The short answer: Losing teeth is linked with a modestly higher risk of dementia, but studies have not shown that it causes dementia. In the newest large study, which followed 47,293 older adults in Japan for about 9 years, people with no teeth had a 27% higher risk of dementia than people with 20 or more teeth (Iwata et al., 2026). Several reviews found that the extra risk was smaller, or no longer clear, in people who wear dentures (Qi et al., 2021; Chen et al., 2026), but no trial has tested whether dentures prevent dementia. Keeping your teeth, and replacing the ones you lose, is worth doing for chewing and eating well either way.
In November 2026, a study from Japan ranked tooth loss as the third-largest dementia risk factor among 13 it compared in older adults, after depressive symptoms and social isolation (Iwata et al., 2026). For many people, that news lands close to home. In the United States, 15% of adults aged 65 or older have lost all their teeth, and 26% have 8 or fewer (Centers for Disease Control and Prevention, 2024).
So it is fair to ask: if you have lost teeth, or are about to, should you worry about your memory? This article covers what the research shows about tooth loss and dementia, whether the link is cause and effect, why missing teeth might matter for the brain, whether dentures, bridges or implants lower the risk, and what you can do now.
Does losing teeth cause dementia?
Losing teeth is consistently linked with a higher risk of dementia, but the studies behind that link cannot prove that tooth loss is the cause. They are observational: researchers count people’s teeth, follow them for years and record who develops dementia. Here is what the largest studies and reviews found.
| Study | Who was studied | What it found |
|---|---|---|
| Iwata et al., 2026 | 47,293 adults aged 65 or older in Japan, followed for a median of 9 years | Compared with 20 or more teeth, dementia risk was 14% higher with 10 to 19 teeth, 12% higher with 1 to 9 teeth and 27% higher with no teeth |
| Qi et al., 2021 | 14 studies, 34,074 people | More tooth loss: 28% higher risk of dementia; no teeth at all: 40% higher |
| Li et al., 2023 | 18 cohort studies, 356,297 people, followed for 8.6 years on average | Tooth loss: 15% higher risk of dementia |
| Chen et al., 2026 | 21 long-term studies, about 35.7 million people | Tooth loss: 26% higher odds of dementia |
| Demmer et al., 2026 | 59 cohort studies, 28 of them pooled for dementia | No teeth: 26% higher risk of dementia or mild cognitive impairment; low tooth count: 27% higher |
These numbers are relative risks. A 27% higher risk does not mean a 27% chance of dementia; it means the risk is about a quarter higher than in the comparison group. In the Japanese study, 17.4% of all participants developed dementia during follow-up (Iwata et al., 2026).
The direction of the link is consistent across countries and study designs, though its size varies widely between studies (Chen et al., 2026; Demmer et al., 2026), and in several reviews the risk rises as more teeth are lost (Qi et al., 2021; Chen et al., 2026). That consistency is why researchers take the link seriously. It still does not tell us which way the arrow points.
Is it cause and effect, or just a link?
Nobody knows yet, and reviewers rate the overall evidence as low to moderate in quality (Asher et al., 2022; Qi et al., 2021). Three things make the link hard to read.
- Early dementia can cause tooth loss. Memory and thinking problems can start years before a diagnosis, and they can make brushing, flossing and dental visits harder (Gao & Kang, 2025). A 2022 review of 47 long-term studies concluded that the links between gum health and dementia were at least partly due to this “reverse causality” (Asher et al., 2022).
- Other factors can drive both. Income, education, smoking, diabetes and access to care affect both tooth loss and dementia risk. A 2026 review of 59 studies found that inadequate adjustment for these factors was common, and said that bias and leftover confounding limit what the results can show about cause (Demmer et al., 2026). The headline Japanese study adjusted for sex, age and income (Iwata et al., 2026).
- No trials exist. Nobody can randomly assign people to lose teeth, and no randomized trial has yet tested whether replacing teeth prevents dementia. Most of the evidence is observational and open to confounding, and reviewers are calling for intervention studies (Gao & Kang, 2025; Demmer et al., 2026).
