There are two main types of bridges.
Conventional bridges involve preparing the teeth on either side of the gap as if you were
preparing it for a crown. The above picture shows three crowns fused together which are
then cemented in place over the prepared (abutment) teeth.
The advantages of a conventional bridge are that they are much more secure and can be
used anywhere in the mouth. The disadvantage is that they require a lot more tooth
preparation than Maryland bridges. Careful consideration needs to be taken when the
adjacent teeth are perfectly sound as preparing any tooth can lead to increased chance of
root canal therapy so ideally we would like to leave sound teeth alone as other alternatives
are available (such as implants)
Conventional bridges are made of the same materials as crowns.
A Maryland bridge involves minimal tooth preparation and can be used to replace front teeth. They have a metal wing which is bonded, out of site, to the back of the adjacent tooth.
The advantage of a Maryland bridge is that it doesn't require much tooth preparation. We are conserving as much of the natural tooth as possible.
The disadvantage of a Maryland bridge over a conventional bridge is that they are not as secure. We are relying only on the bond strength between the tooth and the metal wing. They are not suitable for back teeth which are subject to a lot of force during eating or suitable for teeth where there would be a lot of excessive forces on the bridge tooth.