The “sixth age tooth” is the first permanent molar (commonly known as the first tooth) that grows in children. Each person has four teeth, one on the top and one on the bottom and one on the left. In general, these teeth erupt around the age of six, so they are commonly known as “sixth-age teeth”. According to the clinical data and literature, the rate of decay is the highest in the “sixth age teeth”, and the percentage of extraction and the incidence of dental diseases are higher than other teeth. In terms of function, this tooth is the most important molar, so we should pay special attention to the protection of “sixth age teeth”. As we know, human teeth are born in three stages: the “six-year-old teeth” go through the entire time of the mixed and the permanent teeth. They are used for the longest period of time in a person’s life. Depending on the position of the “sixth tooth” in the full dental row, it is responsible for important chewing functions. However, because it grows at the age of 6, children are not yet able to brush their teeth effectively and do not know the importance of maintaining oral hygiene, and this tooth grows behind the last molar, unlike some other permanent teeth that erupt below the milk teeth, resulting in many parents often mistaking it for a milk tooth, thinking that it will be replaced without paying attention. All of these reasons make this tooth the most susceptible to disease, and when it gets sick, it often goes to the hospital only when the pain is severe or affects chewing, and sometimes it even has to be extracted. Therefore, parents must pay attention to protect this tooth of their children, urge them to brush their teeth in the morning and evening, check their mouth regularly, and treat the decay as early as possible.