A dental bridge is a fixed or removable device that replaces missing or several missing teeth.
A dental bridge will use the teeth either side of the gap to anchor onto. It will only be possible if the teeth supporting the bridge are strong enough and if they have good bone support.
The teeth either side of the gap are prepared, crowns are placed over the prepared teeth and these are attached to the artificial tooth (also called a pontic).
You can find out more about dental bridges on Wikipedia.