El-Ezmerli, Nasreen F.Gregory, Richard L.2020-07-222020-07-222019-01-01El-Ezmerli, N. F., & Gregory, R. L. (2019). Effect of nicotine on biofilm formation of Streptococcus mutans isolates from smoking and non-smoking subjects. Journal of Oral Microbiology, 11(1), 1662275. https://doi.org/10.1080/20002297.2019.1662275https://hdl.handle.net/1805/23323Objectives: To investigate effects of nicotine on biofilm formation of Streptococcus mutans isolates from oral washes of smoker and non-smoker human subjects.Materials and methods: This study was conducted using 60 S. mutans isolates with three S. mutans isolates collected from oral washes of ten smoking subjects and ten from non-smoking subjects. Biofilm was formed by culturing each S. mutans strain (10 μl) in 190 μl of TSB supplemented with 1% sucrose (TSBS) containing 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0, and 32.0 mg/ml of nicotine for 24 h in 5% CO2 at 37°C in 96 well microtiter plates. The absorbance values of biofilm were measured at 490 nm in a microplate spectrophotometer.Results: There was a significant effect (p-value < 0.05) of nicotine concentrations and smoking on the growth of biofilm, planktonic cells, and total absorbance, for all strains of S. mutans. Isolates from smokers had significantly more biofilm at 0–16 mg/ml of nicotine compared to those from non-smokers (p-value < 0.0001).Conclusion: S. mutans smoker isolates are more affected by high nicotine concentrations than non-smoker isolates.Clinical Relevance: The use of nicotine products increases the growth of S. mutans and may place tobacco users at risk for dental decay.en-USAttribution 4.0 InternationalBiofilmNicotineStreptococcus mutansTooth decayArticle