When children sleep at night, they clench their teeth involuntarily, which is known as “teeth grinding”. So what causes teeth grinding? 1, intestinal parasites The most common are pinworms and roundworms. The most common are pinworms and roundworms. After the child goes to sleep, the worms are active in the intestines and secrete a variety of toxins, and if the toxins stimulate the nerves, the nerves are excited, which can lead to teeth grinding. This condition is often accompanied by periumbilical pain, indigestion, sleep disturbance and other symptoms. Cao Hong, Pediatrics, Affiliated Hospital of Shandong University of Traditional Chinese Medicine 2, digestive dysfunction Dinner or bedtime meal, so that the digestive system is overburdened, food stimulation of the gastrointestinal tract, the nerves conduct these stimuli to the brain, so that the management of digestive function of the brain cells excited by the reflex effect of the chewing muscles with the movement of the teeth. 3.Nutritional imbalance Children have poor dietary habits, resulting in a lack of calcium, phosphorus and other vitamins and trace elements in the body, resulting in involuntary contraction of the facial chewing muscles at night, so that the teeth grinding back and forth. 4, mental factors during the day, too nervous, excited, tired or frightened and play too much before bedtime, can make the cerebral cortex in a state of excitement, triggering the movement of masticatory muscles and thus irregular spasm or contraction, resulting in night grinding. 5.Occlusal disorder Occlusal disorder breaks the coordination of masticatory organs, so the organism removes the occlusal disorder by increasing the grinding of teeth. 6, other factors such as dental caries, chronic periodontitis, psychomotor epilepsy, dreaming and eating can cause night grinding. Night grinding has many harmful effects, can cause damage to the teeth, periodontal tissues, chewing muscles and jaw joints, but also affects the quality of sleep, parents should take their children to the hospital to check the cause of teeth grinding.