Researchers suggest vaping may be equally - if not more - harmful for oral health than smoking.
In a study published in the journal Oncotarget, researchers found that the chemicals present in electronic cigarette (e-cigarette) vapor were equally as damaging - in some cases, more damaging - to mouth cells as tobacco smoke.
E-cigarettes are battery-operated devices containing a heating device and a cartridge that holds a liquid solution. The heating device vaporizes the liquid - usually when the user "puffs" on the device - and the resulting vapor is inhaled.
While e-cigarette liquids do not contain tobacco - a highly harmful component of conventional cigarettes - they do contain nicotine and other chemicals, including flavoring agents.
According to the Centers for Disease Control and Prevention (CDC), the use of e-cigarettes has increased in recent years, particularly among young people. In 2015, 16 percent of high-school students reported using the devices, compared with just 1.5 percent in 2011.
E-cigarettes are considered by many to be safer than conventional smoking, but because the devices are relatively new to the market, little is known about the long-term effects of vaping on health.
In particular, study leader Irfan Rahman, Ph.D., professor of environmental medicine at the University of Rochester School of Medicine and Dentistry in New York, and colleagues note that there has been limited data on how e-cigarette vapor affects oral health.
Flavored vapor worsens damage to gum tissue cells
To address this gap in research, the team exposed the gum tissue of nonsmokers to either tobacco- or menthol-flavored e-cigarette vapor.
The tobacco-flavored vapor contained 16 milligrams of nicotine, while the menthol flavor contained 13-16 milligrams of nicotine or no nicotine.
The researchers found that all e-cigarette vapor caused damage to gum tissue cells comparable to that caused by exposure to tobacco smoke.
"We showed that when the vapors from an e-cigarette are burned, it causes cells to release inflammatory proteins, which in turn aggravate stress within cells, resulting in damage that could lead to various oral diseases."
Irfan Rahman, Ph.D.
The researchers note that nicotine is a known contributor to gum disease, but e-cigarette flavoring appeared to exacerbate the cell damage caused by e-cigarette vapor, with menthol-flavored vapor posing the most harm.
While further research is needed to investigate the long-term effects of e-cigarette use, Rahman and team believe their findings indicate that the devices may have negative implications for oral health.
"Overall, our data suggest the pathogenic role of [e-cigarette] aerosol to cells and tissues of the oral cavity, leading to compromised periodontal health," they conclude.
E-cigarette vapor damaged, killed 53 percent of mouth cells in 3 days
Another study recently published in the Journal of Cellular Physiology builds on the findings from Rahman and colleagues, after finding a high rate of mouth cell death with exposure to e-cigarette vapor over just a few days.
To reach their findings, Dr. Mahmoud Rouabhia, of the Faculty of Dental Medicine at Université Laval in Canada, and colleagues placed epithelial cells from the mouth in a chamber that contained a liquid similar to saliva.
To simulate vaping, the researchers pumped e-cigarette vapor into the chamber at a rate of two 5-second puffs every 60 seconds for 15 minutes a day. This was performed over 1, 2, or 3 days.
On analyzing the vapor-exposed epithelial cells under a microscope, the researchers identified a significant increase in the rate of cell damage and death.
The rate of damage or death in unexposed cells is around 2 percent, the researchers note. However, they found that with exposure to e-cigarette vapor, the number of dead or dying cells rose to 18 percent, 40 percent, and 53 percent over 1, 2, and 3 days, respectively.
While the cumulative effects of the cell damage caused by e-cigarette are unclear, the researchers believe their findings are a cause for concern.
"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. This is what we will be investigating in the future."
Dr. Mahmoud Rouabhia