Can teeth move more whilst eating or during sleep?

Teeth that move?: Teeth are not like steel posts in concrete ; can move slightly but should return to their normal position. They should not move substantially while eating or during sleep. Over long periods of time, generally months to years they can drift if other teeth are missing, have severe periodontal disease or post ortho without a retainer. Habits such as bruxism (day or night) increase chance of drifting.