Evidence and Therapeutic Perspectives in the Relationship between the Oral Microbiome and Alzheimer's Disease: A Systematic Review

The association between oral diseases and neurodegenerative disorders

BACKGROUND

The association between cognitive neurodegenerative disease and oral diseases has been under great interest recently. Several studies have suggested a connection between periodontitis and Alzheimer's disease (AD) or other neurodegenerative disorders.

OBJECTIVE

This study aimed to review the potential mechanisms between oral diseases and neurodegenerative diseases.

METHODS

The study was executed as a literature review of English-language publications from 2018-2022. The databases used for the search were PubMed, Cochrane, Scopus, and Web of Science. The search phrases used were "neurodegenerative diseases" AND "oral health" and "neurodegenerative diseases" AND "oral diseases."

RESULTS

The linkage between the two disease groups was observed in several distinct publications and several potential mechanisms were found. The link between periodontitis and AD proved to be the most significant. The effect was accentuated in elderly people where individuals possessed also other risk factors for neurodegenerative diseases and had generally worse oral health conditions.

CONCLUSIONS

Oral diseases may be risks for neurodegenerative changes along many different pathways. Good oral health should be acknowledged as a potential preventative or risk-reducing act against neurodegenerative diseases.

A review of the risks and relationships between oral health and chronic diseases

Advances in medical science and in preventive dentistry have changed the context of oral health. The American population is living longer with numerous complex chronic diseases. This paper is to raise awareness about the impact of multiple chronic diseases and their associations with oral diseases. Comorbidities can worsen the course of dental treatment. Inflammation has been the connecting factor in the bidirectional pattern of oral and systemic diseases. High occurrences of chronic diseases generally occur in aging as well as disadvantaged populations. Serious infections, slow healing, prolonged bleeding, and hospitalizations can escalate in patients with uncontrolled chronic diseases. A multidisciplinary team-based approach to patient management can minimize complications and unexpected challenges.

Periodontitis: etiology, conventional treatments, and emerging bacteriophage and predatory bacteria therapies

Inflammatory periodontal diseases associated with the accumulation of dental biofilm, such as gingivitis and periodontitis, are very common and pose clinical problems for clinicians and patients. Gingivitis is a mild form of gum disease and when treated quickly and properly is completely reversible. Periodontitis is an advanced and irreversible disease of the periodontium with periods of exacerbations, progressions and remission. Periodontitis is a chronic inflammatory condition that damages the tissues supporting the tooth in its socket, i.e., the gums, periodontal ligaments, root cementum and bone. Periodontal inflammation is most commonly triggered by bacteria present in excessive accumulations of dental plaque (biofilm) on tooth surfaces. This disease is driven by disproportionate host inflammatory immune responses induced by imbalance in the composition of oral bacteria and changes in their metabolic activities. This microbial dysbiosis favors the establishment of inflammatory conditions and ultimately results in the destruction of tooth-supporting tissues. Apart microbial shift and host inflammatory response, environmental factors and genetics are also important in etiology In addition to oral tissues destruction, periodontal diseases can also result in significant systemic complications. Conventional methods of periodontal disease treatment (improving oral hygiene, dental biofilm control, mechanical plaque removal, using local or systemic antimicrobial agents) are not fully effective. All this prompts the search for new methods of therapy. Advanced periodontitis with multiple abscesses is often treated with antibiotics, such as amoxicillin, tetracycline, doxycycline, minocycline, clindamycin, or combined therapy of amoxicillin with metronidazole. However, due to the growing problem of antibiotic resistance, treatment does not always achieve the desired therapeutic effect. This review summarizes pathogenesis, current approaches in treatment, limitations of therapy and the current state of research on the possibility of application of bacteriophages and predatory bacteria to combat bacteria responsible for periodontitis. We present the current landscape of potential applications for alternative therapies for periodontitis based on phages and bacteria, and highlight the gaps in existing knowledge that need to be addressed before clinical trials utilizing these therapeutic strategies can be seriously considered.

Oral Microbiome: A Review of Its Impact on Oral and Systemic Health

PURPOSE OF REVIEW

This review investigates the oral microbiome's composition, functions, influencing factors, connections to oral and systemic diseases, and personalized oral care strategies.

