodontitis through diverse pathways. Abnormal immune responses, excessive activation of inflammation, increased levels of advanced glycation end products, and oxidative stress have defined roles in the pathophysiological process of T2DM-associated periodontitis. Furthermore, in the periodontium of diabetic individuals, there are high levels of advanced glycation end-products and glucose. Meanwhile, progress in microbiomics has revealed that dysbacteriosis caused by T2DM also contributes to the progression of periodontitis. Lactobacillus, owing to its fine-tuning function in the local microbiota, has sparked tremendous interest in this field. Accumulating research on Lactobacillus has detailed its beneficial role in both diabetes and oral diseases. In this study, we summarize the newly discovered mechanisms underlying Lactobacillus-mediated improvement of T2DM-associated periodontitis and propose the application of Lactobacillus in the clinic.

Effectiveness of probiotics compared to antibiotics to treat periodontal disease: Systematic review

OBJECTIVES

Probiotics are promising adjuncts to non-surgical periodontal therapy (scaling and root planing (SRP)) for managing gingival and periodontal diseases. Probiotics are considered alternatives to antibiotics, especially with the emergence of antimicrobial resistance. Hence, the present systematic review aims to generate evidence on the role of probiotics compared to antimicrobial agents for managing periodontal diseases (gingivitis and periodontitis).

METHOD

Six electronic databases (PubMed, SCOPUS, Web of Science, EBSCO, Cochrane, Clinical Trial Registry) were searched to collect studies comparing the effect of probiotics with antibiotics for periodontal disease. In total, 5530 articles were retrieved from all databases, of which 1891 were included for title and abstract screening. After screening, a total of ten clinical studies were included for data extraction and analysis. Probing pocket depth (PPD), Clinical attachment loss (CAL), bleeding on probing (BOP), plaque index (PI), gingival index (GI), and microbial profile were recorded.

RESULTS

Probiotics showed a significant reduction in the PPD and CAL compared to antibiotics. Antibiotics were more effective in reducing the PI and GI. A combination of probiotics and antibiotics superior compared to probiotics and antibiotics alone.

CONCLUSION

Probiotics can be used as an alternative to antibiotics, however, a combination is more effective for managing periodontal disease.

The impact of Helicobacter pylori eradication with vonoprazan-amoxicillin dual therapy combined with probiotics on oral microbiota: a randomized double-blind placebo-controlled trial

Background

Helicobacter pylori infection and eradication have been reported to cause dysbiosis of the oral microbiota. Probiotics are increasingly being used to maintain the balance of the oral microbiota. We aimed to investigate the effects of H. pylori infection, H. pylori eradication with vonoprazan-amoxicillin dual therapy, and probiotics supplementation on the oral microbiota.

Methods

H. pylori positive patients were randomly assigned to a vonoprazan-amoxicillin regimen plus probiotics (BtT group) or the placebo (PT group) for 14 days. H. pylori negative population served as normal controls. Tongue coating samples were collected from 60 H. pylori positive patients at three time points (before H. pylori eradication, after H. pylori eradication, and at confirmation of H. pylori infection cure) and 20 H. pylori negative subjects. 16S rRNA gene sequencing was used to analyze the oral microbiota.

Results

H. pylori was detected in the oral cavity in positive (34/60), negative (7/20), and eradicated (1/60) subjects using high-throughput sequencing. Compared with normal controls, H. pylori positive patients exhibited higher richness (p = 0.012) and comparable diversity (p = 0.075) of oral microbiota. Beta diversity and KEGG analysis showed oral flora composition and function differences in H. pylori positive and negative subjects. Alpha diversity dramatically decreased after H. pylori eradication and modestly increased with confirmation of H. pylori eradication. Beta diversity and LEfSe analysis revealed distinct structures, and KEGG analysis showed distinct signaling pathways of tongue coating flora at three time points. There was a significant reduction of Firmicutes and Lactobacillus after H. pylori erdication. The PT group and BtT group had identical compositional and functional differences of oral microbiota at three time points.

Conclusion

No substantial link existed between oral and stomach H. pylori, while removing gastric H. pylori helped eliminate oral H. pylori. H. pylori infection and vonoprazan-amoxicillin dual therapy affected oral microbiota diversity, structure, and function. H. pylori eradication demonstrated a suppressive impact on the proliferation of oral pathogens, specifically Firmicutes and Lactobacillus. Nevertheless, probiotics supplementation did not reduce the oral microbial disturbance caused by H. pylori eradication.

Clinical trial registration

https://www.chictr.org.cn/, identifiers CHICTR2200060023.

Lactobacillus fermentum attenuates the alveolar bone loss in ligature-induced periodontitis in mice

OBJECTIVE

This study investigated the effects of Lactobacillus fermentum BELF11 on periodontitis in mice (LIP).

METHODS

Sixty mice were randomly assigned to a control group (CTL), LIP/PBS group (LIP and PBS applied), or LIP/BELF11 group (LIP and L. fermentum BELF11 applied). For 14 days, PBS or L. fermentum BELF11 was applied twice daily to the mice in the LIP/PBS or LIP/BELF11 group, respectively. After 14 days, radiographic, histological, and pro-inflammatory cytokine assessments were conducted.

RESULTS

The LIP/PBS and LIP/BELF11 groups demonstrated greater alveolar bone loss than the CTL group (p < 0.05). The LIP/BELF11 group showed significantly reduced alveolar bone loss on the mesial side compared to the LIP/PBS group. Histologically, the LIP/BELF11 group showed consistent patterns of connective tissue fiber arrangement, lower levels of inflammatory infiltration, less alveolar bone loss, and higher alveolar bone density than the LIP/PBS group, despite showing more signs of destruction than the CTL group. The LIP/BELF11 group also exhibited significantly lower levels of pro-inflammatory cytokines than the LIP/PBS group.

