A substructure is required for an implant-supported fixed complete denture that is sufficiently strong and supportive to function reliably. A novel prefabricated modular system that allows for the analog generation of a passively fitting, supportive, titanium framework for a 4-implant fixed complete denture is described. The process allows the delivery of an immediate, definitive prosthesis on the same or the next day. (J Prosthet Dent 2020;-:---) THE JOURNAL OF PROSTHETIC DENTISTRY