Is periodontitis a risk factor for cognitive impairment and dementia? A case-control study

Impact of periodontal disease on cognitive disorders, dementia, and depression: a systematic review and meta-analysis

A growing body of research suggested that there was a link between poor periodontal health and systemic diseases, particularly with the early development of cognitive disorders, dementia, and depression. This is especially true in cases of changes in diet, malnutrition, loss of muscular endurance, and abnormal systemic inflammatory response. Our study aimed to determine the extent of these associations to better target the multi-level healthy aging challenge investigating the impact of periodontal disease on cognitive disorders (cognitive impairment and cognitive decline), dementia, and depression. We conducted a comprehensive literature search up to November 2023 using six different electronic databases. Two independent researchers assessed the eligibility of 7363 records against the inclusion criteria and found only 46 records that met the requirements. The study is registered on PROSPERO (CRD42023485688). We generated random effects pooled estimates and 95% confidence intervals (CI) to evaluate whether periodontal disease increased the risk of the investigated outcomes. The quality assessment revealed moderate quality of evidence and risk of bias. Periodontal disease was found to be associated with both cognitive disorders (relative risk (RR) 1.25, 95% CI 1.11-1.40, in the analysis of cross-sectional studies); cognitive impairment (RR 3.01, 95% CI 1.52-5.95 for longitudinal studies, cognitive decline); and dementia (RR 1.22, 95% CI 1.10-1.36). However, no significant increased risk of depression among subjects with periodontal disease was found (RR 1.07, 95% CI 0.95-1.21). Despite the association with two of the three explored outcomes, the available evidence on periodontal diseases and dementia, cognitive disorders, and depression is controversial due to several limitations. Therefore, further investigations involving validated and standardized tools are required.

Association Between Oral Malodor and Dementia: An 11-Year Follow-Up Study in Japan

Background

As infrequent social interaction is a potential risk of dementia, oral malodor may increase the risk of dementia, including Alzheimer's disease.

Objective

This study investigated the association between malodor and dementia.

Methods

We used the Japan Public Health Center-based Prospective Study data obtained at Yokote City. A total of 1,493 individuals aged 56 to 75 years underwent a dental examination and self-reported survey from May 2005 to January 2006. Follow-up for the onset of dementia was conducted using long-term care insurance data from 2006 to 2016. Hazard ratios of oral malodor on dementia were estimated by the Cox proportional hazards model. The inverse probability-weighted Cox model was used as a sensitivity analysis.

Results

The study comprised 1493 participants (53.6% women) with a mean age of 65.6 (SD = 5.8) years old; at the end of the follow-up, 6.4% (n = 96) developed dementia, and the percentage was 20.7 in severe malodor group. Throughout 15274.133 person-years of follow-up, the average incidence rate for the onset of dementia per 1000 person-years was 6.29. The highest incidence rate was seen in participants with severe malodor (22.4 per 1000 person-years). After adjusting for confounders, compared to those with no malodor, there was a 3.8 (95% confidence interval: 1.5 to 9.4) times greater hazard of developing dementia in participants with severe malodor. The inverse probability weighted Cox model confirmed the same trend with an adjusted marginal hazard ratio of 4.4 (1.2 to 16.4).

CONCLUSIONS

A significant association between oral malodor and the onset of dementia exists.

Association of periodontal disease treatment with mortality in patients with dementia: a population-based retrospective cohort study (2002-2018)

Dementia is one of the leading causes of death worldwide. In this study, we analyzed the association of periodontal treatment with the risk of death in patients with dementia. The analyzed data were obtained by linking the National Health Insurance Corporation claims data between 2002 and 2018 to the Statistics Korea death registry. In total, 1,131,406 patients with dementia aged ≥ 65 years had undergone dental treatment during the study period. Time-dependent Cox proportional hazards model was performed. The mortality rate was approximately 10% among the patients with dementia. The 17-years cumulative survival rates for patients who received periodontal treatment and their untreated counterparts were 83.5% and 71.5%, respectively. The crude hazard ratio of the periodontal group was approximately twice as high as that of the non-periodontal group (1.99; P < 0.001). Furthermore, in the regression model that was adjusted for socio-demographic variables and systematic chronic diseases, the risk of death in the non-periodontal group was approximately 1.83 times higher than that of the periodontal group (P < 0.00). These findings suggest that preventive periodontal treatment may decrease mortality risk in older people with dementia.

Periodontal conditions and association of periodontitis with oral-health-related quality of life in patients experiencing different episodes of bipolar disorder compared with healthy controls

AIM

The aim of the present cross-sectional study was to evaluate periodontal conditions and the association of periodontitis with oral-health-related quality of life (OHRQoL) in patients with a history of bipolar disorder.

MATERIALS AND METHODS

A total of 160 participants were recruited in four groups for the study: 40 patients with euthymic episodes, 40 patients with depression, 40 patients with manic episodes and 40 systemically healthy individuals. Clinical periodontal parameters were recorded. Oral Health Impact Profile (OHIP-14) was used to measure the impact of oral health on the quality of life.

RESULTS

Bipolar disorder groups exhibited generally higher clinical parameters compared with the control group (p < .05). OHIP-14 total score (β = 3.32, 95% confidence interval [CI]: 0.08-6.56, p = .044), functional limitation (β = .89, 95% CI: 0.27-1.49, p = .005) and physical pain (β = .64, 95% CI: 0.01-1.27, p = .046) were associated with bipolar depression episodes. Psychological discomfort was associated with the presence of generalized periodontitis (β = .76, 95% CI: 0.01-1.51, p = .047) and psychological disability was associated with the presence of stage III-IV (β = .83, 95% CI: 0.07-1.59, p = .033) and generalized (β = .75, 95% CI: 0.07-1.42, p = .029) periodontitis.

CONCLUSIONS

According to this study, a history of bipolar disorder episodes (exposure) may be associated with increased prevalence and severity of periodontitis and related reported OHRQoL impacts (outcomes). Bipolar depression episodes had a higher impact on OHRQoL than other bipolar episodes.

The oral-brain axis: can periodontal pathogens trigger the onset and progression of Alzheimer's disease?

Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by a progressive cognitive decline. Sporadic AD, accounting for more than 95% of cases, may arise due to the influence of environmental factors. It was reported that periodontitis, a common oral ailment, shares several risk factors with AD, including advanced age, smoking, diabetes, and hypertension, among others. Periodontitis is an inflammatory disease triggered by dysbiosis of oral microorganisms, whereas Alzheimer's disease is characterized by neuroinflammation. Many studies have indicated that chronic inflammation can instigate brain AD-related pathologies, including amyloid-β plaques, Tau protein hyperphosphorylation, neuroinflammation, and neurodegeneration. The potential involvement of periodontal pathogens and/or their virulence factors in the onset and progression of AD by the oral-brain axis has garnered significant attention among researchers with ongoing investigations. This review has updated the periodontal pathogens potentially associated with AD, elucidating their impact on the central nervous system, immune response, and related pathological processes in the brain to provide valuable insights for future research on the oral-brain axis.

Investigating the potential clinical impact of periodontitis on the progression of Alzheimer's disease: a prospective cohort study

OBJECTIVES

This study aimed to investigate the effect of periodontitis and current occlusal relationship on the progression rate of Alzheimer's disease (AD).

METHODS

Ninety Alzheimer's patients, who were divided into three groups as Stage I (n=42), Stage II (n=29), and Stage III (n=19), based on the Clinical Dementia Rating Scale, were included in the study. Cognitive status of the patients was evaluated with Standardized Mini-Mental Test (SMMT) at baseline and repeated 6 months later. Clinical periodontal examinations were recorded and occlusal relationship status was classified according to the Eichner Index.

