Quickly assess the situation to determine the cause of the biting. Attend to the victim. Wash area with soap and water, apply cold compress if swollen, comfort child. Talk to the biter. Teeth are not for biting children.
Teeth are for eating food.
If it is an older child, you can ask her what a better solution might have been. Redirect the child to another area. This might mean feeding the child, putting her down for a nap, or involving her in another toy or activity. Stay with that child until she becomes involved in the new activity. Finish the interaction on a positive note.