Association between periodontal disease, tooth loss and liver diseases risk

Exploring the link between periodontal disease and sperm quality: a comprehensive systematic review study

BACKGROUND

Periodontal diseases are among the most prevalent oral health conditions globally, with evidence suggesting their systemic effects, including potential impacts on male reproductive health. Inflammation associated with periodontitis might interfere with spermatogenesis and alter sperm parameters such as count, motility, morphology, and DNA integrity. This systematic review aims to critically assess existing studies on the relationship between periodontal disease and sperm quality to delineate its clinical implications for male infertility.

METHODS

The research was registered in the International Prospective Register of Systematic Reviews (PROSPERO) at the National Institute for Health Research (PROSPERO code: CRD420251005800). A comprehensive literature search was conducted across multiple databases, including PubMed, EMBASE, ProQuest, Scopus, Web of Science (WOS), and Google Scholar, up to September 2024. Inclusion criteria targeted human studies reporting associations between periodontal health and sperm quality parameters. To assess the quality of the included studies, the Newcastle-Ottawa Scale (NOS) was used. Data were synthesized qualitatively and analyzed for trends.

RESULTS

Nine studies encompassing 1,386 participants were included. Evidence suggests a significant association between periodontitis and decreased sperm motility, abnormal morphology, and increased DNA fragmentation. However, findings on sperm count and concentration were inconsistent. Mechanistic pathways suggest that inflammatory cytokines and oxidative stress contribute to these disruptions.

CONCLUSION

This review highlights the systemic implications of periodontal disease on male reproductive health. Given the global decline in male fertility, maintaining oral health may serve as an adjunct strategy in managing infertility. Future research should prioritize large-scale, longitudinal studies to establish causality and explore preventive interventions.

Porphyromonas gingivalis aggravates alcohol-related liver injury via gut microbiome-HO-1-ACSL4-dependent ferroptosis

Background

Alcoholic liver disease (ALD) is a common liver condition caused by long-term alcohol consumption, and its specific molecular mechanism remains unclear. It may be influenced to some extent by ferroptosis and Porphyromonas gingivalis (P.g), which is an important pathogen of periodontitis.

Materials and methods

C57BL/6 J mice and AML12 cells were selected as the study subjects. The periodontitis model was induced using P.g, and the alcoholic liver model was created. Pathological analysis was performed on the liver, intestine, and periodontal tissues. 16S rRNA sequencing was used to analyze changes in the intestinal flora and intestinal gap junction protein (zonula occludens-1 (ZO-1) and occludin) levels in each group. Ferroptosis indices were detected in the liver tissues and AML12 cells.

Results

Oral exposure to P.g induced mice periodontitis and exacerbated alcohol-related liver injury. Both alcohol and P.g caused intestinal flora disturbance, damage to the intestinal epithelial barrier, increased permeability, and activation of mouse hepatocyte ferroptosis. Furthermore, P.g aggravated such alcohol-induced liver damage.

Conclusion

Both alcohol and P.g can lead to intestinal flora disturbance, damage to the intestinal epithelial barrier, increased permeability, and the activation of mouse hepatocyte ferroptosis, and P.g can aggravate such alcohol-induced liver damage. Acyl-CoA synthetase long-chain family member 4 (ACSL4) and heme oxygenase-1 (HO-1) play important roles in the exacerbation of alcoholic liver injury by P.g.

The role of cytokines as predictors for NAFLD-related diseases: A bidirectional Mendelian randomization study

BACKGROUND

Prior research has highlighted associations between inflammatory cytokines and non-alcoholic fatty liver disease (NAFLD), but causal relationships remain unclear. Employing the Mendelian randomization (MR) approach, this investigation aims to explore the connection between 41 inflammatory cytokines and NAFLD-related diseases.

METHODS

Our research implemented bidirectional study focusing on 41 cytokines in 8,293 Finns, predicting genetic associations with NAFLD, nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. We primarily utilized the inverse variance weighted (IVW) method to evaluate the bidirectional relationships. Additionally, a sensitivity analysis was carried out to ensure the reliability of our findings.

RESULTS

An elevated risk for NAFLD was correlated with both IL-2 (OR = 1.226, 95 % CI = 1.018-1.477, p = 0.031) and TNF-β (OR = 1.151, 95 % CI = 1.011-1.310, p = 0.033). IL-16 is associated with decreased NAFLD risk (OR = 0.820, 95 % CI = 0.719-0.934, p = 0.033). β-NGF (OR = 2.495, 95 % CI = 1.019-6.108, p = 0.045) and SCGFβ (OR = 1.541, 95 % CI = 1.052-2.256, p = 0.026) are linked to higher NASH risk. No significant associations were found for fibrosis and cirrhosis. Furthermore, the causal relationship between genetic predisposition to NAFLD-related diseases and various inflammatory cytokines was established.

CONCLUSIONS

Our MR analysis identifies specific cytokines as genetic predictors for NAFLD and NASH. IL-2 and TNF-β increase NAFLD risk, IL-16 appears protective, and β-NGF and SCGFβ are associated with greater NASH risk. These insights are crucial for understanding the etiology and treatment of NAFLD-related diseases.

Association between chronic diseases and severe periodontal disease progression: A retrospective cohort study in a city of Japan

Background

Chronic periodontal disease primarily causes tooth loss and oral frailty and is linked to chronic conditions such as diabetes mellitus. However, its progression and broader studies on chronic diseases have not been well explored. This study aimed to investigate this association using claims data.

Methods

This retrospective cohort study used linked medical, dental, and pharmacy claims data from a local municipality in Japan. The study included participants aged 40-70 years who had received medical care between April 2017 and March 2018. Exposures included age, sex, and common chronic diseases previously reported to be associated with periodontal diseases (21 diseases). We defined the outcome, "progression of severe periodontitis" as the worsening of periodontal disease to a severe stage requiring surgery or tooth extraction, determined by the presence of a periodontal surgery code or a deeper probing pocket depth (≥6 mm) code along with the tooth extraction procedure code. The participants were followed up until March 2022, and multivariate analysis was conducted using Cox proportional hazard models.