RESULTS

Of 90 Alzheimer's patients, 65 were toothed individuals with periodontitis and 25 were edentulous individuals without active periodontal disease. Stage II and Stage III toothed Alzheimer's patients had higher percentage of bleeding on probing (BOP%) and clinical attachment level (CAL) values than Stage I patients (p<0.05). Stage III Alzheimer's patients had significantly higher probing pocket depth (PPD) values than Stage I individuals (p<0.05). ΔSMMT values showed positive correlation with BOP% (r=0.308, p=0.013) and PPD (r=0.275, p=0.027). Among the evaluated parameters, being in the AD Stage II-Stage III, having periodontitis and age variable had significant effects on ΔSMMT levels (p<0.05).

CONCLUSIONS

Within the limits of our study, it can be concluded that periodontitis may increase the severity and also accelerate the progression rate of AD.

CLINICAL RELEVANCE

These results are precious to show the necessity of proper oral hygiene activities and regular dental visits in patients with toothed AD.

CLINICAL TRIAL REGISTRATION

This study was registered and approved by clinical trials (NCT05807100).

Association between Dental Diseases and Oral Hygiene Care and the Risk of Dementia: A Retrospective Cohort Study

OBJECTIVES

To investigate the associations of dental diseases and oral hygiene care with the risk of dementia.

DESIGN

Retrospective longitudinal cohort study.

SETTING AND PARTICIPANTS

We conducted a population-based study of individuals in the Korean National Health Insurance System. A total of 2,555,618 participants who underwent cardiovascular and dental screenings in 2008 were included.

METHODS

Dental diseases including periodontal diseases, dental caries, and tooth loss were assessed by dentists. Information on oral hygiene care, including professional dental cleaning and the frequency of tooth brushing, was collected using a self-administered questionnaire. Study outcomes were all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD).

RESULTS

Periodontal diseases [adjusted hazard ratio (aHR) 1.07, 95% CI 1.04-1.09], dental caries (aHR 1.03, 95% CI 1.00-1.05), and 8-14 missing teeth (aHR 1.07, 95% CI 1.02-1.12) were associated with an increased risk of all-cause dementia. In contrast, either professional dental cleaning or frequent tooth brushing were associated with decreased risks of all-cause dementia (aHR 0.91, 95% CI 0.89-0.93 each; aHR 0.83, 95% CI 0.80-0.86 for both). The increased risks by dental diseases were reduced by oral hygiene care: periodontal diseases with professional dental cleaning (aHR 0.94, 95% CI 0.91-0.98) or tooth brushing ≥2 times/day (aHR 0.97, 95% CI 0.94-1.00) and 1 to 7 missing teeth with professional dental cleaning (aHR 0.94, 95% CI 0.89-0.98) or tooth brushing ≥2 times/day (aHR 0.92, 95% CI 0.89-0.95). Consistent results were noted for AD and VaD and in various subgroup analyses.

CONCLUSION AND IMPLICATIONS

Periodontal disease, dental caries, and a high number of missing teeth were independently associated with a higher risk of dementia. Conversely, improved oral hygiene care, such as professional dental cleaning and frequent tooth brushing, may modify the risk of dementia associated with dental diseases.

Effect of Periodontal Disease on Alzheimer's Disease: A Systematic Review

The aim of this review was to evaluate the relationship between periodontal disease (PD) and the onset and progression of Alzheimer's disease (AD) and to determine whether patients with PD would be at greater risk of developing AD compared to periodontally healthy subjects. This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search for cross-sectional, cohort, or case-control studies was conducted on five databases (PubMed, ScienceDirect, EBSCO, Web of Science, and Scopus). No restrictions were applied to the language and year of publication. Exposure was PD, and the outcome of interest was the onset and/or progression of AD. The risk of bias of the included studies was assessed using the Newcastle-Ottawa Scale (NOS) designed for non-randomized studies. Six studies fulfilling the selection criteria were included in this systematic review. Four of the studies were of cohort design and two were of case-control design. All except one showed a significant association between PD and the risk of AD onset and progression. According to the NOS bias risk assessment, three studies were found to be of good quality, and three other cohort studies were of low quality. Data from this systematic review indicate that patients with PD present a significantly higher risk of AD compared to individuals with healthy periodontium. However, results should be interpreted with caution given the methodological limitations found. For future research, powerful and comparable epidemiological studies are needed to evaluate the relationship between PD and AD.

Periodontal health status of people with dementia - A systematic review of case-control studies

Background

The number of older people increases globally, so is the risk of cognitive impairment. Periodontal diseases are common among older adults with significant tooth loss and periodontal problems. Thus, this review explored the periodontal disease conditions among individuals with and without dementia.

Methods

Available databases such as Medline/Pubmed, Web of Science, Scopus, Cochrane Library and Embase/OVID were used in the search. Case-control studies reporting on periodontal disease and dementia parameters were selected based on PICO (Population, Intervention, Comparison and Outcomes) framework. A Newcastle-Ottawa Scale (NOS) was used to assess the quality reporting of the studies and PRISMA guideline was used for screening.

Results

A total of ten studies were identified for analysis. Most studies reported higher plaque index score (PI), bleeding on probing (BoP), pocket depth (PD) and clinical attachment loss (CAL) among individuals diagnosed with dementia or Alzheimer's disease compared with clinically healthy controls or individual diagnosed without dementia. A higher prevalence of subjects with severe periodontal disease was also observed in individuals diagnosed with dementia/Alzheimer's disease. The quality of the studies was found to be moderate with lower comparability and ascertainment criteria scores.

Conclusion

This qualitative analysis has shown poor periodontal health and increased inflammatory mediators in case groups compared to the control groups. Thus, more quality studies and novel intervention are warranted to reduce the impact of periodontal health on dementia globally.

The role of microbiome-host interactions in the development of Alzheimer´s disease

Alzheimer`s disease (AD) is the most prevalent cause of dementia. It is often assumed that AD is caused by an aggregation of extracellular beta-amyloid and intracellular tau-protein, supported by a recent study showing reduced brain amyloid levels and reduced cognitive decline under treatment with a beta-amyloid-binding antibody. Confirmation of the importance of amyloid as a therapeutic target notwithstanding, the underlying causes of beta-amyloid aggregation in the human brain, however, remain to be elucidated. Multiple lines of evidence point towards an important role of infectious agents and/or inflammatory conditions in the etiology of AD. Various microorganisms have been detected in the cerebrospinal fluid and brains of AD-patients and have thus been hypothesized to be linked to the development of AD, including Porphyromonas gingivalis (PG) and Spirochaetes. Intriguingly, these microorganisms are also found in the oral cavity under normal physiological conditions, which is often affected by multiple pathologies like caries or tooth loss in AD patients. Oral cavity pathologies are mostly accompanied by a compositional shift in the community of oral microbiota, mainly affecting commensal microorganisms and referred to as 'dysbiosis'. Oral dysbiosis seems to be at least partly mediated by key pathogens such as PG, and it is associated with a pro-inflammatory state that promotes the destruction of connective tissue in the mouth, possibly enabling the translocation of pathogenic microbiota from the oral cavity to the nervous system. It has therefore been hypothesized that dysbiosis of the oral microbiome may contribute to the development of AD. In this review, we discuss the infectious hypothesis of AD in the light of the oral microbiome and microbiome-host interactions, which may contribute to or even cause the development of AD. We discuss technical challenges relating to the detection of microorganisms in relevant body fluids and approaches for avoiding false-positives, and introduce the antibacterial protein lactoferrin as a potential link between the dysbiotic microbiome and the host inflammatory reaction.

Confounding in observational studies evaluating the association between Alzheimer's disease and periodontal disease: A systematic review

Background

Studies investigating the association between periodontitis and Alzheimer's disease (AD) suggested indirect (periodontitis would increase the circulation of inflammation-inducible molecules) and direct (periodontopathogens might colonize brains affected by Alzheimer's disease) pathways. While there seems to be a positive relationship between periodontitis and AD, concerns have been raised about the role of confounding.

