This in vitro study was undertaken to determine which toothpaste represses oral bacteria (Streptococcus mutans and Lactobacillus species) growth most effectively. The toothpaste samples used were nine-fluoride-containing toothpastes (A, B, C, D, F, G, H, I and J) and one non-fluoride containing toothpaste (E). Disc diffusion tests were performed to examine the mean inhibition zones for each toothpaste/bacteria sample using 0.5g/ml and 0.4g/ml concentrated toothpaste slurries. Toothpaste samples B and D showed the highest mean zone of inhibition on exposure to S. mutans and Lactobacillus sp. respectively while the least inhibition zone and no observable zones were exhibited by toothpaste sample I. The challenge test done to determine their behavioural profile at set time intervals of 0.5, 2, 5, 10 and 15 minutes revealed the dentifrices to be intensively bactericidal on Streptococcus mutans while a fluctuative antibacterial activity was obtained with respect to Lactobacillus species. The toothpastes were significantly different (P < 0.05) from each other showing that their effectiveness varies. These results show that the mere presence of any of the toothpastes is capable of repressing the growth of oral bacteria, which is also affected by the toothpaste’s components and the components’ concentration.

Inhibition, Oral Bacteria, Lactobacillus Species, Streptococcus Mutans, Toothpastes