Grinding teeth at night in a 5 year old baby may be related to excited nerves or the presence of parasites in the body. Night grinding of teeth in a 5-year-old baby may be the result of too much nerve excitement or tension, especially during the day when the child is tired from playing and the nervous system is in a state of excitement, and teeth grinding will occur at night. This is normal and does not require treatment. It can also be caused by parasites in the body. At night, the parasites in the intestines are more active, and children will appear to grind their teeth unconsciously, so you can go to the hospital. Teeth grinding in 5-year-old babies may also be caused by other reasons, parents are advised to take their babies to the doctor to identify the causes and carry out targeted treatment.