Results

Among 28,846 participants, 1035 (3.6%) progressed to severe periodontal disease. In the multivariate analysis, only diabetes mellitus was significantly associated with severe periodontal disease, with a hazard ratio of 1.26 (95% confidence interval, 1.08-1.53) among all chronic diseases.

Conclusion

Patients with diabetes mellitus had a high risk of severe periodontal disease progression, suggesting that proactive dental visits should be recommended to prevent severe periodontal disease.

Role of viruses in periodontitis: An extensive review of herpesviruses, human immunodeficiency virus, coronavirus-19, papillomavirus and hepatitis viruses

Periodontitis is the inflammation of the supporting structures around the dentition. Several microbial agents, mostly bacteria, have been identified as causative factors for periodontal disease. On the other hand, oral cavity is a rich reservoir for viruses since it contains a wide variety of cell types that can be targeted by viruses. Traditionally, the focus of research about the oral flora has been on bacteria because the most widespread oral diseases, like periodontitis and dental caries, are outcomes of bacterial infection. However, recently and especially after the emergence of coronavirus disease 2019, there is a growing tendency toward including viruses also into the scope of oral microbiome investigations. The global high prevalence of periodontitis and viral infections may point out to a concomitant or synergistic effect between the two. Although the exact nature of the mechanism still is not clearly understood, this could be speculated through the manipulation of the immune system by viruses; hence facilitating the furthermore colonization of the oral tissues by bacteria. This review provides an extensive and detailed update on the role of the most common viruses including herpes family (herpes simplex, varicella-zoster, Epstein-Barr, cytomegalovirus), Human papillomaviruses, Human immunodeficiency virus and severe acute respiratory syndrome coronavirus 2 in the initiation, progression and prognosis of periodontitis.

Periodontal tissue susceptibility to glycaemic control in type 2 diabetes

AIM

To assess the direct effect of intensive glycaemic control on periodontal tissues in patients with diabetes mellitus.

MATERIALS AND METHODS

Twenty-nine patients with type 2 diabetes were enrolled and hospitalized to receive a 2-week intensive glycaemic control regimen. We observed and analysed the systemic and oral disease indicators before and after treatment and clarified the indicators related to periodontal inflammation.

RESULTS

A significant reduction in glycaemic and periodontal parameters, including glycated albumin levels and periodontal inflamed surface area (PISA), was observed after treatment. The changes in PISA per tooth, indicative of periodontal healing, exhibited a bimodal distribution; the patients were divided into two groups on this basis. Correlations were observed between the changes in PISA per tooth and fasting plasma glucose, acetoacetic acid, and beta-hydroxybutyrate levels in the PISA-improved group. Significantly lower levels of C-peptide, coefficient of variation of R-R interval, and ankle-brachial pressure index were observed before treatment in the PISA non-improved group.

CONCLUSIONS

Glycaemic control treatment can effectively improve periodontitis in patients with type 2 diabetes, even in the absence of specific periodontal treatments. However, the periodontal responsiveness to glycaemic control treatment depends on the systemic condition of the patient.

Epidemiological associations between periodontitis and cancer

There is a postulated association of periodontitis with a number of human cancers. This narrative review provides current epidemiological evidence on the association between periodontitis and cancer. A PubMed search with the relevant keywords (periodontal disease, periodontitis, cancer, and malignancy) was completed to identify relevent articles. We present a narrative review on the association between periodontal disease and a range of cancers, including oral cancer, stomach and esophageal cancer, colorectal cancer, lung cancer, pancreatic cancer, prostate cancer, hematological malignancies, liver cancer, breast cancer, and ovarian cancer. While there is a considerable body of epidemiological evidence that supports the association between periodontal disease and cancer, this is largely from cohort and case-control studies and the association may therefore be circumstantial as little evidence exists in the form of treatment trials that would validate the role of periodontal disease in the process of cancer initiation and development.

Tooth Loss and Systemic Diseases in the Slovenian Elderly Population: A Cross-Sectional Study of the Associaton Between Oral and Systemic Health

Introduction

This study aimed to assess the prevalence of edentulism and tooth loss in the Slovenian elderly population, along with the associated risk factors, and investigate the association between systemic and oral health.

Methods

The study included 445 individuals aged 65 or older (average age: 79.7±8.9 years). Data on preserved teeth, dental history, chronic diseases, and medications were collected through clinical examinations. Height and weight were recorded in order to calculate body mass index (BMI), and the education level was also collected. Chronic systemic diseases and medications were categorized. Statistical analysis was conducted using linear regression and nonparametric tests.

Results

Participants had an average of 4.7±7.7 teeth, with no significant gender differences. Higher age (β=-0.185, p<0.001) and lower education level (p<0.001) were associated with fewer teeth, while higher BMI showed no correlation (β=-0.085, p=0.325). Diabetes mellitus (p=0.031), cardiovascular diseases (p=0.025), and thyroid diseases (p=0.043) were inversely related to retained teeth. This inverse relationship also applied to individuals who recovered from malignancies, not including head and neck malignancies (p=0.019). No significant relationship was found between osteoporosis and the number of teeth (p=0.573). Notably, antidiabetic drug use was inversely related to the number of teeth (p=0.004), while analgesics showed a positive relationship (p=0.022).

Conclusions

This study highlights the association between specific sociodemographic factors, chronic diseases, and retained teeth among elderly individuals in Slovenia. High edentulism rates among the elderly emphasize the need for enhanced preventive measures and risk factor management, particularly for high-risk groups like the elderly.

