For many years conventional bridges were seen as the ideal solution for filling spaces where teeth were missing. Teeth on either side of the gap are prepared (cut down) for crowns, impressions taken and subsequently the bridge cemented into place some two weeks later.
The advantages of bridges is that they are permanent and feel and look like natural teeth. Disadvantages are that the surrounding natural teeth need to be cut down which can cause a reaction from the tooth leading to possible abscess formation in the future. Bridges can also become loose and decay start around their edges. When this occurs you can be left with a gap that of 3 teeth as opposed to the original 1 tooth.
Another type of bridge is called an adhesive bridge, which are bridges that are held in place by a metal wing bonded to the back of a tooth adjacent to the gap.
They are usually quick to complete and often require very minimal amount of tooth cutting. However, they are unreliable as the wing holding the bridge in place can become loose and the bridge can fall off, which can prove quite inconvenient and unpredictable in the long term.