Dental health of patients with Parkinson's disease in Iceland

Ultrastructural localization of Porphyromonas gingivalis gingipains in the substantia nigra of Parkinson's disease brains

Gingipains are protease virulence factors produced by Porphyromonas gingivalis, a Gram-negative bacterium best known for its role in chronic periodontitis. Gingipains were recently identified in the middle temporal gyrus of postmortem Alzheimer's disease (AD) brains, where gingipain load correlated with AD diagnosis and tau and ubiquitin pathology. Since AD and Parkinson's disease (PD) share some overlapping pathologic features, including nigral pathology and Lewy bodies, the current study explored whether gingipains are present in the substantia nigra pars compacta of PD brains. In immunohistochemical techniques and multi-channel fluorescence studies, gingipain antigens were abundant in dopaminergic neurons in the substantia nigra of both PD and neurologically normal control brains. 3-dimensional reconstructions of Lewy body containing neurons revealed that gingipains associated with the periphery of alpha-synuclein aggregates but were occasionally observed inside aggregates. In vitro proteomic analysis demonstrated that recombinant alpha-synuclein is cleaved by lysine-gingipain, generating multiple alpha-synuclein fragments including the non-amyloid component fragments. Immunogold electron microscopy with co-labeling of gingipains and alpha-synuclein confirmed the occasional colocalization of gingipains with phosphorylated (pSER129) alpha-synuclein. In dopaminergic neurons, gingipains localized to the perinuclear cytoplasm, neuromelanin, mitochondria, and nucleus. These data suggest that gingipains localize in dopaminergic neurons in the substantia nigra and interact with alpha-synuclein.

Assessment of periodontal health status in patients with Parkinson's disease-A systematic review and meta-analysis of cross-sectional studies

INTRODUCTION

Parkinson's disease (PKD) is neurodegenerative disorder marked by tremors, bradykinesia, muscle rigidity and reduction in precise hand movements which could lead to improper oral hygiene and Periodontal disease. Current systematic review aims to review existing literature and provide assessment of periodontal health in PKD patients through a meta-analysis METHODS: Review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and registered in PROSPERO-CRD42023451700. Databases were searched for studies having sufficient data on periodontal health in patients with PKD compared to healthy controls and reporting outcomes in terms of various periodontal parameters of probing depth (PD), plaque index (PI), clinical attachment level (CAL), presence of bleeding on probing and gingivitis. Quality assessment of included was evaluated using Newcastle Ottawa Scale (NOS).

RESULTS

Eleven studies fulfilled the eligibility criteria, of which ten studies were suitable for meta-analysis. Pooled estimate through the SMD showed that all periodontal parameters were altered and significantly deteriorated in PKD compared to controls but this group differences were statistically insignificant (p > 0.05). Publication bias through the funnel plot showed symmetric distribution with absence of systematic heterogeneity.

CONCLUSION

Parkinson's disease could be a possible factor in deterioration of periodontal health.

Investigating the Connection between Chronic Periodontitis and Parkinson's Disease: Findings from a Korean National Cohort Study

Recent research suggests a potential relevance between chronic periodontitis (CP) and Parkinson's disease (PD), raising concerns about comorbid PD among elderly CP patients. However, the epidemiologic basis for this association remains unclear. Employing a nested case-control design, this study explored the association between CP and subsequent PD occurrences in Korean adults, leveraging a validated national population-based dataset covering the period from 2002 to 2019. It included 8794 PD patients and 35,176 matched control individuals, established through propensity score matching for age, sex, residential area, and income. Baseline characteristics were compared using standardized differences, and logistic regression was employed to assess the impact of CP histories on PD likelihood while controlling for covariates. We performed a thorough examination of CP events within both 1-year and 2-year intervals preceding the index date, incorporating subgroup analyses. Our analysis revealed no statistically significant association between CP history and PD development overall. However, subgroup analysis revealed a slightly increased likelihood of PD development among CP individuals with a high disease burden (Charlson Comorbidity Index score ≥ 2). In conclusion, although our study did not find a significant overall association between CP history and PD development, the elevated likelihood of PD in subgroups with high disease burden may suggest that comorbidities influence PD probability among certain CP patients. Considering comorbid conditions in PD screening for some individuals with CP may be also important.

Oral health experiences of people living with Parkinson's disease: a scoping review

Background and aim Parkinson's disease is the fastest growing and second most common progressive neurodegenerative condition in the UK; poised to represent a major societal and health care challenge. The scoping review aims to provide an overview of the literature on the oral health (OH) experiences of people living with Parkinson's, identifying current research gaps and future priorities.Method Search strategies included three electronic databases, two grey literature databases, relevant organisations, specialist journals and hand searching of the reference lists. A data extraction tool was developed and piloted.Results A total of 121 items were included in the review. Four themes were identified: OH impact, education and training, service delivery and wider impacts of OH for people with Parkinson's (PwP). The majority of studies included were cross-sectional in design, describing the OH status of PwP.Conclusion The majority of research to date has focused on OH impact. Areas for future research include use of qualitative studies exploring the experiences, attitudes and priorities of PwP and their care partners. Inclusion of medical, dental and allied health care professionals, together with people with lived experience, is required to develop, implement and evaluate interventions to support OH.

Orofacial function and temporomandibular disorders in Parkinson's Disease: a case-controlled study

BACKGROUND

The difficulties and challenges faced by people with Parkinson's disease (PD) in performing daily orofacial function are not systematically investigated. In this study, specific orofacial non-motor and motor symptoms and functions were systematically examined in PD patients in comparison to a matched control group.