RECENT FINDINGS

The oral microbiome is a complex ecosystem consisting of bacteria, fungi, archaea, and viruses that contribute to oral health. Various factors, such as diet, smoking, alcohol consumption, lifestyle choices, and medical conditions, can affect the balance of the oral microbiome and lead to dysbiosis, which can result in oral health issues like dental caries, gingivitis, periodontitis, oral candidiasis, and halitosis. Importantly, our review explores novel associations between the oral microbiome and systemic diseases including gastrointestinal, cardiovascular, endocrinal, and neurological conditions, autoimmune diseases, and cancer. We comprehensively review the efficacy of interventions like dental probiotics, xylitol, oral rinses, fluoride, essential oils, oil pulling, and peptides in promoting oral health by modulating the oral microbiome.

SUMMARY

This review emphasizes the critical functions of the oral microbiota in dental and overall health, providing insights into the effects of microbial imbalances on various diseases. It underlines the significant connection between the oral microbiota and general health. Furthermore, it explores the advantages of probiotics and other dental care ingredients in promoting oral health and addressing common oral issues, offering a comprehensive strategy for personalized oral care.

Cognition and Oral Health: Association Between Alzheimer's Disease and Periodontitis

A relationship between poor oral health conditions and cognitive decline has been clinically observed. A bidirectional association between periodontitis and Alzheimer's disease has been repeatedly identified in clinical and pre-clinical studies. This association is supported by four major overlapped pathways and mechanisms, including the microbiota-gut-brain axis via the vagus nerve pathway, periodontopathogen-involved neuroinflammation via the trigeminal nerve pathway, proinflammatory cytokines, and trained immunity. Partly linked with periodontitis, increased levels of proinflammatory cytokines and decreased levels of anti-inflammatory cytokines can exacerbate the abnormal accumulation of amyloid beta plaques and hyperphosphorylation of tau protein. Periodontitis is considered an important environmental factor involved in Alzheimer's disease development. This review discusses the bidirectional relationship between Alzheimer's disease and periodontitis, focusing on the association between cognitive decline and poor oral health conditions. Thus, oral health intervention strategies have been proposed as potential therapeutic methods for the prevention and management of Alzheimer's disease. [ Psychiatr Ann . 2024;54(8):e230–e234.]

Knowledge, attitude, and practice of patients with oral diseases toward oral examinations: a cross-sectional survey study

Background

Properly adhering to oral hygiene and medical care is an important public health issue. Several studies examined the knowledge, attitudes, and practices (KAP) toward oral care in various populations and generally reported relatively sufficient knowledge but unfavorable attitudes and poor practice. However, no previous studies have examined the KAP toward oral examinations among Chinese patients with oral diseases. This study aimed to examine the KAP toward oral examinations among patients with oral diseases in China.

Methods

This cross-sectional study was conducted in patients with oral diseases who visited The Affiliated Stomatological Hospital of Tongji University between December 2023 and February 2024. Data collection and KAP scores assessment were performed using a self-designed questionnaire.

Results

A total of 519 valid questionnaires were included, with 292 females. The mean knowledge, attitude, and practice scores were 6.42 ± 2.47 (possible range: 0-9 points), 35.04 ± 5.68 (possible range: 10-50 points), and 16.22 ± 2.05 (possible range: 4-20 points), respectively, indicating sufficient knowledge, positive attitudes, and proactive practice. Pearson's correlation analysis showed that knowledge was positively correlated to attitude (r = 0.468, p < 0.001) and practice (OR = 0.416, p < 0.001). Attitude was positively correlated to the practice (r = 0.503, p < 0.001). Moreover, the structural equation model showed that knowledge influenced attitude (estimate = 1.010, p < 0.001) and practice (estimate = 0.169, p < 0.001). Attitude influenced practice (estimate = 0.122, p < 0.001). The frequency of oral examination per year influenced knowledge (estimate = -0.761, p < 0.001) and practice (estimate = -0.515, p < 0.001). Expenses for oral disease per year influenced attitude (estimate = 0.537, p < 0.001).

Conclusion

Patients with oral disease might have sufficient knowledge, positive attitude, and proactive practice toward oral examinations. Specific knowledge items were identified to require improvements.

