Methods for generating and providing a full arch prosthesis from a pre-existing prosthesis are presented, starting from the pre-existing prosthesis. This prosthesis is removed from the mouth, scanned, and replaced within the mouth. An intermediate prosthesis is generated from the scan, and modified to match a final physiological target configuration of the patient's mouth. The intermediate prosthesis is used to generate a final virtual representation of the target configuration, from which final virtual representation the final working prosthesis is fabricated. The intermediate prosthesis is mounted in the patient's mouth in sections, for desirable repositioning, sections then being bonded together. Copings can be digitally subtracted to enable press fit new copings to be installed. Alternatively, the intermediate prosthesis can include integrated false copings. The intermediate prosthesis is scanned to generate a final digital model or virtual representation of the desired final prosthesis. The final working prosthesis may then be fabricated using the final virtual representation.