E-cigarette use might raise the risk of oral disease, say researchers.
Published in the journal PLOS One, the study reveals that the vapor of e-cigarettes (electronic cigarettes) contains toxic compounds and nanoparticles that destroy the outer later of skin cells in the mouth.
The researchers - led by Dr. Shen Hu, an associate professor of oral biology at the University of California-Los Angeles (UCLA) - came to their conclusion by analyzing the effects of e-cigarette vapor on cell cultures in laboratory tests.
The team gathered cell cultures from the top layer of the oral cavity - specifically, the area of the mouth behind the teeth and gums.
Using a machine that generates e-cigarette vapor, effectively simulating human e-cigarette use, the researchers assessed the substances present in the vapor and measured the particle concentration of these substances.
Additionally, the team exposed the cell cultures to two brands of e-cigarette vapor for 24 hours and monitored the effects.
E-cigarette vapor destroyed 85 percent of oral cavity cells
As well as nicotine and menthol, the researchers found that the e-cigarette vapors consisted of metal, silica, and carbon nanoparticles. The concentration of these substances depended on the brand and flavor of the vapor.
On assessing the effects of e-cigarette vapor on oral cavity cell cultures, the researchers found that the vapor reduced levels of glutathione within the cells, which is an important antioxidant that protects them from damage. As a result, the e-cigarette vapor destroyed around 85 percent of the cells.
Given the rising popularity of e-cigarettes across the globe, the researchers believe their findings may have important implications for human health.
According to the Centers for Disease Control and Prevention (CDC), between 2011-2012, e-cigarette use more than doubled among middle and high school students in the United States, and in 2014, more than a fifth of adults who currently smoke reported also using e-cigarettes.
While many studies have suggested that e-cigarettes are an effective tool to help smokers quit, the negative health implications of the devices have been unclear.
Dr. Hu and colleagues say research into the health risks of e-cigarette use has been limited, particularly when it comes to the effects the devices may have on oral health.
Greater public awareness of e-cigarette health risks needed
While human studies are needed to confirm their findings, the researchers say their results indicate e-cigarette use may raise the risk of oral disease:
"EC [electronic cigarette] creates aerosols that consist of nanoparticles and contain small amount of chemicals that may cause toxicological outcome to human oral cavity.
Considering the increasing popularity of ECs in the general population, there is an urgent need to characterize EC aerosols and assess their biological hazard on oral epithelial cells."
Based on their findings, the researchers call for health care providers to increase public awareness of the potential health risks e-cigarettes might pose.
The team now plans to conduct human studies that will further assess how e-cigarette use impacts oral health.
"A small but significant portion of dental patients at UCLA Dental Clinics have used e-cigarettes, which will provide sufficient patient resources for our planned studies," says Dr. Hu. "Our hope is to develop a screening model to help predict toxicity levels of e-cigarette products, so that consumers are better informed."