A British professor of microbiology from the University of Leicester, Primrose Fryston, has settled the debate on the optimal time to change a toothbrush. The debate over when to replace a toothbrush periodically flares up on social media, with some saying it should be changed monthly, while others use it for several months. Fryston explained in an interview with the British newspaper Daily Mail: "Regarding the toothbrush, it should be changed every 3 months. But if you have an infection in your mouth or gums, you need to change the brush more frequently to avoid reinfecting yourself." According to the researcher, the mistake lies not in the timing of the brush replacement but in how it is stored and cleaned after each use. She explained that "food residues left after brushing can stimulate the growth of bacteria and fungi. The mouth contains more than 500 types of bacteria and fungi, some of which transfer to the toothbrush every time you brush your teeth, so cleaning the brush is essential." She emphasized that the toothbrush should be washed under hot running water for at least 30 seconds after each use to remove toothpaste, bacteria, or food debris that may get stuck during brushing. The microbiology professor added that the brush can be thoroughly cleaned by soaking it for 30 minutes in baking soda, hydrogen peroxide, or an antibacterial mouthwash, or by exposing it to hot steam from a kettle for one minute. She added: "As a microbiologist, I wash my toothbrush weekly with antibacterial hand soap to remove food debris and kill any remaining microbes." She continued: "I also make sure my toothbrush is not close to the toilet because the flush spray can contaminate it with bacteria."