Effects of toothpaste containing inactivated Lacticaseibacillus paracasei Probio-01 on plaque-induced gingivitis and dental plaque microbiota

Plaque-induced gingivitis is an inflammatory response in gingival tissues resulting from bacterial plaque accumulation at the gingival margin. Postbiotics can promote the proliferation of beneficial bacteria and optimise the state of microbiota in the oral cavity. In this study, we investigated the effect of inactivated Lacticaseibacillus paracasei Probio-01 on plaque-induced gingivitis and the dental plaque microbiota. A total of 32 healthy gingival participants (Group N, using blank toothpaste for 3 months) and 60 patients with plaque-induced gingivitis (30 in Group F, using inactivated Probio-01 toothpaste for 3 months, and 30 in Group B, using blank toothpaste for 3 months, respectively) were recruited. Clinical indices, which included bleeding on probing (BOP), gingival index (GI), and plaque index (PI), were used to assess the severity of gingivitis. Furthermore, 16SrDNA amplicon sequencing was used to explore changes in the gingival state and dental plaque microbiota in patients with plaque-induced gingivitis. The results showed that inactivated Probio-01 significantly reduced clinical indices of gingivitis, including BOP, GI, and PI, in participants with plaque-induced gingivitis and effectively relieved gingival inflammation, compared with that observed in the control group (group B). Inactivated Probio-01 did not significantly influence the diversity of dental plaque microbiota, but increased the relative abundance of dental plaque core bacteria, such as Leptotrichia and Fusobacterium (P < 0.05). Strong correlations were observed between the indices and abundance of dental plaque microbiota. Overall, the inactivated Probio-01 significantly reduced the clinical indices of gingivitis and effectively improved gingival inflammation in patients with plaque-induced gingivitis. The activity of inactivated Probio-01 against plaque-induced gingivitis was possibly mediated by its ability to regulate the dental plaque microbiota, as indicated by the close correlation between the plaque microbiota and clinical indices of gingivitis.

From Gut Microbiota to Brain Waves: The Potential of the Microbiome and EEG as Biomarkers for Cognitive Impairment

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder and a leading cause of dementia. Aging is a significant risk factor for AD, emphasizing the importance of early detection since symptoms cannot be reversed once the advanced stage is reached. Currently, there is no established method for early AD diagnosis. However, emerging evidence suggests that the microbiome has an impact on cognitive function. The gut microbiome and the brain communicate bidirectionally through the gut-brain axis, with systemic inflammation identified as a key connection that may contribute to AD. Gut dysbiosis is more prevalent in individuals with AD compared to their cognitively healthy counterparts, leading to increased gut permeability and subsequent systemic inflammation, potentially causing neuroinflammation. Detecting brain activity traditionally involves invasive and expensive methods, but electroencephalography (EEG) poses as a non-invasive alternative. EEG measures brain activity and multiple studies indicate distinct patterns in individuals with AD. Furthermore, EEG patterns in individuals with mild cognitive impairment differ from those in the advanced stage of AD, suggesting its potential as a method for early indication of AD. This review aims to consolidate existing knowledge on the microbiome and EEG as potential biomarkers for early-stage AD, highlighting the current state of research and suggesting avenues for further investigation.

Can oral health care be a gateway to improve cardiovascular disease? A scoping review

Background

Cardiovascular diseases (CVDs) are a significant cause of morbidity and mortality worldwide, resulting in a high socioeconomic burden. Growing evidence has shown a link between oral diseases and several chronic conditions including CVDs. The focus of this review is to investigate and summaries the evidence surrounding oral health interventions and their potential impact on reducing both the risk and/or severity of CVDs.

Methods

A scoping review was conducted to examine oral health interventions for managing CVD outcomes and risks. The review adhered to the Joanna Briggs Institute (JBI) framework for evidence synthesis and followed the reporting standards outlined by the Preferred Reporting Items for Systematic Reviews and Meta-analysis- extension to Scoping Review (PRISMA-ScR). A systematic search across EBSCOhost, PubMed, and Scopus databases from 2012 to 2024 was utilized to identify relevant studies. Inclusion criteria focused on English language articles with a sample size of at least 50, evaluating the impact of oral health interventions on CVD outcomes.

Results

Out of the initial 2,154 studies identified in the search, 12 studies met the inclusion and exclusion criteria and were included in the final analysis. Overall, the studies revealed that along with surgical and non-surgical periodontal therapy, regular oral hygiene care practices, including toothbrushing, tongue brushing, and flossing, significantly reduced the risk of cardiovascular events and mortality. These interventions in patients with or without CVD baseline have shown a decrease in CVD risk markers as well as a reduction in bacterial colonization. Similarly, consistent oral hygiene routines, combined with regular dental visits, were associated with a lower risk of heart failure and CVD risk mortality.

