Sinus grafting has been a routine surgical procedure since the 1970s. Computer tomography (e.g., SIM/Plant) is available for planning and simulation, but it has not been used to control the success and the long-term results of the planned surgery. The aim of this work was to apply a prospective examination method to determine (a) the extent to which the success of sinus grafting can be followed through 2D (two-dimensional) and 3D (three-dimensional) CT (computer tomography) reconstruction, (b) when choosing this method is worthwhile, and (c) how to visualize incorporating and transforming various graft materials. Twelve patients received 21 sinus graftings, with immediate implantation. Four 2D and 3D CT reconstructions were performed: (1) preoperatively, (2) 1-2 weeks postoperatively, (3) before loading, and (4) 1 year after completing prosthodontic treatment. The sinus grafts were composed of a mixture of HTR Bioplant polymer and autograft, or from a mixture of Algipore (HA, hydroxyapatite) and autograft. In the bilateral cases, both sinus graft mixtures were used, one on each side. The posterior-anterior, the lateral, and the superior-inferior views provided the most useful information; the usefulness of serial images is very limited. Individual 2D and 3D CT reconstructions are proposed, however, in cases of extensive bone atrophy, if complications are expected, if complications arise during surgery, if healing is protracted, or if the documentation is important for other reasons. The long-term results of the two graft materials could be followed up extremely well. Both materials proved outstandingly suitable for sinus grafting.