Effect of chlorhexidine-sodium fluoride gel applied by tray or by toothbrush on salivary mutans streptococci.

A chlorhexidine (1%)-sodium fluoride (0.2%) gel applied using a dental tray six times during two consecutive days significantly decreased salivary levels of mutans streptococci but had only a slight effect on salivary levels of lactobacilli. The same gel used as a dentifrice for one week (twice a day) also significantly reduced salivary levels of mutans streptococci. However, this treatment was somewhat less effective than that using trays, on the basis of the ratio of mutans streptococci to total aerobes. With both treatments baseline salivary levels of mutans streptococci were re-attained after 70 days. One day after the gel treatment, mutans streptococci were unable to adhere to plastic strips (Dentocult SM Strip mutans) but detectable growth was found on mitis-salivarius-bacitracin agar. This suggests that not only are numbers of mutans streptococci reduced after chlorhexidine-sodium fluoride gel treatment but also mutans streptococci adherence.