Aim

To systematically review the literature to assess confounding and their level of heterogeneity in the association between periodontitis and AD. Also, to examine data reporting and interpretation regarding confounding bias.

Methods

This review followed the PRISMA guidelines and was registered within PROSPERO. Electronic searches were performed in seven main databases and three others to capture the "grey literature". The PECO strategy was used to identify observational studies (cross-sectional, case-control, or cohort studies) assessing the association between periodontal disease and AD without restricting publication language and year. Critical appraisal was performed according to the Joanna Briggs Institute guidelines. Confounders were evaluated following a two-step approach.

Results

A total of 3255 studies were found, of which 18 (13 case-control, four cross-sectional, and one cohort) met the eligibility criteria. Participants with AD were 1399 (mean age 64 ± 9 to 84.8 ± 5.6 years), whereas those without AD were 1730 (mean age 62.6 ± 7.1 to 81.4 ± 4.6). Female patients composed most of the sample for both groups. The confounding variables "age" and "sex" were present in all studies. Four studies used the 2017 AAP/EFP periodontal classification. Most studies had a low risk of bias. Fifty percent of the articles did not consider confounding; variation in the adjustment approaches was observed. Additionally, 62% of the studies did not mention bias, and 40% did not discuss any limitations about confounders.

Conclusions

Given the study's limitations, caution must be taken to properly interpret the association between periodontitis and AD.Registration: CRD42022293884.

Alzheimer's Disease: A Systems View Provides a Unifying Explanation of Its Development

Alzheimer's disease (AD) is a debilitating neurodegenerative disorder affecting 50 million people globally. It is characterized by the presence of extracellular senile plaques and intracellular neurofibrillary tangles, consisting of amyloid-β and hyperphosphorylated tau proteins, respectively. Despite global research efforts, there is currently no cure available, due in part to an incomplete understanding of the disease pathogenesis. Numerous possible mechanisms, or hypotheses, explaining the origins of sporadic or late-onset AD have been proposed, including the amyloid-β, inflammatory, vascular, and infectious hypotheses. However, despite ample evidence, the failure of multiple trial drugs at the clinical stage illuminates the possible pitfalls of these hypotheses. Systems biology is a strategy which aims to elucidate the interactions between parts of a whole. Using this approach, the current paper shows how the four previously mentioned hypotheses of AD pathogenesis can be intricately connected. This approach allows for seemingly contradictory evidence to be unified in a system-focused explanation of sporadic AD development. Within this view, it is seen that infectious agents, such as P. gingivalis, may play a central role. The data presented here shows that when present, P. gingivalis or its virulence factors, such as gingipains, may induce or exacerbate pathologies underlying sporadic AD. This evidence supports the view that infectious agents, and specifically P. gingivalis, may be suitable treatment targets in AD.

Cross-Sectional Analysis of Periodontal Disease and Cognitive Impairment Conducted in a Memory Clinic: The Pearl Study

BACKGROUND

Periodontal disease (PeD) is a risk factor of Alzheimer's disease and is associated with cognitive decline in older adults. However, the relationships between subitems of neuropsychological tests and PeD have not been fully clarified.

OBJECTIVE

To evaluate associations between PeD and subitems of neuropsychological tests.

METHODS

We performed a cross-sectional analysis of data of 183 participants (women: 50%, mean age: 79 years) from a clinical study. We enrolled patients who visited our memory clinic and assessed demographics, dementia-related risk factors, neuropsychological tests, brain magnetic resonance images, and a dental screening check. We evaluated the relationships between cognitive function and PeD using multivariable logistic regression analyses.

RESULTS

Participants with dementia were less likely to make periodical visits to the dentist, had fewer teeth, had less frequent tooth brushing habits, and were more likely to have PeD. Impaired cognitive function was significantly associated with an increasing degree of PeD. In multivariable logistic regression analyses, impaired visuospatial function and attention were associated with twice the risk of moderate or severe PeD compared with individuals with preserved visuospatial function and attention (odds ratio: 2.11, 95% confidence interval: 1.04-4.29, p = 0.037). Impaired word recall and recognition and following commands were associated with increased risk of PeD (odds ratio: 2.80, 95% confidence interval: 1.41-5.32, p = 0.003).

CONCLUSIONS

Cognitive decline, such as impaired visuospatial function, attention, word recall and recognition, and inability to follow commands were independently and strongly associated with PeD. These items can be assessed easily on a daily basis.

Is Periodontitis Associated with Age-Related Cognitive Impairment? The Systematic Review, Confounders Assessment and Meta-Analysis of Clinical Studies

It has been suggested that molecular pathological mechanisms responsible for periodontitis can be linked with biochemical alterations in neurodegenerative disorders. Hypothetically, chronic systemic inflammation as a response to periodontitis plays a role in the etiology of cognitive impairment. This study aimed to determine whether periodontitis (PDS) is a risk factor for age-related cognitive impairment (ACI) based on evidence of clinical studies. A comprehensive, structured systematic review of existing data adhering to the Preferred Reporting Items for Systematic Review and Meta Analyses (PRISMA) guidelines was carried out. Five electronic databases, PubMed, Embase, Scopus, Web of Science, and Cochrane, were searched for key terms published in peer-reviewed journals until January 2021. The Newcastle-Ottawa scale was used to assess the quality of studies and risk of bias. The primary and residual confounders were explored and evaluated. A meta-analysis synthesizing quantitative data was carried out using a random-effects model. Seventeen clinical studies were identified, including 14 cohort, one cross-sectional, and two case-control studies. Study samples ranged from 85 to 262,349 subjects, with follow-up between 2 and 32 years, and age above 45 years, except for two studies. The findings of studies suggesting the PDS-ACI relationship revealed substantial differences in design and methods. A noticeable variation related to the treatment of confounders was observed. Quality assessment unveiled a moderate quality of evidence and risk of bias. The subgroups meta-analysis and pooled sensitivity analysis of results from seven eligible studies demonstrated overall that the presence of PDS is associated with an increased risk of incidence of cognitive impairment (OR = 1.36, 95% CI 1.03-1.79), particularly dementia (OR = 1.39, 95% CI 1.02-1.88) and Alzheimer's disease (OR = 1.03 95% CI 0.98-1.07)). However, a considerable heterogeneity of synthesized data (I2 = 96%) and potential publication bias might affect obtained results. While there is a moderate statistical association between periodontitis and dementia, as well as Alzheimer's disease, the risk of bias in the evidence prevents conclusions being drawn about the role of periodontitis as a risk factor for age-related cognitive impairment.

Risk of dementia according to the severity of chronic periodontitis in Korea: a nationwide retrospective cohort study

OBJECTIVES

We investigated the risk of dementia in older adults with chronic periodontitis according to the severity of periodontitis.

METHODS

Data on patients with chronic periodontitis were extracted from the National Health Insurance Service-Senior cohort database from 2002 to 2014. Among 52,728 subjects eligible for inclusion, 11,953 subjects had newly diagnosed mild chronic periodontitis (MCP), and 40,775 subjects had newly diagnosed severe chronic periodontitis (SCP). Two 1:1 propensity score matched cohorts were created with 8,624 patients each in the MCP and SCP groups. To analyze the risk of dementia, a Cox proportional-hazard model was used to calculate hazard ratios with 95% confidence intervals (CIs).

RESULTS

In the Kaplan-Meier curve, the disease-free probability was significantly lower in the SCP group than in the MCP group (p for log-rank=0.001). In the multivariable-adjusted model, the HR for the occurrence of dementia in the SCP group compared to the MCP group was 1.15 (95% CI, 1.04 to 1.27; p=0.009). A subgroup analysis revealed a significant association between dementia and the severity of periodontitis, especially in subjects who were male, aged ≥70 years, and had comorbidities.

