A bridge spans a space where one or more teeth have been lost in the mouth. The teeth on either end of the span are crowned and a false tooth replaced the space in between. A bridge is fixed in the mouth and can not be removed.
An implant is an artificial tooth which is screwed into the bone and is very natural in appearance and function.
This is a plate made of plastic or metal which can be removed from the mouth (unlike a bridge or implants)