Conclusion

The evidence extracted from this review suggests that periodontal therapy, regular dental cleaning, and re-enforcing of oral health regimes can stabilize oral health conditions and subsequently improve CVD progression/risks. However, limited to no evidence exists regarding the therapeutic effects of oral health promotion in managing CVD markers and its direct impact on disease outcomes, warranting further investigation.

Bridging the gap between omics research and dental practice

AIM

The burgeoning field of omics research has witnessed exponential growth in both medicine and dentistry. However, despite more than a decade of advancements, clinical dentistry, particularly in Low- and Middle-Income Countries (LMICs), has seen limited progress in integrating omics-based approaches into routine practice. This review aims to provide a comprehensive overview of the integration of omics approaches in dentistry, focusing on the challenges and opportunities for translating research findings into clinical practice.

METHODS

we conducted a literature review using key databases to provide a brief overview of the history of genomics in dentistry. Additionally, we summarised recent breakthroughs in omics relevant to oral health practitioners, emphasising the inadequate translation of omics research into clinical practice.

RESULTS

Despite significant growth in omics research in both medicine and dentistry, its translation into routine clinical practice in dentistry remains limited. We summarise recent breakthroughs in omics and highlight the gap between research advancements and clinical implementation.

DISCUSSION AND CONCLUSION

The integration of omics approaches holds promise for enhancing diagnostics, personalised treatment strategies, and preventive measures in dental practice, ushering in a new era of precision oral healthcare. However, several challenges, including infrastructure limitations, cost-effectiveness, and education gaps, hinder the widespread adoption of omics-based approaches in clinical dentistry. A strong commitment to transforming dentistry is required to embrace this transition. This shift has the potential to revolutionise oral healthcare by advancing precision diagnostics and treatment strategies tailored to individual patient needs.

Oral Health as a Risk Factor for Alzheimer Disease

In patients with Alzheimer's disease pathophysiological changes of the brain that initiate the onset of Alzheimer's disease include accumulation of amyloid-β plaques and phosphorylation of tau-tangles. A rather recently considered risk factor for the onset of Alzheimer's disease is poor oral health. The aim of this systematic review of the literature was to assess the potential association(s) of oral health as a risk factor for the onset of Alzheimer's disease. After a systematic search of Pubmed, Embase and Web of Science. A total of 1962 studies were assessed, of which 17 studies demonstrated possible associations between oral health diseases and Alzheimer's disease. 4 theories could be distinguished that describe the possible links between oral health and the development or onset of Alzheimer's disease; 1) role of pathogens, 2) role of inflammatory mediators, 3) role of APOE alleles and 4) role of Aβ peptide. The main common denominator of all the theories is the neuroinflammation due to poor oral health. Yet, there is insufficient evidence to prove a link due to the diversity of the designs used and the quality of the study design of the included studies. Therefore, further research is needed to find causal links between oral health and neuroinflammation that possibly can lead to the onset of Alzheimer's disease with the future intention to prevent cognitive decline by better dental care.

An umbrella review on the association between factors of oral health and cognitive dysfunction

An increasing number of systematic reviews and meta-analyses have been published on the association between oral health and cognitive dysfunction, also known as oral-cognitive links. However, there is great diversity in the oral and cognitive factors included in these studies, with different opinions for clinical practice drawn from the evidence. To understand which oral and cognitive factors are involved in those associations, we conducted an umbrella review of 28 systematic reviews, including 12 meta-analyses, on oral-cognitive links. We found that (a) periodontal diseases, oral microbiome, and dementia were frequently studied, while other factors, such as mastication and mild cognitive impairment, were less commonly investigated, and (b) severe deterioration of oral health, such as severe periodontitis or extensive tooth loss, rather than the presence of oral diseases alone, was strongly associated with cognitive dysfunction. In conclusion, the diversity of oral and cognitive factors included in the review studies reflects the complexity of oral-cognitive links. Clarifying the factors helps to form evidence-based clinical advice for healthcare.

The Association of Oral Microbiome Dysbiosis with Gastrointestinal Cancers and Its Diagnostic Efficacy

BACKGROUND

The second leading mortality cause in the world is cancer, making it a critical issue that impacts human health. As a result, scientists are looking for novel biomarkers for cancer detection. The oral microbiome, made up of approximately 700 species-level taxa, is a significant source for discovering novel biomarkers. In this review, we aimed to prepare a summary of research that has investigated the association between the oral microbiome and gastrointestinal cancers.

