Don't handle it by the delicate root and resist the temptation to clean it off with water. The root membrane is delicate and is needed intact to encourage re-attachment. If the tooth is clean, place it gently back in its socket immediately and apply slight pressure. If the tooth is dirty try and rinse it using milk and then place it back in its socket. Otherwise keep the tooth moist by placing it in a class of milk or tuck it into your cheek.

DO NOT USE WATER.

Make fast tracks to a dentist. If you can be there within 30 minutes, there's an 85% chance the tooth will survive.