Teeth & Gums

Keep your mouth wet

Saliva is the mouth's repair system. It buffers acid with bicarbonate and phosphate, carries the calcium and phosphate that rebuild enamel, clears food, and carries antibodies and antimicrobial proteins. When it stops, as after head-and-neck radiation or in Sjögren's syndrome, teeth can decay rapidly. Everyday dry mouth comes from mouth breathing (especially at night), antihistamines, antidepressants, ADHD drugs, some blood-pressure drugs, dry winter air and, in women around menopause, falling estrogen. Waking up with a dry mouth means the mouth was acidic all night.

Read more: Sleep: breathing

Limit how often acid and sugar hit

Each sugar or acid hit drops the pH for roughly 20–30 minutes before saliva brings it back. The total time spent below pH 5.5 is what dissolves enamel, so how often you're exposed matters more than how much. One sweet drink sipped over 3 hours does more damage than the same drink finished with a meal. Plain acid erodes enamel even without bacteria: soda, sports drinks, kombucha, lemon water and vinegar shots all sit around pH 2–3.5. pH is logarithmic, so pH 3 is 100 times more acidic than pH 5. Black coffee is about pH 5, and with milk it's nearly neutral.

Brush gently, clean between teeth

Plaque is an organised biofilm, not leftover food, and rinsing doesn't remove it. Physically disrupting it does. In the Cochrane review of 35 trials, adding floss or interdental brushes to toothbrushing reduced gum inflammation more than brushing alone. Interdental brushes and water flossers did at least as well as floss. More is not better, though. Hard bristles and gritty "whitening" pastes wear enamel and push the gums back. A paste's abrasiveness is listed as its RDA score.

Treat bleeding gums

Bleeding gums are an open wound. Every time you brush or chew, oral bacteria and inflammatory signals (IL-6, TNF-α) enter the blood. Gum bacteria such as P. gingivalis have been found in artery plaque and in brain tissue. The clearest test of whether it matters comes from diabetes. In the Cochrane review of 35 trials, treating gum disease (deep cleaning) lowered A1c by about 0.43% after 3–4 months, similar to adding a second diabetes drug. The sulfur smell of gum disease is distinctive. Once you can recognise it, you'll notice it everywhere.

Read more: Metabolic Health · Statins, LDL & CVD

Ditch antiseptic mouthwash

Bacteria on the tongue turn nitrate from vegetables into nitrite, which the body turns into nitric oxide, the molecule that relaxes blood vessels. Your body can't do the first step itself, so without these bacteria, arugula and beets do much less. In a London study, a week of chlorhexidine mouthwash cut the mouth's nitrite production by 90% and blood nitrite by 25%, starting within a day. In a Puerto Rican cohort of overweight adults, people who used mouthwash twice a day or more were about twice as likely to develop high blood pressure over 3 years. Alcohol mouthwashes such as Listerine also dry the mouth, and over time the bad-breath bacteria come back while the helpful ones stay suppressed. A dentist-prescribed antiseptic has a place for short-term infection control. As a daily habit, it does more harm than good.

Read more: Heart: nitrate · Beet Juice

Use hydroxyapatite toothpaste

Hydroxyapatite (HA) is the mineral enamel is made of. In toothpaste it fills early weak spots, binds to the surface, and plugs the open tubules in exposed dentin that cause sensitivity. Sensitivity is often the first thing people notice improving. Japan approved it as an anti-cavity ingredient in 1993. In an 18-month trial in 189 adults, an HA toothpaste prevented new cavities as well as a fluoride one: 89% versus 87% of people had no new decay. A 1-year trial in young children found the same. The EU's safety committee has cleared rod-shaped nano-HA for toothpaste. Swallowed, it dissolves into calcium and phosphate.

Fluoride: it does work. It converts the enamel surface into fluorapatite, which resists acid down to about pH 4.5 instead of 5.5. The benefit comes from contact with the tooth, so toothpaste does the job. Swallowing it is another matter. In a 2025 meta-analysis of 74 studies, higher fluoride exposure was linked to lower IQ in children. The link was clear above 1.5 mg/L in drinking water, and US tap water targets 0.7 mg/L. Below 1.5 mg/L the pooled result was null, but the low-bias studies still pointed lower. With HA working as well, you don't need fluoride. If you're getting a lot of cavities while you sort out your diet and dry mouth, a fluoride paste for a while is reasonable.

Chew xylitol gum

Xylitol is a sugar alcohol that cavity bacteria take in but can't ferment, so it doesn't feed them and it puts S. mutans under pressure. Chewing also gets saliva flowing. The trial evidence is weaker than its reputation. In the Cochrane review, adding xylitol to a fluoride toothpaste cut cavities about 13%, and the evidence was rated low quality. A 2024 Cleveland Clinic study found that a xylitol drink containing 30 g raised blood levels and made platelets stickier, and that higher blood xylitol was linked to heart events. A piece of gum has about 1 g.

Feed your gums

A review of nutrition and oral disease concluded that bleeding gums are a sensitive early sign of a poor diet: too much refined carbohydrate and polyunsaturated (seed) oil, too little protein, vitamin C or B12. Vitamin C is needed to make the collagen in gum tissue, and the gums are often the first place a shortfall shows. Vitamin D runs calcium absorption and the mouth's antimicrobial proteins. Low D is consistently linked with more cavities, and severe deficiency (rickets) damages teeth as they form. K2 helps move calcium into bone, including the jawbone. None of these can fix teeth that are bathed in acid all day.