What does “7% of dementia cases” mean?
The Japanese study estimated that tooth loss accounted for 7.2% of dementia cases in its population, and 12.0% in men, where it ranked first (Iwata et al., 2026). This figure, called the population attributable fraction, estimates how many cases might be avoided if the risk factor disappeared, and it assumes the link is causal. Read it as an upper estimate of what keeping teeth could do, not as proof that tooth loss causes 7% of dementia.
Why might missing teeth affect the brain?
Researchers have several ideas, and the real answer may be a mix (Gao & Kang, 2025):
- Chewing and nutrition. Having 8 or fewer teeth makes it harder to eat meat, fruit and vegetables (Centers for Disease Control and Prevention, 2024). In a Chinese cohort of 4,056 older adults, low body weight explained about 7% (6.74%) of the link between tooth loss and cognitive impairment (Ke et al., 2025).
- Chewing itself. In a Singapore study of 973 older adults followed for 6 years, people who reported difficulty chewing had 43% higher odds of developing cognitive impairment, even after accounting for the number of teeth and denture use (Nascimento et al., 2024).
- Long-term inflammation. Gum disease (periodontitis), a common cause of tooth loss, keeps the gums inflamed for years, and one theory is that this adds to inflammation elsewhere in the body, including the brain. High-quality evidence for this is still limited (Gao & Kang, 2025); our article on how oral health affects your overall health covers the gum disease side.
- Less sensory input. Teeth send signals to the brain every time you bite. Losing them reduces that input, which some researchers think could matter over decades (Gao & Kang, 2025).
Do dentures lower the risk of dementia?
Studies suggest that people who wear dentures do better than people with missing teeth who don’t, but they can’t yet show that the dentures are the reason.
- In the 2021 review of 14 studies, more tooth loss was linked with higher dementia risk, but the link was not statistically significant in denture users (Qi et al., 2021).
- The 2026 review of 21 studies found the same: denture wearers had no clear increase in dementia risk (odds ratio 1.03, 95% confidence interval 0.82 to 1.28), though this estimate pooled only three studies (Chen et al., 2026).
- In a Japanese study of 4,425 older adults followed for 4 years, those with few teeth and no dentures had 85% higher risk of developing dementia; not having a regular dentist was linked with 44% higher risk (Yamamoto et al., 2012).
- In 17,079 older adults in China, the link between tooth loss and cognitive impairment was weaker in people who wore dentures, especially those with some natural teeth left (Yang et al., 2022).
Timing may matter. In 27,708 older adults in China followed for 10 years, denture users who still had some natural teeth showed slower cognitive decline, but among people with no teeth, dentures were linked only with better starting scores, not slower decline (Qi et al., 2024). A smaller study of 2,188 older adults in China, followed for 6 years, found that the protective link was strongest in people who still had 21 or more teeth (Zhang & Liu, 2026).
The catch is that people who get dentures differ from people who don’t. They may have more money, see a dentist more often or be healthier to begin with, and studies can only partly adjust for that. Dentures restore chewing, which is a good reason to wear them, but “dentures prevent dementia” goes further than the evidence.
Do dental implants or bridges help too?
Possibly, but the few studies that included implants and bridges grouped them with dentures, and no study has compared implants with dentures for dementia risk. In 64,520 older adults in Taiwan, people who moved up a tooth-count group over 7 years (for example from 10–19 to 20 or more, counting replacement teeth) by getting dentures, bridges or implants had a lower risk of cognitive impairment than people whose tooth count stayed the same. The odds were 29% lower for those starting with 10 to 19 teeth and 57% lower for those starting with 1 to 9 (Chou et al., 2024). A Japanese study of 22,632 older adults with fewer than 20 teeth found that any dental prosthesis (dentures, fixed bridges or implants) was linked with less decline in self-reported everyday functioning over 3 years, especially intellectual activities; that study did not measure dementia (Nakagawa et al., 2026).
Searches for “can dental implants cause dementia” are common, but no study we found shows that implants cause dementia. One small Korean study of 153 older adults found removable dentures and poorer chewing more often in people whose thinking declined, which may reflect how many teeth they had already lost (Kim et al., 2023). The choice between implants and dentures depends on your bone, gums, budget and how easily you can clean them; our guide to what dental implants involve explains the procedure and recovery.
