TREATMENT PLANNING FOR SINUS LIFT AUGMENTATIONS THROUGH USE OF 3-DIMENSIONAL MILLED MODELS DERIVED FROM COMPUTED-TOMOGRAPHY SCANS - A REPORT OF 3 CASES

Objective. Three-dimensional models created by milling machines and st ereolithography on the basis of 3-dimensional computed tomography scan s have become essential in the diagnosis and therapy planning of oral and maxillofacial disorders. The purpose of this study, based on 3 cli nical cases, was to examine the advantages of using 3-dimensional comp uted tomography scans and 3-dimensional milling models of the maxillar y sinus before operative sinus elevation and of developing an operativ e layout with the aid of 3-dimensional models. Report Design. Three pa tients with atrophy of the maxillary alveolar ridge received computed tomography scans before operative sinus elevation with iliac bone tran splants and simultaneous dental implantation. These computed tomograph y data were used to create 3-dimensional graphic and plastic reconstru ctions of the maxillary sinuses. Results. The 3-dimensional milling mo dels enabled the development of an exact preoperative layout that took into consideration the exact shape of the iliac bone and the selectio n of dental screw implants. Furthermore, the models offered the possib ility of producing an acrylic device for precise implant insertion. Pr ecise planning resulted in goad success with implantation 2 years afte r surgery. Conclusion. Three-dimensional diagnosis and treatment layou t have become an acknowledged method of operative maxillary sinus floo r augmentation combined with simultaneous dental implantation in the u pper jaw in difficult cases of sinus lift operations. As far as transp lant shape and sinus anatomy are concerned, this has resulted in great er intraoperative precision. A 1-step procedure can thus be performed for augmentation and implantation through use of a well-adapted block transplant and dental screw implants in patients with extensive alveol ar ridge atrophy.