Analysis of pre- and postoperative casts is essential in evaluating the efficacy of hydroxylapatite implant procedures for denture support. Computergraphics have been used to quantitate the changes in anatomic contour of occlusal surfaces of teeth and in the diagnosis and treatment of patients with craniofacial malformations. They may prove to be a useful adjunct in the planning and execution of preprosthetic oral and maxillofacial surgery for ridge augmentation. Thus computergraphics may be useful in surveying pre- and postaugmentation casts and evaluating clinical outcomes. In addition, computergraphics may also be useful in evaluating the utility of various surgical techniques used to augment ridges. In this study, pre- and postsurgical maxillary and mandibular casts were made from tissue displacing, irreversible hydrocolloid impressions. A comparison of pre- and postsurgical ridge contours, surface areas and volumes were derived from computer digitized two-dimensional tracing of casts sectioned in the frontal plane. This was accomplished using a three-dimensional computergraphics program that reconstructed digitized two-dimensional images into a three-dimensional image which displayed ridge contours, surface areas and volumes. The application of computergraphic technology may also prove useful in quantitating and mapping time-dependent morphological changes in ridges supporting the prostheses. Thus this technique may be useful in monitoring resorption patterns in underlying bone as well as in the revision and compaction of implanted materials.