Screw “Tent-Pole” Grafting Technique for Reconstruction of Large Vertical Alveolar Ridge Defects Using Human Mineralized Allograft for Implant Site Preparation

Abstract

The purpose of this study was to evaluate the effectiveness of using titanium screws in combination with particulate human mineralized allograft, in a "tenting" fashion, to augment large vertical alveolar ridge defects for implant placement. This prospective case study evaluated augmentation in consecutive patients with large (>7 mm) vertical alveolar ridge defects. Vertical ridge augmentation was performed using mineralized allograft placed around titanium screws to tent out the soft tissue matrix. The ridges were clinically evaluated 4 to 5 months after augmentation, and implants were placed at that time. Bone cores were harvested from all patients for histologic evaluations. Fifteen patients were treated in this prospective case study, and the mean vertical augmentation was 9.7 mm. Two patients had wound dehiscence resulting in loss of graft and requiring secondary grafting before implant placement. Five patients required 2-stage grafting procedures to achieve ideal ridge height before implant placement. Clinical evaluation of the grafted sites upon re-entry revealed uniform ridge anatomy. Histomorphometric analysis of 7 specimens revealed a mean bone content of 43%. A total of 32 implants were placed into grafted sites in 15 patients. All implants were integrated and successfully restored. Mean follow-up was 16.8 months after implant placement. Tenting of the periosteum and soft tissue matrix with titanium screws maintains space and minimizes resorption of mineralized particulate allograft. This technique offers predictable functional and esthetic reconstruction of large vertical defects without the use of autogenous bone and is capable of osseointegration. More studies are needed to evaluate the stability of vertically grafted bone after long-term loading.