Objective: The purpose of this study was to determine the association between caries related microorganisms in children’s saliva, such as Streptococcus mutans and lactobacilli, and their demographic factors. Methods: This study involved a sample of 135, both sexes with an age range between 3 and 10 years. Unstimulated saliva was obtained and diluted in normal saline. Saliva was then placed in selective media. Salivaris agar was used for mutans streptococci while Rogosa agar for lactobacilli. After incubation, Streptococcus mutans counting of CFU (colony forming units) with morphology characterization and numbers of CFU per milliliter of saliva for lactobacilli. Demographic factors information was collected using a questionnaire. Results: Both studied salivary microorganisms increased with age. Streptococcus mutans was higher in boys, and associated with breastfeeding, overweight, and not brushing their teeth. Lactobacilli were higher in girls, and associated with mothers who were government employee, mother occupation, children who during sleep were not nursed, and with normal weight. Conclusion: The present study found an association between salivary Streptococcus mutans and lactobacilli and various demographic variables in a group of children.
