Purpose: Implants placed in fresh extraction sites and healed sites were restored simultaneously by cross-arch provisional fixed prostheses. Clinical and radiographic parameters were recorded for up to 36 months. Materials and Methods: Treatment with a full-arch implant prosthesis, either screwretained or cemented, was assigned to 54 patients. A total of 676 implants were placed in either immediate extraction sites (n = 367) or in healed alveoli (n = 309), followed by placement of a one-piece provisional prosthesis. The definitive restoration was placed 3 to 6 months after implant placement. Clinical parameters were recorded and digital radiographs obtained at 6, 18, and 36 months. The chi-square test, t test, and analysis of variance with repeated measures were used for statistical analysis of the outcomes. Results: Osseointegration failed in 21 (3.1%) implants; 13 of these (62%) had been placed immediately after extraction. All occurred within 2 months of the surgical healing phase. Short (8-mm) and narrow (3.3-mm) implant configurations were significantly (P .05) associated with failure. At 6, 18, and 36 months, average crestal bone resorption was 0.18 mm, 0.55 mm, and 0.79 mm for implants placed in fresh extraction sites and 0.31 mm, 0.78 mm, and 1.1 mm for implants placed in healed alveoli, respectively. These differences were statistically significant (P .05 between sites at all examined periods). Crestal bone resorption also correlated to sites with simultaneous bone augmentation and implant placement. Conclusions: Implants placed and restored immediately in a cross-arch mode, whether in extraction sites or in healed alveoli, can be clinically successful and maintainable. Schlagwörter: extraction sites, follow-up, fresh sockets, immediate loading, implant prosthesis, implant success rate