The appearance of night grinding in children at the age of 5.5 years is most likely due to the fact that for children at this stage, permanent teeth have gradually erupted and are about to enter the process of replacing permanent and milk teeth. Due to the continuous eruption of permanent teeth, there will be early contact of individual tooth cusps of milk teeth in the mouth. In this case, the temporomandibular joint and chewing muscles of children are very sensitive, which will lead to the enhancement of the parafunctional movement of the temporomandibular joint and chewing muscles, thus causing the occurrence of night grinding in children. If night grinding is caused by this condition, it usually does not require special agent treatment and will disappear when the permanent and milk teeth are replaced and the permanent teeth establish a uniform and stable occlusal contact. If children have night grinding, it may also be caused by not brushing and rinsing their teeth in time before going to bed. Due to the presence of many food residues on the tooth surface, it will stimulate the taste buds and taste nerve, which will lead to night grinding. If children eat greasy, indigestible food before bedtime, resulting in abdominal pain and bloating during sleep, it will also cause night grinding.