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Tooth Loss-Associated Mechanisms That Negatively Affect Cognitive Function: A Systematic Review of Animal Experiments Based on Occlusal Support Loss and Cognitive Impairment
Wang X, Hu J, Jiang Q.. Frontiers in neuroscience, 2022-02-10
Topic: Risk, prevention and care in population studies
Background There is a dose-response relationship between tooth loss and cognitive impairment, while tooth loss can be an independent risk factor for Alzheimer's disease (AD) and vascular dementia (VaD). Tooth loss can also accelerate nerve damage and neurodegeneration. However, the associated mechanisms remain poorly understood. Objective To conduct a systematic review of animal experiments on cognitive decline caused by the loss of occlusal support performed over the past 10 years and summarize the possible underlying mechanisms. Methods "Tooth Loss," "Edentulous," "Tooth Extraction and Memory Loss," "Cognition Impairment," and "Dementia" were used as keywords to search PubMed, Embase, SCI, ScienceDirect, and OpenGrey. A total of 1,317 related articles from 2010 to 2021 were retrieved, 26 of which were included in the review after screening according to predetermined inclusion and exclusion criteria. Comprehensiveness was evaluated using ARRIVE guidelines and the risk of bias was assessed using SYCLE'S risk of bias tool. Results The putative mechanisms underlying the cognitive impairment resulting from the loss of occlusal support are as follows: (1) The mechanical pathway, whereby tooth loss leads to masticatory motor system functional disorders. Masticatory organ activity and cerebral blood flow decrease. With reduced afferent stimulation of peripheral receptors (such as in the periodontal membrane) the strength of the connections between neural pathways is decreased, and the corresponding brain regions degenerate; (2) the aggravation pathway, in which tooth loss aggravates existing neurodegenerative changes. Tooth loss can accelerates nerve damage through apoptosis and mitochondrial autophagy, increases amyloid deposition in the brain; and (3) the long-term inflammatory stress pathway, which involves metabolic disorders, microbial-gut-brain axis, the activation of microglia and astrocytes, and inflammatory cascade effect in central nervous system. Conclusion The loss of occlusal support may lead to cognitive dysfunction through the reduction of chewing-related stimuli, aggravation of nerve damage, and long-term inflammatory stress.
Key findings
- Results The putative mechanisms underlying the cognitive impairment resulting from the loss of occlusal support are as follows: (1) The mechanical pathway, whereby tooth loss leads to masticatory motor system functional disorders.
Why it matters
Reviewing 26 animal experiments, the authors describe three ways that losing occlusal support (teeth meeting properly when chewing) might harm thinking: less chewing stimulation and brain blood flow, worsening of existing nerve damage including more amyloid build-up, and long-lasting inflammation involving microglia and astrocytes. Because the evidence comes from animals, it offers possible explanations for the reported link between tooth loss and dementia rather than proof in people.
Study details
- Study designsystematic review
- Participants1,317
- Evidence strengthHigh
How this study scored 61/100
Published in a peer-reviewed journal, and it is a systematic review of all the studies on the question. Scored zero for effect reported because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Frontiers in neuroscience) |
| Journal's citation record | 2 / 4 | Frontiers in Neuroscience: journal h-index 226 (OpenAlex, 2026-10-29) |
| Study design | 12 / 12 | A systematic review of all the studies on the question |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 3 / 5 | 2022 — within 6 year(s) of the newest study here |
| Sample size | 3 / 4 | 1,317 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | A review of other studies — randomisation is not credited here |
| Times cited | 4 / 7 | Cited 50 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 8.3 citations a year over 6 year(s) since 2022 |
| Impact for its field and year | 2 / 6 | Cited 2.3× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 2 / 4 | Cited 30 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 1 / 4 | Last-listed author Qingsong Jiang: h-index 15 (OpenAlex, whole career) |
| Institution's track record | 0 / 3 | Capital Medical University: institution h-index 643 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 35221901) |
| Free to read | 2 / 2 | Free to read |
| Total | 61 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.3389/fnins.2022.811335
- PubMed: 35221901
- Original source →
- Free full text: Frontiers in Neuroscience →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Wang, X., Hu, J., & Jiang, Q. (2022). Tooth Loss-Associated Mechanisms That Negatively Affect Cognitive Function: A Systematic Review of Animal Experiments Based on Occlusal Support Loss and Cognitive Impairment. Frontiers in neuroscience. https://doi.org/10.3389/fnins.2022.811335
Vancouver
Wang X, Hu J, Jiang Q. Tooth Loss-Associated Mechanisms That Negatively Affect Cognitive Function: A Systematic Review of Animal Experiments Based on Occlusal Support Loss and Cognitive Impairment. Frontiers in neuroscience. 2022. doi:10.3389/fnins.2022.811335. PMID: 35221901.
BibTeX
@article{wang2022-35221901,
author = {Wang, X. and Hu, J. and Jiang, Q.},
title = {{Tooth Loss-Associated Mechanisms That Negatively Affect Cognitive Function: A Systematic Review of Animal Experiments Based on Occlusal Support Loss and Cognitive Impairment}},
journal = {Frontiers in neuroscience},
year = {2022},
doi = {10.3389/fnins.2022.811335},
pmid = {35221901},
url = {https://doi.org/10.3389/fnins.2022.811335}
}
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