Cost is a real barrier. In most cases, Medicare doesn’t cover dentures or implants (Medicare.gov, n.d.), so check what other dental coverage you have before you plan treatment.
How can you keep your teeth as you age?
Tooth decay and gum disease, the usual routes to tooth loss, are common but controllable (Gao & Kang, 2025):
- Brush twice a day with fluoride toothpaste, and clean between your teeth once a day. See how to prevent cavities.
- Treat bleeding gums early, before gum disease loosens teeth. Read gum disease and bleeding gums.
- Keep sugary snacks and drinks to mealtimes.
- Don’t smoke, and manage diabetes and dry mouth with your doctor.
- See a dentist at the interval they recommend for you, and ask early about replacing any tooth you lose.
For more on how aging changes the mouth, including denture care, see how aging affects your teeth and gums.
What it means for you
If you have lost a few teeth
You do not need to panic. The extra risk in studies is modest and may not be caused by the teeth themselves. Ask your dentist whether replacing the gaps would help you chew a full range of foods, and protect the teeth you still have.
If you have no teeth and don’t wear dentures
People with few or no teeth who did not wear dentures had the highest risk of dementia or cognitive impairment in two studies (Yamamoto et al., 2012; Ke et al., 2025). Well-fitting dentures or implant-supported dentures can restore chewing. Even if the brain benefit is unproven, eating a varied diet is good for your health.
If your dentures are loose or you have stopped wearing them
Dentures help only if you can chew with them. Loose or painful dentures can often be relined, adjusted or replaced, so bring them to a dentist rather than leaving them in a drawer.
If you need several teeth removed
The studies above looked at older adults with tooth loss in general, not at people having infected or broken-down teeth taken out. Taking out teeth that can’t be saved is often needed to treat infection or pain. Ask your dentist about a replacement plan before the extractions, so you are not left without teeth for long.
If you care for someone with dementia
Dementia makes brushing and dental visits harder (Gao & Kang, 2025), and tooth loss can follow. Help with daily brushing, keep dental visits going, and tell the dentist about any change in eating.
Questions to ask your dentist
- How many of my teeth are at risk, and what can we do to keep them?
- Do I have gum disease, and how should we treat it?
- Would dentures, a bridge or implants work best for my missing teeth?
- My dentures feel loose: can they be relined or adjusted?
- What would replacing my teeth cost, and what does my insurance cover?
When to see a dentist
Book a dental visit if:
- Your gums bleed when you brush or floss, or look red and swollen.
- A tooth feels loose, or your bite has changed.
- You have missing teeth that make it hard to chew meat, fruit or vegetables.
- Your dentures are loose, rub, cause sore spots or are no longer worn.
- You or someone you care for has memory problems and has not had a dental checkup in the past year.
For severe pain, swelling or a broken tooth, see what to do in a dental emergency.
The bottom line
Losing teeth is linked with a modestly higher risk of dementia, and the newest study from Japan ranks it alongside better-known risk factors. But the link may run partly the other way, and other factors such as income and health may explain some of it, so no one can say that tooth loss causes dementia. People who replace missing teeth, especially with dentures, tend to do better in studies, though that is not proof that dentures protect the brain. The practical steps are the same either way: keep the teeth you have, replace the ones you lose, and make sure you can chew a healthy diet.
