Microglial morphological/inflammatory phenotypes and endocannabinoid signaling in a preclinical model of periodontitis and depression.

BACKGROUND: Depression is a chronic psychiatric disease of multifactorial etiology, and its pathophysiology is not fully understood. Stress and other chronic inflammatory pathologies are shared risk factors for psychiatric diseases, and comorbidities are features of major depression. Epidemiological evidence suggests that periodontitis, as a source of low-grade chronic systemic inflammation, may be associated with depression, but the underlying mechanisms are not well understood. METHODS: Periodontitis (P) was induced in Wistar: Han rats through oral gavage with the pathogenic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum for 12 weeks, followed by 3 weeks of chronic mild stress (CMS) to induce depressive-like behavior. The following four groups were established (n = 12 rats/group): periodontitis and CMS (P + CMS+), periodontitis without CMS, CMS without periodontitis, and control. The morphology and inflammatory phenotype of microglia in the frontal cortex (FC) were studied using immunofluorescence and bioinformatics tools. The endocannabinoid (EC) signaling and proteins related to synaptic plasticity were analyzed in FC samples using biochemical and immunohistochemical techniques. RESULTS: Ultrastructural and fractal analyses of FC revealed a significant increase in the complexity and heterogeneity of Iba1 + parenchymal microglia in the combined experimental model (P + CMS+) and increased expression of the proinflammatory marker inducible nitric oxide synthase (iNOS), while there were no changes in the expression of cannabinoid receptor 2 (CB2). In the FC protein extracts of the P + CMS + animals, there was a decrease in the levels of the EC metabolic enzymes N-acyl phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), diacylglycerol lipase (DAGL), and monoacylglycerol lipase (MAGL) compared to those in the controls, which extended to protein expression in neurons and in FC extracts of cannabinoid receptor 1 (CB1) and to the intracellular signaling molecules phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) and extracellular signal-regulated kinase 1/2 (ERK1/2). The protein levels of brain-derived neurotrophic factor (BDNF) and synaptophysin were also lower in P + CMS + animals than in controls. CONCLUSIONS: The combined effects on microglial morphology and inflammatory phenotype, the EC signaling, and proteins related to synaptic plasticity in P + CMS + animals may represent relevant mechanisms explaining the association between periodontitis and depression. These findings highlight potential therapeutic targets that warrant further investigation.

Cytokines in gingivitis and periodontitis: from pathogenesis to therapeutic targets.

Chronic inflammatory processes in the oral mucosa and periodontitis are common disorders caused by microflora and microbial biofilms. These factors activate both the innate and adaptive immune systems, leading to the production of pro-inflammatory cytokines. Cytokines are known to play a crucial role in the pathogenesis of gingivitis and periodontitis and have been proposed as biomarkers for diagnosis and follow-up of these diseases. They can activate immune and stromal cells, leading to local inflammation and tissue damage. This damage can include destruction of the periodontal ligaments, gingiva, and alveolar bone. Studies have reported increased local levels of pro-inflammatory cytokines, such as interleukin-1beta (IL-1beta), tumor necrosis factor (TNF), IL-6, IL-17, and IL-23, in patients with periodontitis. In experimental models of periodontitis, TNF and the IL-23/IL-17 axis play a pivotal role in disease pathogenesis. Inactivation of these pro-inflammatory pathways through neutralizing antibodies, genetic engineering or IL-10 function has been demonstrated to reduce disease activity. This review discusses the role of cytokines in gingivitis and periodontitis, with particular emphasis on their role in mediating inflammation and tissue destruction. It also explores new therapeutic interventions that offer potential for research and clinical therapy in these chronic inflammatory diseases.

Meta-analysis of oral microbiome reveals sex-based diversity in biofilms during periodontitis.

Sex is an often overlooked, yet compulsory, biological variable when performing biomedical research. Periodontitis is a common yet progressively debilitating chronic inflammatory disorder affecting the tissues supporting teeth that ultimately leads to tooth loss if left untreated. The incidence of periodontitis is sex biased, with increased prevalence in males compared with females but with unknown etiology. We performed a sex-specific meta-analysis using publicly available oral microbiome data from different sampling sites of patients with periodontitis and periodontally healthy controls; sex balance was established for each periodontal health condition. Our results show sex-based diversity in oral biofilms of individuals with periodontitis but not in their saliva, with increased abundance of several periodontal pathogens in subgingival plaques from females compared with males. We devised a quantitative measure, uniquely defined as the Microsexome Index (MSI), which indicates that sexual dimorphism in subgingival bacterial composition is a distinct feature of reduced microbial diversity during periodontitis but not under healthy conditions. In addition, we found that smoking exacerbates microsexome diversity in supragingival biofilms, particularly during periodontitis. Taken together, we provide insights regarding sex-based diversity in periodontitis, a disease with multiorgan associations, and provide the rationale for further mechanistic, diagnostic, and therapeutic studies.

