Whether a 6-year-old child’s tooth decay needs to be filled depends on which tooth is decayed. If it is the upper and lower front incisors’ milk teeth that have caries, usually children around 6 years old have already entered the period of permanent teeth and milk teeth gradually replacement, most of the upper and lower front incisors have already loosened and will gradually fall off soon, once the cavity of these teeth appears, but the caries has not caused pain, this kind of caries can be suspended without treatment, because the teeth will fall off soon. If the cavities of the milk teeth of 6 years old children are the back teeth, parents should take the children to the doctor in time, because the back teeth of the milk teeth will gradually fall off until about 10 years old, during the period of 6-10 years old, it is easy to make the cavities develop into the pulpitis of the milk teeth, which will cause the children’s pain and the infection of the pulp nerve in a large area, so the back teeth of the milk teeth should be treated for the cavities.