In order to replace missing teeth with a dental bridge, generally, two stable, healthy, teeth must be factored into the equation to replace your missing tooth.

The Advantages:

Restores the function of your teeth like chewing and speaking properly.
Prevents your remaining teeth from shifting which causes a problem in your bite.
The bridges are permanently fixed thus preventing it from moving like dentures.

The disadvantages:

There is a reduction of the structures of natural healthy teeth to accommodate the appliance in place.
The restoration can collapse if the supporting teeth are not strong enough.
In the long run, they need to be eventually replaced.