March 30, 2023

Amanda Phoon Nguyen has seen, and smelled, a lot of people with bad breath.
The Perth-based oral medicine specialist tells Christine Layton of ABC Radio Perth, "There is actually a world-class, gold-standard test for knowing if someone has bad breath or not."
"It's called an organoleptic test — you stick your nose in your patient's mouth and have a good whiff," Dr Phoon Nguyen says.
Mostly, she sees two kinds of patients. People with genuine bad breath (the medical term is halitosis) and people with pseudo halitosis.
"Pseudo halitosis is where the patient doesn't actually have bad breath, but they're really afraid or they feel that they have a bad breath, but no-one else can tell," Dr Phoon Nguyen says.
She has also noticed increased concern about bad breath since the pandemic made mask wearing more common.
"I don't have any evidence of this, but anecdotally, I think now that everyone's wearing masks, breath is definitely something that people are paying more attention to," she says.
Genuine halitosis is most commonly caused by problems with oral hygiene and bacteria in the mouth.
"[Bacteria] produce volatile sulphur compounds, which can have a bit of a bad smell, basically," she says.
"The most common thing that I look for and the most common thing that I find in someone that complains of this are lifestyle factors like diet, smoking, dehydration, coffee.
"Dental disease, dental decay, gum problems tend to be quite common reasons as well."
Dr Phoon Nguyen usually gets involved in a case when a dentist has already checked for infection or gum disease, and some of the more unusual causes need investigation.
There are also instances where medical problems can cause bad breath, but Dr Phoon Nguyen says they are very rare.
"Diabetes, kidney problems, sometimes allergies or sinus problems, nasal drips, and in really severe cases, you can sometimes smell cancer like oropharyngeal carcinoma," she says.
"But the most common reason why someone will have bad breath is if they have a tooth infection or a gum disease, or they're not cleaning their tongue or teeth properly."
Other issues can arise with dentures, which can often be associated with oral thrush.
"People might be surprised that there are quite a few people who actually sleep with their dentures in and I describe it as being the equivalent of going to sleep with your shoes on," Dr Phoon Nguyen says.
"The skin and the oral mucosa needs to breathe."
She suggests for most people, twice daily brushing and daily flossing is a good plan. Unlike we see in advertisements, just a pea-sized quantity of toothpaste is enough to maintain good oral hygiene.
"When you look at the commercials and they put like the whole giant squeeze of toothpaste, that's too much," she says.
She also suggests not rinsing with water after you brush, to leave the fluoride on your teeth.
"Brush your teeth thoroughly and then spit it out so the fluoride can stay in your mouth, so your teeth can absorb it," she says.
Dr Phoon Nguyen says mouthwash, which promises fresh breath, is very much optional.
"I'm equivocal, but if you like mouthwash, you can use it," she says.
"There are some side effects. If you're using for example, chlorhexidine [an antiseptic] mouth rinse, long term it can cause staining of the teeth and taste changes.
"Mouthwash doesn't replace brushing and flossing, and you don't have to use it if your oral hygiene is pretty good."
Dr Phoon Nguyen says it could also be worth paying attention to your tongue if you notice yellow staining on it.
"Sometimes the taste buds on our tongue, they can actually trap bacteria and some of the products that the (bacteria) produce, and sometimes it's just debris like food or staining from wine or cigarettes," she says.
"The good thing to do in this case would be to clean your tongue properly.
"Pharmacies sell tongue scrapers, although you don't want to be overzealous and injure your tongue.
"But as part of your oral hygiene when you're brushing and flossing, you can also use a tongue scraper once a day, and that should get rid of any sort of extrinsic staining."
Tongue problems caused by fungi or oral candidiasis will need medical treatment, she says.
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Dr Phoon Nguyens's job mean she's become accustomed to having conversations many of us find extremely difficult — telling people they have bad breath.
"I think the key is to do it, but do it gently and tactfully," she says.
"Most patients do take it well, because I'm not telling them to be mean, I'm telling them because I'm concerned about their health. And as part of my job, I do have a professional responsibility."
She thinks that if you know someone with bad breath, it is worth trying to find a way to tell them if you can.
"If I had bad breath, I hope somebody would tell me," she says.
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