comparison of the effect of recaldent and xylitol on the amounts of salivary streptococcus mutans

background:dental caries is associated with oral pathogenes and streptococcus mutans (s. mutans)is one of the primary cariogenic organisms. the aim of this clinical study was to evaluate the effect of sugar free chewing gum containing casein phosphopeptide-amorphous calcium phosphate(cpp-acp) and xylitol on salivary streptococcus mutan.   m aterials and methods: 60 dental students, who volunteered after signing an informed consent, were randomly allocated to receive one of the following interventions: (a) chewing gum containing cpp-acp, (b) chewing gum containing xylitol. subjects within the experimental groups chewed gum for 20 minutes, three times a day after meals for 3 weeks. pre- and post-intervention unstimulated saliva samples were quantified for streptococcus mutans count.   r es ults: a statistically significant reduction (p<0.05) of salivary s. mutans was displayed in both groups a and b after the intervention. when results compared with baseline, and group a shows more statistically significant reduction of salivary s. mutans than group b. conclusion: in conclusion, daily chewing gum containing cpp-acp and xylitol reduce the level of salivary s. mutans in a significant way, but chewing gum containing cpp-acp can reduce the level of salivary s. mutans in a significant way than xylitol chewing gum.