METHODS

The clinical case-controlled study was conducted from May 2021 to October 2022 and included persons with PD and age- and gender-matched persons without PD. The participants with PD were outpatients diagnosed with PD at the Department of Neurology at Bispebjerg University Hospital in Copenhagen, Denmark. The participants underwent a systematic clinical and relevant self-assessment of the orofacial function and temporomandibular disorders (TMD). The primary outcomes were objective and subjective assessments of the general orofacial function, mastication, swallowing, xerostomia and drooling. The secondary outcomes were the prevalence of TMD and orofacial pain. The difference in outcome measures between the two groups was analysed using chi-square and Mann-Whitney U test.

RESULTS

The study included 20 persons with PD and 20 age- and gender-matched persons without PD. Both objectively and subjectively, persons with PD had poorer orofacial function than the control group. Persons with PD had also a significantly more severe limitation of jaw mobility and jaw function. The objective masticatory function was also significantly reduced for persons with PD compared to the control group, and 60% of persons with PD found it difficult to eat foods with certain consistencies while 0% of the control group reported that problem. Persons with PD could swallow less water per second and the average swallowing event was significantly longer for PD persons. Even though PD persons reported more xerostomia (58% for persons with PD and 20% for control persons), they also reported significantly more drooling than the control group. Additionally, orofacial pain was more prevalent in PD persons.

CONCLUSIONS

Persons with PD have a compromised orofacial function. Furthermore, the study indicates a link between PD and orofacial pain. In order to screen and treat persons with PD accordingly, healthcare professionals should be aware of and address these limitations and symptoms.

TRIAL REGISTRATION

The trial was approved by the Regional Committee on Research Health Ethics of the Capital Region (H-20,047,464), the Danish Data Protection Agency (514 - 0510/20-3000), and registered at ClinicalTrials.gov (NCT05356845).

Parkinson's disease and oral health: A systematic review

OBJECTIVE

in patients with Parkinson's Disease (PD), oral health can be affected by motor and non-motor symptoms and/or medication use. Therefore, the aim was to systematically review the literature on oral health and associated factors of oral health in PD patients.

DESIGN

a literature search was performed from inception up to April 5th, 2023. Original studies that assessed oral health-related factors in PD patients and were written in English or Dutch, were included.

RESULTS

11276 articles were identified, of which 43 met the inclusion criteria (quality range poor-good). A higher prevalence of dental biofilm, bleeding/gingivitis, pocket depth (≥4 mm), tooth mobility, caries, and number of decayed missing filled teeth/surfaces was found in PD patients than in controls. However, no difference between both groups was found when analysing edentulism and wearing dentures. Poor oral health of PD patients was associated with a longer disease duration, higher disease severity, and more prescribed medications.

CONCLUSIONS

oral health of PD patients is worse than that of healthy individuals. It is associated with the duration and severity of PD and medication use. Therefore, we advise regular appointments with oral health care professionals, with an important focus on prevention.

Salivation in Parkinson's disease: A scoping review

OBJECTIVES

We aimed to provide an overview of the available literature that includes both objective assessments (namely hypersalivation and hyposalivation) and the subjective experience (namely xerostomia and drooling) of salivary problems in patients with Parkinson's disease.

BACKGROUND

In patients with Parkinson's disease, there may be complaints of salivary problems such as xerostomia or drooling. This can have consequences for their oral health and quality of life. To date, systematic reviews have focused on drooling only.

MATERIALS AND METHODS

A literature search in 4 databases was performed up to 12 February 2021. Two researchers independently assessed studies for eligibility.

RESULTS

In total, 63 studies were included. The prevalence of self-reported xerostomia ranged from 49% to 77%, and that of self-reported drooling ranged from 5% to 80%. Ten articles reported a significantly lower mean salivary flow in patients with Parkinson's disease than in controls. None of the articles with both a control group and a patient group reported a significantly higher salivary flow in patients with Parkinson's disease. When questioned about subjective salivary problems, a significantly higher prevalence of both xerostomia (7 studies) and drooling (14 studies) was found in patients with Parkinson's disease than in controls. Patients with Parkinson's disease have a lower salivary flow rate and higher prevalence of both xerostomia and drooling than controls.

CONCLUSION

The complexity of salivary problems present in patients with Parkinson's disease necessitates a multidisciplinary approach in order to avoid mutually counteracting treatments from different healthcare professionals.

Is There an Association Between Parkinson's Disease and Periodontitis? A Systematic Review and Meta-Analysis

BACKGROUND

Multiple observational studies have yielded controversial results regarding the association between Parkinson's disease (PD) and periodontitis.

OBJECTIVE

This systematic review and meta-analysis was conducted to ascertain their bidirectional relationship.

METHODS

A literature search for relevant studies was performed in PubMed, EMBASE, the Cochrane Library, and Web of Science databases from inception to December 19, 2022. Effect sizes (ES) with 95% confidence intervals were pooled under the random-effects model. Then, leave-one-out sensitivity analysis and contour-enhanced funnel plot were applied to assess the stability of the results.

