The Case for Bone Graft Reconstruction Including Sinus Grafting and Distraction Osteogenesis for the Atrophic Edentulous Maxilla

The 2 basic criteria for restoration of the edentulous maxilla are adequate bone mass and orthoalveolar form. These goals can be achieved by augmentation of the available substrate using prescribed techniques such as vertical and lateral augmentation of the alveolus, sinus floor bone grafting, and jaw bone repositioning. 1-4 When the available substrate is too deficient for implant placement, 1 or more of these options can be used to improve load-bearing capacity for implants. The use of vertical alveolar grafting for augmentation without the placement of dental implants remains suspect as a viable long-term strategy for bone mass maintenance. 5,6 Optimal restoration of the edentulous alveolus suggests the concept of orthoalveolar form. Orthoalveolar form is defined as idealized alveolar bone positioned in Class I relation axially aligned with the opposing arch. When orthoalveolar form is achieved, implant prosthetic horizontal cantilever is minimized and crown/implant ratios are favorable. Restorations are short, “gum set,” and axially placed over implants. 7 Resorption of the atrophic maxilla often results in a disparity of the arches mediolaterally and anterior-posteriorly. The resorbed maxilla decreases in bone mass in all directions. The basal maxilla presents up and back in its cephalometric projection and is often in “cross-bite” in its alveolar position as it relates to the lower arch. This means that despite vertical and lateral grafting, the interarch position of the maxilla, as it relates to a dentate mandible, is still Class III. Therefore, orthoalveolar form is largely unachievable in the resorbed retrodisplaced maxilla with bone graft reconstruction alone. Distraction osteogenesis is required to finalize the jaw into a more favorable position. This subjects the patient to a second surgical procedure, which may not be warranted given the ability for prosthetics to make up for surgical inadequacy. 8,9