The elevation of the floor of the maxillary sinus is becoming a routine surgical procedure to develop the site for dental implants. This delicate procedure is best performed with diagnostics of the highest magnitude. To this point, computer tomographic scans provide valuable information, especially when defining the location and extension of septae transversing the sinus. Additional useful information is provided by a replicate resin model that is constructed from a magneto-optical disk compatible with a personal computer. The image data is then converted to a DOS format. Bone structures of interest are thresholded in each slice based on single-pixel gray levels. Object profiles with linear interpolation and their elaboration generate the three-dimensional surface of the object. Finally, the physical resin model is fabricated.