METHODS

We searched online scientific datasets including Web of Science, PubMed, Scopus, and Google Scholar. Eligibility criteria included human studies that reported abundances of the oral microbiome, or its diagnostic/prognostic performance in patients with gastrointestinal cancers.

RESULTS

Some phyla of the oral microbiome have a relationship with cancers. Some particular phyla of the oral microbiome that may be related to gastrointestinal cancers consist of Firmicutes, Actinobacteria, Bacteroidetes, Proteobacteria, and Fusobacteria. Changes in the abundances of Porphyromonas, Fusobacterium, Prevotella, and Veillonella are correlated with carcinogenesis, and may be used for distinguishing cancer patients from healthy subjects. Oral, colorectal, pancreatic, and esophageal cancers are the most important cancers related to the oral microbiome.

CONCLUSION

The results of this study may help future research to select bacteria as an early diagnostic or prognostic biomarker of gastrointestinal cancer. Given the current state of our knowledge, additional research is required to comprehend the multiplex processes underlying the role of bacterial microbiota upon cancer progression and to characterize the complex microbiota-host interaction network.

The Complicated Relationship of Short-Chain Fatty Acids and Oral Microbiome: A Narrative Review

The human oral microbiome has emerged as a focal point of research due to its profound implications for human health. The involvement of short-chain fatty acids in oral microbiome composition, oral health, and chronic inflammation is gaining increasing attention. In this narrative review, the results of early in vitro, in vivo, and pilot clinical studies and research projects are presented in order to define the boundaries of this new complicated issue. According to the results, the current research data are disputable and ambiguous. When investigating the role of SCFAs in human health and disease, it is crucial to distinguish between their local GI effects and the systemic influences. Locally, SCFAs are a part of normal oral microbiota metabolism, but the increased formation of SCFAs usually attribute to dysbiosis; excess SCFAs participate in the development of local oral diseases and in oral biota gut colonization and dysbiosis. On the other hand, a number of studies have established the positive impact of SCFAs on human health as a whole, including the reduction of chronic systemic inflammation, improvement of metabolic processes, and decrease of some types of cancer incidence. Thus, a complex and sophisticated approach with consideration of origin and localization for SCFA function assessment is demanded. Therefore, more research, especially clinical research, is needed to investigate the complicated relationship of SCFAs with health and disease and their potential role in prevention and treatment.

Mapping new pharmacological interventions for cognitive function in Alzheimer's disease: a systematic review of randomized clinical trials

Background and Objective: Alzheimer's disease (AD) is a progressive neurodegenerative disorder, that is, characterized by cognitive decline. To date, there are no effective treatments for AD. Therefore, the objective of this study was to map new perspectives on the effects of pharmacological treatment on cognitive function and the overall psychological state in patients with AD. Methods: Two independent researchers searched for randomized clinical trials (RCTs) exploring new pharmacological approaches related to cognition in Alzheimer's disease in adults from 2018 to 2023 in PubMed, Web of Science, Scopus, and Cochrane Library databases. A total of 17 RCTs were included in this review. Results: The results show that in recent years, new drugs have been tested in patients with Alzheimer's disease, including masitinib, methylphenidate, levetiracetam, Jiannao Yizhi, and Huannao Yicong formulas. Most studies have been conducted in populations with mild to moderate Alzheimer's disease. Conclusion: Although some of the drugs found suggested improvement in cognitive function, the scarcity of available studies highlights the need for further research in this area. Systematic review registration: [www.crd.york.ac.uk/prospero], identifier [CRD42023409986].

Diagnostic performance of two teledentistry tools in elderly care facilities: the ONE-1 protocol for a pilot prospective diagnostic study

INTRODUCTION

Elderly people living in care facilities suffer from difficulties in accessing preventive and curative dental care. This leads to poor oral health, which is an increased risk of systemic diseases, in a fragile and dependent population. All this contributes to a progressive loss of autonomy and a decreased quality of life. The use of information and communication technologies through oral telemedicine could help to overcome these barriers. We described the protocol for evaluating the diagnostic performance of two intraoral cameras against a gold standard clinical examination.