Role of Nonalcoholic Fatty Liver Disease in Periodontitis: A Bidirectional Relationship

Nonalcoholic fatty liver disease (NAFLD) and periodontitis share common risk factors such as obesity, insulin resistance (IR), and dyslipidemia, which contribute to systemic inflammation. It has been suggested that a bidirectional relationship exists between NAFLD and periodontitis, indicating that one condition may exacerbate the other. NAFLD is characterized by excessive fat deposition in the liver and is associated with low-grade chronic inflammation. There are several risk factors for the development of NAFLD, including gender, geriatric community, race, ethnicity, poor sleep quality and sleep deprivation, physical activity, nutritional status, dysbiosis gut microbiota, increased oxidative stress, overweight, obesity, higher body mass index (BMI), IR, type 2 diabetes mellitus (T2DM), metabolic syndrome (MetS), dyslipidemia (hypercholesterolemia), and sarcopenia (decreased skeletal muscle mass). This systemic inflammation can contribute to the progression of periodontitis by impairing immune responses and exacerbating the inflammatory processes in the periodontal tissues. Furthermore, individuals with NAFLD often exhibit altered lipid metabolism, which may affect oral microbiota composition, leading to dysbiosis and increased susceptibility to periodontal disease. Conversely, periodontitis has been linked to the progression of NAFLD through mechanisms involving systemic inflammation and oxidative stress. Chronic periodontal inflammation can release pro-inflammatory cytokines and bacterial toxins into the bloodstream, contributing to liver inflammation and exacerbating hepatic steatosis. Moreover, periodontitis-induced oxidative stress may promote hepatic lipid accumulation and IR, further aggravating NAFLD. The interplay between NAFLD and periodontitis underscores the importance of comprehensive management strategies targeting both conditions. Lifestyle modifications such as regular exercise, a healthy diet, and proper oral hygiene practices are crucial for preventing and managing these interconnected diseases. Additionally, interdisciplinary collaboration between hepatologists and periodontists is essential for optimizing patient care and improving outcomes in individuals with NAFLD and periodontitis.

Association between cognitive rumination and periodontal disease, tooth loss and oral health-related quality of life in a rural Southern Brazil population

OBJECTIVES

Rumination is a maladaptive emotion regulation strategy. It has been associated with several psychological disorders and physical problems. This cross-sectional study aimed to evaluate whether cognitive rumination is associated with periodontal disease (PD), tooth loss (TL), and oral health-related quality of life (OHRQoL).

MATERIALS AND METHODS

A population-based sample from a rural area in southern Brazil was evaluated. Calibrated examiners carried out a complete periodontal examination at six sites-per-tooth. Rumination and Reflection (RRQ) and Oral Health Impact Profile (OHIP-14) questionnaires were administered. Regression modeling was used to assess the prevalence ratio (PR) between rumination and PD and to estimate the rate ratio (RR) between rumination and TL and rumination and OHIP.

RESULTS

Severe periodontitis prevalence of 33% was observed in the sample. In the Poisson-adjusted model (n = 587), individuals who ruminate more have 27% more periodontal disease (PR: 1.27, 95%CI:1.02 - 1.60). Regarding TL and OHIP, negative binomial regression (n = 672) showed an association with rumination, but it was not significant (RR 1.14, 95%CI 0.99 - 1.31) and (RR 1.20, 95%CI 0.98 - 1.48), respectively.

CONCLUSIONS

Cognitive rumination was independently associated with periodontal disease in individuals living in a rural area. Borderline non-significant estimates were observed regarding TL and OHRQoL. More research using different populations and focusing on individual's responses to psychological stress may confirm these results.

CLINICAL RELEVANCE

Emotional regulation is crucial to deal with stress, anxiety, and depression. Since psychopathologies are among the most prevalent diseases in the world, it is critical to understand the role of these issues in dental outcomes.

The impact of metabolic disorders on management of periodontal health in children

Periodontitis is a chronic inflammatory disease caused by plaque biofilm which shares risk factors with systemic chronic diseases such as diabetes, cardiovascular disease, and osteoporosis. Many studies have found increased prevalence and rate of progression of periodontal disease in children with common metabolic disorders. Although the causal relationship and specific mechanism between them has not been determined yet. The aim of this paper is to progress on the impact of metabolic disorders on periodontal health in children and the underlying mechanisms, which provides new evidences for the prevention and intervention of metabolic disorders and periodontitis in children.

Nisin lantibiotic prevents NAFLD liver steatosis and mitochondrial oxidative stress following periodontal disease by abrogating oral, gut and liver dysbiosis

Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum, were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin's ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

The Gum-Gut Axis: Periodontitis and the Risk of Gastrointestinal Cancers

Periodontitis has been linked to an increased risk of various chronic non-communicable diseases, including gastrointestinal cancers. Indeed, dysbiosis of the oral microbiome and immune-inflammatory pathways related to periodontitis may impact the pathophysiology of the gastrointestinal tract and its accessory organs through the so-called "gum-gut axis". In addition to the hematogenous spread of periodontal pathogens and inflammatory cytokines, recent research suggests that oral pathobionts may translocate to the gastrointestinal tract through saliva, possibly impacting neoplastic processes in the gastrointestinal, liver, and pancreatic systems. The exact mechanisms by which oral pathogens contribute to the development of digestive tract cancers are not fully understood but may involve dysbiosis of the gut microbiome, chronic inflammation, and immune modulation/evasion, mainly through the interaction with T-helper and monocytic cells. Specifically, keystone periodontal pathogens, including Porphyromonas gingivalis and Fusobacterium nucleatum, are known to interact with the molecular hallmarks of gastrointestinal cancers, inducing genomic mutations, and promote a permissive immune microenvironment by impairing anti-tumor checkpoints. The evidence gathered here suggests a possible role of periodontitis and oral dysbiosis in the carcinogenesis of the enteral tract. The "gum-gut axis" may therefore represent a promising target for the development of strategies for the prevention and treatment of gastrointestinal cancers.