CONCLUSIONS

L. fermentum BELF11 inhibits alveolar bone loss and periodontitis progression by regulating pro-inflammatory cytokine production. These findings suggest that L. fermentum BELF11 may be a potential adjunctive therapy in periodontal treatment.

Exploring the Role of IL-17A in Oral Dysbiosis-Associated Periodontitis and Its Correlation with Systemic Inflammatory Disease

Oral microbiota play a pivotal role in maintaining homeostasis, safeguarding the oral cavity, and preventing the onset of disease. Oral dysbiosis has the potential to trigger pro-inflammatory effects and immune dysregulation, which can have a negative impact on systemic health. It is regarded as a key etiological factor for periodontitis. The emergence and persistence of oral dysbiosis have been demonstrated to mediate inflammatory pathology locally and at distant sites. The heightened inflammation observed in oral dysbiosis is dependent upon the secretion of interleukin-17A (IL-17A) by various innate and adaptive immune cells. IL-17A has been found to play a significant role in host defense mechanisms by inducing antibacterial peptides, recruiting neutrophils, and promoting local inflammation via cytokines and chemokines. This review seeks to present the current knowledge on oral dysbiosis and its prevention, as well as the underlying role of IL-17A in periodontitis induced by oral dysbiosis and its impact on systemic inflammatory disease.

Antioxidant, anti-inflammatory and antimicrobial activity of natural products in periodontal disease: a comprehensive review

Periodontal diseases (PD) are common chronic inflammatory oral pathologies that are strongly linked to others not found in the mouth cavity. The immune system mediates the host response, which includes the upregulation of proinflammatory cytokines, metalloproteinases, and reactive oxygen species (ROS); the latter may play an important role in the establishment and progression of inflammatory diseases, particularly periodontal disease, via the development of oxidative stress (OS). Natural antioxidants have powerful anti-inflammatory properties, and some can reduce serum levels of key PD indicators such tumor necrosis factor (TNF) and interleukin IL-1. This review compiles, through a thorough literature analysis, the antioxidant, anti-inflammatory, and antibacterial effects of a variety of natural products, as well as their therapeutic potential in the treatment of PD.

Antimicrobial activity of Limosilactobacillus fermentum strains isolated from the human oral cavity against Streptococcus mutans

Oral probiotics have been recently gaining much attention owing to their potential to inhibit the progression of dental caries by controlling the cariogenic effects of Streptococcus mutans. We isolated and genotypically identified 77 lactic acid bacteria including 12 Limosilactobacillus fermentum probiotic candidates from the oral cavity of healthy volunteers. Among the 12 L. fermentum isolates, nine isolates effectively inhibited the growth of S. mutans via hydrogen peroxide (H₂O₂) production. The others neither suppressed the growth of S. mutans nor produced H₂O₂. Eight out of the nine H₂O₂-producing L. fermentum isolates exhibited strong adherence to oral epithelial KB cells while inhibiting the adherence of S. mutans to KB cells. The eight H₂O₂-producing isolates were neither haemolytic based on a blood-agar test, cytotoxic according to lactate dehydrogenase assay, nor resistant to eight antibiotics represented by the European Food Safety Authority guideline, indicating that the isolates have potential to suppress the cariogenesis driven by S. mutans while providing general probiotic benefits.

Current and prospective therapeutic strategies: tackling Candida albicans and Streptococcus mutans cross-kingdom biofilm

Candida albicans (C. albicans) is the most frequent strain associated with cross-kingdom infections in the oral cavity. Clinical evidence shows the co-existence of Streptococcus mutans (S. mutans) and C. albicans in the carious lesions especially in children with early childhood caries (ECC) and demonstrates the close interaction between them. During the interaction, both S. mutans and C. albicans have evolved a complex network of regulatory mechanisms to boost cariogenic virulence and modulate tolerance upon stress changes in the external environment. The intricate relationship and unpredictable consequences pose great therapeutic challenges in clinics, which indicate the demand for de novo emergence of potential antimicrobial therapy with multi-targets or combinatorial therapies. In this article, we present an overview of the clinical significance, and cooperative network of the cross-kingdom interaction between S. mutans and C. albicans. Furthermore, we also summarize the current strategies for targeting cross-kingdom biofilm.

Probiotics in the Treatment of Radiotherapy-Induced Oral Mucositis: Systematic Review with Meta-Analysis

The inflammatory injury of the mucous membranes lining the digestive tract, from the mouth to the anus, is called mucositis. One of the intriguing and compelling new therapeutic modalities that has emerged in recent decades due to advances in our understanding of this condition's pathophysiology is probiotics. The purpose of this meta-analysis is to evaluate the efficiency of probiotics in the treatment of chemotherapy-induced mucositis for head and neck malignancies; a literature search was performed on PubMed, Lilacs, and Web of Science, and articles published from 2000 to 31 January 2023 were considered, according to the keywords entered. The term "Probiotics" was combined with "oral mucositis" using the Boolean connector AND; at the end of the research, 189 studies were identified from the search on the three engines. Only three were used to draw up the present systematic study and metanalysis; this meta-analysis showed that the treatment of mucositis with probiotics is an effective method, and the analysis of the results of these studies showed that the use of probiotics promoted a decrease in the severity of mucositis symptoms.

