Large teeth are clinically referred to as molars, and they are present during the period of milk teeth, as well as during the period of permanent teeth. Usually the milk molar undergoes a tooth replacement, which is followed by the growth of permanent molars, which will not be replaced again. As the body continues to grow, it causes the jaws to grow and widen, and tooth replacement occurs in order to accommodate and strengthen the function of chewing. Generally, the milk teeth are lost first, and the milk molar teeth are usually lost later. Therefore, it may happen that the permanent molar teeth are pushed outward while the milk molar teeth have not yet been lost. However, the loss and replacement of milk teeth usually starts at the age of 5-6 years old and is completed around the age of 14 years old. The replacement permanent molars are harder than the milk molars, and the jawbone is almost fully developed by the time the replacement is completed, so there will be no more tooth replacement. Due to the fact that the molar teeth are in the inner part of the mouth and most children do not like to brush their teeth, it is easy for them to hide dirt in the grooves of the teeth and bacteria multiply, thus causing caries in the molar teeth. Therefore, it is recommended to pay attention to the oral hygiene of children, rinse the mouth in time after meals, and clean up the food debris in the mouth in time to avoid causing caries in the molar teeth, which will lead to tooth pain. In addition, after the completion of the replacement of permanent molars, if you do not pay attention to oral hygiene will also easily lead to the occurrence of dental caries, and when the situation is serious, it will also cause tooth loss. At this time, you can choose to carry out fossa sealing, the use of sealants to fill the fossa area of the molar teeth, can effectively avoid the emergence of dental caries.