When a child reaches 6 years of age, the tooth that erupts at the end of the dental row, i.e. behind the second molar, is the first permanent molar, and the first permanent molar begins to form around 3-4 months of embryonic life, starts to calcify at birth, the crown calcification is completed around 2-3 years of age, and erupts in the oral cavity at 6-7 years of age, one on each side, so it is customarily called “sixth age” because it erupts around 6 years of age. Because it erupts around the age of 6, it is customarily called “sixth age tooth”. It is the earliest permanent tooth to erupt, and it will be with you for the rest of your life, it plays a very important role in the mouth. The sixth tooth is the strongest of the permanent teeth. It has the largest crown, the most cusps, the widest chewing area, and bears more biting force and chewing function than other permanent teeth. It is particularly strong because of the large angle of divergence of its roots. The sixth-aged teeth are located in the middle of the entire dental arch and become the main pillar of the dental arch, which is important for maintaining the normal alignment of the upper and lower jaw teeth, maintaining the correct occlusal relationship and ensuring the normal development of the jaw and face. Because there is no loss of milk teeth when the sixth old tooth erupts, it is easy for parents to ignore the decay of the milk teeth to be replaced, which can cause the loss or extraction to become permanent missing teeth, and its early loss will not only greatly reduce the chewing function of children and cause malnutrition, but also affect the development of jaw bone and cause the inclination of neighboring teeth and the elongation of jaw teeth to cause the disorder of bite relationship, which has a very negative impact on the physical and mental health of children. It has a negative impact on the physical and mental health of children. Because the first permanent molar eruption is the earliest, the mineralization degree is poor, and the sulcus of the joint surface is deep, it is easier to get caries, and the caries progresses quickly, when the sixth age teeth erupt and the caries has not yet occurred, we can take preventive measures in hospital, and the common method is sulcus closure method. It is very necessary to maintain good oral hygiene and regular oral examination. Teach your child the correct way to brush teeth, once in the morning and once in the evening. When brushing, focus on brushing the lifting and cheek surfaces of the six-year-old teeth. Take your child for oral examination once every six months, some caries can only be found with the help of oral apparatus, timely filling and early treatment can help the health of teeth. The special significance of the sixth age teeth for children is manifested in three aspects: firstly, it is the earliest permanent tooth to erupt, which will accompany us for a lifetime with its superb chewing function and biting force and play its chewing function; secondly, the sixth age teeth have a positioning role for the eruption and arrangement of other permanent teeth of children; finally, it has an important influence on whether children’s teeth can bite together normally and the normal development of upper and lower jaws and face.