To help prevent your teeth from decaying, fluoride has been found to help. It has been added to water in some areas where it does not occur naturally. It is also in many types of toothpaste and rinses. Your dentist can prescribe stronger doses, as needed. Many have the conception that fluoride is only for children. However, adults do get cavities. In fact, as we age, there is another phase of cavity prone years for older adults. They are very susceptible to decay along the gum line where recession has occurred and the roots of the teeth are exposed. Also, if you drink mostly bottled water, you may not be getting the benefit of fluoridated water.
For example, in a two days cycle if the first toothbrush is used on Monday morning, the second toothbrush will be use on Monday night, the third toothbrush will be use on Tuesday morning and the fourth toothbrush will be use on Tuesday night. Then on Wednesday morning the cycle begins again with the toothbrush that was used the previous Monday morning which is now dry ( free of bacteria ) and ready to be reuse again. A similar process will apply when six toothbrushes are use, except than an extra day is added to the cycle.
In order to know which was the most recently used toothbrush and which is the next toothbrush to be use, a cycle marker is establish to identify which toothbrush is dry and ready to be reuse.