RESULTS

A total of 34 studies and 24 studies were included for systematic review and quantitative meta-analysis, respectively. Pooled ES indicated that periodontitis was not significantly associated with PD risk (HR = 1.13, 95% CI 0.88-1.45, n = 3; OR = 1.94, 95% CI 0.55-6.90, n = 7), while the Mendelian randomization study revealed no association between PD and periodontitis risk (coefficient [B] = -0.0001, standard error = 0.0001, p = 0.19). Furthermore, PD patients exhibited higher levels of periodontal pocket depth (SMD = 1.10, 95% CI 0.53-1.67), clinical attachment level (SMD = 1.40, 95% CI 0.55-2.26), plaque index (SMD = 0.81, 95% CI 0.22-1.39), and Oral Health Impact Profile-14 score (SMD = 0.91, 95% CI 0.33-1.49) compared to healthy controls.

CONCLUSIONS

Our meta-analysis identified no bidirectional association between PD risk and periodontitis risk, though the prevalence of periodontitis and poorer oral status was higher in PD patients.

Review of general and head and neck/oral and maxillofacial features of Charcot-Marie-Tooth disease and dental management considerations

Charcot-Marie-Tooth disease (CMTD) is an uncommon progressive neuromuscular disorder of the peripheral nervous system and primarily leads to distal extremity weakness and sensory deficits. Frequently, affected patients manifest pes cavus, drop foot, and digit contractures that may pose significant challenges in ambulation and grasping objects. Although there are numerous articles of this syndrome in the medical literature, there is a limited number of dental publications. The objective of this article is to review the general and head and neck/oral and maxillofacial features of CMTD. General guidelines for dental management are also provided.

Self-reported periodontitis and C-reactive protein in Parkinson's disease: a cross-sectional study of two American cohorts

Periodontitis triggers systemic repercussions, such as elevated levels of high-sensitive C-reactive protein (hs-CRP). This has never been studied within Parkinson's Disease (PD). The aim of this study is to compare hs-CRP levels of self-reported periodontitis cases versus cases without periodontitis in PD patients. Data from the National Health and Nutrition Examination Survey (2015-2016 and 2017-2018 waves) were analyzed. PD cases were identified through medication regimens and periodontitis cases through a validated self-report questionnaire. 51 participants were included (24 females, 27 males, with mean age of 62.96 (14.71)). While the self-reported periodontitis group presented elevated levels of circulating hs-CRP (5.36 vs. 1.99 mg/L, p = 0.031), the self-reported without periodontitis group presented higher lymphocyte levels (29.35 vs. 28.03%, p = 0.007). Blood levels of hs-CRP were significantly higher in PD cases with self-reported periodontitis. Apart from the lymphocyte levels, there were no other significant differences according to the self-reported periodontal status. Future studies shall explore this association using clinical measures.

Research progress on the relationship between chronic periodontitis and Parkinson's disease

Chronic periodontitis is an infectious disease, which has a reciprocal relationship with a variety of systemic disorders. Parkinson's disease is a prevalent neurodegenerative disease in which inflammation plays an important role for its progression. A vast number of studies suggest that there is a potential connection between chronic periodontitis and neurodegenerative diseases such as Parkinson's disease. Individuals with Parkinson's disease usually have poor periodontal health, and their oral flora composition differs from that of healthy people; at the same time, patients with chronic periodontitis have a higher risk of Parkinson's disease, which can be reduced with regular periodontal treatment. In fact, the mechanism of interaction between chronic periodontitis and Parkinson's disease is not clear. According to several studies, the clinical symptoms of Parkinson's disease prevent patients to maintain oral hygiene effectively, increasing the risk of periodontitis. Neuroinflammation mediated by microglia may be the key to the influence of chronic periodontitis on Parkinson's disease. Periodontal pathogens and inflammatory mediators may enter the brain and activate microglia in various ways, and ultimately leading to occurrence and development of Parkinson's disease. This article reviews the recent research progress on the association between chronic periodontitis and Parkinson's disease, and its potential mechanism to provide information for further research.

Does parkinsonism affect periodontal health? A cross-sectional study in a tertiary hospital

Background:

Muscular rigidity, tremors, and bradykinesia with diminished motor skills are the characteristic features of Parkinson's disease (PD).

Aim:

The study investigated the influence of reduced motor proficiency on the periodontal health of PD patients and compared it with controls.

Setting and Design:

A cross-sectional study was conducted on PD patients selected from outpatient section of a tertiary healthcare center and compared with age- and gender-matched controls.

Materials and Methods:

Oral health status of the subjects was graded based on decayed, missing, and filled teeth index, oral hygiene index (OHI), modified gingival index, probing pocket depth (PPD), clinical attachment level (CAL), tooth mobility, interproximal PPD, and interproximal CAL measurements. PD patients were categorized based on Hoehn and Yahr scale and duration to assess the influence of PD severity and progression.

Statistical Analysis:

Difference in the mean values of quantitative variables was analyzed by parametric t-test and Chi-square test for categorical variables.

Results:

In PD patients, 84.4% of subjects had moderate–severe gingivitis, while it was 2.4% in the control group. Mean number of interproximal sites with CAL >5 mm in PD patients and control subjects was 8.41 ± 6.37 and 1.12 ± 2.28, respectively (P < 0.05). The mean OHI was 2.90 ± 0.81 in patients with mild PD and increased to 3.77 ± 0.52 as PD severity exalted.

Conclusion:

PD patients had impaired oral condition with higher OHI and increased gingival inflammation with a likelihood of male predisposition. Substantial interproximal tissue destruction, debilitated periodontal health as PD progresses, suggests early attention toward their oral health.

