A bridge is a fixed way of replacing missing teeth. It can be resin retained or conventional.
Resin retained bridges can be bonded to a tooth without any removal of tooth substance. As they require no tooth preparation they are becoming increasingly popular.
Conventional bridges require preparation of the tooth similar to that for a crown. They can replace a missing tooth either from one tooth alone or from two teeth either side of the missing tooth or teeth. They are very robust but do require significant removal of tooth substance.
Your dentist will be able to advise you of the best option for your treatment.