Bacterial Membrane Vesicles: The Missing Link Between Bacterial Infection and Alzheimer Disease.

Periodontitis is a common chronic inflammatory disease, affecting approximately 19% of the global adult population. A relationship between periodontal disease and Alzheimer disease has long been recognized, and recent evidence has been uncovered to link these 2 diseases mechanistically. Periodontitis is caused by dysbiosis in the subgingival plaque microbiome, with a pronounced shift in the oral microbiota from one consisting primarily of Gram-positive aerobic bacteria to one predominated by Gram-negative anaerobes, such as Porphyromonas gingivalis. A common phenomenon shared by all bacteria is the release of membrane vesicles to facilitate biomolecule delivery across long distances. In particular, the vesicles released by P gingivalis and other oral pathogens have been found to transport bacterial components across the blood-brain barrier, initiating the physiologic changes involved in Alzheimer disease. In this review, we summarize recent data that support the relationship between vesicles secreted by periodontal pathogens to Alzheimer disease pathology.

Role of CD86 on granulocyte in mediating the effect of Genus Roseburia on periodontitis.

OBJECTIVES: This study aimed to explore the causal link between the gut microbiota and periodontitis, and to delineate and quantify the intermediary role of immune cells, so as to provide new insights into the pathogenesis, prevention and treatment of periodontitis. MATERIALS AND METHODS: We employed a two-sample Mendelian randomization (MR) approach to analyze the genetic predictors of gut microbiota composition (covering 412 gut microbiota taxa and functions) and periodontitis (involving 4,784 cases and 272,252 controls) derived from genome-wide association study (GWAS) datasets. A subsequent two-step MR analysis was conducted to evaluate the extent to which immune cell traits (encompassing 731 immune cell characteristics) mediate the influence of gut microbiota on periodontitis risk. RESULTS: Our analysis implicated nine gut microbiota taxa as causal factors in periodontitis susceptibility (p < 0.05). Notably, the Genus Roseburia was identified as exerting a protective effect against periodontitis, partially mediated through the upregulation of CD86 expression on granulocytes, with an 8.15% mediation effect observed. CONCLUSIONS: Our findings establish a causal relationship between the gut microbiota and periodontitis, highlighting the protective role of Roseburia against this condition. A notable proportion of this protective effect is mediated via the upregulation of CD86 on granulocytes. CLINICAL RELEVANCE: It can provide new ideas for the pathogenesis, prevention and treatment for periodontitis through exploring the causal link between the gut microbiota and periodontitis, and describing and quantifying the intermediary role of immune cells.

Chronic Oral Inoculation of Porphyromonas gingivalis and Treponema denticola Induce Different Brain Pathologies in a Mouse Model of Alzheimer Disease.

Periodontitis is a chronic inflammatory disease driven by dysbiosis in subgingival microbial communities leading to increased abundance of a limited number of pathobionts, including Porphyromonas gingivalis and Treponema denticola. Oral health, particularly periodontitis, is a modifiable risk factor for Alzheimer disease (AD) pathogenesis, with components of both these bacteria identified in postmortem brains of persons with AD. Repeated oral inoculation of mice with P. gingivalis results in brain infiltration of bacterial products, increased inflammation, and induction of AD-like biomarkers. P. gingivalis displays synergistic virulence with T. denticola during periodontitis. The aim of the current study was to determine the ability of P. gingivalis and T. denticola, grown in physiologically relevant conditions, individually and in combination, to induce AD-like pathology following chronic oral inoculation of female mice over 12 weeks. P. gingivalis alone significantly increased all 7 brain pathologies examined: neuronal damage, activation of astrocytes and microglia, expression of inflammatory cytokines interleukin 1ß (IL-1ß) and interleukin 6 and production of amyloid-ß plaques and hyperphosphorylated tau, in the hippocampus, cortex and midbrain, compared to control mice. T. denticola alone significantly increased neuronal damage, activation of astrocytes and microglia, and expression of IL-1ß, in the hippocampus, cortex and midbrain, compared to control mice. Coinoculation of P. gingivalis with T. denticola significantly increased activation of astrocytes and microglia in the hippocampus, cortex and midbrain, and increased production of hyperphosphorylated tau and IL-1ß in the hippocampus only. The host brain response elicited by oral coinoculation was less than that elicited by each bacterium, suggesting coinoculation was less pathogenic.

