Dental bridges replace natural teeth. Without them, you may lose your ability to chew food. This may cause digestive problems. Therefore, they are needed until you decide to replace them with a different type of restoration.

Bridges are permanent. They are likely to last 10 yrs. Consider implants as an option.

Hi, I am not sure if i completely understand your question. However, dental bridges are commonly used to fill in for missing tooth space by preparing the adjacent teeth for crowns and the missing area receives a crown (bridged by the adjacent teeth). If they are maintained well they last for quite a while.

Fixed bridge work comes into the specialty of prosthodontics and is meant to be permanent because it is placed permanently with cement and is meant to last a lifetime

A dental bridge will replace a lost tooth, and you will need to have that tooth replaced for your lifetime.

A dental bridge is used to replace one or more missing teeth. One reason to replace missing teeth would be for appearance reasons.In this case you would need the bridge as long as the appearance of the missing teeth is a concern to you. Another reason to replace missing teeth is for chewing food. You would need the bridge as long as this in a concern.
A third reason would be to prevent movement of teeth near the missing teeth, or the teeth biting against the missing teeth.These teeth can move and cause problems which can lead to loss to one or more of these other teeth.You will need your dental bridge as long as you want to preserve these other teeth.

Fixed bridges are usually a lifetime commitment in order to preserve your bite.

They usually last at least 10 years. You could use them the rest of your life