Figure 1: Effects of e-cigarette usage
The use of electronic cigarettes (e-cigarettes) represents a significant and increasing proportion of tobacco consumption, posing a tremendous threat to oral health. This article will look at the following aspects of e-cigarettes:
- Overview of e-cigarette usage
- Statistics on the current prevalence of e-cigarettes
- Three chemicals contained in e-cigarettes and their effects on oral health
When compared to traditional tobacco use, an argument that e-cigarette use may be as dangerous to oral health—if not more dangerous—can be made.
Using e-cigarettes, referred to as vaping, works by heating a liquid to generate an aerosol that the user inhales. The liquid in the e-cigarette, called e-liquid, is usually made up of propylene glycol, glycerin, flavorings, water, and nicotine, although some users will substitute THC for nicotine. In practice, e-cigarette users tend to reach lower blood nicotine concentrations than tobacco smokers, although it is difficult to make a direct comparison because nicotine concentrations in e-cigarettes vary widely.
Reasons individuals vape include the following:
- Smoking cessation
- The thought that vaping is less harmful than cigarettes
- Circumvention of smoke-free areas
- Recreational enjoyment (1)
Researchers and anti-tobacco advocates are especially concerned that irresponsible marketing has made e-cigarettes appeal to a younger population who does not have a history of tobacco usage. Tobacco use among middle and high school students has been steadily decreasing since 2014. However, since the introduction of the e-cigarette, that number is now increasing, and it is estimated that one in five high school students may now be using tobacco products. (2) E-cigarette use from 2017 to 2018 increased 78% among high school students and 48% among middle school students. (3)
The first danger of e-cigarettes is associated with the carrier product known as propylene glycol (PG). PG is primarily used in the production of polymers and in food processing. It can be found in various edible items, such as liquid sweeteners, ice cream, and whipped dairy products. It can also act as a carrier for various inhalant pharmaceutical products, including nicotine. PG is a viscous, colorless liquid that possesses a faintly sweet taste and is one of the major ingredients of the e-liquid used in e-cigarettes. When used orally, the breakdown products of PG include acetic acid, lactic acid, and propionaldehyde, which are all toxic to enamel and soft tissue. (4) In addition, PG is a hygroscopic product, which means water molecules in saliva and oral tissue will bond to the PG molecules, leading to tissue desiccation. (5) The result of this is xerostomia, or "dry mouth," which has been shown to lead to an increase in cavities, gum disease, and other oral health issues.
Vegetable glycerin and flavorings
The second danger of e-cigarettes is due to other major component of e-liquid: glycerin and flavorings. Vegetable glycerin (VG) is a colorless, odorless, viscous, and sweet-tasting liquid. It has a myriad of applications, including medical, pharmaceutical, and personal care. In the food industry, it serves as a humectant, solvent, and sweetener. It is 60% as sweet as sucrose and is not metabolized by cariogenic bacteria, and is therefore thought not to cause cavities. However, studies have shown that the combination of VG with flavorings produces a fourfold increase in microbial adhesion to enamel and a twofold increase in biofilm formation. (6) In addition, a 27% decrease in enamel hardness was demonstrated when flavorings were added to e-liquid as compared to unflavored controls. The viscosity of the e-liquid also allowed Streptococcus mutans to adhere to pits and fissures. In other words, e-liquid allows more cavity-causing bacteria to stick to a softer tooth and can lead to rampant decay.
The final danger associated with e-cigarettes has to do with nicotine. Although the percentage of nicotine is much lower (0.3%–1.8%) than traditional tobacco products, one electronic cartridge (200–400 puffs) can equal the smoking of two to three packs of regular cigarettes. The dangerous effects of nicotine on gum tissue are well known. The literature suggests that nicotine affects gingival blood flow as it is a vasoconstrictor. It also affects cytokine production, neutrophil function, and other immune cell function. (7) In addition, nicotine decreases connective tissue turnover. All of this results a much higher chance of developing gum disease and tooth loss.
