FIG 3.

S. mutans has a significantly higher growth rate than the commensal streptococcal species. Overnight cultures of S. sanguinis (SS), S. gordonii (SG), and S. mutans (SM) were diluted 1:10 in TSB (A) or e-cig aerosol that was nicotine free (B), nicotine containing (C), nicotine free with menthol (D), or nicotine containing with menthol (E). Optical density was measured every 5 min, and growth curves were analyzed. Slopes for linear regression are presented based on the derivative of the averaged log₂ transform. Data are representative of one biological (n = 3) replicate repeated at least twice. For each condition, the commensal’s growth rate was compared to that of S. mutans using one-way ANOVA (Dunnett’s correction). *, P < 0.05; **, P < 0.01; ****, P < 0.0001.