If a six-year-old child has a cavity, it is necessary to fill and treat it as early as possible if it is a permanent tooth that has already erupted; if it is a milk tooth, and the symptoms are obvious or the tooth will not be replaced in the short term, it can be filled and treated, observed, or extracted, and on the contrary, observation is often taken. 1. Permanent teeth: around the age of six, some children have already erupted the first molar and upper and lower incisors, for permanent tooth decay, it is recommended to fill and treat as early as possible to prevent the disease from progressing and aggravating, which may lead to pulpitis or apical periodontitis. 2. Milk teeth: For decayed milk teeth that will be lost within six months, if there are clinical symptoms such as pain, it is recommended that they be extracted directly; if there are no symptoms, they can be observed; for decayed teeth that cannot be lost and replaced within six months, it is recommended that they be filled to prevent the disease from worsening and affecting the eruption of permanent teeth. Children’s awareness of oral hygiene is poor, and parental guidance is one of the key factors; in addition, it is recommended to check the oral cavity regularly for early detection and treatment.