Associations between Periodontal Status and Liver Function in the Japanese Population: A Cross-Sectional Study

A relationship between periodontitis and liver function has been suggested. Indeed, patients with severe periodontal disease have been found to be more prone to liver dysfunction. The periodontal inflammatory surface area (PISA) has been shown to be a useful indicator of periodontal and systemic diseases. However, little information is available regarding whether the PISA is associated with liver function markers, such as gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). This study aimed to clarify relationship between liver function markers, AST, ALT, and GGT, and PISA level in a cross-sectional study. The subjects were recruited between 2018 and 2021 at the Medical and Dental Collaboration Center of Kanagawa Dental College Hospital. A periodontal clinical examination was performed, and the PISA was calculated. Peripheral blood samples were collected, and serum levels of liver function markers were measured. The levels of liver function markers were examined in different values of PISA. Participants with high PISA scores were more likely to have increased GGT levels while AST and ALT were not changed with PISA. Increased GGT was found in 10.8% and 29.4% (p = 0.0056), increased AST in 48.2% and 52.9% (p = 0.62), and increased ALT in 35.2% and 47.0% (p = 0.20) among <300 mm² and ≧300 mm² PISA groups, respectively. It was found that males with a PISA of 300 mm² or higher had an elevated level of serum GGT. In conclusion, elevated GGT was found in the high PISA group, particularly in males, while AST and ALT did not differ by PISA.

Periodontal health status in cirrhotic patients: a systematic review and meta-analysis

OBJECTIVES

Liver cirrhosis is a disease with widespread prevalence and high mortality. Oral manifestations, particularly periodontal-related manifestations such as bleeding gums, red and swollen gums, are common in cirrhotic patients but may often be overshadowed by other systemic complications, making them easy to ignore. So this article conducts a systematic review and meta-analysis of periodontal health status in patients with cirrhosis.

MATERIAL AND METHODS

We performed electronic searches on the following databases: PubMed, EMBASE, Scopus, Web of Science, and Cochrane Library. Risk of bias evaluation was carried out according to the Fowkes and Fulton guidelines. Meta-analyses were performed with tests for sensitivity and statistical heterogeneity.

RESULTS

Of the 368 potentially eligible articles, 12 studies were included for qualitative analysis, and 9 contributed to the meta-analysis. In terms of periodontal-related parameters, cirrhotic patients presented a greater mean of clinical attachment loss (CAL) (weighted mean differences [WMD] = 1.078, 95% confidence interval [95% CI]: 0.546-1.609, p < 0.001), probing depth (PD) (WMD = 0.796, 95% CI: 0.158 to 1.434, p = 0.015) and alveolar bone loss (ABL) (WMD = 3.465, 95% CI: 2.946-3.984, p < 0.001) than those without, while no statistical difference was found in the papillary bleeding index (PBI) (WMD = 0.166, 95% CI: -0546 to 0.878, p = 0.647) and bleeding on probing (BOP) (WMD = 4.913, 95% CI: -3.099 to 12.926, p = 0.229). The prevalence of periodontitis was higher in cirrhotic patients than in the control group (odds ratio [OR] = 2.630, 95% CI: 1.531-4.520, p < 0.001).

CONCLUSIONS

The results indicate that cirrhotic patients have poor periodontal conditions and a higher prevalence of periodontitis. We advocate that they should receive regular oral hygiene and basic periodontal treatment.

Mendelian Randomization Analyses of Chronic Immune-Mediated Diseases, Circulating Inflammatory Biomarkers, and Cytokines in Relation to Liver Cancer

Liver cancer is closely linked to chronic inflammation. While observational studies have reported positive associations between extrahepatic immune-mediated diseases and systemic inflammatory biomarkers and liver cancer, the genetic association between these inflammatory traits and liver cancer remains elusive and merits further investigation. We conducted a two-sample Mendelian randomization (MR) analysis, using inflammatory traits as exposures and liver cancer as the outcome. The genetic summary data of both exposures and outcome were retrieved from previous genome-wide association studies (GWAS). Four MR methods, including inverse-variance-weighted (IVW), MR-Egger regression, weighted-median, and weighted-mode methods, were employed to examine the genetic association between inflammatory traits and liver cancer. Nine extrahepatic immune-mediated diseases, seven circulating inflammatory biomarkers, and 187 inflammatory cytokines were analyzed in this study. The IVW method suggested that none of the nine immune-mediated diseases were associated with the risk of liver cancer, with odds ratios of 1.08 (95% CI 0.87-1.35) for asthma, 0.98 (95% CI 0.91-1.06) for rheumatoid arthritis, 1.01 (95% CI 0.96-1.07) for type 1 diabetes, 1.01 (95% CI 0.98-1.03) for psoriasis, 0.98 (95% CI 0.89-1.08) for Crohn's disease, 1.02 (95% CI 0.91-1.13) for ulcerative colitis, 0.91 (95% CI 0.74-1.11) for celiac disease, 0.93 (95% CI 0.84-1.05) for multiple sclerosis, and 1.05 (95% CI 0.97-1.13) for systemic lupus erythematosus. Similarly, no significant association was found between circulating inflammatory biomarkers and cytokines and liver cancer after correcting for multiple testing. The findings were consistent across all four MR methods used in this study. Our findings do not support a genetic association between extrahepatic inflammatory traits and liver cancer. However, larger-scale GWAS summary data and more genetic instruments are needed to confirm these findings.

Periodontal disease and systemic health: An update for medical practitioners

INTRODUCTION

Chronic periodontal disease is a highly prevalent dental condition affecting tooth-supporting tissues. Scientific evidence is accumulating on links between periodontal disease and various systemic conditions. This narrative review provides a holistic yet succinct overview that would assist medical practitioners to deliver integrated care for better clinical outcomes.

METHOD

Scientific evidence on associations between periodontal disease and systemic conditions was synthesised and critically appraised. Key findings of latest prospective cohort studies, randomised clinical trials, and meta-analysis were closely assessed and compiled.

RESULTS

A bidirectional relationship has been established, indicating that diabetes and periodontal disease are closely linked and amplify one another, if not successfully controlled. Existing evidence also supports the associations of periodontal disease with cardiovascular diseases and adverse pregnancy outcomes. Successful treatment of periodontal disease and dental prophylaxis has been shown to improve clinical outcomes in these systemic conditions. Other systemic conditions associated with periodontal disease include respiratory diseases, Alzheimer's disease, rheumatoid arthritis and chronic kidney disease. Although the underlying mechanisms remain to be fully elucidated, it is generally accepted that the inflammatory burden of chronic periodontal disease has an important systemic impact.