The Role of Pathogens and Anti-Infective Agents in Parkinson's Disease, from Etiology to Therapeutic Implications

Parkinson's disease is a debilitating neurodegenerative disorder whose etiology is still unclear, hampering the development of effective treatments. There is an urgent need to identify the etiology and provide further effective treatments. Recently, accumulating evidence has indicated that infection may play a role in the etiology of Parkinson's disease. The infective pathogens may act as a trigger for Parkinson's disease, the most common of which are hepatitis C virus, influenza virus, and Helicobacter pylori. In addition, gut microbiota is increasingly recognized to influence brain function through the gut-brain axis, showing an important role in the pathogenesis of Parkinson's disease. Furthermore, a series of anti-infective agents exhibit surprising neuroprotective effects via various mechanisms, such as interfering with α-synuclein aggregation, inhibiting neuroinflammation, attenuating oxidative stress, and preventing from cell death, independent of their antimicrobial effects. The pleiotropic agents affect important events in the pathogenesis of Parkinson's disease. Moreover, most of them are less toxic, clinically safe and have good blood-brain penetrability, making them hopeful candidates for the treatment of Parkinson's disease. However, the use of antibiotics and subsequent gut dysbiosis may also play a role in Parkinson's disease, making the long-term effects of anti-infective drugs worthy of further consideration and exploration. This review summarizes the current evidence for the association between infective pathogens and Parkinson's disease and subsequently explores the application prospects of anti-infective drugs in Parkinson's disease treatment, providing novel insights into the pathogenesis and treatment of Parkinson's disease.

Evaluation of the association between periodontitis and risk of Parkinson's disease: a nationwide retrospective cohort study

The objective of this study was to examine the association between periodontitis and risk of incident Parkinson’s disease using large-scale cohort data on the entire population of South Korea. Health checkup data from 6,856,180 participants aged 40 and older were provided by the National Health Insurance Service of South Korea between January 1, 2009, and December 31, 2009, and the data were followed until December 31, 2017. The hazard ratio (HR) of Parkinson’s disease and 95% confidence interval (CI) were estimated using a Cox proportional hazards model adjusted for potential confounders. The incidence probability of Parkinson’s disease was positively correlated with the presence of periodontitis. The HR of Parkinson’s disease for the participants without the need of further dentist visits was 0.96 (95% CI 0.921–1.002); the HR of Parkinson’s disease increased to 1.142 (95% CI 1.094–1.193) for the individuals who needed further dentist visits. Compared to individuals without periodontitis and without metabolic syndrome, the HR of incident Parkinson’s disease gradually increased for individuals with periodontitis, with metabolic syndrome, and with both periodontitis and metabolic syndrome. People with periodontitis and metabolic syndrome had the highest HR of incident Parkinson’s disease, at 1.167 (95% CI 1.118–1.219). In conclusion, a weak association between periodontitis and Parkinson’s disease was suggested after adjusting for confounding factors from the population-based large-scale cohort of the entire South Korean population.

Oral Factors That Impact the Oral Microbiota in Parkinson's Disease

Patients with Parkinson’s disease (PD) are at increased risk of aspiration pneumonia, their primary cause of death. Their oral microbiota differs from healthy controls, exacerbating this risk. Our goal was to explore if poor oral health, poor oral hygiene, and dysphagia status affect the oral microbiota composition of these patients. In this cross-sectional case-control study, the oral microbiota from hard and soft tissues of patients with PD (n = 30) and age-, gender-, and education-matched healthy controls (n = 30) was compared using 16S rRNA gene sequencing for bacterial identification. Study participants completed dietary, oral hygiene, drooling, and dysphagia questionnaires, and an oral health screening. Significant differences in soft tissue beta-diversity (p < 0.005) were found, and a higher abundance of opportunistic oral pathogens was detected in patients with PD. Factors that significantly influenced soft tissue beta-diversity and microbiota composition include dysphagia, drooling (both p < 0.05), and salivary pH (p < 0.005). Thus, patients with PD show significant differences in their oral microbiota compared to the controls, which may be due, in part, to dysphagia, drooling, and salivary pH. Understanding factors that alter their oral microbiota could lead to the development of diagnostic and treatment strategies that improve the quality of life and survivability of these patients.

Oral Health Disorders in Parkinson's Disease: More than Meets the Eye

Despite clinical evidence of poor oral health and hygiene in Parkinson’s disease (PD) patients, the mouth is often overlooked by both patients and the medical community, who generally focus on motor or psychiatric disorders considered more burdensome. Yet, oral health is in a two-way relationship with overall health—a weakened status triggering a decline in the quality of life. Here, we aim at giving a comprehensive overview of oral health disorders in PD, while identifying their etiologies and consequences. The physical (abnormal posture, muscle tone, tremor, and dyskinesia), behavioral (cognitive and neuropsychiatric disorders), and iatrogenic patterns associated with PD have an overall detrimental effect on patients’ oral health, putting them at risk for other disorders (infections, aspiration, pain, malnutrition), reducing their quality of life and increasing their isolation (anxiety, depression, communication issues). Interdisciplinary cooperation for prevention, management and follow-up strategies need to be implemented at an early stage to maintain and improve patients’ overall comfort and condition. Recommendations for practice, including (non-)pharmacological management strategies are discussed, with an emphasis on the neurologists’ role. Of interest, the oral cavity may become a valuable tool for diagnosis and prognosis in the near future (biomarkers). This overlooked but critical issue requires further attention and interdisciplinary research.