CONCLUSIONS

Reducing the severity of chronic periodontitis can help to reduce the risk of dementia. Therefore, it is necessary to aggressively conduct early dementia-prevention programs for males under the age of 70 that include dental health to prevent the progression of periodontitis from mild to severe.

Clinical utility of Phototest via teleneuropsychology in Chilean rural older adults

The COVID-19 pandemic has shown the need for neuropsychological care for older adults with memory complaints in different contexts, including rural areas or areas with difficult access.

Objective

This study aimed to analyze the clinical utility of the Phototest, through telemedicine, to identify mild cognitive impairment in rural older adults with memory complaints, during the COVID-19 pandemic.

Methods

We performed a cross-sectional, case-control, and clinical utility comparison of brief cognitive tests (BCTs). The sample included 111 rural elderly people with mild cognitive impairment (MCI) and 130 healthy controls from the Los Lagos region, Chile. The instruments adopted were modified Mini-Mental State Examination (MMSEm) and adapted version of the Phototest (PT) for Chile.

Results

To identify mild cognitive impairment, using a cutoff score of 27-28 points, the Phototest showed a sensitivity of 96.6% and a specificity of 81.8%; indicators superior to those of the MMSEm.

Conclusions

The Phototest is more accurate than the MMSEm in identifying cognitive alterations in rural older adults with cognitive memory complaints through telemedicine. Therefore, its use in primary care is recommended in order to perform early detection of preclinical cognitive alterations in mild cognitive impairment or neurodegenerative diseases.

The Red and Orange Complex Subgingival Microbiome of Cognitive Impairment and Cognitively Normal Elderly with Periodontitis

Increasing evidence has shown an association between periodontitis and cognitive impairment. Subgingival microbiota play a great role in periodontitis pathogenesis. However, the correlation between the subgingival microbiome and cognitive impairment remains unclear. This study aimed to evaluate the red and orange complex subgingival microbiome of cognitively impaired and cognitively normal elderly Indonesian subjects with periodontitis. Twenty-eight elderly subjects diagnosed with periodontitis underwent two cognitive examinations using the Hopkins Verbal Learning Test and the Mini-Mental State Examination. Gingival crevicular fluid taken from the periodontal pocket, at a depth between 5 and 7 mm, using a paper point was used as the subgingival samples. The subgingival microbiome in the cognitive impairment group (n = 14) and cognitively normal group (n = 14) was compared using the 16S rRNA Metagenomic iSeq™ 100 Sequencing System. There was β-diversity in the subgingival microbiota between the cognitively impaired and cognitively normal subjects. The metagenomic analysis showed a higher abundance of Porphyromonas and Treponema bacteria in the cognitive impairment group than in the normal cognitive group (p < 0.05). The abundance of Porphyromonas gingivalis and Treponema denticola was higher in the cognitively impaired elderly subjects. The role of P. gingivalis and T. denticola in the pathogenesis of cognitive impairment needs further investigation.

Possible Role of Porphyromonas gingivalis in the Regulation of E2F1, CDK11, and iNOS Gene Expression in Neuronal Cell Cycle: A Preliminary Study

Objective:

This study aimed at evaluating the in vitro effect of Porphyromonas gingivalis exposure in gene expression of E2F1 (family of transcription factors), cyclin-dependent kinase-1 (CDK11), and inducible nitric oxide synthase (iNOS) of the neuronal cell cycle.

Materials and Methods:

The culture of neuronal cell line SH-SY5Y was exposed to P. gingivalis ATCC 33277, and the gene expression of E2F1, CDK11, and iNOS was analyzed by using a real-time polymerase chain reaction.

Results:

It was shown that E2F1, a G1 phase biomarker and transcription factor, was upregulated in neuronal cells exposed to P. gingivalis compared with that in control cells. However, CDK11, a biomarker of G2/M checkpoint and iNOS, was downregulated in neuronal cells exposed to P. gingivalis compared with that in control cells.

Conclusions:

P. gingivalis can regulate the neuronal cell cycle, as indicated in the E2F1, CDK11, and iNOS gene expression.

Combined association of cognitive impairment and poor oral health on mortality risk in older adults: Results from the NHANES with 15 years of follow-up

Background

Cognitive impairment and poor oral health are frequently seen among older adults. Both conditions have been identified as risk factors for mortality. However, the combined associations of cognitive impairment and poor oral health with mortality have not been well studied and are therefore the aim of this cohort study.

Methods

We analyzed data from the National Health and Nutrition Examination Survey (1999–2002) linked with mortality data obtained from the 2015 public‐use linked mortality file. Cognitive impairment was defined as a digit symbol substitution test score lower than the lowest quartile. Oral health status was assessed based on presence of untreated caries, moderate to severe periodontitis, and edentulism. The combined effects of caries/periodontitis or edentulism and cognitive impairment on all‐cause and cardiometabolic mortality were examined using the Cox proportional hazard models after adjusting for potential confounders including demographic characteristics, lifestyle, biomarkers, and comorbidities.

Results

In total, 1973 participants were enrolled in the prospective study. At a median follow‐up of 13.4 years, 978 participants had died (264 deaths because of cardiometabolic disease). Cognitive impairment, periodontitis, and edentulism were each found to be significant predictors of all‐cause mortality. Caries, however, was not significantly related to mortality. When analyzing these predictors in combination, a diagnosis of cognitive impairment and periodontitis was associated with an 83.1% increase in all‐cause mortality risk and an 87.7% increase in cardiometabolic mortality risk compared with healthy controls. Similarly, the risk for all‐cause mortality was highest in cases where impaired cognition and edentulism co‐occurred (adjusted hazard ratio = 1.701, 1.338–2.161).

Conclusion

Concomitant presence of cognitive impairment and periodontitis or edentulism can be associated with a higher risk of mortality among older U.S. adults.

The Association of Periodontitis and Alzheimer's Disease: How to Hit Two Birds with One Stone

Alzheimer's disease (AD) is the leading cause of cognitive impairment in the elderly. Recent evidence suggests that preventive interventional trials could significantly reduce the risk for development of dementia. Periodontitis is the most common dental disease characterized by chronic inflammation and loss of alveolar bone and perialveolar attachment of teeth. Growing number of studies propose a potential link between periodontitis and neurodegeneration. In the first part of the paper, we overview case-control studies analyzing the prevalence of periodontitis among AD patients and healthy controls. Second, we survey observational libraries and cross-sectional studies investigating the risk of cognitive decline in patients with periodontitis. Next, we describe the current view on the mechanism of periodontitis linked neural damage, highlighting bacterial invasion of neural tissue from dental plaques, and periodontitis induced systemic inflammation resulting in a neuroinflammatory process. Later, we summarize reports connecting the four most common periodontal pathogens to AD pathology. Finally, we provide a practical guide for further prevalence and interventional studies on the management of cognitively high-risk patients with and without periodontitis. In this section, we highlight strategies for risk control, patient information, dental evaluation, reporting protocol and dental procedures in the clinical management of patients with a risk for periodontitis and with diagnosed periodontitis. In conclusion, our review summarizes the current view on the association between AD and periodontitis and provides a research and intervention strategy for harmonized interventional trials and for further case-control or cross-sectional studies.

