The best and worst foods for your breath
Interdental brushes can be used to clean between your teeth to dislodge bits of food and to remove plaque in between your teeth and around the line of the gum.
They come in different sizes so ask your dentist which is the best fit for your mouth. Hold it between your forefinger and thumb and gently put it through the gaps in your teeth. Don’t force it through a gap, use a smaller brush head instead.
Your dentist may suggest using dental floss, especially if there's not enough room between your teeth to use interdental brushes.
Using floss - or dental tape that is a bit thicker - helps get rid of tiny bits of food stuck in your teeth. It also helps remove the plaque that collects around your gum line. As plaque contributes to bad breath, getting rid of it makes breath fresher.
Don't be too hard on your gums. Hold a length of floss between your fingers and gently scrape in between the teeth. Ask your dentist or hygienist to show you how to use it correctly.
It's not just the brushing that helps to keep breath fresh, it's the toothpaste too.
"Toothpaste is important as it contains fluoride to keep teeth strong, but also other ingredients with a fresh flavour which is good for your breath," says Professor Walmsley.
A mouthwash may help prevent bad breath. One that contains fluoride can help prevent tooth decay.
Don't use mouthwash just after you've brushed your teeth as you'll wash away the fluoride in the toothpaste. Use it after a snack or a meal instead.
A mouthwash should not be used to mask bad breath caused by bad dental hygiene – correct teeth-brushing or a visit to the dentist is a better option.
Smoking, snoring and sleeping
Smoking is an obvious cause of bad breath.
Ever wondered why you wake up with 'morning breath'? It could be that you have been breathing through your mouth, or snoring as you slept, and your saliva has dried up, Professor Walmsley says. A dry mouth can make your breath smelly.
Medical condition or medication
Bad breath is sometimes the result of a medical condition or a side-effect of a medication you are taking.
There's a condition called xerostomia, which is known as dry mouth. As you have less saliva this may lead to more bacteria in your mouth, which may lead to bad breath. There's a condition called Sjorgen's syndrome that affects the salivary glands and can lead to dry mouth.
A blocked nose that makes you breathe through your mouth may cause dry mouth. Diabetes can cause bad breath and so may infections that affect your nasal passages, mouth, throat or lungs.
Gastrointestinal conditions may cause bad breath, for example, certain stomach infections and gastro-oesophageal reflux disease ( GORD).
A range of medications may lead to smelly breath. They include antihistamines and some anti-depressants.
"Bad breath can be a red flag for tummy issues like stomach ulcer or severe constipation," says Ana-Kristinia. "The smell of your breath can tell us a lot about a person's health. So if you feel you have got bad breath, or a child has got it, further investigation is a good idea."
If you are concerned about bad breath, or if it hasn't gone away despite your efforts, see your GP or dentist for advice.