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

Abstract

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

The Role of Periodontitis and Periodontal Bacteria in the Onset and Progression of Alzheimer’s Disease: A Systematic Review

“…In 2017, a pilot study on patients with dementia and Alzheimer's disease investigating the presence of antibodies in serum and CSF (against P. gingivalis, T. forsythia, T. denticola, T. socranskii, and A. actinomycetemcom) found no statistically significant difference between the two groups [14]. This study does not confirm the hypothesis of microorganisms playing a role in the progression and onset of AD pathology [75].…”

“…Nevertheless, there is indirect evidence. Given that tooth loss can be related to multiple causes, including periodontitis, it has been noticed that tooth loss is associated both with dementia and Alzheimer's disease [75]. This evidence has been found by studies performed on two different population samples [76,77], showing a greater incidence of tooth loss associated with cognitive decline.…”

Diagnostic Accuracy of Oral Fluids Biomarker Profile to Determine the Current and Future Status of Periodontal and Peri-Implant Diseases

“…The initiation and progression of these events are the consequences of an interaction between pathogenic bacteria in the subgingival dental biofilm around teeth and the host response [ 2 ]. The effects of periodontitis are not confined locally to the periodontium, and the association with various systemic diseases, such as diabetes, atherosclerosis, cancers, and Alzheimer’s disease, has been suggested [ 3 , 4 , 5 , 6 ]. In general, the destruction of periodontal tissues is slow, being characterized by periods of disease activity and remission without obvious alarming symptoms.…”

Education and income-based inequality in tooth loss among Brazilian adults: does the place you live make a difference?

“…Tooth loss is an important oral health problem with consequences for physical and psychosocial health as well as the quality of life [ 1 – 3 ]. It is a good proxy for the cumulative oral health status [ 4 ] summarizing the impacts of adverse circumstances throughout the life course of individuals [ 5 ].…”