Replacement of single teeth
A single tooth is missing. Often healthy adjacent teeth had to be polished in order to attach a bridge. Nowadays only the missing tooth is replaced by an implant, the healthy teeth are not being touched.
The posterior teeth on one or both sides are missing, a removable prosthesis would be needed. Implants replace the missing teeth, everything is like it was before, a removable prosthesis is not needed anymore.
In this case even few implants can fix a prosthesis that’s not holding, in some cases even make a prosthesis unnecessary due to new fixed teeth.