It is normal for a 6 year old child to have big teeth. The big teeth, which are the first permanent molars in children, tend to erupt at the age of five to seven, so it is a normal condition for a six-year-old to have big teeth. Since they erupt around the age of six, they are also called six-year-old teeth. The six-year-old teeth have the largest crowns among the permanent teeth, wider occlusal surfaces, high and numerous cusps, and bifurcated and long roots, which can be buried in the alveolar sockets. The permanent molars bear the greatest masticatory force, so they play an important role in processes such as crunching and grinding solid foods. However, it is important to note that the six-age teeth are not replaced throughout their lives and are prone to accumulating food debris and forming plaque, which makes them difficult to clean when brushing and leads to dental caries. Therefore, it is necessary to brush the teeth carefully, and the fissures can be closed as soon as possible after eruption under the guidance of the doctor.