Vaping may be worse for people's oral health than smoking cigarettes is. They both lead down the same road to gum disease, but there's now evidence that vaping does it quicker.

Cigarettes substantially raise a smoker's risk of cancer and heart disease. Because of the seriousness of these diseases, the effects smoking has on the mouth often fly under the radar. Cigarettes increase smokers' risk of developing periodontitis — serious gum disease — four-fold. And while this may take over a decade to appear, it leaves signs that the process is occurring along the way.

It was hoped that vaping might be less toxic. A recent study argues strongly against its being less damaging to the mouth and gums. And it doesn't matter whether or not there's any nicotine.

“Vaping is such a big assault on the oral environment, and the change happens dramatically and over a short period of time,” said Purnima Kumar, professor of periodontology at Ohio State University and senior author of the study.

The most striking finding was in vapers who had never smoked.

Chief among the changes was that many of the bacteria that normally live in the mouth develop an outer layer of mucopolysaccharide — slime. This slimy coating causes the immune system to now see these bacteria as invaders instead of as normal residents of the mouth and is a prelude to gum inflammation, inflammation that helps destroy what was once healthy gum tissue.

“The reason we're all healthy is because our immune system has recognized these bacteria and their functions since birth and has established a sense of harmony,” Kumar said. “The problem is when you throw a curve ball with an environmental shift like this [by vaping], your immune system doesn't recognize the bacteria as friends anymore. You have to call the police on them, and that causes a huge inflammatory response.”

Samples of oral plaque were taken from under the gums of five different groups of people and the profiles of the bacteria in the samples were compared. The groups were: smokers, non-smokers, vapers, dual users (smoke and vape) and former smokers who had switched to vaping.

All were healthy young people (21-35) with no signs of periodontal disease — their gums appeared normal.

The most striking finding was in vapers who had never smoked, the above-mentioned slime formation and presence of proteins that signaled the immune system was on standby to activate. All the more startling was that the vapers in the study had only been vaping for an average of seven months. The smokers in the study had been smoking for an average of five years.

Even the longtime and former smokers in the study who had taken up vaping showed the more worrisome oral profile of vapers after their few months of vaping. The finding calls into question claims that vaping reduces the harm caused by smoking. “If you stop smoking and start vaping instead, you don't move back toward a healthy bacterial profile but shift up to the vaping profile,” Kumar explained.

Two possible reasons are that the heat from the vaping aerosol invokes a stress response in oral bacteria and that the glycerol and propylene glycol in the vaping aerosol act as an additional source of sugary food for these bacteria.

On a positive note, previous research has found that people who stop smoking cigarettes have an oral bacterial profile similar to people who have never smoked, suggesting that the changes caused by smoking are not permanent. Hopefully, the same will be true for people who quit vaping.

For more details, see the article in Science Advances.