Association between residual teeth number in later life and incidence of dementia: A systematic review and meta-analysis

Abstract

BackgroundIt has been suggested that tooth loss in later life might increase dementia incidence. The objective of this analysis is to systematically review the current evidence on the relationship between the number of remaining teeth and dementia occurrence in later life.MethodsA search of multiple databases of scientific literature was conducted with relevant parameters for articles published up to March 25th, 2017. Multiple cohort studies that reported the incidence of dementia and residual teeth in later life were found with observation periods ranging from 2.4 to 32 years. Random-effects pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated to examine whether high residual tooth number in later life was associated with a decreased risk of dementia. Heterogeneity was measured by I2. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to assess the overall quality of evidence.ResultsThe literature search initially yielded 419 articles and 11 studies (aged 52 to 75 at study enrollment, n = 28,894) were finally included for analysis. Compared to the low residual teeth number group, the high residual teeth number group was associated with a decreased risk of dementia by approximately 50% (pooled OR = 0.483; 95% CI 0.315 to 0.740; p < 0.001; I2 = 92.421%). The overall quality of evidence, however, was rated as very low.ConclusionDespite limited scientific strength, the current meta-analysis reported that a higher number of residual teeth was associated with having a lower risk of dementia occurrence in later life.Electronic supplementary materialThe online version of this article (10.1186/s12877-018-0729-z) contains supplementary material, which is available to authorized users.

Oral diseases and inflammatory burden and Alzheimer's disease among subjects aged 75 years or older

“…It has been hypothesized that certain oral diseases could have an influence on AD either by causing a low‐grade inflammation, by activating microglia cells via proinflammatory molecules, or by microbial invasion into the brain . It has also been speculated that the effects of oral diseases on cognitive function might be mediated through changes in diet that in turn are related to impaired mastication …”

“…[8][9][10]22,23 It has also been speculated that the effects of oral diseases on cognitive function might be mediated through changes in diet that in turn are related to impaired mastication. 24,25 It must be emphasized that this study has a cross-sectional design and that we cannot draw any conclusions about the causal role of oral diseases in the development and progression of AD because we do not have data about the initiation and progression of AD, or other dementias, or oral diseases. This prevents us from determining whether oral diseases are a cause or a consequence of dementia.…”

Prefrontal Consolidation and Compensation as a Function of Wearing Denture in Partially Edentulous Elderly Patients

“…Epidemiologic studies have suggested associations between cognitive ability and oral conditions, such as number of teeth (Luo et al, 2015;Li et al, 2017;Oh et al, 2018) and dental occlusion (Ono et al, 2010;Franco et al, 2012;Takeuchi et al, 2015). Furthermore, occlusal force (Takeshita et al, 2016;Ikebe et al, 2018) and chewing ability have been shown to have effects on cognitive ability (Chen et al, 2015;Natalie et al, 2015;Seraj et al, 2017).…”

Oral health for a healthy mind: the unexplored links between oral health and dementia

“…Several recent studies have attempted to summarize the evidence that correlates oral health conditions with dementia [2][3][4][5]. The importance of adequate mental health on the drive and ability to care for oneself is somewhat intuitive.…”

“…Recent systematic reviews showed somewhat contradictory conclusions regarding the connection between tooth loss and dementia. They ranged from identifying positive association [2,3], in which tooth loss resulted in approximately 20% to 50% increase in the risk of developing dementia, to suggesting no association at all [5]. Although most current literature positively associates tooth loss with dementia, the quality of this evidence is arguable [3,4].…”