If a 4-year-old child grinds his teeth in bed, it is mainly considered to be caused by the following reasons: First, caused by emotional tension. If the child is more active during the day, more fatigue, and emotional excitement, which will lead to sleep grinding teeth. Just need to give the child to adjust the habits of life and rest, so that the child is not too excited before going to bed, in a quiet state, sleep teeth grinding situation will be significantly improved. Second, due to gastrointestinal disorders caused by. In addition to grinding teeth in bed, often accompanied by abdominal pain, and stools or dry or thin intestinal disorders. You can supplement your child with probiotics, such as Pepcid, Mamie’s Love and so on, because these probiotics have the role of regulating flora disorders, which can improve the gastrointestinal tract dysfunction. Third, consider the structural problems of the teeth. If the teeth are not aligned, there will also be a situation of grinding teeth in bed, to go to the Department of Dentistry in a timely manner to rectify the dental treatment.