EFFECT OF FLUORIDATED DENTIFRICES ON STREPTOCOCCUS MUTANS AND LACTOBACILLUS ACIDOPHILUS – AN IN-VITRO STUDY

Introduction: Dentifrices have widely been used for the delivery of oral therapeutic ingredients such as fluorides. Tooth-cleaning with a dentifrice involves a number of factors which could influence efficacy, one of which could be amount of fluoride in the dentifrice. However, there are not many studies to demonstrate the effect of different concentrations of fluoride in dentifrices on caries causing organisms like Streptococcus mutans and Lactobacillus acidophilus. Aim: To compare the antimicrobial effectiveness of two dentifrices with different fluoride concentrations on Streptococcus mutans and Lactobacillus acidophilus. Method: Pure strains of Streptococcus mutans and Lactobacillus acidophilus were inoculated in MRS broth tubes at 37°C for 48 hours. An amount of 0.5g of 1000 ppm regular toothpaste and 5000 ppm fluoridated toothpaste was made to 2ml with sterile saline. The tubes were spun at 2500rpm for 10min. The upper layer was then taken and centrifuged again at 3500 rpm for 10min. The supernatant thus obtained was used to assessits effect on Streptococcus mutans and Lactobacillus acidophilus. In 40 ml of MRS broth, 1ml each of the inoculum was taken. Around 1.75ml of this inoculated suspension was dispensed into test tubes to which each of the prepared samples was added. The growth was observed after 48 hours. Result: The inhibitory effect of 5000 ppm fluoride dentifrice on Streptococcus mutans is significantly better than that of regular toothpaste while regular toothpaste on Lactobacillus acidophilus is significantly better than that of 5000 ppm fluoride toothpaste.