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

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

The role of NF-kappaB in the inflammatory processes related to dental caries, pulpitis, apical periodontitis, and periodontitis-a narrative review.

Tooth-related inflammatory disorders, including caries, pulpitis, apical periodontitis (AP), and periodontitis (PD), are primarily caused by resident oral microorganisms. Although these dental inflammatory conditions are typically not life-threatening, neglecting them can result in significant complications and greatly reduce an individual's quality of life. Nuclear factor κB (NF-κB), a family formed by various combinations of Rel proteins, is extensively involved in inflammatory diseases and even cancer. This study reviews recent data on NF-κB signaling and its role in dental pulp stem cells (DPSCs), dental pulp fibroblasts (DPFs), odontoblasts, human periodontal ligament cells (hPDLCs), and various experimental animal models. The findings indicate that NF-κB signaling is abnormally activated in caries, pulpitis, AP, and PD, leading to changes in related cellular differentiation. Under specific conditions, NF-κB signaling occasionally interacts with other signaling pathways, affecting inflammation, bone metabolism, and tissue regeneration processes. In summary, data collected over recent years confirm the central role of NF-κB in dental inflammatory diseases, potentially providing new insights for drug development targeting NF-κB signaling pathways in the treatment of these conditions. Keywords: NF-κB, dental caries, pulpitis, apical periodontitis, periodontitis.

The influence of the psychosocial stress on oral health status in the conditions of being in Ukraine during the prolonged state of martial law.

OBJECTIVE: Aim: To study the presence of clinical and biochemical correlations between psycho-emotional stress, level of cortisol and periodontal oral health status of the patients in Ukraine during prolonged martial law. PATIENTS AND METHODS: Materials and Methods: The comprehensive clinical and laboratory study covered 49 persons, including 20 patients with Gingivitis (40.8%) and 29 with Periodontitis (59.2%). Biochemical blood test was performed to determine the level of "stress hormone" - cortisol. Patients filled out the questionnaire by the method of V. Zung (low mood-subdepression scale) to determine psycho-emotional state in the conditions of prolonged martial law in Ukraine. RESULTS: Results: The research results showed that in the conditions of martial law in Ukraine, "stabilization" and "improvement" of the process of patients with Gingivitis was established in 50%, with Periodontitis - only in 41.4% of patients. In 54% of patients, a significant deterioration of clinical indices was established, compared to the indicators before the war. In patients with Periodontitis, РВІ index was 1.33 (0.62-1.43) score, which was not statistically significantly different from the initial level (p>0.05). Biochemical blood tests revealed an increased level of the hormone cortisol in 18% of patients. According to the method by V. Zung scale of mental states, the majority of patients (87%) showed low mood and emotional instability within the medium level (range 2 and 3). Correlation was identified, according to the Spearman coefficient (R=0.39, р<0.05), between scale assessments by V.Zung and the blood level of cortisol. CONCLUSION: Conclusions: Psycho-emotional stress is one of the leading pathogenetic factors in the deterioration of oral health status and the development of periodontal diseases, especially in people in Ukraine during prolonged martial law. Indicators of method by V. Zung scale of mental states and the level of cortisol are optimal markers of the need to correct the psycho-emotional state. For patients with increased levels of stress and fear, it is necessary to create special treatment-prevention schemes, taking into account greater attention to motivation to maintain the health of the oral cavity, as well as more frequent hygiene procedures.

Impact of body mass index and polycystic ovary syndrome (PCOS) subtypes on periodontal health in Chinese women with PCOS and periodontitis.