METHODS AND ANALYSIS

We conduct a pilot multicentric and prospective diagnostic study (a minimal-risk, minimal-burden interventional research called ONE-1 (for Oral graNd Est step 1)) on two intraoral diagnostic tools (Soprocare camera and consumer camera) compared with a reference intraoral examination. Patients in four elderly care facilities will be included, with randomisation of participant selection and randomisation of the order of the three intraoral examinations performed by a dental surgeon. We will evaluate the diagnostic performance of each device with the asynchronous analysis of videos by two independent dental surgeons against the clinical gold standard examination performed by a single, third dental examiner. The primary outcome is the presence of at least one tooth decay in the dentition of each study participant. Second, we will evaluate the presence of other dental or oral diseases, and the time required to perform each examination. Finally, we will evaluate the organisation of patient follow-up.

ETHICS AND DISSEMINATION

The protocol has been approved by the French ethics committee (Protection to Persons Committee, Nord-Ouest IV on 9 June 2021 and on 28 November 2022). Results will be disseminated through conferences' presentations and publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05089214.

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

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

Unlocking Modifiable Risk Factors for Alzheimer's Disease: Does the Oral Microbiome Hold Some of the Keys?

Advancing age is recognized as the primary risk factor for Alzheimer's disease (AD); however approximately one third of dementia cases are attributable to modifiable risk factors such as hypertension, diabetes, smoking, and obesity. Recent research also implicates oral health and the oral microbiome in AD risk and pathophysiology. The oral microbiome contributes to the cerebrovascular and neurodegenerative pathology of AD via the inflammatory, vascular, neurotoxic, and oxidative stress pathways of known modifiable risk factors. This review proposes a conceptual framework that integrates the emerging evidence regarding the oral microbiome with established modifiable risk factors. There are numerous mechanisms by which the oral microbiome may interact with AD pathophysiology. Microbiota have immunomodulatory functions, including the activation of systemic pro-inflammatory cytokines. This inflammation can affect the integrity of the blood-brain barrier, which in turn modulates translocation of bacteria and their metabolites to brain parenchyma. Amyloid-β is an antimicrobial peptide, a feature which may in part explain its accumulation. There are microbial interactions with cardiovascular health, glucose tolerance, physical activity, and sleep, suggesting that these modifiable lifestyle risk factors of dementia may have microbial contributors. There is mounting evidence to suggest the relevance of oral health practices and the microbiome to AD. The conceptual framework presented here additionally demonstrates the potential for the oral microbiome to comprise a mechanistic intermediary between some lifestyle risk factors and AD pathophysiology. Future clinical studies may identify specific oral microbial targets and the optimum oral health practices to reduce dementia risk.

Effects of oral health intervention strategies on cognition and microbiota alterations in patients with mild Alzheimer's disease: A randomized controlled trial

We explored the effects of an oral health intervention on the oral microbiome and cognitive function of patients with mild Alzheimer's disease (AD) and determined the influence on disease progression. Sixty-six patients with mild AD were randomly assigned to intervention or control groups and received a 24-week oral health intervention and routine care, respectively. Data were collected at baseline and week 24. 16 S rRNA sequencing was used to analyze oral microbiota. After 24 weeks of oral health intervention, Kayser-Jones Brief Oral Health Status Examination (BOHSE), Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI), Nursing Home Adjustment Scale (NHAS), and Alzheimer's Disease Cooperative Study-ADL (ADCS-ADL) scores were different between groups (p < 0.05). Subgingival plaque in patients with AD showed significant differences in the diversity and abundance of oral microbiomes, with a higher abundance of normal oral flora in the intervention group. We found oral health intervention strategies are effective in modifying subgingival microbiota differences and slowing cognitive decline in mild AD patients.

Oral Microbiota, Its Equilibrium and Implications in the Pathophysiology of Human Diseases: A Systematic Review

Imbalances of the oral microbiota and dysbiosis have traditionally been linked to the occurrence of teeth and oral diseases. However, recent findings indicate that this microbiota exerts relevant influence in systemic health. Dysbiosis of the oral microbiota is implicated in the apparition and progression of cardiovascular, neurodegenerative and other major human diseases. In fact, the oral microbiota are the second most diverse and largely populated microbiota of the human body and its relationships with systemic health, although widely explored, they still lack of proper integration. The purpose of this systematic review is thus to widely examine the implications of oral microbiota in oral, cardiovascular and neurodegenerative diseases to offer integrative and up-to-date interpretations. To achieve that aim, we identified a total of 121 studies curated in PUBMED from the time interval January 2003–April 2022, which after careful screening resulted in 79 studies included. The reviewed scientific literature provides plausible vias of implication of dysbiotic oral microbiota in systemic human diseases, and encourages further research to continue elucidating the highly relevant and still poorly understood implications of this niche microbiota in systemic health. PROSPERO Registration Number: CRD42022299692. This systematic review follows relevant PRISMA guidelines.