Is There Any Association Between Neurodegenerative Diseases and Periodontitis? A Systematic Review

Background: Neurodegenerative diseases are a group of progressive disorders that affect the central nervous system (CNS) such as Alzheimer, Parkinson, and multiple sclerosis. Inflammation plays a critical role in the onset and progression of these injuries. Periodontitis is considered an inflammatory disease caused by oral biofilms around the tooth-supporting tissues, leading to a systemic and chronic inflammatory condition. Thus, this systematic review aimed to search for evidence in the association between neurodegenerative disorders and periodontitis.

Methods: This systematic review was registered at International Prospective Register of Systematic Reviews (PROSPERO) under the code CRD 42016038327. The search strategy was performed in three electronic databases and one gray literature source—PubMed, Scopus, Web of Science, and OpenGrey, based on the PECO acronym: observational studies in humans (P) in which a neurodegenerative disease was present (E) or absent (C) to observe an association with periodontitis (O). The Fowkes and Fulton checklist was used to critically appraise the methodological quality and the risk of bias of individual studies. The quality of evidence was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Results: From 534 articles found, 12 were included, of which eight were case–control, three were cross-sectional, and one was a cohort, giving a total of 3,460 participants. All the included studies reported an association between some neurodegenerative diseases and periodontitis and presented a low risk of bias. According to the GRADE approach, the level of evidence of probing pocket depth was considered very low due to the significant heterogeneity across the studies' upgrading imprecision and inconsistency.

Conclusions: Although all the included studies in this review reported an association between neurodegenerative diseases and periodontitis, the level of evidence was classified to be very low, which suggests a cautious interpretation of the results.

Causal Association between Periodontitis and Parkinson's Disease: A Bidirectional Mendelian Randomization Study

The latest evidence revealed a possible association between periodontitis and Parkinson’s disease (PD). We explored the causal relationship of this bidirectional association through two-sample Mendelian randomization (MR) in European ancestry populations. To this end, we used openly accessible data of genome-wide association studies (GWAS) on periodontitis and PD. As instrumental variables for periodontitis, seventeen single-nucleotide polymorphisms (SNPs) from a GWAS of periodontitis (1817 periodontitis cases vs. 2215 controls) and eight non-overlapping SNPs of periodontitis from an additional GWAS for validation purposes. Instrumental variables to explore for the reverse causation included forty-five SNPs from a GWAS of PD (20,184 cases and 397,324 controls). Multiple approaches of MR were carried-out. There was no evidence of genetic liability of periodontitis being associated with a higher risk of PD (B = −0.0003, Standard Error [SE] 0.0003, p = 0.26). The eight independent SNPs (B = −0.0000, SE 0.0001, p = 0.99) validated this outcome. We also found no association of genetically primed PD towards periodontitis (B = −0.0001, SE 0.0001, p = 0.19). These MR study findings do not support a bidirectional causal genetic liability between periodontitis and PD. Further GWAS studies are needed to confirm the consistency of these results.

Network Protein Interaction in Parkinson's Disease and Periodontitis Interplay: A Preliminary Bioinformatic Analysis

Recent studies supported a clinical association between Parkinson's disease (PD) and periodontitis. Hence, investigating possible interactions between proteins associated to these two conditions is of interest. In this study, we conducted a protein-protein network interaction analysis with recognized genes encoding proteins with variants strongly associated with PD and periodontitis. Genes of interest were collected via the Genome-Wide Association Studies (GWAS) database. Then, we conducted a protein interaction analysis, using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, with a highest confidence cutoff of 0.9 and sensitivity analysis with confidence cutoff of 0.7. Our protein network casts a comprehensive analysis of potential protein-protein interactions between PD and periodontitis. This analysis may underpin valuable information for new candidate molecular mechanisms between PD and periodontitis and may serve new potential targets for research purposes. These results should be carefully interpreted, giving the limitations of this approach.

Oral P. gingivalis impairs gut permeability and mediates immune responses associated with neurodegeneration in LRRK2 R1441G mice

Background

The R1441G mutation in the leucine-rich repeat kinase 2 (LRRK2) gene results in late-onset Parkinson’s disease (PD). Peripheral inflammation and gut microbiota are closely associated with the pathogenesis of PD. Chronic periodontitis is a common type of peripheral inflammation, which is associated with PD. Porphyromonas gingivalis (Pg), the most common bacterium causing chronic periodontitis, can cause alteration of gut microbiota. It is not known whether Pg-induced dysbiosis plays a role in the pathophysiology of PD.

Methods

In this study, live Pg were orally administrated to animals, three times a week for 1 month. Pg-derived lipopolysaccharide (LPS) was used to stimulate mononuclear cells in vitro. The effects of oral Pg administration on the gut and brain were evaluated through behaviors, morphology, and cytokine expression.

Results

Dopaminergic neurons in the substantia nigra were reduced, and activated microglial cells were increased in R1441G mice given oral Pg. In addition, an increase in mRNA expression of tumor necrosis factor (TNF-α) and interleukin-1β (IL-1β) as well as protein level of α-synuclein together with a decrease in zonula occludens-1 (Zo-1) was detected in the colon in Pg-treated R1441G mice. Furthermore, serum interleukin-17A (IL-17A) and brain IL-17 receptor A (IL-17RA) were increased in Pg-treated R1441G mice.

Conclusions

These findings suggest that oral Pg-induced inflammation may play an important role in the pathophysiology of LRRK2-associated PD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02027-5.