BACKGROUND: This study aimed to investigate the impact of body mass index (BMI) and Polycystic Ovary Syndrome (PCOS) subtypes on periodontal parameters in Chinese women with PCOS and periodontitis. METHOD: We conducted a retrospective case-control study analyzing data from 88 women with PCOS and 82 healthy controls. Participants were categorized by BMI (<24.0 kg/m2and ≥24.0 kg/m2) and PCOS subtypes. We compared periodontal parameters [including probing depth (PD), gingival bleeding index (GBI)] and reproductive hormone-related parameters. RESULTS: Women with PCOS and periodontitis had a significantly higher GBI (2.71 ± 0.53) compared to controls (2.25 ± 0.41, p < 0.0001). Among patients with BMI <24.0 kg/m2, those with PCOS had a younger age [25.00(5.00) vs. 26.00(6.00) years, p < 0.05], lower PD [3.24(0.55) mm vs. 3.43 (0.48) mm, p < 0.01], and higher GBI [2.63(0.76) vs. 2.23(0.55), p < 0.0001]. For BMI ≥24.0 kg/m2, PCOS patients had a higher GBI [2.91(0.36) vs. 2.38(0.59), p < 0.01] but a lower percentage of severe periodontal disease (p < 0.05). CONCLUSION: PCOS could potentially worsen gingival inflammation among women already suffering from periodontitis, and a higher BMI might further intensify this correlation.

The effect of periodontal treatments on endothelial function in degrees of periodontitis patients: A systematic review and meta-analysis.

OBJECTIVE: This article focus on patients with moderate-to-severe periodontitis and periodontitis patients with cardiovascular disease. After they received periodontal initial therapy or antimicrobial drug treatment, was there any improvement in endothelial function during short- and long-term followups? METHOD: Relevant randomized controlled trials and clinical trials up to 30th June 2024 were identified and retrieved from electronic databases including PubMed, Cochrane Library, Web of Science and CNKI databases, with periodontitis therapy, periodontal disease and endothelial function as the keywords. The weighted (WMD) or standardized mean difference (SMD) was calculated using a fixed- or random-effect model and assessed heterogeneous results. RESULT: Generally, 14 studies published between 2004 and 2022 were eligible for the meta-analysis, which are all randomised clinical trials. A total of 491 periodontitis patients were screened. All participants received whole-mouth supragingival and subgingival scaling and root planing of the teeth, some trials combined with antimicrobial drug treatment as well as extracting teeth that could not be saved. The outcome indicators were measured by flow-mediated dilatation(FMD) levels. The results of the short term (≤3 months) periodontitis initial therapy group showed positive results (WMD = -3.78,95%CI = [-5.49,-2.07], P<0.0001), while the results of the long term (6 months) periodontitis therapy group exhibited significant difference (WMD = -0.96,95%CI = [-2.06,0.14],P = 0.09). Furthermore, study population were categorized according to the severity of periodontitis, the presence of comorbidities, endothelial dysfunction, and the inclusion of extractions and antimicrobial therapy in the treatment process. The effects of each of these factors on FMD were explored and the results of these subgroups all support periodontitis therapy. CONCLUSION: The results showed that periodontal treatment enhances endothelial function. Additionally, after subgroup analysis of long-term and short-term follow-up, patients with severe periodontitis, and different periodontal treatments, periodontal therapy was shown to increase FMD levels.

Association of periodontitis with all-cause and cause-specific mortality among individuals with depression: a population-based study.

To detect the association between periodontitis and all-cause as well as cause-specific mortality rates among adults diagnosed with depression. Participants diagnosed with depression were selected from NHANES across three periods (1988-1994; 1999-2004; 2009-2014). Cox proportional hazards and Weibull accelerated failure time (AFT) models were utilized to calculate hazard ratios (HRs), time ratios (TRs), and their 95% confidence intervals (CIs) to evaluate the association between moderate-to-severe periodontitis and all-cause as well as cause-specific mortality among participants with depression. white blood counts and C-reactive protein were used to assess the mediating role of systemic inflammation. Among the 1,189 participants with a median follow-up of 9.25 years, 133 deaths were recorded. After adjusting for multiple variables, moderate-to-severe periodontitis was obvious associated with an increased risk of cancer-related mortality in individuals with depression (Cox: HR 3.22, 95% CI 1.51-6.83, P = 0.002; AFT: TR 0.70, 95% CI 0.52-0.94, P = 0.017). Neither WBC nor CRP significantly mediate the association between periodontitis and cancer-related mortality. The risk of cancer-related mortality rose with the severity of periodontitis (P for trend = 0.021). However, no association was observed between moderate-to-severe periodontitis and other kinds of mortality. Moderate-to-severe periodontitis is linked to an elevated risk of cancer-related mortality among adults diagnosed with depression, with the mortality risk increasing alongside the severity of periodontitis. No significant mediating effect of systemic inflammation was found in this association. These findings highlight the importance of addressing periodontal health in individuals with depression. By uncovering the association between periodontitis and mortality in this population, our study underscores the potential benefits of preventive dental care and periodontal treatment in reducing the risk of cancer-related mortality in individuals with depression.