References
Asher S, Stephen R, Mäntylä P, Suominen AL, Solomon A. (2022). Periodontal health, cognitive decline, and dementia: A systematic review and meta-analysis of longitudinal studies. Journal of the American Geriatrics Society, 70(9), 2695–2709. https://doi.org/10.1111/jgs.17978
Centers for Disease Control and Prevention. (2024). Tooth loss facts. https://www.cdc.gov/oral-health/data-research/facts-stats/fast-facts-tooth-loss.html
Chen H, Ji L, Wang Y, Klineberg I, Chen H. (2026). Dentition-cognition relationship in aging populations: A meta-analysis of longitudinal data. Journal of Oral Rehabilitation, 53(4), 924–938. https://doi.org/10.1111/joor.70149
Chou YC, Weng SH, Cheng FS, Hu HY. (2024). Denture use mitigates the cognitive impact of tooth loss in older adults. The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 80(1), glae248. https://doi.org/10.1093/gerona/glae248
Demmer RT, Watson D, Goh CE, Slashcheva LD, Tom SE, Zhou MX, et al. (2026). Periodontitis, tooth loss, and risk of cognitive impairment and dementia: A systematic review with meta-analysis. Journal of Periodontal Research. Advance online publication. https://doi.org/10.1111/jre.70177
Gao C, Kang J. (2025). Oral diseases are associated with cognitive decline and dementia. Advances in Experimental Medicine and Biology, 1472, 171–183. https://doi.org/10.1007/978-3-031-79146-8_11
Iwata M, Kusama T, Aida J, Yamamoto T, Shirai K, Osaka K, et al. (2026). Comparative population impact of oral health and established modifiable risk factors for dementia: A 9-year population-based cohort study. Journal of the American Medical Directors Association, 27(12), 106536. https://doi.org/10.1016/j.jamda.2026.106536
Ke P, Lu Z, Ni W, Zhang Y, Zhang H, Zheng Y, et al. (2025). Does low body weight mediate the relationship between tooth loss and cognitive impairment? A longitudinal cohort study of an older Chinese population. BMC Geriatrics, 25(1), 111. https://doi.org/10.1186/s12877-025-05750-x
Kim KS, Ahn S, Han JW, Cho SH, Lee JT, Lee HJ, et al. (2023). Oral health and risk of cognitive disorders in older adults: A biannual longitudinal follow-up cohort. Journal of Oral Rehabilitation, 50(9), 792–801. https://doi.org/10.1111/joor.13486
Li L, Zhang Q, Yang D, Yang S, Zhao Y, Jiang M, et al. (2023). Tooth loss and the risk of cognitive decline and dementia: A meta-analysis of cohort studies. Frontiers in Neurology, 14, 1103052. https://doi.org/10.3389/fneur.2023.1103052
Medicare.gov. (n.d.). Dental services. https://www.medicare.gov/coverage/dental-services
Nakagawa M, Takeuchi K, Kusama T, Abbas H, Kondo K, Egusa H, et al. (2026). Dental prosthesis use and subsequent functional capacity decline among older adults: A three-year cohort study based on self-reported measures from the JAGES. Frontiers in Oral Health, 7, 1784871. https://doi.org/10.3389/froh.2026.1784871
Nascimento GG, Li H, Malhotra R, Leite FRM, Peres KG, Chan A, et al. (2024). Chewing disability is associated with cognitive impairment among older adults: A population-based cohort study. The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 79(5), glae074. https://doi.org/10.1093/gerona/glae074
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Qi X, Zhu Z, Plassman BL, Wu B. (2021). Dose-response meta-analysis on tooth loss with the risk of cognitive impairment and dementia. Journal of the American Medical Directors Association, 22(10), 2039–2045. https://doi.org/10.1016/j.jamda.2021.05.009
Yamamoto T, Kondo K, Hirai H, Nakade M, Aida J, Hirata Y. (2012). Association between self-reported dental health status and onset of dementia: A 4-year prospective cohort study of older Japanese adults from the Aichi Gerontological Evaluation Study (AGES) Project. Psychosomatic Medicine, 74(3), 241–248. https://doi.org/10.1097/PSY.0b013e318246dffb
Yang HL, Li FR, Chen PL, Cheng X, Mao C, Wu XB. (2022). Tooth loss, denture use, and cognitive impairment in Chinese older adults: A community cohort study. The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 77(1), 180–187. https://doi.org/10.1093/gerona/glab056
Zhang R, Liu X. (2026). Timing matters: Denture use for cognitive protection is most effective before major tooth loss. The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 81(8), glag162. https://doi.org/10.1093/gerona/glag162
References checked November 2026 · Editorial policy · Report a correction
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