Read more: Vitamin C · Vitamin D · Vitamin K2 · Linoleic Acid paper

Scrape your tongue

Bad breath comes mostly from volatile sulfur compounds made by bacteria in the grooves at the back of the tongue, and from gum pockets. A tongue scraper removes that coating physically, which rinsing can't do. A thin white coating is normal. A thick, smelly one, or breath that smells sulfurous, means gum disease, dry mouth or tonsil stones are worth checking. The catch: the tongue also hosts the nitrate-reducing bacteria, and heavy scraping can reduce them.

Read more: Beet Juice: timing

Mouth bacteria and the rest of the body

Mouth bacteria reach the rest of the body in two main ways. Helpful bacteria turn food nitrate into nitric oxide, which is why you don't want to sterilise the mouth. Harmful bacteria get into the blood through bleeding gums, or are swallowed or inhaled. Here's what each organ link rests on, roughly from strongest to weakest.

• Blood vessels (nitrate). Tongue bacteria turn nitrate from arugula and beets into nitrite, which becomes nitric oxide and relaxes blood vessels. Antiseptic mouthwash breaks the chain. Within a day, blood nitrite falls and blood pressure rises. In a 3-year cohort, people who used mouthwash twice a day or more got high blood pressure about twice as often. Heart: nitrate
• Blood sugar. Bleeding gums leak inflammatory signals that interfere with insulin. In trials, treating gum disease lowered A1c by about 0.43%. The link runs both ways: high blood sugar also feeds gum disease. Regular mouthwash use has also been linked to a higher risk of prediabetes. Metabolic Health
• Lungs. Frail and bedbound older people inhale mouth bacteria, which is the main cause of aspiration pneumonia. In Japanese nursing homes, regular professional mouth cleaning cut throat bacteria and pneumonia. If you care for an older relative, clean their teeth, dentures and tongue.
• Stomach. Swallowed nitrite turns into nitric oxide in stomach acid and protects the stomach lining. In rats, mouthwash abolished that protection. There are no human studies of this. Gut guide
• Gut. Mouth bacteria are normally killed by stomach acid. When the gut's own bacteria are disrupted (by antibiotics or acid blockers), some can settle in the gut. In mice given human saliva, Klebsiella from the mouth drove gut inflammation of the kind seen in IBD. Gut guide
• Joints. Gum bacteria (A. actinomycetemcomitans and P. gingivalis) trigger the protein changes, called citrullination, that the immune system attacks in rheumatoid arthritis. People with rheumatoid arthritis have more gum disease. In one case report, a patient's arthritis went into remission after the gum infection was cleared. Joints & Bones
• Arteries. Gum bacteria and their DNA turn up inside artery plaque, and gum disease tracks with heart disease. The link is consistent, but cause and effect haven't been shown. Statins, LDL & CVD
• Brain. P. gingivalis and its tissue-digesting enzymes (gingipains) have been found in Alzheimer's brains. In mice, the bacterium spread to the brain and raised amyloid. A drug that blocks gingipains missed its main goals in a human trial, so this is still a hypothesis. Brain & Focus
• Colon. Fusobacterium nucleatum, a mouth bacterium, was found enriched in colon tumours. An independent attempt to repeat that finding mostly failed. Unsettled.
• Pregnancy. Gum disease is linked to preterm birth. But in a trial of 823 pregnant women, treating gum disease during pregnancy didn't reduce it (12.0% vs 12.8%). If there's a benefit, it probably needs healthy gums before pregnancy.

Worth considering

• Feed the good bacteria. Oral probiotics shift the microbiome only while you take them. Changing the conditions lasts longer: nitrate-rich greens, polyphenols such as green tea, less frequent sugar and xylitol. Green Tea
• Red and blue light mouthpieces. Red light (about 630–660 nm) eases gum inflammation. In clinic trials it was added to a deep cleaning and gave a modestly bigger shrink in gum pockets: about 0.9 mm more at 3 months across 6 trials. Blue light kills P. gingivalis and its relatives preferentially in the lab, because they store a light-sensitive pigment. Unlike mouthwash, that could spare the helpful bacteria, but this hasn't been tested in people. Home devices (CuraYou and others) have no trials of their own, and a blue-light toothbrush did no better than a manual one. It's worth adding if you have gum pockets of 4 mm or more and are being treated. It doesn't replace brushing and flossing. Keep the blue light away from your eyes.
• Mouth tape at night. A thin strip keeps you breathing through your nose. Only use it if your nose is clear, and get a sleep study first if you snore loudly or stop breathing in your sleep.
• Early cavities can be reversed. A chalky white spot that hasn't broken through can remineralise with the steps above. Ask your dentist about the P11-4 peptide (Curodont) for early lesions before drilling.
• Kids: chewy food and nasal breathing. Jaws grow to the work they're given. Treating allergies and blocked noses early prevents a mouth-breathing habit that affects how the face develops. Advice like this is for growing children. It won't change an adult's face.