CONCLUSION

Oral-systemic links are multifaceted and complex. While evidence linking periodontal disease with a variety of systemic conditions is still emerging, the nature of the relationship is becoming clearer. The updated understanding of these associations warrants the attention of medical experts and policymakers for a concerted effort to develop a patient-centric, integrated model for the treatment of comorbid dental and medical conditions.

Is the Number of Missing Teeth Associated With Mortality? A Longitudinal Study Using a National Health Screening Cohort

This study aimed to estimate the risk of mortality related to the number of missing teeth in a South Korean population. The ≥ 40-year-old population of the Korean National Health Insurance Service-Health Screening Cohort 2002–2003 was analyzed. Participants were selected from a total of 220,189 participants and included in groups of 0 teeth lost, 1–2 teeth lost, and ≥ 3 teeth lost. Among the total population, 17,211 participants were included in no missing teeth, 1–2 missing teeth, and ≥ 3 missing teeth and were randomly matched 1:1:1 for age and sex. Mortality from specific causes and all-cause mortality were compared among the groups. The hazard ratio (HR) of the number of missing teeth for all-cause mortality or each cause of mortality was analyzed using Cox proportional hazard models. According to the cause of death, the HRs for metabolic disease, digestive disease, and trauma were greater in the group with ≥ 3 missing teeth than in the no missing teeth group. The group with ≥ 3 missing teeth indicated a 1.19-fold higher HR for all-cause mortality than the no missing teeth group [95% confidence intervals (95% CIs) = 1.12–1.27, P &lt; 0.001]. The group with 1- 2 missing teeth did not show a higher HR for all-cause mortality. In the group with 1–2 missing teeth, the HRs for mortality from mental disease and digestive disease were higher than those in the no missing teeth group. The group with 1–2 missing teeth did not show a higher HR for all-cause mortality. The number of missing teeth was linked with a higher risk of mortality. For specific causes of mortality, mortality from metabolic disease, digestive disease, and trauma was higher in the participants with the number of missing teeth.

Periodontal disease could be a potential risk factor for non-alcoholic fatty liver disease: An 11-year retrospective follow-up study

OBJECTIVE

This study aimed to evaluate the association of periodontal disease with non-alcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

A retrospective follow-up study using the National Health Insurance Service-National Sample Cohort was performed from 2002 to 2015 in the Korean population. A total of 165,032 subjects were followed up for incident NAFLD during 11 years. Periodontal disease and NAFLD were defined by a diagnosis using the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) codes. Periodontal status was used as the severity of periodontal status and the number of dental visit due to PD.

RESULTS

Periodontitis was associated with a 4% increase in risk for NAFLD after adjusting for socio-demographic factor, health behaviors, and systemic diseases (adjusted hazard ratio [aHR] = 1.04, 95% CI = 1.01 to 1.07). Between the number of dental visit due to PD and the risk for NAFLD was observed a dose-effect association (aHR = 1.02, 95% CI = 0.99 to 1.05 for once; aHR = 1.10, 95% CI = 1.06 to 1.15 for two times; aHR = 1.14, 95% CI = 1.06 to 1.24 for three times).

CONCLUSIONS

Our data confirmed that periodontitis showed an association with a higher incidence of NAFLD.

CLINICAL RELEVANCE

Prevention and management of periodontal disease could be beneficial for reducing the risk of NAFLD.

Titanium Dental Implants: An Overview of Applied Nanobiotechnology to Improve Biocompatibility and Prevent Infections

This review addresses the different aspects of the use of titanium and its alloys in the production of dental implants, the most common causes of implant failures and the development of improved surfaces capable of stimulating osseointegration and guaranteeing the long-term success of dental implants. Titanium is the main material for the development of dental implants; despite this, different surface modifications are studied aiming to improve the osseointegration process. Nanoscale modifications and the bioactivation of surfaces with biological molecules can promote faster healing when compared to smooth surfaces. Recent studies have also pointed out that gradual changes in the implant, based on the microenvironment of insertion, are factors that may improve the integration of the implant with soft and bone tissues, preventing infections and osseointegration failures. In this context, the understanding that nanobiotechnological surface modifications in titanium dental implants improve the osseointegration process arouses interest in the development of new strategies, which is a highly relevant factor in the production of improved dental materials.

Bmal1 promotes cementoblast differentiation and cementum mineralization via Wnt/β-catenin signaling

Remodeling of the cementum plays a crucial role in periodontal regenerative therapy, while the precise mechanism of cementogenesis has yet been adequately understood. Recent studies have indicated the connection between osteogenic differentiation and Brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein-1 (Bmal1). Besides, Wnt/β-catenin signaling is proven to be an essential regulator in cementogenesis. In this study, we found a robust expression of Bmal1 in cementoblasts in the mandibular first molar of mice by immunohistochemical staining. To further explore the role of Bmal1 in cementogenesis, we examined the expression pattern of Bmal1 in OCCM-30, an immortalized murine cementoblast cell line by qRT-PCR and western blot. Our data demonstrated the upregulation of Bmal1 at both mRNA and protein levels during differentiation. Additionally, stable knockdown of Bmal1 in OCCM-30 cells resulted in downregulation of osteogenic markers such as alkaline phosphatase (Alp), osteopontin (Opn), and osteocalcin (Ocn), and reduced formation of mineralized nodules. Moreover, qRT-PCR and western blot results exhibited that the expression of β-catenin was attenuated by Bmal1 deficiency. We also found that the mRNA levels of Tcf1 and Lef1, the target transcription factors of β-catenin, were reduced by Bmal1 deficiency. In conclusion, this study preliminarily confirms that Bmal1 promotes cementoblast differentiation and cementum mineralization via Wnt/β-catenin signaling, which contributes to a potential strategy in periodontal regenerative therapy.

Association between liver cirrhosis and peri-implant diseases: a case-control study on implant- and patient-related risk factors

OBJECTIVE

The objective of this study was to evaluate the potential association between liver cirrhosis and peri-implant diseases, as well as the influence of different risk indicators on this association.