Analysis the Link between Periodontal Diseases and Alzheimer's Disease: A Systematic Review

The hypothesis of an infectious connection from the oro-pharyngeal sphere to the brain underlines the interest in analyzing the link between periodontal disease and Alzheimer’s disease. The aim of this systematic review was to examine the link between Alzheimer’s disease and periodontal disease in patients aged 65 and over. Databases (PubMed (MEDLINE), the Cochrane Library, and Embase) were analyzed for relevant references up to 21 June 2021. The authors independently selected the studies and extracted the data. The quality of included studies was checked using the National Institutes of Health’s quality assessment tools. Five studies were included. The selected studies described in their results an increase in F. nucleatum in Alzheimer’s disease patients (adjusted p = 0.02), and its incidence was linked to C. rectus and P. gingivalis (adjusted HR = 1.22 (1.04–1.43), p = 0.012) as well as A. naeslundii (crude HR = 2.0 (1.1–3.8)). The presence of periodontitis at baseline was associated with a six-fold increase in the rate of cognitive decline over a 6-month follow-up period (ADAS-Cog mean change = 2.9 ± 6.6). The current review suggests an association between periodontal disease and Alzheimer’s disease. The treatment of periodontal disease could be a way to explore Alzheimer’s disease prevention.

Treatment planning considerations in the older adult with periodontal disease

Periodontal health in the elderly is influenced by numerous factors, including systemic conditions, patient compliance, age-associated changes, and restorative procedures. The numerous comorbidities seen in the elderly necessitate individualized approaches for treatment planning. In this paper, we review how age, comorbidities, oral hygiene, and restorative dental procedures collectively influence the treatment and management of the periodontium in the elderly. The elderly population is predicted to double in 30 years, which will have an economic impact the dental profession needs to plan for. Preventative and noninvasive treatment, supportive periodontal therapy, and patient-specific maintenance plans are imperative to maintaining oral health in the older population. Multiple coexisting changes, including xerostomia, altered wound healing, altered bone physiology, altered microbiome, and diminished plaque control, can add complexity to periodontal management. Considerations of the patient's general health, the selected periodontal treatment plan, and the selected completed restorative procedures need to be considered. The influence of caries, fixed prosthodontics, partial dentures, shortened dental arch, and implant therapy can have unintended impacts on periodontal health in the elderly. Adverse periodontal outcomes in the elderly can be minimized by carefully assessing the patient's medical history, impact of medications, functional needs, properly finishing and contouring restorations to avoid plaque accumulation, and designing restorations to allow access for hygiene. Partial dentures can be a source of plaque accumulation leading to periodontal disease, caries, and recession around abutment teeth. A shortened dental arch should be considered as a functional and cost-effective alternative to partial dentures. With dental implants, the patient's tissue phenotype, keratinized tissue quantity, risk of peri-implantitis, and patient access for maintaining adequate oral hygiene are all important to consider. Implant risk-assessment tools show promise by providing a systematic approach for early diagnosis to avoid future complications.

Periodontal disease and the risk of Alzheimer's disease and mild cognitive impairment: a systematic review and meta-analysis

BACKGROUND

Results of studies on the association between periodontal disease (PD) and Alzheimer's disease (AD) or mild cognitive impairment (MCI) are inconsistent, and a previous meta-analysis published in 2017 included inadequate studies and is thus outmoded. This study aims to systematically evaluate the correlation between PD and the risk of AD or MCI.

METHODS

The following electronic databases were screened by two investigators independently, without restriction of language: CENTRAL (Cochrane library), PubMed (MEDLINE), EMBASE, China National Knowledge Interne, China Science and Technology Journal Database, Wanfang Data, www.ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform. Meta-analysis was conducted using random-effects model or fixed-effects model according to the heterogeneity of included studies.

RESULTS

Thirteen eligible studies, of which eight reported AD (291 114 participants) and eight reported MCI (4805 participants), were included in this meta-analysis. The pooled results showed that compared with the non-PD population, the risk of AD and MCI in PD patients was significantly higher (for AD: odds ratio (OR) = 1.78, 95% CI 1.15-2.76; for MCI: OR = 1.60, 95% CI 1.24-2.06), and especially in those with severe PD (for AD: OR = 4.89, 95% CI 1.60-14.97; for MCI, OR = 2.32, 95% CI 1.24-4.36).

CONCLUSIONS

This meta-analysis indicated that PD was related to an elevated risk of AD and cognitive impairment, and that it should receive early intervention.

The Effect of Periodontitis on Dementia and Cognitive Impairment: A Meta-Analysis

The association between periodontal disease and dementia/cognitive impairment continues to receive increasing attention. However, whether periodontal disease is a risk factor for dementia/cognitive impairment is still uncertain. This meta-analysis was conducted to comprehensively analyze the effect of periodontitis on dementia and cognitive impairment, and to assess the periodontal status of dementia patients at the same time. A literature search was undertaken on 19 October 2020 using PubMed, Web of Science, and Embase with different search terms. Two evaluators screened studies according to inclusion and exclusion criteria, and a third evaluator was involved if there were disagreements; this process was the same as that used for data extraction. Included studies were assessed with the Newcastle-Ottawa Scale (NOS), and results were analyzed using software Review Manager 5.2. Twenty observational studies were included. In the comparison between periodontitis and cognitive impairment, the odds ratio (OR) was 1.77 (95% confidence interval (CI), 1.31–2.38), which indicated that there was a strong relationship between periodontitis and cognitive impairment. There was no statistical significance in the effect of periodontitis on dementia (OR = 1.59; 95%CI, 0.92–2.76). The subgroup analysis revealed that moderate or severe periodontitis was significantly associated with dementia (OR = 2.13; 95%CI, 1.25–3.64). The mean difference (MD) of the community periodontal index (CPI) and clinical attachment level (CAL) was 0.25 (95%CI, 0.09–0.40) and 1.22 (95%CI, 0.61–1.83), respectively. In this meta-analysis, there was an association between periodontitis and cognitive impairment, and moderate or severe periodontitis was a risk factor for dementia. Additionally, the deterioration of periodontal status was observed among dementia patients.

Malocclusion of Molar Teeth Is Associated with Activities of Daily Living Loss and Delirium in Elderly Critically Ill Older Patients

A single-center retrospective cohort study examined the association between molar malocclusion status at ICU admission and loss of activities of daily living (ADL) at hospital discharge among acutely ill patients. Patients were assigned to the bilateral occlusion group or malocclusion group (N = 227 and 93, respectively). The following data were collected from electronic medical records: age, sex, Clinical Frailty Scale (CFS) on admission, Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ score, confirmed diagnosis (neurological disorders or others), CFS at hospital discharge, and occlusion condition. Patients who were frail at admission (CFS > 5) were excluded from analysis, and ADL loss was defined as CFS > 5 at hospital discharge. Multivariate analysis showed malocclusion was independently associated with ADL loss [OR, 2.03; 95% CI, 1.13-3.64; p = 0.02]. For those aged 65 and older, malocclusion was significantly associated with both ADL loss [OR, 3.25; 95% CI, 1.44-7.32; p < 0.01] and the incidence of delirium [OR, 2.61; 95% CI, 1.14-5.95; p = 0.02]. Malocclusion on ICU admission was associated with ADL loss in critically ill patients, and was associated with ADL loss and the incidence of delirium in the elderly. Poor oral health was a poor prognostic factor among critically ill patients.

Exploring the reciprocal relationship between cognitive function and edentulism among middle-aged and older adults in China

OBJECTIVE

Previous longitudinal studies have found that cognitive function affected oral health, and vice versa. However, research is lacking on the reciprocal relationships between cognitive function and edentulism simultaneously, especially in developing countries. The present study aimed to examine the reciprocal relationship between cognitive function and edentulism among middle-aged and older adults in China.

METHODS

Data were derived from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study. The sample included 14,038 respondents aged 45 or older. A two-wave cross-lagged analysis was adopted to test the hypothesized model.

RESULTS

Among respondents aged 45-59, baseline cognitive function was associated with subsequent edentulism [b = -0.017, standard deviation (SD) = 0.006, P < 0.01]. In contrast, baseline edentulism was not significantly associated with poorer cognitive function at the follow-up wave (b = -0.744, SD = 0.383, P > 0.05). However, among respondents aged 60 or older, baseline cognitive function was associated with subsequent edentulism (b = -0.017, SD = 0.005, P < 0.01), and baseline edentulism was also associated with follow-up lower levels of cognitive function (b = -0.419, SD = 0.143, P < 0.01).