Beneficial modulation of human health in the oral cavity and beyond using bacteriocin-like inhibitory substance-producing streptococcal probiotics

The human oral cavity contains a diversity of microbial habitats that have been adopted and adapted to as homeland by an amazingly heterogeneous population of microorganisms collectively referred to as the oral microbiota. These microbes generally co-habit in harmonious homeostasis. However, under conditions of imposed stress, as with changes to the host’s physiology or nutritional status, or as a response to foreign microbial or antimicrobial incursions, some components of the oral “microbiome” (viz. the in situ microbiota) may enter a dysbiotic state. This microbiome dysbiosis can manifest in a variety of guises including streptococcal sore throats, dental caries, oral thrush, halitosis and periodontal disease. Most of the strategies currently available for the management or treatment of microbial diseases of the oral cavity focus on the repetitive “broad sweep” and short-term culling of oral microbe populations, hopefully including the perceived principal pathogens. Both physical and chemical techniques are used. However, the application of more focused approaches to the harnessing or elimination of key oral cavity pathogens is now feasible through the use of probiotic strains that are naturally adapted for oral cavity colonization and also are equipped to produce anti-competitor molecules such as the bacteriocins and bacteriocin-like inhibitory substances (viz BLIS). Some of these probiotics are capable of suppressing the proliferation of a variety of recognized microbial pathogens of the human mouth, thereby assisting with the restoration of oral microbiome homeostasis. BLIS K12 and BLIS M18, the progenitors of the BLIS-producing oral probiotics, are members of the human oral cavity commensal species Streptococcus salivarius. More recently however, a number of other streptococcal and some non-streptococcal candidate oral probiotics have also been promoted. What is becoming increasingly apparent is that the future for oral probiotic applications will probably extend well beyond the attempted limitation of the direct pathological consequences of oral microbiome dysbiosis to also encompass a plethora of systemic diseases and disorders of the human host. The background to and the evolving prospects for the beneficial modulation of the oral microbiome via the application of BLIS-producing S. salivarius probiotics comprises the principal focus of the present review.

Probiotics and metabolites regulate the oral and gut microbiome composition as host modulation agents in periodontitis: A narrative review

Periodontitis is defined as an oral bacterial dysbiosis-induced persistent inflammation on dental supporting tissue resulting in periodontal tissue breakdown and alveolar bone destruction. The disease is initiated by the interaction between periodontopathogens and the host immune system. Its development and severity can be associated with several systemic diseases, such as cardiovascular disease (CVD), diabetes mellitus, and rheumatoid arthritis (RA). Moreover, the latest research has suggested that the oral and gut microbiome hypothesis lays the oral and systemic connection mechanism. Bacterial homeostasis and restoration in the oral cavity and intestine become therapeutics concepts. Concerning the treatment of periodontitis, a local inflammatory condition, prolonged systemic administration of antibiotics is no longer recommended due to bacterial resistance issues. Probiotics and several bioactive metabolites have been widely investigated to address the needs of host modulation therapy in periodontitis. Evidence suggests that the use of probiotics helps downregulate the inflammation process through the regulation of toll-like receptor 4 (TLR4) and the production of fatty acid, targeting reactive oxygen species (ROS). In brief, several herbals have anti-inflammatory properties by inhibiting pro-inflammatory cytokines and mediators, including mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB). Consistently, improvement of periodontal pocket depth (PPD) and gingival index (GI) was seen in a group given melatonin as an adjunct treatment. In all, this review will highlight host modulation agents regarding periodontitis therapy, plausible mechanisms on how probiotics and metabolites work on periodontal restoration, and their reported studies. Limitations given by published studies will be elaborated, while future directions will be proposed.

Antimicrobial potential of known and novel probiotics on in vitro periodontitis biofilms

Several oral diseases are characterized by a shift within the oral microbiome towards a pathogenic, dysbiotic composition. Broad-spectrum antimicrobials are often part of patient care. However, because of the rising antibiotic resistance, alternatives are increasingly desirable. Alternatively, supplying beneficial species through probiotics is increasingly showing favorable results. Unfortunately, these probiotics are rarely evaluated comparatively. In this study, the in vitro effects of three known and three novel Lactobacillus strains, together with four novel Streptococcus salivarius strains were comparatively evaluated for antagonistic effects on proximal agar growth, antimicrobial properties of probiotic supernatant and the probiotic's effects on in vitro periodontal biofilms. Strain-specific effects were observed as differences in efficacy between genera and differences within genera. While some of the Lactobacillus candidates were able to reduce the periodontal pathobiont A. actinomycetemcomitans, the S. salivarius strains were not. However, the S. salivarius strains were more effective against periodontal pathobionts P. intermedia, P. gingivalis, and F. nucleatum. Vexingly, most of the Lactobacillus strains also negatively affected the prevalence of commensal species within the biofilms, while this was lower for S. salivarius strains. Both within lactobacilli and streptococci, some strains showed significantly more inhibition of the pathobionts, indicating the importance of proper strain selection. Additionally, some species showed reductions in non-target species, which can result in unexpected and unexplored effects on the whole microbiome.

The oral microbiome in the pathophysiology of cardiovascular disease

Despite advances in our understanding of the pathophysiology of many cardiovascular diseases (CVDs) and expansion of available therapies, the global burden of CVD-associated morbidity and mortality remains unacceptably high. Important gaps remain in our understanding of the mechanisms of CVD and determinants of disease progression. In the past decade, much research has been conducted on the human microbiome and its potential role in modulating CVD. With the advent of high-throughput technologies and multiomics analyses, the complex and dynamic relationship between the microbiota, their 'theatre of activity' and the host is gradually being elucidated. The relationship between the gut microbiome and CVD is well established. Much less is known about the role of disruption (dysbiosis) of the oral microbiome; however, interest in the field is growing, as is the body of literature from basic science and animal and human investigations. In this Review, we examine the link between the oral microbiome and CVD, specifically coronary artery disease, stroke, peripheral artery disease, heart failure, infective endocarditis and rheumatic heart disease. We discuss the various mechanisms by which oral dysbiosis contributes to CVD pathogenesis and potential strategies for prevention and treatment.