Oral-Hygiene-Related Mobile Apps in the French App Stores: Assessment of Functionality and Quality

Mobile health apps can contribute to increased quality of individual oral hygiene behaviors. This study provides an overview and an evaluation of quality of oral-hygiene-related mobile apps currently available in Google Play Store and the French Apple App. A shortlist of nine apps was assessed by 10 oral health professionals using the Mobile App Rating Scale. Intraclass correlation was used to evaluate interrater agreement. Best quality scores were obtained by Oral-B (3.4 ± 0.97), Colgate Connect (3.20 ± 0.63), and Preventeeth (3.10 ± 1.1) and worst ones by Mimizaur se brosse les dents (1.80 ± 0.79) and Kolibree (2.30 ± 0.82). The subjective quality scores ranged from 2.62 ± 0.61 (Oral-B) to 1.5 ± 0.61 (MSD). Specificity of the content ranged from 3.46 ± 0.84 (Preventeeth) to 1.78 ± 0.47 (Mimizaur se brosse les dents). Thus, even if oral health professionals positively evaluated the quality of oral-hygiene-related mobile apps, they are less assertive concerning their impact on the user's knowledge, attitudes, and intentions to change, as well as the likelihood of actual change in the oral hygiene behavior. Further investigations are needed to assess whether information from these apps is consistent with oral hygiene recommendations and to determine the long-term impacts of these apps.

Associations between self-reported periodontal disease and nutrient intakes and nutrient-based dietary patterns in the UK Biobank

AIM

To examine the cross-sectional associations between single nutrient intakes and posteriori nutrient-based dietary patterns and periodontal disease risk in a subset of the UK Biobank cohort.

MATERIALS AND METHODS

Dietary data were collected by 24-h dietary recall on up to five separate occasions over 16 months. A touchscreen questionnaire was used to collect oral health information. Participants were considered at high risk of periodontal disease if they reported having painful gums and/or bleeding gums and/or loose teeth. Principal component analysis identified four nutrient-based dietary patterns from 20 nutrients. Logistic regression was used to estimate the odds ratio of periodontal disease risk for single nutrients and nutrient-based dietary patterns.

RESULTS

A total of 9476 participants (mean age 56.2 years [SD 8.0]) were included in the analysis. Higher intakes of vitamin B6, B12, C, and E, folate, iron, potassium, magnesium, polyunsaturated fatty acids, and total sugar were associated with a lower risk of periodontal disease. Higher intake of saturated fat was associated with an increased risk. A dietary pattern characterized by high micronutrients and fibre intake was associated with low risk of periodontal disease.

CONCLUSION

Within this sample of middle-aged and older adults, a "high micronutrient and fibre" dietary pattern was associated with reduced risk of periodontal disease.

Combination Therapy in Alzheimer’s Disease: Is It Time?

Alzheimer’s disease (AD) is the most common cause of dementia globally. There is increasing evidence showing AD has no single pathogenic mechanism, and thus treatment approaches focusing only on one mechanism are unlikely to be meaningfully effective. With only one potentially disease modifying treatment approved, targeting amyloid-β (Aβ), AD is underserved regarding effective drug treatments. Combining multiple drugs or designing treatments that target multiple pathways could be an effective therapeutic approach. Considering the distinction between added and combination therapies, one can conclude that most trials fall under the category of added therapies. For combination therapy to have an actual impact on the course of AD, it is likely necessary to target multiple mechanisms including but not limited to Aβ and tau pathology. Several challenges have to be addressed regarding combination therapy, including choosing the correct agents, the best time and stage of AD to intervene, designing and providing proper protocols for clinical trials. This can be achieved by a cooperation between the pharmaceutical industry, academia, private research centers, philanthropic institutions, and the regulatory bodies. Based on all the available information, the success of combination therapy to tackle complicated disorders such as cancer, and the blueprint already laid out on how to implement combination therapy and overcome its challenges, an argument can be made that the field has to move cautiously but quickly toward designing new clinical trials, further exploring the pathological mechanisms of AD, and re-examining the previous studies with combination therapies so that effective treatments for AD may be finally found.