CONCLUSIONS

These findings demonstrated the reciprocal relationships of cognitive function and edentulism. However, such relationships varied across age groups. This study demonstrates the importance of developing programs and services to promote both cognitive and oral health, especially for those in older age.

Periodontitis Is Associated With Risk of Conventional Stent Restenosis: Pilot Case-Control Study

Objectives: Percutaneous coronary angioplasty with stent implantation has been established as the main form of treatment of atherosclerosis. However, 16 to 44% of patients may evolve with stent restenosis. Periodontitis is an inflammatory condition associated with bacterial infection, that may lead to periodontal tissue destruction and tooth loss. This study aimed to evaluate the association between stent restenosis and periodontitis.

Materials and Methods: Coronary angiography exams presenting stent imaging with and without restenosis were analyzed. Patients meeting the inclusion and exclusion criteria were selected and allocated in 2 groups: case (restenosis) and control (without restenosis). We evaluated if systemic and periodontal variables were predictors of restenosis (primary outcome) using a multivariable stepwise logistic regression. Additionally, we compared clinical and periodontal conditions between the control and case groups (secondary outcomes) using Chi-square test and ANOVA test.

Results: Data from 49 patients (case n = 15; control n = 34) were analyzed. The results showed that stages III and IV periodontitis and lack of physical activity were significant predictors of stent restenosis (OR 5.82 and 5.98, respectively). Comparisons regarding the diagnosis of periodontal conditions between control and case groups did not present significant differences in the incidence of periodontitis and alveolar bone loss.

Conclusion: Stages III and IV periodontitis increased the incidence of stent restenosis. These findings suggest that advanced stages of periodontal disease might lead to the occurrence of negative outcomes after coronary angioplasty with stent placement.

Oral Treponema denticola Infection Induces Aβ1-40 and Aβ1-42 Accumulation in the Hippocampus of C57BL/6 Mice

Accumulation of amyloid-β (Aβ) in the brain is a central component of pathology in Alzheimer's disease. A growing volume of evidence demonstrates close associations between periodontal pathogens including Porphyromonas gingivalis (P. gingivalis) and Treponema denticola (T. denticola) and AD. However, the effect and mechanisms of T. denticola on accumulation of Aβ remain to be unclear. In this study, we demonstrated that T. denticola was able to enter the brain and act directly on nerve cells resulting in intra- and extracellular Aβ_1-40 and Aβ_1-42 accumulation in the hippocampus of C57BL/6 mice by selectively activating both β-secretase and γ-secretase. Furthermore, both KMI1303, an inhibitor of β-secretase, as well as DAPT, an inhibitor of γ- secretase, were found to be able to inhibit the effect of T. denticola on Aβ accumulation in N2a neuronal cells. Overall, it is concluded that T. denticola increases the expression of Aβ_1-42 and Aβ_1-40 by its regulation on beta-site amyloid precursor protein cleaving enzyme-1 and presenilin 1.

Evaluation of Cognitive Impairment in Type 2 Diabetic Patients with Chronic Periodontitis: A Cross-sectional Study

Background

Type 2 diabetes mellitus is an important risk factor for dementia; it also shares a bidirectional relationship with periodontitis. It is hypothesized that the increased severity of periodontitis is associated with cognitive decline in patients having uncontrolled diabetes mellitus. An added risk for future development as well as progression of dementia may be prophesied in such a scenario. Therefore, the present study was conducted to find a correlation between the cognitive impairment (CI) and periodontitis in type 2 diabetes mellitus patients.

Materials and Methods

A total of 160 older adults aged ≥60 years in Mangalore, Karnataka, India, were included in the present analysis. Known T2DM patients aged ≥60 years and diagnosed with periodontitis with a minimum clinical attachment loss (CAL) of ≥2 mm were considered in the present study. Montreal cognitive assessment test assessed the CI. The analysis was carried out using the χ² test, an independent t-test. Binary logistic regression analysis (enter method) was performed to derive the odds ratios (95% confidence interval).

Results

The study included 160 participants, out of which 120 had CI and 40 did not have CI. A statistically significant association was observed between moderate-to-severe periodontitis, HbA1c levels ≥7%, and CI after excluding the confounding factors like age, gender, diet, lifestyle habits, and education.

Conclusion

In the present study, cognitive impairment was found to coexist with HbA1c levels ≥7% and moderate-to-severe periodontitis in the elderly diabetics. The clinical implication of these findings adds opportunities to form disease modifiable areas in the elderly diabetic population at a risk for the development of dementia. Additionally, the impact of pre-existing CI on progression of periodontitis and vice versa has been discussed.

Relationship between oral and nutritional status of older residents with severe dementia in an aged care nursing home

OBJECTIVE

The aim of this study was to investigate the relationships between the oral and nutritional status of older residents with dementia in an aged care nursing home.

BACKGROUND

Insufficient oral evaluation and care due to refusal of treatment in older people with dementia may cause deterioration in oral and nutritional status.

MATERIALS AND METHODS

The subjects were 123 older residents with dementia who had been admitted to an aged care nursing home. Oral condition and body mass index (BMI) as a measure of nutritional status were investigated, and the results for the mild and severe dementia groups were compared. BMI was compared by the food consistency between the mild and severe dementia groups.

RESULTS

In the severe dementia group, fewer older adults had removable dentures and many had no molar occlusion. The rate of subjects who had refused oral care by the caregivers was significantly higher in the severe dementia group than in the mild dementia group. In the severe dementia group, the BMI of those having texture-modified foods was significantly lower than those having a normal diet. The BMI of subjects without molar occlusion and with a history of cerebrovascular disease was significantly lower in the severe dementia group.

CONCLUSIONS

The BMI of subjects in the severe dementia group having texture-modified food was significantly lower than that of those with a normal diet. The BMI of subjects in the severe dementia group without molar occlusion was significantly lower than those with molar occlusion.

Oral health and healthy chewing for healthy cognitive ageing: A comprehensive narrative review

INTRODUCTION

Ageing leads to physiological cognitive decline that it is worsened in people with neurodegenerative diseases such as Alzheimer's disease. Despite the ongoing search for a solution to this cognitive decline, no effective remedies have been established. It has been determined that modifiable external factors, such as oral health and occlusal function, prevent cognitive decline.

OBJECTIVE

To analyse the primary interactions between occlusal function and cognitive functions.

MAIN FINDINGS

Masticatory function is related to cognitive functions. In particular, current evidence, from both animal and human studies, suggests that the activation of masticatory muscles and proper mastication, with natural teeth or dental prosthesis, induces the release of several mediators and the activation of specific brain areas. Together, they result in higher neuronal activity, neurotrophic support, blood flow and the prevention of amyloid-beta plaque formation. Thus, all the components of the masticatory system must work together in order to preserve cognitive function.

CONCLUSIONS

Available evidence suggests that oral and cognitive health are more interconnected than previously thought. Therefore, maintenance and adequate restoration of the whole masticatory system are important for the prevention of cognitive decline. In summary, oral and chewing health lead to healthy cognitive ageing.

Risk of dementia in patients with periodontitis and related protective factors: A nationwide retrospective cohort study

AIM

We aimed to evaluate the long-term risk of dementia in patients with periodontitis and its associated factors.

MATERIALS AND METHODS

Using Taiwan's National Health Insurance Database, we identified 56,018 patients aged ≥50 years with newly diagnosed periodontitis in 2000-2008. A cohort of 56,018 adults without periodontitis was selected for comparison, with matching by age and sex. Both cohorts were followed from 2000 to the end of 2013, and incident dementia was identified during the follow-up period. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of dementia associated with periodontitis were calculated in the multivariate regressions.