The Oral Microbiota in Valvular Heart Disease: Current Knowledge and Future Directions

Oral microbiota formation begins from birth, and everything from genetic components to the environment, alongside the host's behavior (such as diet, smoking, oral hygiene, and even physical activity), contributes to oral microbiota structure. Even though recent studies have focused on the gut microbiota's role in systemic diseases, the oral microbiome represents the second largest community of microorganisms, making it a new promising therapeutic target. Periodontitis and dental caries are considered the two main consequences of oral bacterial imbalance. Studies have shown that oral dysbiosis effects are not limited locally. Due to technological advancement, research identified oral bacterial species in heart valves. This evidence links oral dysbiosis with the development of valvular heart disease (VHD). This review focuses on describing the mechanism behind prolonged local inflammation and dysbiosis, that can induce bacteriemia by direct or immune-mediated mechanisms and finally VHD. Additionally, we highlight emerging therapies based on controlling oral dysbiosis, periodontal disease, and inflammation with immunological and systemic effects, that exert beneficial effects in VHD management.

Effects of oral administration of Bifidobacterium animalis subsp. lactis HN019 on the treatment of plaque-induced generalized gingivitis

OBJECTIVES

This double-blind, randomized, placebo-controlled clinical trial evaluated the adjuvant effects of Bifidobacterium lactis HN019 on the treatment of plaque-induced generalized gingivitis.

MATERIALS AND METHODS

Sixty patients were submitted to professional supragingival scaling and prophylaxis. They were randomly assigned to test (probiotic lozenges containing B. lactis HN019, n = 30) or control (placebo lozenges, n = 30) groups. Lozenges were consumed twice a day for 8 weeks. Bleeding on probing (BoP), Gingival Index (GI), Plaque Index (PI), probing depth (PD), and clinical attachment level (CAL) were evaluated at baseline and after 2 and 8 weeks. Gingival crevicular fluid (GCF) was collected at baseline and at 8 weeks for analysis of the inflammatory mediators IL-1β, IL-1α, IL-8, MCP-1, and MIP-1β. Data were statistically analyzed (p < 0.05).

RESULTS

After 8 weeks, both groups showed reduction in the percentage of PI, with no significant difference between groups (p = 0.7423). The test group presented a lower percentage of BoP and a higher percentage of sites with GI ≤ 1 when compared with the control group at the end of the study (p < 0.0001). At 8 weeks, the test group had a greater number of patients without generalized gingivitis than the control group (20 and 11 patients, respectively; p < 0.05). The test group presented significantly lower levels of IL-1α, IL-1β, and MCP-1 in GCF than the control group at the end of the study (p < 0.05).

CONCLUSION

The adjunct use of B. lactis HN019 promotes additional clinical and immunological benefits in the treatment of generalized gingivitis.

CLINICAL RELEVANCE

B. lactis HN019 can be an efficient and side-effect-free adjunct strategy in the treatment of generalized gingivitis.

Inhibitory Effect of Genomic DNA Extracted from Pediococcus acidilactici on Porphyromonas gingivalis Lipopolysaccharide-Induced Inflammatory Responses

This study aimed to assess whether genomic DNA (gDNA) extracted from Pediococcus acidilactici inhibits Porphyromonas gingivalis lipopolysaccharide (LPS)-induced inflammatory responses in RAW 264.7 cells. Pretreatment with gDNA of P. acidilactici K10 or P. acidilactici HW01 for 15 h effectively inhibited P. gingivalis LPS-induced mRNA expression of interleukin (IL)-1β, IL-6, and monocyte chemoattractant protein (MCP)-1. Although both gDNAs did not dose-dependently inhibit P. gingivalis LPS-induced mRNA expression of IL-6 and MCP-1, they inhibited IL-1β mRNA expression in a dose-dependent manner. Moreover, pretreatment with both gDNAs inhibited the secretion of IL-1β, IL-6, and MCP-1. When RAW 264.7 cells were stimulated with P. gingivalis LPS alone, the phosphorylation of mitogen-activated protein kinases (MAPKs) was increased. However, the phosphorylation of MAPKs was reduced in the presence of gDNAs. Furthermore, both gDNAs restored IκBα degradation induced by P. gingivalis LPS, indicating that both gDNAs suppressed the activation of nuclear factor-κB (NF-κB). In summary, P. acidilactici gDNA could inhibit P. gingivalis LPS-induced inflammatory responses through the suppression of MAPKs and NF-κB, suggesting that P. acidilactici gDNA could be effective in preventing periodontitis.

Influence of Lactobacillus reuteri, Bifidobacterium animalis subsp. lactis, and prebiotic inulin on dysbiotic dental biofilm composition ex vivo

BACKGROUND

Probiotic bacterial supplementation has shown promising results in the treatment of periodontitis and the maintenance of periodontal health. The purpose of this investigation was to evaluate the influence of Lactobacillus reuteri or Bifidobacterium animalis subsp. lactis supplementation with and without prebiotic inulin on biofilm composition using an ex vivo biofilm model.

METHODS

Subgingival plaque specimens from three periodontitis-affected human donors were used to grow biofilms on hydroxyapatite disks in media supplemented with varying combinations of prebiotic inulin, Lactobacillus reuteri, and Bifidobacterium animalis subsp. lactis. Relative abundances of bacterial genera present in mature biofilms were evaluated using 16S rRNA next-generation sequencing. Diversity metrics of microbial communities were evaluated using a next-generation microbiome bioinformatics platform.

RESULTS

Inulin supplementation produced statistically significant dose-dependent increases in relative abundances of Lactobacillus and Bifidobacterium species (p < 0.001) with concomitant decreases in relative abundances of Streptococcus, Veillonella, Fusobacterium, Parvimonas, and Prevotella species (p < 0.001). Inoculation with L. reuteri or B. animalis subsp. lactis increased the relative abundance of only the supplemented probiotic genera (p < 0.05). Supplemental inulin led to a statistically significant decrease in biofilm alpha diversity (p < 0.001).

CONCLUSIONS

The described ex vivo model appears suitable for investigating the effects of probiotic bacteria, prebiotic oligosaccharides, and combinations thereof on biofilm composition and complexity. Within the limitations imposed by this model, results from the present study underscore the potential for prebiotic inulin to modify biofilm composition favorably. Additional research further elucidating biologic rationale and controlled clinical research defining therapeutic benefits is warranted.

