These can often be avoided with implants in which the adjacent teeth are left untouched. On some occasions a dental bridge is still the best way to restore a gap. Sometimes an implant will not be a possibilty. However, Dickon will always discuss all of the options and give you his recommendations. In this way you will have all the information you need to make a wise decision.
A bridge will often be a cheaper option to an implant. However, in terms of damage to other teeth and the effect that this may have on these teeth, it may be more expensive in the long run.
In some cases a false tooth can be bonded to the adjacent tooth with very little damage to the adjacent tooth (Maryland bridge or adhesive bridge). This is the type of bridge that is pictured. These can be extremely effective and a cheaper alternative to an implant. If a Maryland bridge is possible, then this option would always be preferable to a regular bridge due to the reduced damage involved.