Each fruity plume of vapour from an e-cigarette may have not-so-sweet repercussions for your pearly whites, according to a study.
Researchers reviewed thousands of patient records from a university dental clinic and found people who reported vaping were at higher risk of tooth decay and cavities than people who said they didn't vape.
The study was published in the Journal of the American Dental Association today.
Karina Irusa from Tufts University in the US, who led the study, says it's not possible to say that vaping definitely causes tooth cavities, but there's a likely association between the two.
"We stumbled upon this [potential link] by accident, and then the more we learned about it, the more we thought, 'OK, this could be a bad thing.'"
Vaping's effects emerge from the haze
E-cigarette or vape liquid, which is heated and inhaled, is mostly a thick liquid base, such as glycerol and propylene glycol, mixed with a whole bunch of artificial flavourings and other chemicals.
And vaping is taking off in Australia, especially among young people.
People aged 18-24 are more likely to vape than any other age group, with 5 per cent reporting they currently use a device, according to the National Health Survey 2021.
But vaping can be harmful to our health, particularly for non-smokers and young people, according to an Australian report published in April. We know users are at higher risk of developing, for instance, seizures and lung damage.
Today's research is not the first to suggest a link between tooth decay and vaping.
A 2017-18 survey of 4,600 people in the US found those who currently used e-cigarettes were more likely to have untreated cavities than their non-smoking counterparts.
It's something one of Dr Irusa's colleagues noticed in his Chicago dental practice a few years ago.
He saw three patients, ranging in age from 21 to 52 years, each of whom had multiple cavities in unusual places.
For instance, one woman had decayed patches along the smooth biting edge of her top front teeth.
What the trio had in common was regular e-cigarette use — eight to 12 times a day — using vaping liquids containing THC, the main psychoactive compound found in cannabis.
To see if they could find a link between vaping and tooth decay risk in a wider patient cohort, Dr Irusa and her colleagues analysed patient records for around 13,000 people over 16 who visited a Tufts teaching dental clinic from the start of 2019 to the end of 2021.
Of those, 91 people (or less than 1 per cent) said they used e-cigarettes or vapes.
And they were more likely to be in the "high-risk" group for tooth decay (79 per cent) compared to non-vapers (60 per cent).
The Melbourne Dental School's Matt Hopcraft, who was not involved in the study, said while 91 people who reported vaping wasn't a terribly large group — more on why that might be later — the results hint at potential issues down the track for younger vapers.
By their teenage years, around 40 per cent of Australian children already have decay in their adult teeth, Dr Hopcroft said.
"If kids are turning into young adults who are vaping on a regular basis, that's increasing their risk [for cavities] further — and that's a real concern."
How vaping might leave a sour taste in your mouth
The relatively low proportion of dental patients in the study who reported vaping could be down to a few reasons, Dr Irusa said.
"We purely looked at records, so we are assuming record-keeping was accurate, and we're also assuming the [dental] students did everything correctly.
"Was their [cavities] risk assessment accurate? Did they ask everyone about vaping?
"And even if they asked, did everyone tell the truth?"
Patient records lacked detail such as how often each person vaped, or what was in their vape liquid of choice.
There's also the possibility that people who vape are more likely to partake in cavity-encouraging activities, such as eating more sugary food.
But there are a few different ways vaping in general might contribute to a mouth full of fillings.
The vapourised liquid is thick and coats the teeth, getting into nooks and crannies.
Some compounds commonly found in vape liquids become acidic when aerosolised.
And while the hard, enamel shell that covers our teeth is pretty tough, prolonged contact with acidic substances can erode it.
Fruity and creamy-smelling vapes often include, unsurprisingly, a whole bunch of different sugars.
Some of these sugars are food for acid-producing bacteria that live on and around our teeth. Other sugars affect how those microbes behave.
A 2018 study examined how the bacterium Streptococcus mutans, which is naturally present in our mouth and the main player in tooth decay, acts when bathed in flavoured vapour.
It found bacteria become "stickier" and more likely to clump together as a film on our tooth enamel — what we know as dental plaque.
If not brushed away, bacteria in plaque pump out acids, which soften and dissolve the enamel underneath.
Vaping may also affect how much saliva we make, which can, in turn, contribute to cavities, Dr Irusa said.
"Saliva dilutes whatever's in your mouth, whether it's acid or sugar, and saliva pH also helps to keep everything neutral.
"But if you don't have enough saliva, then you have acid [on your teeth] for longer periods of time. And that's not good."
Editor's note (28/11/22): The original version of this article incorrectly stated that nearly two-thirds of respondents aged 18-24 to the 2019 National Drug Strategy Household Survey had reported vaping at least once. This statistic is only true of current smokers. The ABC apologises for this error.