Probiotic Bifidobacteria in Managing Periodontal Disease: A Systematic Review

Although various probiotic organisms have been evaluated for their utility in the management of periodontitis, their strain-specific mechanisms of action are still unclear. We aimed to systematically review the effect of bifidobacterial probiotics on periodontopathogens and host immune responses in periodontal diseases. An electronic search of articles published until June 2022 in Medline, PubMed, Web of Science, and Cochrane Library databases was performed. Randomised controlled trials (RCTs) and in vitro and animal studies were assessed, and the data regarding antimicrobial properties, immunomodulation, and clinical outcomes were analysed. A total of 304 studies were screened, but only 3 RCTs and 6 animal and in vitro studies met the inclusion criteria. The use of different strains of bifidobacteria led to (1) a reduction of key players of the red complex periodontopathogens; (2) reduced levels of pro-inflammatory cytokines (eg, interleukin [IL]1-β and IL-8) and higher levels of anti-inflammatory cytokines (IL-10); (3) enhanced levels of osteoprotegerin and reduced levels of receptor activator of nuclear factor kappa-B ligand; and (4) a reduction of the dental plaque, bleeding on probing, alveolar bone loss, and clinical attachment loss. Bifidobacterial probiotic adjuvant supplementation, especially with Bifidobacterium animalis subspecies lactis, appears to help improve clinical periodontal parameters and develop a healthy plaque microbiome through microbiological and immunomodulatory pathways. Further human and animal studies are warranted prior to the therapeutic use of bifidobacteria in the routine management of periodontal infections.

Complete Genome Sequence of Lacticaseibacillus rhamnosus DM065, Isolated from the Human Oral Cavity

The 3.0-Mb complete genome of Lacticaseibacillus rhamnosus strain DM065, which was isolated from the oral cavity of healthy volunteers in South Korea, was sequenced using a combination of PacBio and Illumina technologies. The genome consists of one circular chromosome and two plasmids and lacks antimicrobial resistance genes.

Drugs for the Quorum Sensing Inhibition of Oral Biofilm: New Frontiers and Insights in the Treatment of Periodontitis

Chemical molecules are used by microorganisms to communicate with each other. Quorum sensing is the mechanism through which microorganisms regulate their population density and activity with chemical signaling. The inhibition of quorum sensing, called quorum quenching, may disrupt oral biofilm formation, which is the main etiological factor of oral diseases, including periodontitis. Periodontitis is a chronic inflammatory disorder of infectious etiology involving the hard and soft periodontal tissues and which is related to various systemic disorders, including cardiovascular diseases, diabetes and obesity. The employment of adjuvant therapies to traditional scaling and root planing is currently being studied to further reduce the impact of periodontitis. In this sense, using antibiotics and antiseptics involves non-negligible risks, such as antibiotic resistance phenomena and hinders the re-establishment of eubiosis. Different quorum sensing signal molecules have been identified in periodontal pathogenic oral bacteria. In this regard, quorum sensing inhibitors are emerging as some interesting solutions for the management of periodontitis. Therefore, the aim of this review is to summarize the current state of knowledge on the mechanisms of quorum sensing signal molecules produced by oral biofilm and to analyze the potential of quorum sensing inhibitors for the management of periodontitis.

Periodontal disease in pregnancy and adverse pregnancy outcomes: Progress in related mechanisms and management strategies

Periodontal disease is an inflammatory and destructive disease of tissues supporting the tooth. A large number of studies have confirmed that periodontal pathogens and their metabolites can lead to adverse pregnancy outcomes in direct or indirect ways. Adverse pregnancy outcomes, such as preterm birth, low birth weight, and pre-eclampsia, have a serious impact on human reproductive health. In recent years, although the level of global medical technology has gradually improved, the incidence of adverse pregnancy outcomes has not declined and is still a global public health problem. The purpose of this review is to summarize the current data on periodontal disease in pregnancy and adverse pregnancy outcomes, including the association between periodontal disease and adverse pregnancy outcomes, the pathogenic mechanism related to this association, the efficacy of different nutrition supplements for both periodontal disease and adverse pregnancy outcomes and the effect of providing periodontal treatment on the occurrence of adverse pregnancy outcomes, to provide guidance for the prevention and treatment of adverse pregnancy outcomes in clinical practice.

Microbiome dysbiosis inhibits carcinogen-induced murine oral tumorigenesis

Oral cancer is one of the most common cancers worldwide and ranks fourth for the mortality rate of cancers in males in Taiwan. The oral microbiota is the microbial community in the oral cavity, which is essential for maintaining oral health, but the relationship between oral tumorigenesis and the oral microbiota remains to be clarified. This study evaluated the effect of microbiome dysbiosis on oral carcinogenesis in mice, and the impact of the microbiome and its metabolic pathways on regulating oral carcinogenesis. We found that antibiotics treatment decreases carcinogen-induced oral epithelial malignant transformation. Microbiome analysis based on 16S rRNA gene sequencing revealed that the species richness of fecal specimens was significantly reduced in antibiotic-treated mice, while that in the salivary specimens was not decreased accordingly. Differences in bacterial composition, including Lactobacillus animalis abundance, in the salivary samples of cancer-bearing mice was dramatically decreased. L. animalis was the bacterial species that increased the most in the saliva of antibiotic-treated mice, suggesting that L. animalis may be negatively associated with oral carcinogenesis. In functional analysis, the microbiome in the saliva of the tumor-bearing group showed greater potential for polyamine biosynthesis. Immunochemical staining proved that spermine oxidase, an effective polyamine oxidase, was upregulated in mouse oral cancer lesions. In conclusion, oral microbiome dysbiosis may alter polyamine metabolic pathways and reduce carcinogen-induced malignant transformation of the oral epithelium.

