Purpose: To evaluate a new method to treat the posterior atrophic edentulous maxilla: dental implants placed in the ulna and transplanted with their surrounding bone blocks as inlays into the sinus. Conventional sinus augmentation with particulated autogenous bone grafts served as a control procedure. Materials and Methods: Fifty-two implants were placed in the ulnas of 20 patients. After 6 weeks, bone blocks containing 1 to 3 implants were harvested and transplanted into the sinuses protruding 3 to 4 mm. Implants were left to heal for 6 weeks. Twenty patients with similar treatment indications treated with particulated bone grafts from the mental symphysis, tibia, or iliac crest acted as controls. Grafts were allowed to heal for 6 months in the control group. Fifty-two control-group implants were allowed to heal for 4 months. The main outcome measures were prosthetic and implant success. Stability of individual implants was assessed with Osstell and Periotest at baseline and after 6 and 12 months of loading. Independent sample chi-square tests, t tests, and paired t tests were used with a significance level of .05. Results: No patient dropped out or withdrew; no prosthesis or implant failed. No major surgical complications were occurred. There were no differences between the 2 groups at any time point in implant stability. Both modalities resulted in a significant increase of implant stability at 6 and 12 months. The mean change (SD) from baseline to 1 year in Periotest measurements was 1.44 (0.48) in the test and 1.29 (0.58) in the control (paired t tests; P .001). For the Osstell, these values were -5.88 (4.18) and -5.48 (3.93) for the test and control groups, respectively (paired t tests: P .001). Conclusions: Ulna implant block grafting represents an alternative to conventional sinus augmentation, particularly when vertical augmentation is desirable or large iliac crest grafts are needed. Schlagwörter: bone grafting, dental implants, sinus augmentation, ulna