Methods: The behavioral aspects that were assessed included sucrose-induced biofilm formation, saliva-induced biofilm formation, metabolic activity, growth kinetics and growth kinetics with H2O2 (0.5 and 16.3 mM). The nicotine concentrations investigated in this study ranged between 0.00-32.00 mg/ml.
Results: It was found that biofilm formation in sucrose or saliva medium was significantly better (p<0.05) anaerobically (highest at 8 and 2 mg/ml, respectively) while the presence of oxygen enhanced the metabolic activity of UA159 in a nicotine-dependent concentration manner up to 16 mg/ml. Growth kinetics indicated slower growth of S. mutans aerobically with a maximum absorbance at 0.25 mg/ml of nicotine concentration. With 0.5 mM H2O2 the maximum absorbance was noticed in the total absence of nicotine, but no growth was noticed at 16.3 mM.
Conclusions: The absence of oxygen leads the S. mutans to behave differently with some enhanced abilities (biofilm) and some others suppressed (metabolic activity) at different concentrations of nicotine. This suggests that the different microaerophilic environments that S. mutans may grow in will stimulate various effects on the biofilm and growth characteristics of the bacterium.
Keywords: Bacterial, Caries, Infection, Tobacco and nicotine