Wnt7B enhances the osteogenic differentiation of lipopolysaccharide-stimulated human periodontal ligament stem cells and inhibits the M1 polarization of macrophages by binding FZD4.

Periodontitis, a common oral disease characterized by the progressive infiltration of bacteria, is a leading cause of adult tooth loss. Periodontal stem cells (PDLSCs) possess good self­renewal and multi­potential differentiation abilities to maintain the integrity of periodontal support structure and repair defects. The present study aimed to analyze the roles of Wnt7B and frizzled4 (FZD4) in the osteogenic differentiation and macrophage polarization during periodontitis using an in vitro cell model. First, Wnt7B expression in the periodontitis­affected gingival tissue of patients and lipopolysaccharide (LPS)­stimulated PDLSCs was assessed using the GSE23586 dataset and western blot analysis, respectively. In Wnt7B­overexpressing PDLSCs exposed to LPS, the capacity of osteogenic differentiation was evaluated by detecting alkaline phosphatase activity, the level of Alizarin Red S staining and the expression of genes related to osteogenic differentiation. Subsequently, conditioned medium from PDLSCs overexpressing Wnt7B was used for M0 macrophage culture. The expression of CD86 and INOS was examined using immunofluorescence staining and western blot analysis. In addition, reverse transcription­quantitative PCR was employed to examine the expression of TNF­α, IL­6 and IL­1ß in macrophages. The binding between Wnt7B and FZD4 was estimated using co­immunoprecipitation. In addition, FZD4 was silenced to perform the rescue experiments to elucidate the regulatory mechanism between Wnt7B and FZD4. The results demonstrated a decreased expression of Wnt7B in periodontitis­affected gingival tissue and in LPS­exposed PDLSCs. Wnt7B overexpression promoted the osteogenic differentiation of LPS­exposed PDLSCs and suppressed the M1 polarization of macrophages. Additionally, Wnt7B bound to FZD4 and upregulated FZD4 expression. FZD4 silencing reversed the effects of Wnt7B overexpression on the osteogenic differentiation in LPS­exposed PDLSCs and the M1 polarization of macrophages. In summary, Wnt7B plays an anti­periodontitis role by binding FZD4 to strengthen the osteogenic differentiation of LPS­stimulated PDLSCs and suppress the M1 polarization of macrophages.

Protective effect of carvacrol hydrogel on the alveolar bone in rats with periodontitis.

OBJECTIVES: This study aimed to investigate the protective effect and mechanism of carvacrol hydrogel on the alveolar bone in rats with periodontitis. METHODS: A thermosensitive hydrogel supported by carvacrol was prepared using poloxamer and hydroxypropyl methyl cellulose as matrix. SD rats were randomly divided into blank group, periodontitis group, blank hydrogel group, and low-, medium-, and high-dose hydrogel groups. The periodontitis symptoms and the CT structure of the alveolar bone were observed. The changes in liver, spleen, kidney, and periodontal tissues were observed. The related indexes of bone metabolism in serum were detected. The expression of osteoprotegerin (OPG) and nuclear transcription factor-κB (NF-κB) pathway proteins was determined by Western blot. The levels of inflammatory factors were assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: Carvacrol hydrogel had good slow release, biocompatibility, and cell adhesion. The periodontitis of rats in the carvacrol hydrogel group was significantly alleviated, the expression of OPG protein in gingival tissue was significantly increased (P<0.01), and the levels of receptor activator of NF-κB ligand (RANKL), receptor activator of NF-κB (RANK), NF-κB protein, and inflammatory factors were significantly decreased (P<0.01). CONCLUSIONS: Carvacrol hydrogel can regulate the OPG and NF-κB pathways, reduce alveolar bone absorption, and improve periodontal inflammation.

Integrative microbiome and metabolome profiles reveal the impacts of periodontitis via oral-gut axis in first-trimester pregnant women.