Effects of extracellular vesicles derived from oral bacteria on osteoclast differentiation and activation

Dysbiosis of the oral microbiota plays an important role in the progression of periodontitis, which is characterized by chronic inflammation and alveolar bone loss, and associated with systemic diseases. Bacterial extracellular vesicles (EVs) contain various bioactive molecules and show diverse effects on host environments depending on the bacterial species. Recently, we reported that EVs derived from Filifactor alocis, a Gram-positive periodontal pathogen, had osteoclastogenic activity. In the present study, we analysed the osteoclastogenic potency and immunostimulatory activity of EVs derived from the Gram-negative periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia, the oral commensal bacterium Streptococcus oralis, and the gut probiotic strain Lactobacillus reuteri. Bacterial EVs were purified by density gradient ultracentrifugation using OptiPrep (iodixanol) reagent. EVs from P. gingivalis, T. forsythia, and S. oralis increased osteoclast differentiation and osteoclstogenic cytokine expression in osteoclast precursors, whereas EVs from L. reuteri did not. EVs from P. gingivalis, T. forsythia, and S. oralis preferentially activated Toll-like receptor 2 (TLR2) rather than TLR4 or TLR9, and induced osteoclastogenesis mainly through TLR2. The osteoclastogenic effects of EVs from P. gingivalis and T. forsythia were reduced by both lipoprotein lipase and polymyxin B, an inhibitor of lipopolysaccharide (LPS), while the osteoclastogenic effects of EVs from S. oralis were reduced by lipoprotein lipase alone. These results demonstrate that EVs from periodontal pathogens and oral commensal have osteoclastogenic activity through TLR2 activation by lipoproteins and/or LPS.

Use of the Probiotic Bifidobacterium animalis subsp. lactis HN019 in Oral Diseases

The oral cavity is one of the environments on the human body with the highest concentrations of microorganisms that coexist harmoniously and maintain homeostasis related to oral health. Several local factors can shift the microbiome to a pathogenic state of dysbiosis. Existing treatments for infections caused by changes in the oral cavity aim to control biofilm dysbiosis and restore microbial balance. Studies have used probiotics as treatments for oral diseases, due to their ability to reduce the pathogenicity of the microbiota and immunoinflammatory changes. This review investigates the role of the probiotic Bifidobacterium animalis subsp. lactis (B. lactis) HN019 in oral health, and its mechanism of action in pre-clinical and clinical studies. This probiotic strain is a lactic acid bacterium that is safe for human consumption. It mediates bacterial co-aggregation with pathogens and modulates the immune response. Studies using B. lactis HN019 in periodontitis and peri-implant mucositis have shown it to be a potential adjuvant treatment with beneficial microbiological and immunological effects. Studies evaluating its oral effects and mechanism of action show that this probiotic strain has the potential to be used in several dental applications because of its benefit to the host.

Host Response Modulation Therapy in the Diabetes Mellitus—Periodontitis Conjuncture: A Narrative Review

The inflammatory response of the host in periodontitis is the phenomenon that underlies the onset and evolution of periodontal destructive phenomena. A number of systemic factors, such as diabetes mellitus (DM), can negatively affect the patient with periodontitis, just as the periodontal disease can aggravate the status of the DM patient. Host response modulation therapy involves the use of anti-inflammatory and anti-oxidant products aimed at resolving inflammation, stopping destructive processes, and promoting periodontal healing, all important aspects in patients with high tissue loss rates, such as diabetic patients. This paper reviews the data available in the literature on the relationship between DM and periodontitis, the main substances modulating the inflammatory response (nonsteroidal anti-inflammatory drugs, sub-antimicrobial doses of doxycycline, or omega-3 fatty acids and their products, specialized pro-resolving mediators), as well as their application in diabetic patients.

Characteristics of Probiotic Preparations and Their Applications

The probiotics market is one of the fastest growing segments of the food industry as there is growing scientific evidence of the positive health effects of probiotics on consumers. Currently, there are various forms of probiotic products and they can be categorized according to dosage form and the site of action. To increase the effectiveness of probiotic preparations, they need to be specifically designed so they can target different sites, such as the oral, upper respiratory or gastrointestinal tracts. Here we review the characteristics of different dosage forms of probiotics and discuss methods to improve their bioavailability in detail, in the hope that this article will provide a reference for the development of probiotic products.

Nisin and Nisin Probiotic Disrupt Oral Pathogenic Biofilms and Restore Their Microbiome Composition towards Healthy Control Levels in a Peri-Implantitis Setting

Peri-implantitis is characterized by chronic inflammation of the peri-implant supporting tissues that progressively and irreversibly leads to bone loss and, consequently, implant loss. Similar to periodontal disease, oral dysbiosis is thought to be a driver of peri-implantitis. However, managing peri-implantitis with traditional treatment methods, such as nonsurgical debridement or surgery, is not always successful. Thus, novel strategies have been proposed to address these shortcomings. One strategy is the use of probiotics as antimicrobial agents since they are considered safe for humans and the environment. Specifically, the probiotic Lactococcus lactis produces nisin, which has been used worldwide for food preservation. The objective of this study was to determine whether nisin and the wild-type (WT) nisin-producing L. lactis probiotic can disrupt oral pathogenic biofilms and promote a healthier oral microbiome within these oral biofilms on titanium discs. Using confocal imaging and 16S rRNA sequencing, this study revealed that nisin and WT L. lactis probiotic disrupt oral pathogenic biofilms in a peri-implantitis setting in vitro. More specifically, nisin decreased the viability of the pathogen-spiked biofilms dose-dependently from 62.53 ± 3.69% to 54.26 ± 3.35% and 44.88 ± 2.98%, respectively. Similarly, 105 CFU/mL of WT L. lactis significantly decreased biofilm viability to 52.45 ± 3.41%. Further, both treatments shift the composition, relative abundance, and diversity levels of these biofilms towards healthy control levels. A total of 1 µg/mL of nisin and 103 CFU/mL of WT L. lactis were able to revert the pathogen-mediated changes in the Proteobacteria (from 80.5 ± 2.9% to 75.6 ± 2.0%, 78.0 ± 2.8%, and 75.1 ± 5.3%, respectively) and Firmicutes (from 11.6 ± 1.6% to 15.4 ± 1.3%, 13.8 ± 1.8%, and 13.7 ± 2.6%, respectively) phyla back towards control levels. Thus, nisin and its nisin-producing L. lactis probiotic may be useful in treating peri-implantitis by promoting healthier oral biofilms, which may be useful for improving patient oral health.

