There may be several reasons for children to grind their teeth at the age of 6: 1, children do not brush and rinse their teeth carefully before going to bed, food residues are still stored on the surface of the teeth and tongue, food residues will stimulate the taste buds and taste nerve, resulting in the symptoms of night grinding at bedtime. 2, children at the age of 6 will have the replacement of milk teeth and permanent teeth, individual milk teeth will have early contact of the cusps, early contact of the cusps will cause temporomandibular 3, improper feeding methods, feeding greasy, indigestible food, or children with their own digestive malfunction, resulting in symptoms such as accumulation of food, indigestion, abdominal pain and bloating, can also cause children to grind their teeth.