1, there are parasites in the intestine: roundworms are parasitic in the small intestine, not only plundering nutrients, but also stimulating the intestinal wall, secreting toxins and causing indigestion. The frequent vague pain in the stomach will cause insomnia, irritability and grinding of teeth at night. In addition, pinworms can also cause teeth grinding. The pinworm is usually parasitic in the human colon, after going to sleep, the pinworm will quietly crawl to the anal opening to lay eggs, causing anal itching, so that the baby sleep unsteadily, teeth grinding. 2, dinner eaten too much, or before going to bed to add meals: this not only affects nutrient absorption, but also increases the burden on the gastrointestinal tract. The reason is that when you go to sleep, the gastrointestinal tract still accumulates a lot of undigested food, the entire digestive system will have to “work overnight”, continuous work, even the chewing muscle is mobilized, involuntary contraction, causing teeth grinding. 3, lack of vitamin D: due to disorders in the body calcium, phosphorus metabolism, will cause bone decalcification, muscle pain and Plant nerve disorders, often sweating, night terrors, restlessness and night grinding. 4, mental tension or excitement, excessive stress or emotional excitement will also appear night grinding symptoms. 5, dental problems: teeth misalignment chewing muscle force too much or long-term chewing with one side of the teeth, as well as the teeth bite relationship is not good, the occurrence of temporomandibular joint dysfunction, will also cause night grinding. Moreover, the teeth are not aligned baby, chewing muscle position is often abnormal, night sleep, chewing muscle often unconsciously contraction, causing teeth grinding. 6, bad sleep position: If the head is often tilted to one side when sleeping, will cause the chewing muscle is not coordinated, so that the side under pressure chewing muscle occurs abnormal contraction, and thus the teeth grinding. Sleeping with your head covered at night, due to excessive accumulation of carbon dioxide and insufficient oxygen supply, will also cause teeth grinding.