Try 21D Target Smile™
21D Patient Community
Your mouth is connected to the rest of you. Explore the body below to see what the strongest published studies — including our own peer-reviewed work — actually show.
Our published research
Three papers published by 21D Clinical Research, alongside the field’s leading meta-analyses.
Front Public Health · 2026
Direct healthcare costs of oral diseases in the UK
Vijayanarayanan R, Coote et al. A cost-of-illness projection to 2050. 14:1863227.
Cost Eff Resour Alloc · 2026
Periodontal therapy in cardiovascular disease
Vijayanarayanan R, Coote et al. Cost-effectiveness of non-surgical treatment. 24:786.
J Oral Microbiol · 2026
The oral–gut axis: a systematic review
Vijayanarayanan R, Coote et al. 18(1):2705699.
Every claim below is traceable to a published systematic review, meta-analysis or umbrella review.
Strong — large, consistent evidence
Moderate — consistent, with limits
Emerging — early but promising
1
Strong evidence
Gums & inflammation
Gum disease is one of the most common chronic conditions on earth, affecting more than a billion people. It is a slow, low-grade inflammation of the tissue that holds your teeth — and that same inflammation is the thread connecting the mouth to everything below.
How it’s linked
Gum disease is one of the most common chronic conditions on earth, affecting more than a billion people. It is a slow, low-grade inflammation of the tissue that holds your teeth — and that same inflammation is the thread connecting the mouth to everything below.
What you can do
Brush twice a day with fluoride toothpaste, clean between your teeth daily, avoid smoking, and see a dentist or hygienist regularly. Healthy gums are one of the more controllable parts of long-term health.
References
◆ Vijayanarayanan R, Coote et al. (2026). Direct healthcare costs of oral diseases in the UK: a cost-of-illness projection to 2050. Front Public Health, 14:1863227. — 21D Clinical Research
Global Burden of Disease Study 2021 — severe periodontitis burden (>1 billion affected).
2
Moderate
Brain & memory
Poor gum health and tooth loss are linked to a modestly higher risk of cognitive decline and dementia in later life — roughly 15–20% higher in pooled studies. The evidence is consistent, but it comes from observational research, so cause and effect isn’t settled.
How it’s linked
Long-running inflammation and certain oral bacteria may affect the brain over decades. Losing teeth may also matter indirectly, through changes to diet and nutrition.
What you can do
Keeping your natural teeth and healthy gums is worth prioritising as you age. The habits that protect the mouth are low-risk and may help protect more than your smile.
References
Asher et al. (2022). Periodontal health, cognitive decline and dementia: meta-analysis of longitudinal studies. J Am Geriatr Soc, 70(9):2695–2709.
Li et al. (2023). Tooth loss and risk of cognitive decline and dementia: meta-analysis of cohort studies. Front Neurol, 14:1103052.
3
Strong
Heart & circulation
People with gum disease have a higher risk of heart disease and stroke. This is an association — the two share inflammation as a common driver — rather than proof that one directly causes the other.
How it’s linked
Oral bacteria and inflammatory signals are thought to contribute to fatty plaques building up inside arteries (atherosclerosis), which narrows them over time. Across dozens of reviews the risk runs roughly 1.2 to 2.9 times higher.
What you can do
Look after your gums alongside the other things that protect your heart — not smoking, staying active, and eating well.
References
◆ Vijayanarayanan R, Coote et al. (2026). Cost-effectiveness of non-surgical periodontal therapy in cardiovascular disease. Cost Eff Resour Alloc, 24:786. — 21D Clinical Research
Arbildo-Vega et al. (2024). Periodontal disease and cardiovascular disease: umbrella review. BMC Oral Health, 24:1308.
American Heart Association scientific statement (2025). Circulation.
4
Strong
Blood sugar & diabetes
Gum disease and type 2 diabetes feed into each other. High blood sugar makes gum disease worse, and severe gum disease can make blood sugar harder to control — a genuine two-way street.
How it’s linked
Inflammation from the gums appears to interfere with how the body responds to insulin. Encouragingly, treating gum disease produces a small but real improvement in blood-sugar control — around a 0.4% drop in HbA1c in clinical trials.
What you can do
If you have diabetes, treat gum care as part of managing it and keep both your dentist and doctor in the loop. If you don’t, healthy gums are one less thing nudging your risk upward.
References
Simpson et al. (2022). Treatment of periodontal disease for glycaemic control in people with diabetes. Cochrane Database Syst Rev, CD004714.
Baeza et al. (2020). Effect of periodontal treatment in patients with periodontitis and diabetes. J Appl Oral Sci.
5
Moderate
Kidneys
Gum disease tends to be more common and more severe in people with chronic kidney disease, and the link runs in both directions. Severe gum disease is associated with roughly twice the odds of kidney disease.
