Antibacterial effectiveness of acetic acid disinfection in toothbrushes inoculated with Streptococcus mutans: an in vitro study

The aim of this study was to determine the antibacterial effectiveness of acetic acid, as disinfectant or cleaning agent for toothbrushes contaminated with Streptococcus mutans bacteria, in Franja Laboratory, a controlled environment. The study hypothesis stated that, the higher the concentration of acetic acid as a chemical agent in the disinfection of toothbrushes inoculated with Streptococcus mutans, the greater the antibacterial effectiveness. The sample used consisted of 120 toothbrushes, divided into 60 culture mediums (before and after treatment), classified into 4 groups of 15 brushes each. All 60 samples planted in the Petri dishes were submerged (before treatment); afterwards each of the samples were introduced into acetic acid in specific concentrations (5%, 10% and 15%) and were seeded again into Petri dishes (after treatment), then incubated at ± 37o C, anaerobically for 48 hours. As a result, 15% acetic acid agents showed the highest level of disinfection in toothbrushes (98.90%) within a 20 minutes time frame. Followed by 10% acetic acid with 95.0% effectiveness, followed by the 5% concentration acetic acid as the lowest degree of disinfection. Water was used as a control group and presented a very low effectiveness of disinfection leaving 80% of contamination. In conclusion, Streptococcus mutans was found to be sensitive in vitro to chemicals such as acetic acid in concentrations such as 5, 10 and 15%; showing greater sensitivity to the agent in 15% concentration.