The Intermittent Effect of Nicotine on Streptococcus mutans Biofilm Formation

Oral health is a key benefactor in keeping the body healthy and maintaining overall well-being. The purpose of this study was to determine the intermittent effect nicotine has on S. mutans bacterial growth and biofilm formation. S. mutans strain UA159 and nicotine dilutions, ranging from 0-32 mg/ml, made using Tryptic Soy Broth (TSB), and TSB supplemented with 1% sucrose (TSBS) were used in this study. The nicotine treated cells were incubated for 24 hour continuous and intermittent times, with intermittent concentrations being incubated with bacteria for three 10 minute time intervals, followed by incubation in TSBS. Biofilm measurement was performed using a spectrophotometer and crystal violet assay to quantify the results of both total absorbance and biofilm formation in the continuous and intermittent plates. The crystal violet staining assay concluded that the continuous treatment had significantly lower (p < 0.05) biofilm than the intermittent at 0, 0.5, and 32 mg nicotine/ml, but higher at 4, 8, 16 mg/ml, and total absorbance at 4 mg/mL, but lower than the intermittent at 32 mg/ml. The continuous application of nicotine was significantly greater than the intermittent, suggesting that intermittent application of nicotine to S. mutans biofilm may be more relevant to the average smoker.

Supervisor: Richard L. Gregory
Department: Biomedical Science and Comprehensive Care