The bottom line is vaping can be just as dangerous, if not more dangerous, when compared with smoking. The problem is that vaping is thought to be a safer alternative to traditional tobacco products, and companies are adding flavoring products to attract younger generations. According to a 2013–2014 survey, 81% of current youth e-cigarette users cited the availability of appealing flavors as the primary reason for use. (8)
For example, one patient who had a history of drug abuse (figure 1) and quit started smoking cigarettes during rehabilitation. Trying to make a healthier lifestyle choice, the patient believed that vaping would be better for health reasons, especially after hearing the commercials promoting e-cigarette use. Unfortunately, due to the high use of vaping, symptoms of dry mouth led to continued development of smooth-surface caries and oral tissue destruction, even though the patient believed vaping was a healthier alternative. Within a year, cervical enamel demineralization and interproximal lesions were present on the mandibular anterior sextant, consistent with the primary point of contact of the e-liquid aerosol.
In another, more serious example, a young patient who had been using e-cigarettes for four years along with an intake of energy drinks having high sugar content experienced rampant decay with smooth-surface lesions and tooth loss (figure 2).
Figure 2: Effects of e-cigarettes
In summary, for those of us in the health-care professions, a tidal wave of oral health problems is heading our way.
1. Tsai J, Walton K, Coleman BN, et al. Reasons for electronic cigarette use among middle and high school students—National Youth Tobacco Survey, United States, 2016. MMWR Morb Mortal Wkly Rep. 2018;67(6):196-200. doi:10.15585/mmwr.mm6706a5.
2. Wang TW, Gentzke A, Sharapova S, Cullen KA, Ambrose BK, Jamal A. Tobacco product use among middle and high school students—United States, 2011–2017. MMWR Morb Mortal Wkly Rep. 2018;67(22):629-633. doi: 10.15585/mmwr.mm6722a3.
3. Cullen KA, Ambrose BK, Gentzke AS, Apelberg BJ, Jamal A, King BA. Notes from the field: use of electronic cigarettes and any tobacco product among middle and high school students—United States, 2011–2018. MMWR Morb Mortal Wkly Rep. 2018;67(45):1276-1277. doi:0.15585/mmwr.mm6745a5.
4. Ruddick JA. Toxicology, metabolism, and biochemistry of 1,2-propanediol. Toxicol Appl Pharmacol. 1972;21(1):102-111.
5. American Medical Association. AMA Department of Drugs. AMA Drug Evaluations. 3rd ed. Littleton, MA: PSG Publishing Co., Inc.; 1977:656.
6. Kim SA, Smith S, Beauchamp C, et al. Cariogenic potential of sweet flavors in electronic-cigarette liquids. PLoS One. 2018;13(9):e0203717. doi: 10.1371/journal.pone.0203717.
7. Malhotra R, Kapoor A, Grover V, Kaushal S. Nicotine and periodontal tissues. J Indian Soc Periodontol. 2010;14(1):72-79. doi:10.4103/0972-124X.65442.
8. Villanti AC, Johnson AL, Ambrose BK, et al. Flavored tobacco product use in youth and adults: findings from the first wave of the PATH Study (2013-2014). Am J Prev Med. 2017;53(2):139-151. doi:10.1016/j.amepre.2017.01.026.
Editor's note: This article first appeared in the Perio-Implant Adviory e-newsletter. To subscribe, visit this page.
Scott Froum, DDS, a graduate of the State University of New York, Stony Brook School of Dental Medicine, is a periodontist in private practice at 1110 2nd Avenue, Suite 305, New York City, New York. He is the editorial director of Perio-Implant Advisory and serves on the editorial advisory board of Dental Economics. Dr. Froum, a diplomate of the American Board of Periodontology, is a clinical associate professor at SUNY Stony Brook School of Dental Medicine in the Department of Periodontology. He serves on the board of editorial consultants for the Academy of Osseointegration's Academy News. Contact him through his website at drscottfroum.com or (212) 751-8530.
Alisa Neymark, DDS, graduated with a Bachelor of Arts in anthropology and biology from Amherst College, and then pursued her dental degree at Stony Brook School of Dental Medicine. Upon completion of a two-year residency at Long Island Jewish Medical Center, she has been in private practice both on Long Island and in Brooklyn. Dr. Neymark practices with an emphasis on cosmetic dentistry and restoring implants.