Parkinson's Disease, Periodontitis and Patient-Related Outcomes: A Cross-Sectional Study

Background and objectives: People with Parkinson’s disease (PD) may be at risk of having bad periodontal status. A consistent periodontal examination is critical to investigate how it impacts on PD quality of life. We aimed to assess the periodontal status of people with PD, and its association with quality of life and self-perceived xerostomia. Materials and Methods: To this end, from February to March 2020, we consecutively enrolled 28 PD individuals, and motor and non-motor symptoms of PD were assessed using the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). We performed full-mouth periodontal examination and gathered information on self-perceived quality of life in PD, oral health impact profile (OHIP-14) and xerostomia. Results: The prevalence of periodontitis was 75.0% and most cases were identified as severe (46.4%). Upper extremity rigidity, hand posture and kinetic tremors were significantly correlated with worse periodontal status. PDQ-8 showed to be correlated with self-perceived oral health-related quality of life and xerostomia levels. Conclusions: This group of people with PD had a high prevalence of periodontitis. Deteriorated levels of the upper extremities in advanced stages of PD were associated with worse periodontal status and hygiene habits. Quality of life in PD appears to be associated with self-perceived OHRQoL and xerostomia.

Relationship between Blood and Standard Biochemistry Levels with Periodontitis in Parkinson's Disease Patients: Data from the NHANES 2011-2012

People with Parkinson's Disease (PD) are associated with the presence of periodontitis. We aimed to compare blood and standard biochemical surrogates of PD patients diagnosed with periodontitis with PD individuals without periodontitis. This retrospective cohort study used a sample from the National Health and Nutrition Examination Survey (NHANES) 2011-2012 that underwent periodontal diagnosis (n = 3669). PD participants were identified through specific PD reported medications. Periodontitis was defined according to the 2012 case definition, using periodontal examination data provided. Then, we compared blood levels and standard chemical laboratory profiles of PD patients according to the presence of periodontitis. Multivariable regression was used to explore this dataset and identify relevant variables towards the presence of periodontitis. According to the medication report, 37 participants were eligible, 29 were secure and 8 were unsecure PD medications regimens. Overall, PD cases with periodontitis presented increased levels of White Blood Cells (WBC) (p = 0.002), Basophils (p = 0.045) and Segmented neutrophils (p = 0.009), and also, lower levels of Total Bilirubin (p = 0.018). In the PD secure medication group, a significant difference was found for WBC (p = 0.002) and Segmented neutrophils (p = 0.002) for the periodontitis group. Further, WBC might be a discriminating factor towards periodontitis in the global sample. In the secure PD medication, we found gender, segmented neutrophils and Vitamin D2 to be potential discriminative variables towards periodontitis. Thus, periodontitis showed association with leukocyte levels alterations in PD patients, and therefore with potential systemic changes and predictive value. Furthermore, Vitamin D2 and gender showed to be associated with periodontitis in with secure medication for PD. Future studies should assess in more detail the potential systemic repercussion of the presence of periodontitis in PD patients.

A comprehensive review of the diagnosis and treatment of Parkinson's disease dysphagia and aspiration

INTRODUCTION

Bulbar dysfunction is common in Parkinson's disease (PD) with more than 80% of affected individuals developing dysphagia during the course of the disease. Symptoms can begin in the preclinical stage and individuals may remain clinically asymptomatic for years. Furthermore, patients may be unaware of swallowing changes, which contributes to the difference between the prevalence of self-reported dysphagia and deficits identified during instrumental evaluations. Dysphagia is underrecognized and contributes to the development of aspiration pneumonia which is the leading cause of death in PD. Dysphagia in PD is complex and not completely understood. Both dopaminergic and nondopaminergic pathways likely underpin dysphagia.

AREAS COVERED

This comprehensive review will cover the epidemiology, pathophysiology, clinical evaluation, and expert management of dysphagia and aspiration in patients with PD.

EXPERT OPINION

A multidisciplinary team approach is important to properly identify and manage PD dysphagia. Regular clinical screenings with objective instrumental assessments are necessary for early detection of dysphagia. Studies are needed to better understand the mechanism(s) involved in PD dysphagia, establish markers for early detection and progression, and develop evidence-based treatment options.

Periodontitis, Low-Grade Inflammation and Systemic Health: A Scoping Review

Background and objectives: Periodontitis is a multifactorial chronic inflammatory infectious disease in which an infection is necessary, but not sufficient, for development of the condition. Individual susceptibility strictly linked to the immune and inflammatory response of the organism must also be present. Low-grade inflammation (LGI) is a systemic status of chronic sub-clinical production of inflammatory factors. This condition represents a risk factor for many chronic diseases including diabetes, cardiovascular disease, cerebrovascular disease, neurodegenerative disease and cancer. This scoping review aims to clarify, summarize and disseminate current knowledge on the possible link between periodontitis, LGI and systemic health. Materials and Methods: PRISMA Extension for Scoping Reviews guidelines were followed. An ad-hoc created keyword string was used to search the electronic databases of PubMed/Medline, Embase, The Cochrane Library and ClinicalTrials.gov. A hand search of specialized journals and their reference lists was also performed. Results: 14 studies that respected eligibility criteria were selected and analyzed. There is emerging evidence of strong links between periodontitis, LGI and systemic health. On the one hand, periodontitis influences the systemic status of LGI and on the other hand, the systemic production of inflammatory factors affects periodontitis with a bidirectional connection. Conclusions: LGI and the subsequent onset of a systemic inflammatory phenotype can be considered the common substrate of many chronic inflammatory diseases including periodontitis, with multiple mutual connections between them. Understanding of the biological principles and mechanisms underlying such a complex interrelationship could lead to significant improvements in the field of personalized diagnostics and therapeutic protocols.