The role of oral microbiome in periodontitis under diabetes mellitus

Periodontitis is among most common human inflammatory diseases and characterized by destruction of tooth-supporting tissues that will eventually lead to tooth loss. Diabetes mellitus (DM) is a group of metabolic disorders characterized by chronic hyperglycemia which results from defects in insulin secretion and/or insulin resistance. Numerous studies have provided evidence for the inter-relationship between DM and periodontitis that has been considered as the sixth most frequent complication of DM. However, the mechanisms are not fully understood yet. The impact of DM on periodontitis through hyperglycemia and inflammatory pathways is well described, but the effects of DM on oral microbiota remain controversial according to previous studies. Recent studies using next-generation sequencing technology indicate that DM can alter the biodiversity and composition of oral microbiome especially subgingival microbiome. This may be another mechanism by which DM risks or aggravates periodontitis. Thus, to understand the role of oral microbiome in periodontitis of diabetics and the mechanism of shifts of oral microbiome under DM would be valuable for making specific therapeutic regimens for treating periodontitis patients with DM or preventing diabetic patients from periodontitis. This article reviews the role of oral microbiome in periodontal health (symbiosis) and disease (dysbiosis), highlights the oral microbial shifts under DM and summarizes the mechanism of the shifts.

Antiplanktonic and Antibiofilm Activity of Rheum palmatum against Streptococcus oralis and Porphyromonas gingivalis

Periodontitis and peri-implantitis are inflammatory conditions with a high global prevalence. Oral pathogens such as Porphyromonas gingivalis play a crucial role in the development of dysbiotic biofilms associated with both diseases. The aim of our study was to identify plant-derived substances which mainly inhibit the growth of “disease promoting bacteria”, by comparing the effect of Rheum palmatum root extract against P. gingivalis and the commensal species Streptococcus oralis. Antiplanktonic activity was determined by measuring optical density and metabolic activity. Antibiofilm activity was quantified using metabolic activity assays and live/dead fluorescence staining combined with confocal laser scanning microscopy. At concentrations of 3.9 mg/L, R. palmatum root extract selectively inhibited planktonic growth of the oral pathogen P. gingivalis, while not inhibiting growth of S. oralis. Selective effects also occurred in mature biofilms, as P. gingivalis was significantly more stressed and inhibited than S. oralis. Our studies show that low concentrations of R. palmatum root extract specifically inhibit P. gingivalis growth, and offer a promising approach for the development of a potential topical agent to prevent alterations in the microbiome due to overgrowth of pathogenic P. gingivalis.

Assessing the drug resistance profiles of oral probiotic lozenges

Background

Probiotic lozenges have been developed to harvest the benefits of probiotics for oral health, but their long-term consumption may encourage the transfer of resistance genes from probiotics to commensals, and eventually to disease-causing bacteria.

Aim

To screen commercial probiotic lozenges for resistance to antibiotics, characterize the resistance determinants, and examine their transferability in vitro.

Results

Probiotics of all lozenges were resistant to glycopeptide, sulfonamide, and penicillin antibiotics, while some were resistant to aminoglycosides and cephalosporins. High minimum inhibitory concentrations (MICs) were detected for streptomycin (>128 µg/mL) and chloramphenicol (> 512 µg/mL) for all probiotics but only one was resistant to piperacillin (MIC = 32 µg/mL). PCR analysis detected erythromycin (erm(T), ermB or mefA) and fluoroquinolone (parC or gyr(A)) resistance genes in some lozenges although there were no resistant phenotypes. The dfrD, cat-TC, vatE, aadE, vanX, and aph(3")-III or ant(2")-I genes conferring resistance to trimethoprim, chloramphenicol, quinupristin/dalfopristin, vancomycin, and streptomycin, respectively, were detected in resistant probiotics. The rifampicin resistance gene rpoB was also present. We found no conjugal transfer of streptomycin resistance genes in our co-incubation experiments.

Conclusion

Our study represents the first antibiotic resistance profiling of probiotics from oral lozenges, thus highlighting the health risk especially in the prevailing threat of drug resistance globally.

Oral health's inextricable connection to systemic health: Special populations bring to bear multimodal relationships and factors connecting periodontal disease to systemic diseases and conditions