METHODS

This case-control study included 64 cases with liver cirrhosis and 128 controls without liver diseases that presented the same socio-demographic and economic profile. The specific inclusion criteria were the following: aged group of 35-55 years and presenting at least one osseointegrated implant functioning for >5 years. A full-mouth peri-implant and periodontal examination was performed and risk variables were recorded. The association between risk variables and the occurrence of peri-implant diseases was tested through univariate analysis and multivariate logistic regression, stratified by alcohol status. Additionally, a mediation analysis was performed to examine the mediating effect of age with peri-implantitis.

RESULTS

A high prevalence of peri-implantitis (29.7%) was observed among cases when compared to controls (18.0%). Individuals with cirrhosis presented ~2.5 higher chance of having peri-implantitis than controls (p<0.001). Significant variables associated with the occurrence of peri-implantitis in the final logistic model were the following: cirrhosis, alcohol use, age (>55 years), male sex, smoking, periodontitis, and number of ≤14.

CONCLUSIONS

An important risk association between liver cirrhosis and peri-implantitis was reported. Future studies with a larger sample size controlling for the patient- and implant-related confounders are needed to better understand the link between peri-implantitis and liver cirrhosis.

CLINICAL RELEVANCE

Cirrhosis individuals, age, and periodontitis, as well as alcohol use and smoking interaction, should be considered as potential risk indicators for peri-implantitis.

The validity of self-reported number of teeth and edentulousness among Norwegian older adults, the HUNT Study

Background

Number of teeth is an established indicator of oral health and is commonly self-reported in epidemiological studies due to the costly and labor-intensive nature of clinical examinations. Although previous studies have found self-reported number of teeth to be a reasonably accurate measure, its accuracy among older adults ≥ 70 years is less explored. The aim of this study was to assess the validity of self-reported number of teeth and edentulousness in older adults and to investigate factors that may affect the accuracy of self-reports.

Methods

This study included two different samples of older adults ≥ 70 years drawn from the fourth wave of the Trøndelag Health Study (the HUNT Study), Norway. Sample 1 (n = 586) was used to evaluate the validity of self-reported number of teeth and sample 2 (n = 518) was used to evaluate self-reported edentulousness. Information on number of teeth and background variables (education, smoking, cognitive function, and self-perceived general and oral health) were self-reported in questionnaires, while clinical oral health examinations assessed number of teeth, number of teeth restored or replaced by fixed prosthodontics and edentulousness. Spearman and Pearson correlation coefficients, Bland–Altman plot, chi-square test and kappa statistics were used to assess the agreement between self-reported and clinically recorded number of teeth.

Results

The mean difference between self-reported and clinically recorded number of teeth was low (− 0.22 teeth), and more than 70% of the participants reported their number of teeth within an error of two teeth. Correlations between self-reports and clinical examinations were high for the total sample (0.86 (Spearman) and 0.91 (Pearson)). However, a lower correlation was found among participants with dementia (0.74 (Spearman) and 0.85 (Pearson)), participants having ≥ 20 teeth (0.76 (Spearman) and 0.67 (Pearson)), and participants with ≥ 5 teeth restored or replaced by fixed prosthodontics (0.75 (Spearman) and 0.77 (Pearson)). Self-reports of having teeth or being edentulous were correct in 96.3% of the cases (kappa value 0.93, p value < 0.001).

Conclusions

Among older Norwegian adults, self-reported number of teeth agreed closely with clinical tooth counts and nearly all the edentulous participants correctly reported having no teeth.

Porphyromonas gingivalis Induces Increases in Branched-Chain Amino Acid Levels and Exacerbates Liver Injury Through livh/livk

Porphyromonas gingivalis, a keystone periodontal pathogen, has emerged as a risk factor for systemic chronic diseases, including non-alcoholic fatty liver disease (NAFLD). To clarify the mechanism by which this pathogen induces such diseases, we simultaneously analyzed the transcriptome of intracellular P. gingivalis and infected host cells via dual RNA sequencing. Pathway analysis was also performed to determine the differentially expressed genes in the infected cells. Further, the infection-induced notable expression of P. gingivalis livk and livh genes, which participate in branched-chain amino acid (BCAA) transfer, was also analyzed. Furthermore, given that the results of recent studies have associated NAFLD progression with elevated serum BCAA levels, which reportedly, are upregulated by P. gingivalis, we hypothesized that this pathogen may induce increases in serum BCAA levels and exacerbate liver injury via livh/livk. To verify this hypothesis, we constructed P. gingivalis livh/livk-deficient strains (Δlivk, Δlivh) and established a high-fat diet (HFD)-fed murine model infected with P. gingivalis. Thereafter, the kinetic growth and exopolysaccharide (EPS) production rates as well as the invasion efficiency and in vivo colonization of the mutant strains were compared with those of the parental strain. The serum BCAA and fasting glucose levels of the mice infected with either the wild-type or mutant strains, as well as their liver function were also further investigated. It was observed that P. gingivalis infection enhanced serum BCAA levels and aggravated liver injury in the HFD-fed mice. Additionally, livh deletion had no effect on bacterial growth, EPS production, invasion efficiency, and in vivo colonization, whereas the Δlivk strain showed a slight decrease in invasion efficiency and in vivo colonization. More importantly, however, both the Δlivk and Δlivh strains showed impaired ability to upregulate serum BCAA levels or exacerbate liver injury in HFD-fed mice. Overall, these results suggested that P. gingivalis possibly aggravates NAFLD progression in HFD-fed mice by increasing serum BCAA levels, and this effect showed dependency on the bacterial BCAA transport system.

