To restore oral function in patients with missing teeth, single-tooth implants are a well-documented treatment option. As the aesthetic factors have become an important clinical outcome variable for evaluating treatment success of implant-supported restorations, selection of restoration materials should be based on proper optical charachteristics in addition to biocompatibility and sufficient strength of the materials. Abutments and crowns based on zirconia are one of the most recent alternatives to metal abutments and metal-ceramic crowns. This presentation is about the results of comparative clinical and laboratory studies of zirconia-based and metal-based implant-supported single-tooth restorations.