RESULTS

Periodontitis was associated with dementia risk (HR: 1.79, 95% CI: 1.67-1.93), and the association between periodontitis and dementia risk was significant in men, women, and people aged more than 60 years. Among patients with periodontitis, the use of statins (HR: 0.78, 95% CI: 0.71-0.87), metformin (HR: 0.53, 95% CI: 0.44-0.62), and influenza vaccination (HR: 0.67, 95% CI: 0.61-0.74) were associated with a reduced risk of dementia, while diabetes, mental disorders, and stroke were major significant risk factors.

CONCLUSIONS

Periodontitis was a risk factor for dementia, while the use of statins and metformin may reduce the risk of dementia.

Association between periodontitis and Alzheimer's disease and its impact on the self-perceived oral health status: a case-control study

PURPOSE

To test the hypothesis that periodontitis is associated with AD and search whether periodontal and other variables would negatively impact the oral health-related quality of life (OHRQoL) perception.

MATERIALS AND METHODS

Oral examinations and interview on self-perceived oral health status (Geriatric Oral Health Assessment Index (GOHAI) questionnaire (higher score corresponds to better perceived oral status)) were carried out and socio-demographic data were collected from outpatients with mild to moderate AD (cases, n = 50) and from their age- and sex-matched family caregivers (controls, n = 52). Full-mouth periodontal examination was performed. Significance of differences between groups was sought by chi-square, Student's t, or the Mann-Whitney test. The association between the variables periodontitis, probing depth (PD) ≥ 5 mm, and clinical attachment loss (CAL) ≥ 5 mm with the variable group was tested in binary logistic regression models (LRMs). LRMs were used to test the association of oral findings, demographics, and group with GOHAI.

RESULTS

Cases had fewer teeth and greater CAL than controls. Cases had a superior percentage of sites with plaque, calculus, and bleeding on probing than controls. Cases had greater GOHAI scores than controls. Periodontitis was a variable most likely associated with AD (OR = 11.08, p < 0.001). None of the oral findings or demographics, but group, was associated with GOHAI (OR = 14.45, p < 0.001).

CONCLUSION

Periodontitis is associated with AD, but not with patients' OHRQoL.

CLINICAL RELEVANCE

Health care professionals must be aware that AD patients should have a periodic thorough oral examination and preventive intervention aiming at their welfare and maintenance of a pain-free functional dentition.

Porphyromonas gingivalis and Alzheimer disease: Recent findings and potential therapies

Epidemiological studies have identified an association between periodontitis and Alzheimer disease (AD); however, the nature of this association has been unclear. Recent work suggests that brain colonization by the periodontal pathogen Porphyromonas gingivalis may link these two inflammatory and degenerative conditions. Evidence of P. gingivalis infiltration has been detected in autopsy specimens from the brains of people with AD and in cerebrospinal fluid of individuals diagnosed with AD. Gingipains, a class of P. gingivalis proteases, are found in association with neurons, tau tangles, and beta-amyloid in specimens from the brains of individuals with AD. The brains of mice orally infected with P. gingivalis show evidence of P. gingivalis infiltration, along with various neuropathological hallmarks of AD. Oral administration of gingipain inhibitors to mice with established brain infections decreases the abundance of P. gingivalis DNA in brain and mitigates the neurotoxic effects of P. gingivalis infection. Thus, gingipain inhibition could provide a potential approach to the treatment of both periodontitis and AD.

Association between periodontitis and bipolar disorder: A nationwide cohort study

Whether periodontitis is a risk factor for developing bipolar disorders (BD) has not been investigated. We aimed to determine whether periodontitis is associated with the subsequent development of BD and examine the risk factors for BD among patients with periodontitis.Using ambulatory and inpatient claims data from the National Health Insurance Research Database (NHIRD), we identified 12,337 patients who were aged at least 20 years and newly diagnosed with periodontitis between 2000 and 2004. The date of the first claim with a periodontitis diagnosis was set as the index date. For each patient with periodontitis, 4 subjects without a history of periodontitis were randomly selected from the NHIRD and frequency-matched with the patients with periodontitis according to sex, age (in 5-year bands), and index year.The periodontitis group had a mean age of 44.0 ± 13.7 years and slight predominance of men (51.3%). Compared with the subjects without periodontitis, the patients with periodontitis had higher prevalence of diabetes mellitus, hyperlipidemia, hypertension, ischemic heart disease, stroke, head injury, major depressive disorder, chronic obstructive pulmonary disease (COPD), and asthma (P < .001). The incidence rate of BD was higher in the periodontitis group than in the non-periodontitis group (2.74 vs 1.46 per 1000 person-year), with an adjusted hazard ratio of 1.82 (95% confidence interval = 1.59-2.08) after adjustment for sex, age, and comorbidities.The patients with periodontitis exhibited a significantly higher risk of developing BD. Keep the better oral hygiene to reduce periodontitis might be a preventive strategy for BD.

Influence of periodontal disease on risk of dementia: a systematic literature review and a meta-analysis

Periodontal disease (PD) is common and increases cardiovascular diseases. However, it is unclear whether PD is associated with increased risk of dementia. We carried out a systematic review and meta-analysis to investigate the influence of PD on dementia. We projected the number of dementia cases to be saved by reducing PD prevalence in the world. We searched cohort and case-control studies reporting the association of PD with all dementia (or any specific type of dementia) through PubMed, MEDLINE, PsycINFO, SocINDEX, CINHAL, and CNKI until 7th November 2018. Five cohorts and seven case-control studies were identified for review. We pooled eligible data to calculate relative risk (RR) of dementia in relation to PD and computed the number of dementia cases saved through reducing PD prevalence. Of 12 studies, six were undertaken in Asia, four in Europe and two in America. Eleven studies showed a positive association between PD and the risk of dementia, of which 10 were significant, and one reported a non-significant inverse association. Overall their quality was good. Pooled RR of dementia in relation to PD from all high quality studies was 1.38 (95%CI 1.01-1.90); in the five cohorts was 1.18 (1.06-1.31) and in the two case-control studies 2.25 (1.48-3.42). A 50% reduction in the current prevalence of 20% of PD in the population could save 850,000 (630,000-1,420,000) patients with dementia in the world. PD could increase the risk of incident dementia. Preventing and treating PD could contribute to controlling the global epidemic of dementia.

Can chronic oral inflammation and masticatory dysfunction contribute to cognitive impairment?

PURPOSE OF REVIEW

This article provides an overview of current literature focused on oral health and cognitive impairment in older adulthood, focusing in particular on whether oral inflammation, tooth loss and masticatory dysfunction might increase the risk of cognitive impairment in this age group.

RECENT FINDINGS

There is now general acceptance that cognitive impairment contributes to poor oral health, largely through detrimental changes in behaviours related to maintaining good oral hygiene. There is more limited evidence for the reverse causal direction, but at least some studies now suggest that inflammatory mechanisms, tooth loss and masticatory dysfunction each have the potential to contribute to cognitive decline.

SUMMARY

Poorer oral health significantly correlates with cognitive dysfunction, and at least some studies suggest that there may be a bi-directional causal relationship. Randomized controlled trials assessing cognitive abilities in relation to oral hygiene or oral health interventions, or provision of removable or fixed (implant-supported) dentures, are encouraged.

Association between periodontitis and risk of Alzheimer's disease, mild cognitive impairment and subjective cognitive decline: A case-control study

AIMS

To test the hypothesis that periodontal disease contributes to increased risk of mild cognitive impairment (MCI), subjective cognitive decline (SCD) and Alzheimer's disease (AD).

MATERIALS AND METHODS

This case-control study was conducted over a 3-year period in the municipality of Huddinge, Sweden. In total, 154 cases were consecutively enrolled from the Karolinska Memory Clinic at the Karolinska University Hospital and allotted to three diagnostic groups: AD, MCI and SCD, collectively referred to as "cases." Seventy-six cognitively healthy age- and gender-matched controls were randomly sampled through the Swedish population register. All cases and controls underwent clinical and radiographic oral examinations. Statistical analysis was based on logistic regression models adjusted for potential confounders.

