Toothbrush is an indispensable oral hygiene tool in our daily life, but not everyone knows about the maintenance of toothbrush. Some people don't change their toothbrushes for years. Some people put their toothbrushes in a closed toothbrush box after brushing their teeth, and even two or three people use a toothbrush. These methods of using toothbrushes can not only clean the mouth, but also become the source of oral bacteria. The correct method of toothbrush maintenance is as follows: after brushing your teeth, wash it thoroughly with clear water, not only to wash off the toothpaste and food residue left on the toothbrush, but also to dry the water on the toothbrush as much as possible, put the toothbrush head up in a mouthwash cup and put it in a dry and ventilated place. Because wet toothbrushes are easy to breed bacteria. Some scholars have found that a toothbrush without diagnosis is a healthy person or a patient. After one month of use, a large number of bacteria proliferated on the toothbrush. An unclean toothbrush can not only cause gum inflammation, but also be the source of infection for many diseases. Most toothbrushes are made of nylon thread, which is easy to deform when heated, and cannot be cleaned with high-temperature water, let alone boiled and disinfected. Toothbrushes can't be used for a long time. Generally, they should be replaced once every quarter, or when the bristles are found to be curled and bifurcated, they should be replaced in time to avoid the bristles stabbing the gums. We should adhere to the principle of one toothbrush per person to avoid the cross-spread of infectious diseases.