The Effect of Cigarette and Hookah Smoke on Oral Bacterial Growth, Streptococcus mutans and Streptococcus sanguis: An In vitro Study

Background: Streptococcus mutans and Streptococcus sanguis are two important bacteria of the oral microflora. S. mutans is the most important cause of dental caries and S. sanguis plays an important role in formation of microbial plaque. Objectives: The present study aimed to determine the effect of cigarettes and hookah on thebacterial growth of S. mutans and S. sanguis. Methods: The standard strains of S. mutans (PTCC = 1683) and S. sanguis (PTCC = 1449) were cultured on blood agar and incubated for 48 hours in different environments, including atmospheric air, carbon dioxide, three types of cigarette smoke (Winston, ultralight Winston, and Kent), and fruity tobacco. Then, the diameter of colonies was measured and data was compared using statistical tests, such as one-way ANOVA. Results: Bacterial growth was 80%, 100%, 61%, 48%, and 59% in carbon dioxide, Winston, Kent, Ultralight Winston, fruit tobacco, respectively, for S.mutans (P < 0.001) and 134%, 38%, 169%, 105%, and 61%, respectively, for S. sanguis, which were higher than ordinary air (P < 0.001), in addition, the growth of S. mutans was more than S. sanguis in the Winston group. Conclusions: These findings showed that the growth of S. sanguis was significantly greater than S. mutans in all groups, except in the Winston group.