PubMed ID (PMID): 17694950Pages 267-275, Language: EnglishRebaudi, AlbertoThis paper introduces a new system for planning implant positions directly on the working cast, called the ray setting procedure. It allows clinicians to obtain, on a master cast, the correct implant positions through the correction of previously planned expected positions. The device used is the Ray Set, a machine that can be used to precisely define, on the plaster working cast of the mouth, hard and soft tissue anatomy and correlate it with an articulator and computed tomographic data from the patient. This cast is used to build an individual surgical stent that perfectly matches the teeth and soft tissues as well as a provisional or definitive implant-supported prosthesis for partially or completely edentulous patients. A clinical case is presented to explain the procedure. A definitive all-ceramic cemented and screw-retained prosthesis, fabricated from a rigid material and with passive fit, was created before implant surgery and was placed with an immediate occlusal load applied a few minutes after implant placement. The prosthesis was retained with both cement and screws so as to make removal easy for accurate finishing of the margins immediately before cementation. The prosthesis was built, before implant surgery, according to the PIP method (presurgical implant prosthesis). The ray setting procedure can be used for planning immediate or delayed loading of implants.