As with other techniques, vertical distraction osteogenesis (VDO) can also induce complications. The case of a patient with a residual alveolar ridge in the symphyseal area of 8 mm is presented. After performing VDO, the patient returned at 1-day postoperatively complaining of pain and dislocation of the distractor device, due to a fracture of the lower mandibular segment on the right side. After removal of the distractor device and application of osteosynthesis plates, the patient returned 2 weeks later due to a second fracture of the lower segment, yet on the left side. After removing the osteosynthesis material, stabilization of the mandible was achieved with an acrylic splint, which was fixated with peri-mandibular wiring. Finally, reconstruction was accomplished by lower border onlay grafting, limited to the symphyseal area, in preparation for implant insertion. Ultimately, after a healing period of 5 months, two endosseous implants were installed. The patient’s function has remained satisfactory for 3 years. Reinforcement of the extreme resorbed edentulous mandible after fracture healing by lower border bone augmentation can be a reliable method to allow implant installation in a second stage.
Edentulous patients with an extremely resorbed mandible (Cawood V or VI) often have reduced retention and instability of the lower dentures. Besides impaired masticatory function, the diminished vertical height of the alveolar process results in loss of vertical dimension of the face and poor facial aesthetics. Improvement of denture retention can be obtained by installation of endosseous implants. In extreme cases, jaw atrophy even impedes implant placement. To create more bone height, various augmentation techniques have been proposed using autologous bone as well as bone substitutes. Vertical distraction osteogenesis (VDO) can also be performed. However, VDO of fully or partially edentulous regions is prone to a high rate of complications, such as mandibular fracturing.
To deal with a fracture of an extremely edentulous mandible and at the same time allow implant placement at a second stage, application of a bone graft onto the lower body of the mandible that is restricted to the interforaminal mandibular region (i.e. submentally) is advocated.
A 65-year-old male required dental implants to improve the retention and stability of his dentures. Intra-orally, a diminished alveolar ridge was visible as a heightening of both the floor of the mouth and the buccal sulcus. A panoramic, lateral cephalometric radiograph and cone beam computed tomography (CBCT) were performed to determine the available residual bone volume of the mandible. The bone height in the symphyseal area was 8 mm ( Fig. 1 a ). It was decided to augment the mandible by VDO using an intra-osseous device (IOD) (Endo-Distraction Krenkel ® , Mondeal ® , Tuttlingen, Germany) prior to placement of the two endosseous implants.