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.

Oral Health of Parkinson's Disease Patients: A Case-Control Study

The aim of the study was to examine the oral health status of Parkinson's disease (PD) patients, to compare their oral health status to that of a control group, and to relate it to the duration and severity of PD. Materials and Methods. 74 PD patients and 74 controls were interviewed and orally examined. Among PD patients, the duration and the Hoehn and Yahr stage (HY) of the disease were registered. Results. More PD patients than controls reported oral hygiene care support as well as chewing/biting problems, taste disturbance, tooth mobility, and xerostomia, whereas dentate patients had more teeth with carious lesions, tooth root remnants, and biofilm. Both longer duration and higher HY were associated with more chewing problems and, in dentates, more teeth with restorations. In dentates, longer duration of the disease was associated with higher number of mobile teeth. Higher HY was associated with more oral hygiene care support as well as biting problems and, in dentates, more teeth with carious lesions and tooth root remnants. Conclusions. Comparatively, PD patients had weakened oral health status and reduced oral hygiene care. Both duration and severity of the disease were associated with more oral health and hygiene care problems.

Alpha-synuclein is present in dental calculus but not altered in Parkinson's disease patients in comparison to controls

INTRODUCTION

In autopsy cases staged for sporadic Parkinson's disease (PD), the neuropathology is characterized by a preclinical phase that targets the enteric nervous system of the gastrointestinal tract (GIT). Therefore, the ENS might be a source of potential (presymptomatic) PD biomarkers.

METHODS

In this clinically based study, we examined the alpha-synuclein (αSyn) concentration in an easily accessible protein storage medium of the GIT, dental calculus, in 21/50 patients with PD and 28/50 age- and gender-matched controls using ELISA.

RESULTS

αSyn was detectable in dental calculus and the median concentration in the control patients was 8.6 pg/mg calculus (interquartile range 2.6-13.1 pg/mg). αSyn concentrations were significantly influenced by blood contamination and samples with a hemoglobin concentration of > 4000 ng/mL were excluded. There was no significant difference of αSyn concentrations in the dental calculus of PD patients (5.76 pg/mg, interquartile range 2.91-9.74 pg/mg) compared to those in controls (p = 0.40).

CONCLUSION

The total αSyn concentration in dental calculus is not a suitable biomarker for sporadic PD. Disease-related variants such as oligomeric or phosphorylated αSyn in calculus might prove to be more specific.

Oral health and implant therapy in Parkinson's patients: review

Parkinson's Disease (PD) is one of the most frequent neurodegenerative diseases, second only to Alzheimer's disease. It is a progressive disease that inevitably leads the patient to death, in most cases for pneumonia ab ingestis. It affects 120 people out of 100,000 and more frequently affects men than women. The main symptoms are divided into motor, non-motor and behavioral ones. The main motors symptoms are tremor, bradykinesia and postural instability. Non-motor symptoms include autonomic nervous dysfunction (orthostatic hypotension, cardiac arrhythmia, sexual dysfunction, excessive sweating due to hypothalamic dysfunction, constipation), insomnia, OSAS, and olfactory dysfunction. Behavioral symptoms are depression, dementia and psychosis. The purpose of this study is to evaluate, through a systematic review of literature, the oral health status of the Parkinson's patient compared with the general population with particular reference to the incidence of caries and periodontal disease, the patient's management during dental interventions and the possibility of rehabilitating the patient with implanted therapy.

Comorbidity of periodontal disease: two sides of the same coin? An introduction for the clinician

Increasing evidence has suggested an independent association between periodontitis and a range of comorbidities, for example cardiovascular disease, type 2 diabetes, rheumatoid arthritis, osteoporosis, Parkinson’s disease, Alzheimer’s disease, psoriasis, and respiratory infections. Shared inflammatory pathways are likely to contribute to this association, but distinct causal mechanisms remain to be defined. Some of these comorbid conditions may improve by periodontal treatment, and a bidirectional relationship may exist, where, for example, treatment of diabetes can improve periodontal status. The present article presents an overview of the evidence linking periodontitis with selected systemic diseases and calls for increased cooperation between dentists and medical doctors to provide optimal screening, treatment, and prevention of both periodontitis and its comorbidities.

Are Chronic Periodontitis and Gingivitis Associated with Dementia? A Nationwide, Retrospective, Matched-Cohort Study in Taiwan

BACKGROUND

Chronic periodontitis and gingivitis are associated with various diseases; however, their impact on dementia is yet to be elucidated. This study is aimed at investigating the association between chronic periodontitis and gingivitis, and the risk of developing dementia.

METHODS

A total of 2,207 patients, with newly diagnosed chronic periodontitis and gingivitis between January 1, 2000 and December 31, 2000, were selected from the National Health Insurance Research Database of Taiwan, along with 6,621 controls matched for sex and age. After adjusting for confounding factors, Cox proportional hazards analysis was used to compare the risk of developing dementia during the 10-year follow-up period.

RESULTS

Of the study subjects, 25 (1.13%) developed dementia compared to 61 (0.92%) in the control group. Cox proportional hazards regression analysis revealed that the study subjects were more likely to develop dementia (hazard ratio (HR) 2.085, 95% CI 1.552-4.156, p < 0.001). After adjusting for sex, age, monthly income, urbanization level, geographic region, and comorbidities, the HR for dementia was 2.54 (95% CI 1.297-3.352, p = 0.002).

CONCLUSIONS

Patients with chronic periodontitis and gingivitis have a higher risk of developing dementia. However, further studies on other large or national data sets are required to support the current findings.

