Almost everyone has bad breath sometimes, especially first thing in the morning or after garlic and coffee. Persistent bad breath, known as halitosis, is different. It can be embarrassing and affect confidence at work and in relationships. The good news is that in most cases it starts in the mouth and can be treated.
What causes bad breath?
Around nine in ten cases of persistent bad breath come from the mouth itself. Bacteria break down food particles and proteins and release sulphur compounds with a strong smell. The main sources are:
The tongue
The back of the tongue has a rough surface where bacteria, food debris and dead cells collect, forming a whitish or yellowish coating. It’s the single most common source of bad breath.
Gum disease
Bacteria in the pockets around inflamed gums produce strong-smelling compounds. Bad breath that doesn’t improve with brushing is a common sign of gum disease.
Food trapped between teeth
Food caught between teeth, under bridges, or around crowded teeth decays and smells if it isn’t cleaned out daily.
Tooth decay and infections
Large cavities, broken fillings and dental abscesses can all cause an unpleasant taste and odour.
Dry mouth
Saliva washes away bacteria. When the mouth is dry, during sleep, after exercise, when dehydrated, or because of medications, odour builds up. This is why morning breath happens.
Dentures and appliances
Dentures, retainers and aligners that aren’t cleaned properly harbour bacteria and smell.
Other causes
- Foods and drinks: garlic, onion, spices, coffee and alcohol
- Smoking and vaping, which also dry the mouth and increase gum disease
- Low-carbohydrate or fasting diets, which can cause a distinctive smell
- Sinus, nose and throat problems, such as post-nasal drip or tonsil stones
- Reflux
- Some medical conditions, including poorly controlled diabetes and kidney or liver problems; these are much less common causes
How to tell if you have bad breath
It’s hard to smell your own breath, because we become used to it. Some simple checks:
- Lick the inside of your wrist, let it dry for a few seconds, then smell it
- Scrape the back of your tongue gently with a spoon and smell it
- Ask a trusted family member or friend for an honest opinion
What helps at home
- Brush twice a day for two minutes with fluoride toothpaste.
- Clean between your teeth every day with floss or interdental brushes.
- Clean your tongue once a day with a tongue scraper or your toothbrush, working from back to front.
- Drink plenty of water through the day.
- Chew sugar-free gum after meals to stimulate saliva.
- Clean dentures and appliances daily and leave dentures out overnight.
- Cut back on smoking, alcohol and coffee.
Mouthwashes can mask odour for a short time. Alcohol-free formulas are less likely to dry the mouth. A mouthwash isn’t a fix if the cause is gum disease or decay.
How a dentist can help
If bad breath persists despite good home care, see a dentist. At your appointment we will:
- Ask about your medical history, medications, diet and when you notice the odour
- Check your teeth for decay, broken fillings and food traps
- Measure your gums for signs of gum disease
- Look at your tongue, tonsils and the rest of your mouth
- Check dentures, bridges and appliances
Treatment depends on the cause. It may include a professional scale and clean, deeper gum treatment, replacing a leaking filling, managing a dry mouth, or adjusting a denture. If we suspect a cause outside the mouth, we’ll suggest seeing your GP.
Common myths about bad breath
“Mints and gum fix it”
They only cover it up for a short time. Sugar-free gum does help by increasing saliva, but sugary mints feed the bacteria that cause decay and odour.
“If I brush well, it can’t be my mouth”
Brushing alone misses about a third of tooth surfaces: the areas between teeth. The tongue is also frequently missed. Most people who brush well but still have bad breath improve once they clean between their teeth and clean their tongue.
“Strong mouthwash kills the problem”
Alcohol-based mouthwashes can actually dry the mouth, which may make breath worse later. If you use a mouthwash, choose an alcohol-free one and use it as well as, not instead of, cleaning.
“Bad breath is just something some people have”
Persistent bad breath almost always has a cause, and most causes can be treated. It’s worth getting it checked rather than putting up with it.
A daily routine for fresh breath
- Morning: brush for two minutes, clean your tongue, and drink a glass of water.
- After meals: rinse with water or chew sugar-free gum, especially after coffee or strong foods.
- Through the day: keep a water bottle with you. Thirst and dry mouth go hand in hand.
- Evening: clean between all your teeth, brush for two minutes and clean your tongue. Spit out the toothpaste but don’t rinse.
- Every six months: a check-up and professional clean to remove tartar and check your gums.
Bad breath with braces, aligners or dentures
Appliances add surfaces for plaque to stick to. Brush braces carefully around every bracket and use interdental brushes under the wire. Rinse aligners whenever you take them out and brush them gently with cool water daily. Take dentures out at night, brush them over a basin of water, and soak them in a denture cleaner. If an appliance still smells after cleaning, bring it to your next visit.
Bad breath FAQs
Why is my breath worse in the morning?
Saliva flow drops during sleep, letting bacteria multiply. Brushing your teeth and tongue and drinking water usually freshens morning breath quickly.
Can bad breath come from my stomach?
It’s much less common than people think. Reflux can contribute, but most persistent bad breath comes from the mouth.
What are tonsil stones?
Small, whitish lumps that form in the crevices of the tonsils and can smell strongly. Gargling and good oral hygiene help; persistent problems are a question for your GP.
Can children have bad breath?
Yes, often from mouth breathing, a coated tongue or food trapped between teeth. Persistent bad breath in a child is worth a dental check.
Find out more about gum disease treatment in Hornsby.
Book a visit at Hornsby Dental
Hornsby Dental is at Suite 21, 14 Edgeworth David Avenue, Hornsby, about three minutes’ walk from Hornsby Station, with free street parking nearby. We’re open Monday to Friday 9am–6pm and Saturday 8:30am–4pm. Book online or call (02) 8090 1100.
This article is general information only. It isn’t a substitute for advice from your dentist about your own mouth and health.