Periodontitis, chronic liver diseases, and the emerging oral-gut-liver axis

The liver carries out a wide range of functions ranging from the control of metabolites, nutrient storage, and detoxification to immunosurveillance. While inflammation is essential for the tissue remodeling and maintenance of homeostasis and normal liver physiology, constant exposure to dietary and microbial products creates a niche for potentially prolonged immune activation and unresolved inflammation in susceptible host. Failure to restrain inflammation can lead to development of chronic liver diseases characterized by fibrosis, cirrhosis and eventually liver failure. The liver maintains close interactions with numerous organs which can influence its metabolism and physiology. It is also known that oral cavity microenvironment can influence the physiological conditions of other organs and emerging evidence implicates that this could be true for the liver as well. Presence of chronic inflammation and dysbiotic microbiota is a common feature leading to clinical pathology both in periodontitis and chronic liver diseases (CLDs). In fact, known CLDs appear to have some relationship with periodontitis, which impacts the onset or progression of these conditions in a bidirectional crosstalk. In this review, we explore the emerging association between oral‐gut‐liver axis focusing on periodontitis and common CLDs including nonalcoholic fatty liver disease, chronic viral hepatitis, liver cirrhosis, and hepatocellular cancer. We highlight the immune pathways and oral microbiome interactions which can link oral cavity and liver health and offer perspectives for future research.

Poor oral health and risks of total and site-specific cancers in China: A prospective cohort study of 0.5 million adults

BACKGROUND

There is a strong connection between oral health and overall wellness. We aim to examine the association between poor oral health and the risk of developing or dying of cancer, and whether the association differs by residential area.

METHODS

Between 2004 and 2008, a total of 510,148 adults free of cancer were included from the China Kadoorie Biobank study and thereafter followed up to 2015. Poor oral health was assessed from a self-reported baseline questionnaire and defined as a combination of rarely brushing teeth and always gum bleeding. We used Cox proportional hazards models to estimate the hazard ratio (HR) of cancer risk and its associated 95% confidence interval (CI) according to oral health status.

FINDINGS

Overall, 14.9% of participants (19.7% in rural areas and 8.8% in urban areas) reported poor oral health at baseline. After 4,602,743 person-years of follow-up, we identified 23,805 new cancer cases and 11,973 cancer deaths, respectively. Poor oral health was associated with higher risks of total cancer incidence (HR: 1.08, 95% CI: 1.04-1.12) and death (HR: 1.10, 95% CI: 1.05-1.16). For the site-specific cancers, poor oral health was significantly associated with higher risk of stomach cancer incidence (cases: 2964, HR: 1.10, 95% CI: 1.00-1.22), esophageal cancer incidence (cases: 2119, HR: 1.19, 95% CI: 1.07-1.33), esophageal cancer death (cases: 1238, HR: 1.29, 95% CI: 1.12-1.49), liver cancer incidence (cases: 2565, HR: 1.18, 95% CI: 1.06-1.32), and liver cancer death (cases: 1826, HR: 1.20, 95% CI: 1.05-1.36). This positive association was stronger among rural residents compared to urban residents (interaction test P < 0.01).

INTERPRETATION

Our findings indicate that poor oral health is associated with higher risk for cancers, especially digestive system cancers. Promotion of oral health in the general population, especially for rural residents, could have valuable public health significance in preventing major systemic diseases.

FUNDING

Supported by grants (2021YFC2500400, 2016YFC0900500, 2016YFC0900501, 2016YFC0900504) from the National Key Research and Development Program of China, grants from the Kadoorie Charitable Foundation in Hong Kong and grants grants (088158/Z/09/Z, 104085/Z/14/Z, 202922/Z/16/Z) from Wellcome Trust in the UK. CKB is supported by the Kadoorie Charitable Foundation (KCF) in Hong Kong.

Oral Health and Liver Disease: Bidirectional Associations—A Narrative Review

Several links between chronic liver disease and oral health have been described and are discussed in this narrative review. Oral manifestations such as lichen planus, ulcers, xerostomia, erosion and tongue abnormalities seem to be particularly prevalent among patients with chronic liver disease. These may be causal, coincidental, secondary to therapeutic interventions, or attributable to other factors commonly observed in liver disease patients. In addition, findings from both experimental and epidemiological studies suggest that periodontitis can induce liver injury and contribute to the progression of chronic liver disease through periodontitis-induced systemic inflammation, endotoxemia, and gut dysbiosis with increased intestinal translocation. This has brought forward the hypothesis of an oral-gut-liver axis. Preliminary clinical intervention studies indicate that local periodontal treatments may lead to beneficial liver effects, but more human studies are needed to clarify if treatment of periodontitis truly can halt or reverse progression of liver disease and improve liver-related outcomes.

Deciphering the toxicological role of Porphyromonas gingivalis derived endotoxins in liver diseases

Periodontitis is a most prevalent and infectious multifactorial inflammatory disease and is characterized by the progressive destruction of the tooth-supporting tissues. Porphyromonas gingivalis, a Gram‑negative oral anaerobe, mainly causes periodontitis and it is one of the most important risk factors responsible for aggravation of existing systemic diseases. Several experimental and clinical studies have shown the positive association between periodontitis and different forms of liver disease. Periodontal diseases increase the prevalence of non-alcoholic fatty liver diseases and cirrhosis. Infected periodontium and pathogens in the periodontal microenvironments release pathogen-associated molecular patterns such as peptidoglycan, lipopolysaccharides, gingipain, fimbria, bacterial DNA, etc, and damage-associated molecular patterns such as interleukins-1α, β, - 8, and galectin-3, etc. These virulence factors and cytokines enter the bloodstream, disseminate into the whole body, and induce a variety of systemic pathological effects, including liver diseases (steatosis and fibrosis). Maintaining oral hygiene by scaling and root planning significantly improves liver damage in patients with periodontitis. Dentists and physicians should have more awareness in understanding the bidirectional nature of the relationship between oral and systemic diseases. Importantly, periodontitis condition aggravates simple fatty liver into fibrotic disease and therefore, the aim of this review is to understand the possible link between periodontitis and liver diseases.

Edentulism and select chronic diseases among adults aged ≥45 years in China, 2011-2018: A longitudinal study

OBJECTIVES

Information on the association between edentulism and chronic medical conditions in developing countries is lacking. We investigated such information among adults aged ≥45 years in China.

METHODS

A national longitudinal data set from the China Health and Retirement Longitudinal Study (CHARLS) 2011-2018 was analysed. A multilevel logistic regression model was applied to analyse the association between edentulism and select chronic diseases.

