“Sixth-aged teeth are the permanent molars with the earliest eruption time, which usually start to erupt at the age of six, and its occlusal surface is very large, bearing the most important chewing function. When parents find that their children’s sixth-age teeth are decayed, they often think that they are also milk teeth and will be replaced in the future, so even if they are a little decayed now, they can not be treated. In fact, once the sixth-age teeth grow out, they will not be replaced for life. If the caries is not treated timely, the early decayed sixth-age teeth will easily develop from surface to depth and more serious disease will appear. If the caries of sixth age teeth is serious or even missing prematurely, the chewing function of children may be reduced, and food is not easy to chew, so they do not like to eat meat, vegetables, fruits and other food that are not easy to chew, which affects the nutrition intake. Once the teeth are severely damaged and the bite is out of balance, the child may habitually chew with the opposite side of the teeth alone and the habit of chewing on the side for a long time may affect the symmetry of facial development. In addition, if there is an early loss of the sixth age teeth, or the height of the alveolar bone is not developed enough and deep overlap may occur, the neighboring teeth may move in the direction of the missing teeth, causing the teeth to be misaligned and the bite is confused. Therefore, it is important not to ignore the caries of the sixth age teeth. However, there are many changes in the teeth in the mouth of children during the period of tooth replacement, so parents may easily confuse the milk teeth and permanent teeth, so we suggest you to take your children to the hospital for oral health examination regularly (usually once every three to six months), and once the caries of the sixth age teeth is found, you should seek professional medical consultation in time. Of course, the most important thing to avoid the occurrence of dental caries is to do a good job of prevention, to urge children to develop a good habit of brushing teeth before bedtime and rinsing mouth after meals. In addition, sulcus closure is the most effective method to prevent sulcus caries of permanent molar. Vulval closure is to apply a layer of liquid resin substance on the tooth surface, especially in the sulcus of the tooth, without grinding the tooth tissue, so that it can penetrate into the sulcus on the tooth surface, and then solidify after light, and the surface solidifies to form a protective barrier covering the sulcus, just like putting on a protective coat for the tooth, thus blocking the way of pathogenic bacteria eroding the tooth, making the tooth free from bacterial erosion and achieving the prevention of sulcus caries. This prevents the occurrence of sulcus caries. This kind of preventive measure is more effective when done within 1~2 years after the sixth age teeth have just erupted.