Controlled study of the association of smoking with lactobacilli, mutans streptococci and yeasts in saliva.

The effect of smoking on salivary microbe levels was studied in 780 subjects by multivariate analysis, taking into account some confounding factors. Lactobacilli, mutans streptococci and yeasts were detected with Dentocult-LB, Dentocult-SM and Oricult-N tests. The explanatory variables considered were gender, presence of natural teeth, presence of removable denture, presence of decayed teeth, toothbrushing frequency, use of sugar in coffee or tea, consumption frequency of sugary products, secretion rate of stimulated and unstimulated saliva, buffering capacity of saliva, pH of saliva, oral hygiene and tobacco smoking habits. Smoking was strongly associated with higher lactobacilli counts and presence of yeasts, independently of oral status, hygiene or salivary factors. The relation between smoking and mutans streptococci was weaker. The overall associations of lactobacilli and yeasts with the study variables followed a very similar pattern.