We have performed 3D CT examinations before and after 21 uni- and bilateral sinus elevations, immediately prior to loading of the implants and 1 year after the loading. Comparison of the results with those of panoramic and the customary CT examinations yielded the following useful information. Any possible difference between planning and performance may be controlled. The fate of biomaterial implanted in the maxillary sinus was followed. The 3D CT projections providing most information were established (from a superior position downwards; from lateral and posterior positions forwards). Possible errors can be discovered before the implant is loaded. The cases in which it is worthwhile to perform this costly examination were determined: surgical complications, documentation, extensive alveolar atrophy etc. The results of sinus elevation with different bone substitute materials can readily be compared (e.g. autogenous bone + HTR Bioplant on one side, and autogenous bone + Algipore on the other side).