Vaping may put your smile at risk | Science News for Students

Vaping may put your smile at risk

New cell study shows e-cigarette vapors damage cells of the mouth
Nov 14, 2016 — 7:00 am EST
girl vaping

E-cigarette vapors are not benign. They can damage cells in the mouth, threatening the health of gums and teeth, a new study finds.


Here’s news that could put a frown on your face. New data show that electronic cigarettes pose a threat to cells in the mouth — and ultimately a vaper’s smile.

Electronic-cigarette use, or vaping, among teens is on the rise. The number of kids that tried vaping quadrupled between 2013 and 2015. In the United States, more kids now vape than smoke tobacco cigarettes. Ads on TV and the internet show e-cigarettes as being safe and fun. However, scientists have been turning up evidence that vaping is not harmless. And now researchers have found that e-cigarette vapors can pose risks to the gums and teeth.

Irfan Rahman works at the University of Rochester in New York. This biochemist studies the potential harm posed by-products and pollutants, including e-cigs. Last year, Rahman told Science News that many teens and young adults said vaping made their throats dry and scratchy. Some told his group that vaping made them cough and their mouths bleed. “We’ve got to start looking into these things and see what’s going on,” Rahman concluded.

E-cigarettes are battery-operated devices. A metal coil inside the device gets very hot. When a flavored liquid passes over these coils, it vaporizes into a gas that users breathe in. E-liquids contain mixtures of chemicals that produce different flavors. Most mixes contain some nicotine, too. (Nicotine is the addictive substance that gives cigarettes their “buzz.”) The liquids tend to be labeled as food grade, which means they are safe enough to eat. But heating these liquids can change their chemical composition. Experts say these chemical changes can make the vapors more toxic — more harmful — than the e-liquids themselves.

3 boys vaping
For most of the last three-quarters of a century, boys thought it “cool” to sneak a smoke. That’s changing. Today, more teens are instead turning to vaping.

His team has now started to do just that.
The researchers have begun to probe what e-cig vapors do to cells of the mouth. They started by growing different types of human mouth cells in the lab. They looked at cells that make up the gums. They also looked at ligament cells that attach teeth to the gums. They exposed each type of cells to the chemicals from e-cigarette vapors.

Those vapors can alter the DNA in these cells, the scientists found. Exposing the cells to e-cig vapors damaged their DNA. DNA damage can change the genetic instructions that tell a cell how to grow and function. Over time, such changes might trigger the development of cancer. The vapors also can harm the cells by causing sustained inflammation.

Taken together, these changes point to a risk of cancer, gum disease and possibly tooth loss for anyone using e-cigarettes. Rahman’s team described its new findings in a paper published October 24 in the journal Oncotarget.

Inflammation a chemical red flagof danger

Mouth cells exposed to e-cigarette vapors gave off warning signals known as inflammatory markers. These markers signal that a process called inflammation is underway. Flavored e-cigs caused more of these inflammatory markers and signs of DNA damage to appear than did unflavored e-cig vapors. Because these flavor chemicals are not present in regular cigarettes, Rahman calls this finding especially worrisome. Indeed, he says, the flavored vapors may pose cellular risks that are unique to e-cigarettes.

Overall, Rahman saw lower levels of inflammation in cells treated with e-cig vapors than would be expected from treating cells with smoke from tobacco cigarettes. Still, that doesn’t mean e-cigs are safer than regular cigarettes, Rahman cautions, because researchers still don’t know what the long-term health effects of e-cig use might be.

Inflammatory markers are chemicals that “tell our bodies that something is going wrong. They send signals that these cells have been damaged,” explains Maciej Goniewicz. He’s a toxicologist at the Roswell Park Cancer Institute in Buffalo, N.Y. Like Rahman, he studies the health effects of e-cigarette vapors. Goniewicz was not involved in the new research on mouth cells.

Inflammation can be helpful. It helps turn on the body’s immune system. This allows it to fight off foreign invaders that don’t belong in the body, such as bacteria and viruses. Inflammation also can help the body heal itself after an injury.

But chronic inflammation, the type that doesn’t go away, is not good. And chronic inflammation is what Rahman and his colleagues worry might occur in a vaper’s mouth. Long-term inflammation of the gums can cause disease. Gum disease can destroy the tissue and bone that hold teeth in place. Severe gum disease even can lead to tooth loss.

The new research corroborates a study Goniewicz published earlier this fall. The bronchial (BRON-kee-ul) tubes are airways that lead to the lungs. Flavored e-cigarette vapors caused similar signs of inflammation to bronchial tube cells as Rahman’s group now reports in mouth cells. The e-cig vapors caused less damage to the bronchial cells than tobacco smoke did. Still, Goniewicz emphasizes, “We are seeing that the e-cigarettes do some harm to cells.”

Looking for the big picture

Fawad Javed is a dentist at the University of Rochester. Studying cells in the lab are important for several reasons, he says. “If somebody that smokes or vapes comes to me with oral disease, I need to understand why this is happening.” Javed worked with Rahman on the new study. Seeing changes on the chemical level can point dentists to the root cause of disease, he argues. And once that’s known, he explains, heath professionals can begin to figure out how to prevent disease.

cell dish
Researchers test the effects of e-cigarette vapors on human mouth cells grown in a lab “dish,” like this one.
I. Rahman

In the lab, scientists can control and manipulate growing conditions. This allows them to scout for specific effects. Still, the scientists know there are many more things at play in the body than can be probed with dishes of cells in some laboratory. To get the full picture of what the new research means for oral health, scientists will have to combine what they learn in cell studies with data from human vapers.