Oral Health in Elders with Parkinson's Disease

Abstract This study aimed to evaluate objectively and subjectively the oral health of elders with Parkinson's disease (PD), using clinical oral assessments and the General Oral Health Assessment Index (GOHAI). Subjects included 37 removable prosthesis wearers, 17 with PD (mean age 69.59±5.09 years) and 20 without PD (mean age 72.00±5.69 years). The objective assessment included an evaluation of oral characteristics, including the number of remaining teeth, decayed, missing and filled teeth (DMFT), visible plaque index (VPI), salivary flow rate and removable prosthesis conditions. The subjective assessment included self-perception of oral health collected using the GOHAI index. The number of remaining teeth, DMFT, VPI, salivary flow rate and GOHAI data were compared between the groups using t-tests. Removable prosthesis conditions were analyzed using χ2 tests (p<0.05). There were no group differences in the number of remaining teeth, DMFT, VPI or salivary flow rate (p>0.05). Greater maxillary prosthesis defects were observed in the control group (p=0.037). GOHAI scores were low for the PD group and moderate for controls, yielding a group difference (p=0.04). In conclusion, elders with PD have similar oral health to controls. Although all elders had few remaining teeth, high DMFT and high VPI, PD elders had more negative self-perceptions of their oral health than did the controls.

Disorders of the oral cavity in Parkinson's disease and parkinsonian syndromes

Awareness of nonmotor symptoms of Parkinson's disease is growing during the last decade. Among these, oral cavity disorders are, although prevalent, often neglected by the patients, their caregivers, and physicians. Some of these disorders include increased prevalence of caries and periodontal disease, sialorrhea and drooling, xerostomia, orofacial pain, bruxism, and taste impairment. Though many of these disorders are not fully understood yet and relatively few controlled trials have been published regarding their treatment, physicians should be aware of the body of evidence that does exist on these topics. This paper reviews current knowledge regarding the epidemiology, pathophysiology, and treatment options of disorders of the oral cavity in Parkinson's disease patients.

Drooling in Parkinson's disease: a review

Parkinson's disease (PD) is a neurodegenerative disease causing both motor and non-motor symptoms. Drooling, an excessive pooling and spillover of saliva out of the oral cavity, is one of the non-motor symptoms in PD patients that produces various negative physical and psychosocial consequences for patients and their caregivers. At present, the pathophysiology of drooling in PD is not completely certain; however, impaired intra-oral salivary clearance is likely the major contributor. There are neither standard diagnostic criteria nor standard severity assessment tools for evaluating drooling in PD. In accordance with the possible pathophysiology, dopaminergic agents have been used to improve salivary clearance; however, these agents are not completely effective in controlling drooling. Various pharmacological and non-pharmacological treatment options have been studied. Local injection with botulinum toxin serotypes A and B into major salivary glands is most effective to reduce drooling. Future research to explore the exact pathophysiology and develop standard diagnostic criteria and standard severity assessment tools are needed to formulate specific treatment options and improve patient care.

Oral health, temporomandibular disorder, and masticatory performance in patients with Charcot-Marie-Tooth type 2

Background. The aim of this study was to evaluate the oral health status of temporomandibular disorders (TMD) and bruxism, as well as to measure masticatory performance of subjects with Charcot-Marie-Tooth type 2 (CMT2). Methods and Results. The average number of decayed, missing, and filled teeth (DMFT) for both groups, control (CG) and CMT2, was considered low (CG = 2.46; CMT2 = 1.85, P = 0.227). The OHIP-14 score was considered low (CG = 2.86, CMT2 = 5.83, P = 0.899). The prevalence of self-reported TMD was 33.3% and 38.9% (P = 0.718) in CG and CMT2 respectively and for self-reported bruxism was 4.8% (CG) and 22.2% (CMT2), without significant difference between groups (P = 0.162). The most common clinical sign of TMD was masseter (CG = 38.1%; CMT2 = 66.7%) and temporalis (CG = 19.0%; GCMT2 = 33.3%) muscle pain. The geometric mean diameter (GMD) was not significantly different between groups (CG = 4369; CMT2 = 4627, P = 0.157). Conclusion. We conclude that the CMT2 disease did not negatively have influence either on oral health status in the presence and severity of TMD and bruxism or on masticatory performance.

The association between periodontal disease and seizure severity in refractory epilepsy patients

PURPOSE

Periodontal diseases are common in most populations and affect people at all socioeconomic levels. Evidence suggests that patients with epilepsy actually have higher risks of dental disease and increased oral health needs, but the frequency and consequences of poor controlled seizures on dental and periodontal health have not been reported before. We aimed to assess the impact of seizure frequency on periodontal status and oral hygiene in a sample of epilepsy patients.

METHODS

One hundred and nine consecutive patients treated for epilepsy at the outpatient clinic of our University Hospital were invited to take part in an oral examination to determine their periodontal disease status, together with a control group. In addition, seizure frequency and use of medication were documented.

RESULTS

In logistic regression model, patients were significantly more susceptible to bad oral hygiene, gingivitis and periodontitis that controls (p<0.001); seizure frequency was significantly related to bad oral hygiene (p=0.010), gingivitis (p<0.001) and periodontitis (p<0.001). Tooth brushing habits and presence of caries were associated with oral health in patients group.

CONCLUSION

Our study found a significant positive correlation between periodontal disease and seizure severity. Epilepsy patients need to focus more on their oral health and quality of oral hygiene.