You've undoubtedly crossed a bridge at least once in your life, but you might not have thought much about its purpose at the time. A bridge is a functional way to close the gap between one point and another. A dental bridge serves much the same purpose in your mouth: it literally "bridges" the gap created by one or more missing teeth.
That's a good thing because missing teeth can cause surrounding teeth to shift, which may change your bite or make your jaw sore. Shifting teeth create new places for dental plaque to hide, increasing your chances of needing a tooth filling or gum disease treatment.
Dental bridges serve an aesthetic purpose, allowing you to show off your beautiful smile without shame or fear that your missing tooth is what people will remember. They help your wallet, too, because dental bridges cost less than other methods of tooth replacement.