E-cigarette vapours can kill a large number of mouth cells, that increases the risk of infection, gum disease inflammation and even cancer, a new study has warned.
Researchers found that exposing gingival epithelial cells to e-cigarette vapour in the laboratory causes them to die within a few days.
"Mouth epithelium is the body's first line of defence against microbial infection. This epithelium protects us against several microorganisms living in our mouths," said Mahmoud Rouabhia from Universite Laval in Canada.
To simulate what happens in a person's mouth while vaping, researchers placed epithelial cells in a small chamber containing a saliva-like liquid.
Electronic cigarette vapour was pumped into the chamber at a rate of two five-second "inhalations" per minute for 15 minutes a day.
Observations under the microscope showed that the percentage of dead or dying cells, which is about two per cent in unexposed cell cultures, rose to 18 per cent, 40 per cent, and 53 per cent after one, two and three days of exposure to e-cigarette vapour respectively.
"Contrary to what one might think, e-cigarette vapor is not just water," said Rouabhia.
"Although it does not contain tar compounds like regular cigarette smoke, it exposes mouth tissues and the respiratory tract to compounds produced by heating the vegetable glycerin, propylene glycol, and nicotine aromas in e-cigarette liquid," he said.
The cumulative effects of this cell damage have not yet been documented, but they are worrying, said Rouabhia.
"Damage to the defensive barrier in the mouth can increase the risk of infection, inflammation, and gum disease. Over the longer term, it may also increase the risk of cancer," Rouabhia said.
The study was published in the Journal of Cellular Physiology.