Bad Breath, Explained

Where Does Bad Breath Come From?

Nearly all bad breath, or halitosis, starts in the mouth. Bacteria living on the back of the tongue, between the teeth and just below the gum line break down food debris and dead cells, and the sulphur gases they release are what you smell. Those bacteria thrive wherever cleaning doesn't reach: the deep furrows at the back of the tongue, the tight spaces between back teeth, around a broken filling, and inside the pockets that form when gums become inflamed.

Saliva normally keeps the mouth rinsed and the bacteria in check, which is why breath is worse first thing in the morning, after a long flight, or when you're dehydrated. Anything that dries the mouth, from mouth breathing to some common medicines, makes it worse. The good news is that because the cause is usually mechanical, the fix is usually mechanical too: remove the deposits and the smell goes with them.

The Most Common Causes

• Bacteria on the tongue, especially the coating at the back that brushing alone misses
• Plaque between the teeth, where a toothbrush can't reach
• Gum disease, from early inflammation to deep pockets that trap bacteria below the gum line
• A dry mouth, worse in the morning, with mouth breathing, or with some medicines
• Smoking, which smells in itself and makes gum disease more likely
• Strong foods such as garlic, onion and spices, which linger for a day or so
• Decay or a broken filling trapping food that rots in place
• Dentures, retainers and aligners that aren't cleaned every day
• Crash diets and fasting, which can give breath a sharp, chemical smell

A Daily Routine That Works

• Brush twice a day for two minutes with a fluoride toothpaste, angling the bristles towards the gum line
• Clean between your teeth every day with interdental brushes, or floss where the gaps are tight. This is the step most people skip and the one that makes the biggest difference
• Brush or scrape your tongue, working from the back forwards. A tongue scraper is more effective than a toothbrush for the coating at the back
• Spit after brushing rather than rinsing, so the fluoride keeps working
• Drink water through the day, and chew sugar-free gum after meals if your mouth tends to be dry
• Don't skip breakfast. Eating gets saliva flowing and clears morning breath
• Clean dentures, retainers and aligners every day, and take dentures out at night
• If you smoke, stopping helps your breath and your gums more than anything else on this list
• Keep your hygiene visits, so tartar and stain are removed before they harbour more bacteria

Give the routine two to three weeks. If your breath is no better by then, the cause is probably something you can't reach at home.

How Do I Know If It's Gum Disease?

Gum disease is the cause we find most often when bad breath won't shift. Plaque that sits along the gum line hardens into tartar, the gums become inflamed and start to pull away from the teeth, and the pockets that form are the perfect place for the bacteria that cause the smell. The warning signs are gums that bleed when you brush or clean between your teeth, redness or puffiness along the gum line, gums that look as if they've shrunk back, and a bad taste that returns soon after brushing.

Early gum disease, gingivitis, usually reverses with a professional clean and better home care. More advanced gum disease, periodontitis, needs deep cleaning below the gum line in stages, at £100 per stage.² Our guide to gum disease explains the signs and the treatment in detail.

How a Hygiene Visit Helps

A hygiene visit with Bronagh O'Dowd or Anisha Pariyarath, our dental therapists, is usually 30 minutes. We check your gums and measure for early signs of gum disease, remove tartar from above and just below the gum line, and lift plaque and stain with air polishing, a fine stream of warm water, air and powder that reaches around implants, bridges and braces. Then we show you exactly where the bacteria are hiding in your own mouth and which brushes to use.

A 30-minute hygiene visit is £70, or £100 with air polishing, and both are included in our dental plans. A 60-minute deep clean is £130 if there's a lot to remove.² For most people with persistent bad breath, one visit plus a better routine at home is enough to solve it.

Dry Mouth, Dentures and Aligners

A dry mouth is one of the most overlooked causes. Saliva washes bacteria away and neutralises the acids they make, so when there's less of it, breath gets worse quickly. Common reasons include breathing through your mouth at night, some medicines for blood pressure, allergies, depression and bladder problems, and simply not drinking enough. Sipping water, sugar-free gum and avoiding alcohol-based mouthwashes all help. If dryness is constant, tell your GP, as a change of medicine sometimes makes a difference.

Dentures, retainers and Invisalign aligners pick up the same plaque as teeth. Clean them every day with a soft brush and the cleaner recommended for them, never hot water, and leave dentures out overnight so your gums get a rest. Anything that sits in your mouth for hours needs to be as clean as your teeth.

When Might It Be Something Else?

Occasionally bad breath comes from outside the mouth. Sinus infections and post-nasal drip, tonsil stones, acid reflux and some stomach problems can all cause it, and a sweet, chemical smell can be a sign of poorly controlled diabetes. The clue is a mouth that's healthy and well cleaned but breath that persists regardless, or that gets worse when a cold or heartburn flares up. If we've checked your teeth and gums and found nothing, see your GP and tell them your mouth has been checked, which helps them look elsewhere.

Questions

This guide is general information, not a diagnosis. A dentist needs to examine you to say what is right for your teeth.