RESULTS

Poor oral health and marginal alveolar bone loss were more prevalent among cases than among controls. The cases group was associated with generalized marginal alveolar bone loss (odds ratio [OR] = 5.81; 95% confidence interval [CI] = 1.14-29.68), increased number of deep periodontal pockets (OR = 8.43; CI 4.00-17.76) and dental caries (OR = 3.36; CI 1.20-9.43).

CONCLUSION

The results suggest that marginal periodontitis is associated with early cognitive impairment and AD. However, the study design does not preclude noncausal explanations.

Oral Bacteria and Intestinal Dysbiosis in Colorectal Cancer

The human organism coexists with its microbiota in a symbiotic relationship. These polymicrobial communities are involved in many crucial functions, such as immunity, protection against pathogens, and metabolism of dietary compounds, thus maintaining homeostasis. The oral cavity and the colon, although distant anatomic regions, are both highly colonized by distinct microbiotas. However, studies indicate that oral bacteria are able to disseminate into the colon. This is mostly evident in conditions such as periodontitis, where specific bacteria, namely Fusobacterium nucrelatum and Porphyromonas gingivalis project a pathogenic profile. In the colon these bacteria can alter the composition of the residual microbiota, in the context of complex biofilms, resulting in intestinal dysbiosis. This orally-driven disruption promotes aberrant immune and inflammatory responses, eventually leading to colorectal cancer (CRC) tumorigenesis. Understanding the exact mechanisms of these interactions will yield future opportunities regarding prevention and treatment of CRC.

The Possible Causal Link of Periodontitis to Neuropsychiatric Disorders: More Than Psychosocial Mechanisms

Increasing evidence implies a possible causal link between periodontitis and neuropsychiatric disorders, such as Alzheimer's disease (AD) and major depression (MD). A possible mechanism underlying such a link can be explained by neuroinflammation induced by chronic systemic inflammation. This review article focuses on an overview of the biological and epidemiological evidence for a feasible causal link of periodontitis to neuropsychiatric disorders, including AD, MD, Parkinson's disease, and schizophrenia, as well as the neurological event, ischemic stroke. If there is such a link, a broad spectrum of neuropsychiatric disorders associated with neuroinflammation could be preventable and modifiable by simple daily dealings for oral hygiene. However, the notion that periodontitis is a risk factor for neuropsychiatric disorders remains to be effectively substantiated.

Masticatory Dysfunction by Extensive Tooth Loss as a Risk Factor for Cognitive Deficit: A Systematic Review and Meta-Analysis

Background: An amount of cognition decline is normal with aging; however, intrinsic and extrinsic risk factors may exacerbate it, affecting social and occupational tasks. Masticatory dysfunction (MD), as a general term, refers to an impairment in the masticatory function triggered by a structural factor, such as tooth loss; functional factors, such as weaker bite force or a poorer masticatory performance; or both factors. MD acting as a source of chronic stress, promotes functional and morphological changes on the hippocampus, a brain area crucial for learning and memory abilities. This study aimed to synthesize evidence on the association between MD and cognitive deficit (CD), and demonstrate whether might be adequately considered as a risk factor.

Methods: Observational studies were screened in seven online databases; the search strategy (PECO) was focused in observational studies with humans as a population (P), presenting groups exposed (E), and non-exposed (C) to tooth loss, in which cognition parameters were measured and compared between groups (O). The final selection included only those studies comparing the effect in cognition between subjects having ≥20 remaining teeth and <20 remaining teeth, considering the latter as a structural factor triggering MD by the literature. Searching and data extraction were conducted following PRISMA guidelines. Qualitative and risk of bias evaluations were performed. The meta-analysis (MA) was constructed including the odds ratio (OR) and its 95% confidence interval (CI) comparing two groups—with/without MD. The level of evidence was rated by Grading Recommendations Assessment, Development and Evaluation (GRADE) approach.

Results: In total, 5,666 citations were identified, 14 accomplished our eligibility criteria, and nine were include in the MA. The MA demonstrates that individuals with MD had 46% higher chance to presented CD (OR 2.24 [1.73, 2.90], p < 0.00001, I² = 46%). The level of evidence was rated as low by GRADE.

Conclusion: Despite the low certainty in evidence, according to our MA, MD is positively associated with increased risk of CD. However, more studies including other factors underlying MD and similar measurements should be conducted to obtain a strong estimate of the risk.

Association between periodontitis and cognitive impairment: Analysis of national health and nutrition examination survey (NHANES) III

OBJECTIVES

Periodontitis has been hypothesized as being one of the most common potential risk factors for the development of dementia and cognitive impairment. In order to investigate the relationship between periodontitis and cognition impairment, the National Health and Nutrition Examination Survey (NHANES) database was analysed after adjusting for potential confounding factors, including age and other systemic co-morbidities.

MATERIALS AND METHODS

In total, 4,663 participants aged 20-59 years who had received full-mouth periodontal examination and undergone the cognitive functional test were enrolled. The grade of periodontal disease was categorized into severe, moderate, and mild. Cognitive function examinations, including the simple reaction time test (SRTT), symbol digit substitution test (SDST), and serial digit learning test (SDLT), were adopted for the evaluation of cognitive impairment.

RESULTS

The subjects with mild and moderate to severe periodontitis had higher SDLT and SDST scores, which indicated decreased cognitive function, compared with the healthy group. After adjusting for demographic factors, education, smoking, cardiovascular diseases, and laboratory data, periodontitis was significantly correlated with elevated SDST and SDLT scores (p values for trend = 0.014 and 0.038, respectively) by generalized linear regression models.

CONCLUSION

Our study highlighted that periodontal status was associated with cognitive impairment in a nationally representative sample of US adults.

The Association between Tooth Loss and Alzheimer's Disease: a Systematic Review with Meta-Analysis of Case Control Studies

Alzheimer's disease is classified as a neurodegenerative condition, a heterogeneous group of illnesses characterized by the slow and progressive loss of one or more functions of the nervous system. Its incidence tends to increase gradually from 65 years of age, up to a prevalence of 4% at age 75. The loss of dental elements is more prevalent in this population and might negatively affect the masticatory capacity, quality of life, and pathogenesis of Alzheimer's disease. This study investigated problems related to oral health and the loss of dental elements in elderly patients suffering from Alzheimer's and considered whether local inflammatory processes could affect the etiopathogenesis of Alzheimer's disease. The purpose of this systematic review is to identify a link between the causes leading to tooth loss and the onset/progression of Alzheimer's disease. We also studied whether there is a higher incidence of tooth loss (primary outcome) and edentulism (secondary outcome) among Alzheimer's patients. We searched records in electronic databases such as PubMed, EBSCO, and Web of Science using the following keywords: Alzheimer's Disease AND periodontal, Alzheimer's Disease AND periodontitis, dementia AND (periodontitis OR periodontal) "Alzheimer's Disease" AND "tooth" OR "dental loss," "dementia" AND "edentulous," "Alzheimer's Disease" AND "edentulous," "dementia" AND "tooth" OR "dental loss." The records were screened, and after applying the eligibility and inclusion criteria, nine articles were left, six of which were analyzed for the primary outcome (loss of dental elements) and six for the secondary outcome (tooth loss). Results from this meta-analysis revealed that Alzheimer's disease patients have an increased risk of dental loss (hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.00-2.30, p = 0.05) and edentulous condition (HR 2.26, 95% CI 1.70-3.01, p < 0.001). A quantitative analysis of the included studies indicated that patients suffering from Alzheimer's disease are characterized by a greater number of lost dental elements and general edentulism compared to the control groups.