BACKGROUND: Periodontitis results from host-microbe dysbiosis and the resultant dysregulated immunoinflammatory response. Importantly, it closely links to numerous systemic comorbidities, and perplexingly contributes to adverse pregnancy outcomes (APOs). Currently, there are limited studies on the distal consequences of periodontitis via oral-gut axis in pregnant women. This study investigated the integrative microbiome-metabolome profiles through multi-omics approaches in first-trimester pregnant women and explored the translational potentials. METHODS: We collected samples of subgingival plaques, saliva, sera and stool from 54 Chinese pregnant women at the first trimester, including 31 maternal periodontitis (Perio) subjects and 23 Non-Perio controls. By integrating 16S rRNA sequencing, untargeted metabolomics and clinical traits, we explored the oral-gut microbial and metabolic connection resulting from periodontitis among early pregnant women. RESULTS: We demonstrated a novel bacterial distinguisher Coprococcus from feces of periodontitis subjects in association with subgingival periodontopathogens, being different from other fecal genera in Lachnospiraceae family. The ratio of fecal Coprococcus to Lachnoclostridium could discriminate between Perio and Non-Perio groups as the ratio of subgingival Porphyromonas to Rothia did. Furthermore, there were differentially abundant fecal metabolic features pivotally enriched in periodontitis subjects like L-urobilin and kynurenic acid. We revealed a periodontitis-oriented integrative network cluster, which was centered with fecal Coprococcus and L-urobilin as well as serum triglyceride. CONCLUSIONS: The current findings about the notable influence of periodontitis on fecal microbiota and metabolites in first-trimester pregnant women via oral-gut axis signify the importance and translational implications of preconceptional oral/periodontal healthcare for enhancing maternal wellbeing.

Clinical outcomes and supragingival microbiota analysis around dental implants and teeth in patients with a history of periodontitis: a preliminary study of 6 months follow-up.

OBJECTIVES: To investigate the supragingival microbiome surrounding dental implants and neighbouring tooth in periodontitis history and periodontally healthy patients. METHODS: Subjects with a history of periodontitis (test) and periodontally healthy subjects (control) received one of two types of dental implants with different surface characteristics: sandblasted acid-etched (SLA) or precision dimension laser-treated (PDL). Periodontal clinical measurements were collected at baseline (V1), 3 months after implant placement (V4), at zirconia crown placement (V6) and 3 months after zirconia crown placement (V8). Supragingival bacterial microbiota was studied using Illumina MiSeq sequencing. RESULTS: Supragingival microbial community on SLA implants in test group significantly differed to control group at V8 (p < 0.05). A longitudinal shift displaying microbial dysbiosis occurred on SLA implants (p < 0.05) and adjacent teeth (p < 0.05) among test patients from V6 to V8. On PDL implants and the adjacent tooth, no significant difference between test and control groups from V6 to V8 (p > 0.05). Co-occurrence network in test group of SLA implants and the adjacent tooth at V8 showed increased disease-associated bacteria and reduced health-associated bacteria. Health-associated bacteria were dominant in control group of SLA implants at V8. CONCLUSION: The surface characteristics and prosthetic components of dental implants may be important risk factors in patients with a history of periodontitis. CLINICAL RELEVANCE: Dysbiosis of supragingival microbiome may predispose dental implants to peri-implant diseases. Thus, a strict supportive periodontal care plan is imperative to prevent early onset of biological complications.

M2 macrophage-derived exosomes enable osteogenic differentiation and inhibit inflammation in human periodontal ligament stem cells through promotion of CXCL12 expression.

BACKGROUND: Periodontitis is a dental disease characterized by inflammation of periodontal tissues and loss of the periodontal ligaments and alveolar bone. Exosomes are a class of extracellular vesicles that are involved in a variety of diseases by releasing active substances. In this study, we aimed to investigate the effect and mechanism of exosomes from M2 polarized macrophages (M2-exos) on osteogenic differentiation in human periodontal ligament stem cells (hPDLSCs). METHODS: M2-exos were isolated from IL-4-induced RAW264.7 cells (M2 macrophages) and then treated on hPDLSCs. Osteogenic differentiation was assessed by alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining, measurement of osteogenic differentiation-related genes and proteins, and inflammation was evaluated by measuring the levels of inflammatory factors. The mechanism of M2-exo was confirmed through qPCR, western blot, ALP and ARS staining. RESULTS: Results suggested that M2-exo improved osteogenic differentiation and inhibited inflammation in LPS-induced hPDLSCs. CXCL12 expression was elevated in M2 macrophages, but decreased in LPS-induced hPDLSCs. Moreover, the effect of M2-exo on osteogenic differentiation and inflammation in LPS-induced hPDLSCs was reversed by CXCL12 knockdown. CONCLUSION: We demonstrated that M2-exo facilitated osteogenic differentiation and suppressed inflammation in LPS-induced hPDLSCs through promotion of CXCL12 expression. These results suggested the potential of M2-exo in the treatment of periodontitis, which may provide a new theoretical basis for M2-exo treatment of periodontitis.