How it’s linked
Shared drivers such as diabetes and high blood pressure play a large part, and chronic inflammation from the gums may add extra strain on the kidneys over time.
What you can do
If you have kidney disease, mention it to your dentist and keep up regular gum care. Managing blood pressure and blood sugar protects your kidneys and your gums at the same time.
References
Deschamps-Lenhardt et al. (2019). Association between periodontitis and chronic kidney disease: systematic review and meta-analysis. Oral Dis, 25(2):385–402.
Yang et al. (2024). Meta-analysis of chronic periodontitis and chronic kidney disease. World J Clin Cases, 12(22):5094.
6
Emerging
Gut & digestion
The mouth and gut are the two busiest microbial communities in the body, and researchers are increasingly mapping how they talk to each other — the “oral–gut axis.” Gum disease is linked to a higher rate of inflammatory bowel conditions, at roughly twice the odds.
How it’s linked
Bacteria swallowed from an unhealthy mouth can survive and settle in the gut, where they may stir up inflammation. This is a fast-moving field and the full picture is still forming.
What you can do
The basics still apply: healthy gums mean fewer harmful bacteria heading downstream. A good oral routine supports your gut as well as your mouth.
References
◆ Vijayanarayanan R, Coote et al. (2026). The oral–gut axis: a systematic review. J Oral Microbiol, 18(1):2705699. — 21D Clinical Research
Zhang et al. (2021). Association between periodontitis and inflammatory bowel disease: meta-analysis. Biomed Res Int, 6692420.
Wang et al. (2024). Bidirectional associations between periodontitis and IBD. J Periodontal Res, 59(6):1083–1094.
Methodology
How we assess the evidence
We only summarise findings that have survived pooling across multiple studies — then we say plainly how confident that makes us.
01 — Source
We start from systematic reviews, meta-analyses and umbrella reviews rather than single studies, plus our own peer-reviewed publications.
02 — Weigh
We look at how large and consistent the pooled effect is, how many people it covers, and whether independent reviews agree.
03 — Label
Strong, moderate or emerging — and we distinguish association from proven cause throughout.
04 — Cite
Every claim carries its full citation on this page, so you can read the original for yourself.
About this page. This is a plain-language summary of published research, provided for general information. These findings describe associations between oral health and general health — they are not a diagnosis or medical advice, and for most links it isn’t yet proven that treating the gums prevents the other condition. For any concern about your teeth, gums or general health, speak to a dentist or doctor. Diamond-marked references (◆) are our own peer-reviewed work.
Company Disclosure:
21D, Unit 602 Birchwood One Business Park, Dewhurst Road, Birchwood, Warrington, United Kingdom, WA3 7GB. Telephone 0800 0073199. 21D Clinical Limited trading as 21D is a credit broker not a lender and is authorised and regulated by the Financial Conduct Authority, 976995. Registered in England & Wales 09476584. Registered Address: Unit 602 Birchwood One Business Park, Dewhurst Road, Birchwood, Warrington, United Kingdom, WA3 7GB.
Medenta Disclosure:
Where required by law, loans will be regulated by the Financial Conduct Authority and the Consumer Credit Act 1974. Medenta Finance Limited, authorised and regulated by the Financial Conduct Authority No: 715523. Registered in Scotland, No: SC276679. Registered address: 50 Lothian Road, Festival Square, Edinburgh, EH3 9WJ. Tel: 01691684175. Medenta act as a credit broker, not a lender and will introduce practices to V12 Retail Finance Limited for which Medenta will receive an introduction commission from Secure Trust Bank plc, V12 Retail Finance Limited’s parent company.V12 Retail Finance Limited is authorised and regulated by the Financial Conduct Authority. Registration number:679653. Registered office: Yorke House, Arleston Way, Solihull, B90 4LH. Correspondence address: 25-26 Neptune Court, Vanguard Way, Cardiff, CF24 5PJ.
V12 Retail Finance Limited act as a credit broker, not a lender, and only offers credit products from Secure Trust Bank PLC. Secure Trust Bank PLC trading as V12 Retail Finance is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the Prudential Regulation Authority. Registration number: 204550. Registered office: Yorke House, Arleston Way, Solihull, B90 4LH.
Terms and conditions apply. Written quotations are available on request from Secure Trust Bank PLC. Credit facilities are subject to status and affordability checks and only available to UK residents over the age of 18. Secure Trust Bank PLC reserves the right to decline any application. APR and repayment details are correct at time of publish.
Not all products offered by Secure Trust Bank PLC are regulated by the Financial Conduct Authority. Telephone calls are recorded for training and compliance purposes.
Copyright © 21D 2026. All rights reserved. | Updated 6th August 2026
.webp)
