Truth: Compared with the cleanliness of toilet water, dishcloth water and coins, what can a used toothbrush do except make people sick? If it is to make people stop using toothbrushes, it is really misleading. If it is to remind everyone to keep their toothbrushes clean and replace them in time, it is really well-intentioned.
The truth on the toothbrush
There are hundreds of kinds of microorganisms in our mouth. When brushing your teeth, some bacteria may indeed transfer to the toothbrush. When not in use, bacteria in the environment may also come to the toothbrush. How many bacteria there are on toothbrushes, different people and different storage environments, the difference is great. Some studies [1] reported that the total number of living microorganisms on toothbrushes was between 0 ~ 1 100 million, and some studies [2] reported that the number was between 1 10,000 ~ 1 100,000. It can be seen that the difference between different situations is great.
There is nothing wrong with saying that there are bacteria on the toothbrush. There are also manufacturers developing toothbrush disinfection and antibacterial toothbrush products. However, the current clinical evidence does not show that the microorganisms on the toothbrush will have a great impact on oral health and human health. Our bodies are exposed to potentially threatening microbial environments. Under normal circumstances, our bodies have mechanisms to resist these threats. So people are not bound to get sick as soon as they come into contact with pathogenic microorganisms.
However, the cleaner the toothbrush, the better. Rumor shredder investigators provided several suggestions from the American Dental Association:
1, don't share your toothbrush with others. * * * People who use toothbrushes will exchange body fluids and microorganisms, increasing the risk of cross-infection. This behavior should pay special attention to people with low immunity and people with disease infection.
2. After brushing your teeth, thoroughly clean the toothpaste and dirt on the toothbrush. Raise the toothbrush head as high as possible after use. Keeping dry helps to reduce bacteria. Separate multiple toothbrushes to avoid cross infection.
3. Avoid putting the toothbrush in a closed container. It is difficult to keep the toothbrush dry in a closed container. Compared with the dry environment, the humid environment is more conducive to the rapid propagation of microorganisms.
The above is aimed at the general situation. Reinfection caused by these pathogenic microorganisms will be a very serious problem for people with low immunity, such as patients taking immunosuppressants and receiving radiotherapy and chemotherapy. For this kind of people, we should pay special attention to the cleanliness of toothbrushes, use qualified toothbrush disinfection products, and change toothbrushes frequently.
What is "changing your toothbrush every three months"?
There is also a saying about toothbrushes that is often mentioned: "Change it every three months". The basis of this statement is that after a period of use, the bristles of the toothbrush will curl and break, so the cleaning ability of the old toothbrush will become worse, and the health and hygiene of teeth will not be well guaranteed. The time limit of three months is based on the damage of most people's toothbrushes.
This statement has some basis in the early days. 1986 An article published in the Journal of Clinical Periodontology studied whether the old toothbrush was ineffective in removing dental plaque. [1] A group of volunteers/kloc-0 did not change their toothbrushes for 0/0 weeks. Another group of volunteers changed their toothbrushes every two weeks. 10 weeks later, the researchers compared their gum condition and the number of dental plaque. The results showed that the number of dental plaque on the teeth of the first group of volunteers was significantly higher than that of the latter group of volunteers. There was no difference in gingival condition between the two groups. It seems that using an old toothbrush is really inferior in removing dental plaque. The experiment also shows why the difference between people is so big. Some people's toothbrushes are rotten after only two weeks of use; Yes, it looks good after 10 weeks.
However, with the deepening of the investigation, the rumor factory investigators found a surprising follow-up study. 1996 Another article published in Journal of Clinical Periodontology discussed this issue again. [2] This time, the researcher's experimental scheme is slightly different from the last one. They compared the dental plaque of the same subject using the same toothbrush at different stages. The experiment lasted for 9 weeks, and every 3 weeks was a stage. With the increase of toothbrush wear, the number of dental plaque decreases. Similarly, for different people, the wear of toothbrushes is different after the same time. Even if volunteers were divided into "severe" and "mild" groups according to the degree of toothbrush wear, there was no significant difference in the ability to remove dental plaque between the groups. Various experiments have concluded that old toothbrushes are not inferior in effectively controlling dental plaque formation.
Similar conclusions were further verified in two studies in 2000 [3] and 2002 [4]. Although the experimental scheme is different, both studies investigated the effect of removing dental plaque between the toothbrush used for 3 months and the new toothbrush. The conclusion is also "no significant difference". However, a study published in the Journal of Dental Research in 2006 [6] took children (7 or 8 years old) as the survey object. The researchers also found that there was no statistical difference in plaque removal between the toothbrush used for 14 weeks and the new toothbrush.
The toothbrush used by the children in the experiment
Conclusion: There may be many microorganisms on the toothbrush, and the current clinical evidence does not think that this will pose a major threat to our health. However, keeping the toothbrush as clean as possible is a daily concern. As for the saying that you need to change your toothbrush every three months, it seems more important to develop better brushing habits and brush your teeth in the right way.