Vertical distraction of the severely resorbed mandible. The Groningen distraction device.

In this paper, both the surgical procedure and the clinical results of a novel distraction device to augment a severely resorbed anterior edentulous mandible are described. The distraction device is non-voluminous, and consists of two distraction screws and one guide screw. Two months after the last day of distraction, both distraction screws are replaced by endosseous implants and the guide screw is removed. Three months after implantation, the prosthetic treatment can be started. So far three patients have been treated. In all patients, the severely resorbed mandible (mandibular height in the canine region: 5, 6 and 7 mm, respectively) could be sufficiently enlarged to enable reliable insertion of endosseous implants with a length of at least 12 mm. No complications occurred. Biopsies taken from the distraction site revealed formation of lamellar bone parallel to the distraction vector. From this preliminary study it is concluded that the Groningen vertical distraction device has the potential for reliable augmentation of the anterior segment of a severely resorbed edentulous mandible to enable insertion of endosseous implants with adequate length and primary stability.