The landscape in dentistry is changing as emerging studies continue to reveal that periodontal health impacts systemic health, and vice versa. Population studies, clinical studies, and in vitro animal studies underscore the critical importance of oral health to systemic health. These inextricable relationships come to the forefront as oral diseases, such as periodontal disease, take root. Special populations bring to bear the multimodal relationships between oral and systemic health. Specifically, periodontal disease has been associated with diabetes, metabolic syndrome, obesity, eating disorders, liver disease, cardiovascular disease, Alzheimer disease, rheumatoid arthritis, adverse pregnancy outcomes, and cancer. Although bidirectional relationships are recognized, the potential for multiple comorbidities, relationships, and connections (multimodal relationships) also exists. Proposed mechanisms that mediate this connection between oral and systemic health include predisposing and precipitating factors, such as genetic factors (gene polymorphisms), environmental factors (stress, habits-such as smoking and high-fat diets/consumption of highly processed foods), medications, microbial dysbiosis and bacteremias/viremias/microbemias, and an altered host immune response. Thus, in a susceptible host, these predisposing and precipitating factors trigger the onset of periodontal disease and systemic disease/conditions. Further, high-throughput sequencing technologies are shedding light on the dark matter that comprises the oral microbiome. This has resulted in better characterization of the oral microbial dysbiosis, including putative bacterial periodontopathogens and shifts in oral virome composition during disease. Multiple laboratory and clinical studies have illustrated that both eukaryotic and prokaryotic viruses within subgingival plaque and periodontal tissues affect periodontal inflammation, putative periodontopathogens, and the host immune response. Although the association between herpesviruses and periodontitis and the degree to which these viruses directly aggravate periodontal tissue damage remain unclear, the benefits to periodontal health found from prolonged administration of antivirals in immunocompromised or immunodeficient individuals demonstrates that specific populations are possibly more susceptible to viral periodontopathogens. Thus, it may be important to further examine the implications of viral pathogen involvement in periodontitis and perhaps it is time to embrace the viral dark matter within the periodontal environment to fully comprehend the pathogenesis and systemic implications of periodontitis. Emerging data from the coronavirus disease 2019 pandemic further underscores the inextricable connection between oral and systemic health, with high levels of the severe acute respiratory syndrome coronavirus 2 angiotensin-converting enzyme 2 receptor noted on oral tissues (tongue) and an allostatic load or overload paradigm of chronic stress likely contributing to rapid breakdown of oral/dental, periodontal, and peri-implant tissues. These associations exist within a framework of viremias/bacteremias/microbemias, systemic inflammation, and/or disturbances of the immune system in a susceptible host. A thorough review of systemic and oral diseases and conditions and their mechanistic, predisposing, and precipitating factors are paramount to better addressing the oral and systemic health and needs of our patients.

Probiotics for periodontal health-Current molecular findings

Dysbiosis of the oral microbiome is associated with a variety of oral and systemic diseases, including periodontal disease. Oral dysbiosis in periodontal disease leads to an exacerbated host immune response that induces progressive periodontal tissue destruction and ultimately tooth loss. To counter the disease‐associated dysbiosis of the oral cavity, strategies have been proposed to reestablish a “healthy” microbiome via the use of probiotics. This study reviews the literature on the use of probiotics for modifying the oral microbial composition toward a beneficial state that might alleviate disease progression. Four in vitro and 10 preclinical studies were included in the analysis, and these studies explored the effects of probiotics on cultured biofilm growth and bacterial gene expressions, as well as modulation of the host response to inflammation. The current molecular findings on probiotics provide fundamental evidence for further clinical research for the use of probiotics in periodontal therapy. They also point out an important caveat: Changing the biofilm composition might alter the normal oral flora that is beneficial and/or critical for oral health.

The oralome and its dysbiosis: New insights into oral microbiome-host interactions

The oralome is the summary of the dynamic interactions orchestrated between the ecological community of oral microorganisms (comprised of up to approximately 1000 species of bacteria, fungi, viruses, archaea and protozoa - the oral microbiome) that live in the oral cavity and the host. These microorganisms form a complex ecosystem that thrive in the dynamic oral environment in a symbiotic relationship with the human host. However, the microbial composition is significantly affected by interspecies and host-microbial interactions, which in turn, can impact the health and disease status of the host. In this review, we discuss the composition of the oralome and inter-species and host-microbial interactions that take place in the oral cavity and examine how these interactions change from healthy (eubiotic) to disease (dysbiotic) states. We further discuss the dysbiotic signatures associated with periodontitis and caries and their sequalae, (e.g., tooth/bone loss and pulpitis), and the systemic diseases associated with these oral diseases, such as infective endocarditis, atherosclerosis, diabetes, Alzheimer's disease and head and neck/oral cancer. We then discuss current computational techniques to assess dysbiotic oral microbiome changes. Lastly, we discuss current and novel techniques for modulation of the dysbiotic oral microbiome that may help in disease prevention and treatment, including standard hygiene methods, prebiotics, probiotics, use of nano-sized drug delivery systems (nano-DDS), extracellular polymeric matrix (EPM) disruption, and host response modulators.

The Role of the Oral Microbiota Related to Periodontal Diseases in Anxiety, Mood and Trauma- and Stress-Related Disorders

The prevalence of anxiety, mood and trauma- and stress-related disorders are on the rise; however, efforts to develop new and effective treatment strategies have had limited success. To identify novel therapeutic targets, a comprehensive understanding of the disease etiology is needed, especially in the context of the holobiont, i.e., the superorganism consisting of a human and its microbiotas. Much emphasis has been placed on the role of the gut microbiota in the development, exacerbation, and persistence of psychiatric disorders; however, data for the oral microbiota are limited. The oral cavity houses the second most diverse microbial community in the body, with over 700 bacterial species that colonize the soft and hard tissues. Periodontal diseases encompass a group of infectious and inflammatory diseases that affect the periodontium. Among them, periodontitis is defined as a chronic, multi-bacterial infection that elicits low-grade systemic inflammation via the release of pro-inflammatory cytokines, as well as local invasion and long-distance translocation of periodontal pathogens. Periodontitis can also induce or exacerbate other chronic systemic inflammatory diseases such as atherosclerosis and diabetes and can lead to adverse pregnancy outcomes. Recently, periodontal pathogens have been implicated in the etiology and pathophysiology of neuropsychiatric disorders (such as depression and schizophrenia), especially as dysregulation of the immune system also plays an integral role in the etiology and pathophysiology of these disorders. This review will discuss the role of the oral microbiota associated with periodontal diseases in anxiety, mood and trauma- and stress-related disorders. Epidemiological data of periodontal diseases in individuals with these disorders will be presented, followed by a discussion of the microbiological and immunological links between the oral microbiota and the central nervous system. Pre-clinical and clinical findings on the oral microbiota related to periodontal diseases in anxiety, mood and trauma- and stress-related phenotypes will be reviewed, followed by a discussion on the bi-directionality of the oral-brain axis. Lastly, we will focus on the oral microbiota associated with periodontal diseases as a target for future therapeutic interventions to alleviate symptoms of these debilitating psychiatric disorders.