Rahman and Javed have begun doing just that. They have started collecting samples from the mouths of vapers. Called gingival (JIN-jih-vul) crevicular (Kreh-VIC-u-ler) fluid, this watery substance comes from the tiny pockets between the gums and the teeth. That fluid shows evidence that vaping has caused similar inflammation in the saliva and gum fluid of e-cigarette users that Rahman’s team has seen in the cells they exposed in the lab.

But their work is far from over. More research is needed before they will know for sure what potential threats vaping poses to the mouth and gums, Rahman says.

Power Words

(more about Power Words)

battery     A device that can convert chemical energy into electrical energy.

cancer     Any of more than 100 different diseases, each characterized by the rapid, uncontrolled growth of abnormal cells. The development and growth of cancers, also known as malignancies, can lead to tumors, pain and death.

cell     The smallest structural and functional unit of an organism. Typically too small to see with the naked eye, it consists of watery fluid surrounded by a membrane or wall. Animals are made of anywhere from thousands to trillions of cells, depending on their size. Some organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

chemical     A substance formed from two or more atoms that unite (become bonded together) in a fixed proportion and structure. For example, water is a chemical made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H2O. Chemical can also be an adjective that describes properties of materials that are the result of various reactions between different compounds.

chronic     A condition, such as an illness (or its symptoms, including pain), that lasts for a long time.

coil     Concentric rings or spirals formed by winding wire or other fiber around and around a core.

colleague     Someone who works with another; a co-worker or team member.

crevicular      An adjective for something related to crevices. (in dentistry) The fluid between the gums (or gingiva) and teeth is known as the gingival crevicular fluid.

development     (in biology) The growth of an organism from conception through adulthood, often undergoing changes in chemistry, size and sometimes even shape. (in economics and social sciences) The conversion of land from its natural state into another so that it can be used for housing, agriculture, or resource development.

DNA     (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. It is built on a backbone of phosphorus, oxygen, and carbon atoms. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

e-cigarette     (short for electronic cigarette) Battery-powered device that disperses nicotine and other chemicals as tiny airborne particles that users can inhale. They were originally developed as a safer alternative to cigarettes that users could use as they tried to slowly break their addiction to the nicotine in tobacco products. These devices heat up a flavored liquid until it evaporates, producing vapors. People use these devices are known as vapers.

e-liquid     A term for the solutions heated to the evaporation point in an electronic cigarette. These solutions are the basis of the vapors that will be inhaled. The liquid typically contains a solvent into which flavorings and nicotine have been dissolved.

genetic     Having to do with chromosomes, DNA and the genes contained within DNA. The field of science dealing with these biological instructions is known as genetics. People who work in this field are geneticists.

gingival      A term in oral medicine for things having to do with the gums.

immune     Able to ward off a particular infection. Alternatively, this term can mean to show no impacts from a particular poison or process. More generally, the term may signal that something cannot be hurt by a particular drug, disease or chemical.

immune system     The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.

inflammation     The body’s response to cellular injury and obesity; it often involves swelling, redness, heat and pain. It is also an underlying feature responsible for the development and aggravation of many diseases, especially heart disease and diabetes.

ligament     A fibrous and elastic material that connects one bone to another.

marker     (in biomedicine) The presence of some substance that usually can only be present because it signals some disease, pollutant or event (such as the attachment of some stain or molecular flag). As such, this substance will serve as a sign — or marker — of that related thing.

nicotine     A colorless, oily chemical produced in tobacco and certain other plants. It creates the ‘buzz’ effect associated with smoking. It also is highly addictive, making it hard for smokers to give us their use of cigarettes. The chemical is also a poison, sometimes used as a pesticide to kill insects and even some invasive snakes or frogs.

oral     An adjective that refers to things in or affecting the mouth.

pollutant     A substance that taints something — such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.

respiratory tract     Parts of the body involved in breathing (also called the respiratory system). It includes the lungs, nose, sinuses, throat and other large airways.

risk     The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.

smoke     Plumes of microscopic particles that float in the air. They can be comprised of anything very small. But the best known types are pollutants created by the incomplete burning of oil, wood and other carbon-based materials.

tissue     Any of the distinct types of material, comprised of cells, which make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues. And brain tissue will be very different from bone or heart tissue.

tobacco     A plant cultivated for its leaves. Dried tobacco leaves are burned in cigars, cigarettes, and pipes. Tobacco leaves are also sometimes chewed. The main constituent of tobacco leaves is nicotine.

toxic     Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity. Scientists who study such impacts are known as toxicologists.

tract     A particular, well-defined area. It can be a patch of land, such as the area on which a house is located. Or it can be a bit of real estate in the body. For instance, important parts of an animal’s body will include its respiratory tract (lungs and airways), reproductive tract (gonads and hormone systems important to reproduction) and gastro-intestinal tract (the stomach and intestines — or organs responsible for moving food, digesting it, absorbing it and eliminating wastes).

vaping     (v. to vape) A slang term for the use of e-cigarettes because these devices emit vapor, not smoke. People who do this are referred to as vapers.

vaporize     To convert from a liquid to a gas (or vapor) through the application of heat.

vapors     Fumes released when a liquid transforms to a gas, usually as a result of heating.


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Journal: I.K. Sundar et al. E-cigarettes and flavorings induce inflammatory and pro-senescence responses in oral epithelial cells and periodontal fibroblasts. Oncotarget. Published online October 24, 2016. doi: 10.18632/oncotarget.12857.

Journal: N.J. Leigh et al. Flavourings significantly affect inhalation toxicity of aerosol generated from electronic nicotine delivery systems (ENDS). Tobacco Control. Published online September 15, 2016. doi: 10.1136/tobaccocontrol-2016-053205.