Volume 7 • 2020 • Issue 7

Vaping May Increase Caries‑Causing Bacteria There is a lack of solid evidence on the effects of vaping on oral health, partly because the electronic cigarette is a relatively new technology. Dr. Mahmoud Rouabhia says that although it isn’t known if vaping contributes to dental caries, his team’s in vitro study demonstrates that it does increase the growth of Streptococcus mutans . S. mutans is the primary causal agent and the pathogenic species responsible for dental caries, specifically in the initiation and development stages. Dr. Mahmoud Rouabhia Professor of Oral Immunology, Oral Pathology and Biomaterials, Faculty of Dental Medicine, Laval University Objective: Evaluate the effect of vaping on the growth of S. mutans , the formation of biofilm, and the expression of certain virulence genes, as well as the interaction with human teeth. The vapour from e-cigarettes consists of aerosol droplets containing propylene glycol, glycerine, flavours, and often nicotine. This vapour is viscous and may adhere to teeth. “We surmised that bacteria can then more easily adhere to the teeth via saliva and start to proliferate and potentially degrade the teeth,” says Dr. Rouabhia. Methods: S. mutans cells were exposed (or not, in the case of the control) to different vapours twice a day for 15 minutes each exposure period. Vapours included:  ¾ e-vapour with nicotine  ¾ e-vapour without nicotine  ¾ traditional cigarette smoke The expression of glucosyltranferase, competence, and glucan‐ binding genes were evaluated after 24 hours. Biofilm formation was assessed after 1, 2 and 3 days. S. mutans adhesion and growth to vapour-exposed human teeth were assessed after 3-day exposures. Results: The presence of vapour promoted the growth of S. mutans . There was an increase in cell growth of the bacteria with all vapour types. The effects of nicotine-rich vapour was comparable to cigarette smoke. Biofilmmass increase ranged up to 47 ± 5 mg after six exposures to nicotine‐rich e‐vapour (compared to 8 ± 0.5 mg with e-vapour without nicotine). Bacteria exposed to e-vapour showed greater expression of virulent genes, including glucosyltranferase, competence, and glucan‐binding genes. S. mutans cells adhered better to e-vapour exposed teeth compared to control. How Dentists Can Help “Ask patients whether they are vaping and explain its dangers,” says Dr. Rouabhia. “Stress the importance of tooth brushing after vaping.” Watch Dr. Rouabhia discuss this study more on CDA Oasis: bit.ly/2HhMtDH Reference: 1. Rouabhia M, Semlali A. Electronic cigarette vapor increases Streptococcus mutans growth, adhesion, biofilm formation, and expression of the biofilm-associated genes. Oral Dis 2020 Jul 19 doi: 10.1111/odi.13564. I ssues and P eople 31 Issue 7 | 2020 |