Experimental computer-assisted alloplastic sandwich augmentation of the atrophic mandible

Purpose: This study evaluated the effectiveness of a technique that combined computer-aided surgery with alloplastic augmentation and implant-borne prosthodontic rehabilitation of the atrophic mandible. Materials and Methods: Computed tomographic CCT) data from an atrophic cadaver mandible were transferred to a computer-aided design (CAD) system that prepared an anterior sandwich osteotomy. The cranial segment was moved upward and backward to provide an ideal alveolar relationship, and the geometry of the intermediate space was used to design a titanium implant. Furthermore, a surgical template was derived for the osteotomies, and insertion of dental implants was planned to stabilize both the transposed bone and the intermediate implant on the bony base. An identical implant for augmentation was also fabricated from poly-D,L-lactide in a mold as a possible resorbable carrier for osteoinductive proteins. Results: The experimental surgery was successfully performed with maximum precision on the dried mandible. The fabrication of an implant made out of poly-D,L-lactide for the same purpose was also possible. Conclusions: This preliminary experiment showed that, it is possible to use CAD/computer-aided manufacturing (CAM) technology to prepare a prefabricated template and a corresponding titanium implant for mandibular augmentation with a high degree of exactness. Dental implants could be planned and integrated in this procedure as well. The fabrication of a mold using this method also provided the opportunity to give a complex shape to possible carriers of osteoinductive substances.