RESULTS

There were 74 240 Chinese adults aged ≥45 years in this study. The prevalence of self-reported edentulism was 8.8% in 2011 and had increased to 16.4% by 2018.

CONCLUSION

Edentulism was a factor associated with a higher risk of various self-reported chronic diseases among adults aged ≥45 years in China. Edentulism is one of the comorbidities among ageing people with chronic conditions. Preventive public health policy should consider controlling shared risk factors at an earlier age.

Periodontal disease-related nonalcoholic fatty liver disease and nonalcoholic steatohepatitis: An emerging concept of oral-liver axis

Periodontal disease, a chronic inflammatory disease of the periodontal tissues, is not only a major cause of tooth loss, but it is also known to exacerbate/be associated with various metabolic disorders, such as obesity, diabetes, dyslipidemia, and cardiovascular disease. Recently, growing evidence has suggested that periodontal disease has adverse effects on the pathophysiology of liver disease. In particular, nonalcoholic fatty liver disease, a hepatic manifestation of metabolic syndrome, has been associated with periodontal disease. Nonalcoholic fatty liver disease is characterized by hepatic fat deposition in the absence of a habitual drinking history, viral infections, or autoimmune diseases. A subset of nonalcoholic fatty liver diseases can develop into more severe and progressive forms, namely nonalcoholic steatohepatitis. The latter can lead to cirrhosis and hepatocellular carcinoma, which are end‐stage liver diseases. Extensive research has provided plausible mechanisms to explain how periodontal disease can negatively affect nonalcoholic fatty liver disease and nonalcoholic steatohepatitis, namely via hematogenous or enteral routes. During periodontitis, the liver is under constant exposure to various pathogenic factors that diffuse systemically from the oral cavity, such as bacteria and their by‐products, inflammatory cytokines, and reactive oxygen species, and these can be involved in disease promotion of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Also, gut microbiome dysbiosis induced by enteral translocation of periodontopathic bacteria may impair gut wall barrier function and promote the transfer of hepatotoxins and enterobacteria to the liver through the enterohepatic circulation. Moreover, in a population with metabolic syndrome, the interaction between periodontitis and systemic conditions related to insulin resistance further strengthens the association with nonalcoholic fatty liver disease. However, most of the pathologic links between periodontitis and nonalcoholic fatty liver disease in humans are provided by epidemiologic observational studies, with the causal relationship not yet being established. Several systematic and meta‐analysis studies also show conflicting results. In addition, the effect of periodontal treatment on nonalcoholic fatty liver disease has hardly been studied. Despite these limitations, the global burden of periodontal disease combined with the recent nonalcoholic fatty liver disease epidemic has important clinical and public health implications. Emerging evidence suggests an association between periodontal disease and liver diseases, and thus we propose the term periodontal disease–related nonalcoholic fatty liver disease or periodontal disease–related nonalcoholic steatohepatitis. Continued efforts in this area will pave the way for new diagnostic and therapeutic approaches based on a periodontologic viewpoint to address this life‐threatening liver disease.

Bone healing around titanium implants in a preclinical model of bile duct ligation-induced liver injury

Objectives

Chronic liver disease increases the risk for periodontal disease and osteoporotic fractures, but its impacts on bone regeneration remain unknown. Herein, we studied the impact of liver cirrhosis on peri‐implant bone formation.

Material and Methods

A total of 20 male Wistar rats were randomly divided into two groups: one with the common bile duct ligated (BDL) and the respective sham‐treated control group (SHAM). After four weeks of disease induction, titanium mini‐screws were inserted into the tibia. Successful induction of liver cirrhosis was confirmed by the presence of clinical symptoms. Another four weeks later, peri‐implant bone volume per tissue volume (BV/TV) and bone‐to‐implant contact (BIC) were determined by histomorphometric analysis.

Results

Peri‐implant bone formation was not significantly different between the SHAM and BDL groups. In the cortical compartment, the median percentage of peri‐implant new bone was 10.1% (95% CI of mean 4.0–35.7) and 22.5% (13.8–30.6) in the SHAM and BDL groups, respectively (p = .26). Consistently, the new bone in direct contact with the implant was 18.1% (0.4–37.8) and 23.3% (9.2–32.8) in SHAM and BDL groups, respectively (p = .38). When measuring the medullary compartment, the new bone area was 7.1% (4.8–10.4) and 10.4% (7.2–13.5) in the SHAM and BDL groups, respectively (p = .17). Medullary new bone in direct contact with the implant was 10.0% (1.2–50.4) and 20.6% (16.8–35.3) in SHAM and BDL groups, respectively, and thus comparable between the two groups (p = .46).

Conclusions

Bile duct ligation has no significant impact on the early stages of peri‐implant bone formation.

Relationship between NAFLD and Periodontal Disease from the View of Clinical and Basic Research, and Immunological Response

Periodontal disease is an inflammatory disease caused by pathogenic oral microorganisms that leads to the destruction of alveolar bone and connective tissues around the teeth. Although many studies have shown that periodontal disease is a risk factor for systemic diseases, such as type 2 diabetes and cardiovascular diseases, the relationship between nonalcoholic fatty liver disease (NAFLD) and periodontal disease has not yet been clarified. Thus, the purpose of this review was to reveal the relationship between NAFLD and periodontal disease based on epidemiological studies, basic research, and immunology. Many cross-sectional and prospective epidemiological studies have indicated that periodontal disease is a risk factor for NAFLD. An in vivo animal model revealed that infection with periodontopathic bacteria accelerates the progression of NAFLD accompanied by enhanced steatosis. Moreover, the detection of periodontopathic bacteria in the liver may demonstrate that the bacteria have a direct impact on NAFLD. Furthermore, Porphyromonas gingivalis lipopolysaccharide induces inflammation and accumulation of intracellular lipids in hepatocytes. Th17 may be a key molecule for explaining the relationship between periodontal disease and NAFLD. In this review, we attempted to establish that oral health is essential for systemic health, especially in patients with NAFLD.