The association between periodontal microbial biomarkers and primary therapy outcome.

OBJECTIVE: This study aims to analyse the association between the baseline microbial load of selected periodontopathogenic bacteria collected from gingival crevicular fluid (GCF) and the primary outcome of steps I and II therapy. MATERIALS AND METHODS: 222 patients with stage III periodontitis were included into this retrospective analysis that received steps 1 and 2 periodontal therapy without adjunctive systemic antibiotics. Baseline GCF samples were quantitatively analysed using ELISA-based kits for levels of periodontopathogens (Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn), Treponema denticola (Td), and Tannerella forsythia (Tf)) and associated with the primary therapy outcome using a "treat-to-target" therapy endpoint (TE) defined as ≤ 4 sites with PD ≥ 5 mm six months after therapy. RESULTS: 38.2% of the patients achieved TE. Patients failing to achieve TE revealed significantly increased levels of Pg, Fn, and Tf at baseline (Pg: p = 0.010, Fn: p = 0.008 Tf: p = 0.004). Multivariate binary logistic regression adjusted for sex, mean probing depth, diabetes, and current smoking status showed an independent relationship between Tf and the TE (aOR 2.570, p = 0.023). CONCLUSION: Increased microbial load is associated with decreased responsiveness to therapy. The findings suggest that specifically baseline Tf levels are associated with poorer treatment outcomes and might improve the accuracy of periodontal diagnosis. CLINICAL RELEVANCE: The findings of this study support the concept of a critical biomass that is sufficient to induce and maintain an immune response within the periodontal pocket, which ultimately leads to irreversible tissue destruction. However, calculating this level in advance may serve as an early indicator for intervention. KEY FINDING: Baseline Tannerella forsythia levels are associated with poorer treatment outcome.

Periodontitis: orthodontic implications and management.

Orthodontics is increasingly ingrained in the overall management of patients with periodontitis. Advanced periodontitis is often characterised by pathological tooth migration, loss of posterior support and incisal proclination. Orthodontics may therefore offer both aesthetic and therapeutic benefit. A tailored approach to treatment, however, is necessary given the myriad of presentations and associated risk. The nuances underpinning effective treatment planning, space creation, treatment mechanics, and retention in the periodontal patient are described.

Discovering common pathogenetic processes between periodontitis and Alzheimer's disease by bioinformatics and system biology approach.

BACKGROUND: There is increasing evidence that inflammation plays a key role in the pathophysiology of periodontitis (PT) and Alzheimer's disease (AD), but the roles of inflammation in linking PT and AD are not clear. Our aim is to analyze the potential molecular mechanisms between these two diseases using bioinformatics and systems biology approaches. METHODS: To elucidate the link between PT and AD, we selected shared genes (SGs) with gene-disease-association scores of ≥ 0.1 from the Disease Gene Network (DisGeNET) database, followed by extracting the hub genes. Based on these genes, we constructed gene ontology (GO) enrichment analysis, pathway enrichment analysis, protein-protein interaction (PPI) networks, transcription factors (TFs)-gene networks, microRNAs (miRNAs)-gene regulatory networks, and gene-disease association analyses. Finally, the Drug Signatures database (DSigDB) was utilized to predict candidate molecular drugs related to hub genes. RESULTS: A total of 21 common SGs between PT and AD were obtained. Cell cytokine activity, inflammatory response, and extracellular membrane were the most important enriched items in GO analysis. Interleukin-10 Signaling, LTF Danger Signal Response Pathway, and RAGE Pathway were identified as important shared pathways. IL6, IL10, IL1B, TNF, IFNG, CXCL8, CCL2, MMP9, TLR4 were identified as hub genes. Both shared pathways and hub genes are closely related to endoplasmic reticulum (ER) stress and mitochondrial dysfunction. Importantly, glutathione, simvastatin, and dexamethasone were identified as important candidate drugs for the treatment of PT and AD. CONCLUSIONS: There is a close link between PT and AD pathogenesis, which may involve in the inflammation, ER and mitochondrial function.