Purpose Allogeneic cortical bone plates (CP) might be used for alveolar ridge augmentation as an alternative to autogenous grafts (AG) and bone substitutes (BS). We report about a multicenter case series and our experiences of more than 300 cases using CP and the shell technique for reconstruction of the alveolar process to illustrate surgical key steps, variations, and complication management. Methods Different types of alveolar ridge defects were augmented using the shell technique via CP. The space between the CP and the alveolar bone was filled with either autogenous or allogeneic granules (AUG, ALG) or a mixture of both. Implants were placed after 4–6 months. Microscopic and histological assessments were performed. In addition, space filling using AUG, ALG and bovine BS was discussed. Results Scanning electron microscopy demonstrated the compact cortical structure of CP and the porous structure of ALG allowing micro-vessel ingrowth and bone remodeling. Histological assessment demonstrated sufficient bone remodeling and graft resorption after 4–6 months. In total, 372 CP cases and 656 implants were included to data analysis. The mean follow-up period was about 3.5 years. Four implants failed, while all implant failures were caused by peri-implantitis. Next, 30 CP complications were seen, while in 26 CP complications implant placement was possible. CP rehydration, stable positioning by adjusting screws, smoothing of sharp edges, and a tension-free wound closure were identified as relevant success factors. Space filling using ALG and a mixture of AUG/ALG resulted in sufficient bone remodeling, graft resorption and stability of the augmented bone. Conclusions CP and the shell technique is appropriate for alveolar ridge augmentation with adequate bone remodeling and low complication rates. Allografts can prevent donor site morbidity and therefore may decrease discomfort for the patient.

Tooth loss generally leads to a corresponding loss of supporting bone structures, jeopardizing correct implant placement. Bone augmentation procedures facilitate reconstruction of the alveolar contours but lengthen treatment time by about 4 to 9 months. The aim of this case series report is to describe the short-term results of the combination of three-dimensional bone augmentation using the shell technique in conjunction with simultaneous implantation. A total of 10 patients who underwent autologous bone augmentation using the shell technique with simultaneous implantation were retrospectively examined. The shell technique is an augmentation procedure using thin cortical bone plates adapted to the buccal and oral walls of the defect to rebuild the contours of the alveolar ridge. The remaining spaces are filled with bone chips. Healing time before second stage surgery was 4 months. The vertical bone defect at the beginning (VD), the height of the vertical bone graft, resorption at the time of second-stage surgery (BR1) and 1 year after prosthetic rehabilitation (BR2), the total resorption between augmentation and 1 year (BRtot), and the vertical bone loss of the implant (VBL) were measured. VD was 3.1 mm. Values for BR1 and BR2 were 0.4 and 0.45 mm, respectively, resulting in a total bone loss of 0.85 mm of bone loss (BRtot). VBL was 0.45 mm 1 year after prosthetic rehabilitation. The simultaneous approach of vertical bone augmentation in the shell technique and implantation shows excellent results in bone reconstruction and stability up to 1 year after prosthetic reconstruction and can shorten treatment time by 4 to 9 months.

Objective: The shell technique is a well-established procedure for GBR with which extensive osseous defects can be predictably restored by using cortical bone struts harvested from various intraoral aspects. Recent publications have demonstrated comparable results for autologous and allogeneic bone grafts, whereas the evidence on allogeneic cortical struts remains limited. Clinical considerations: In this case series, we demonstrate the regeneration of five complex alveolar bone defects in four patients with subsequent insertion of fixed dental implants. In all cases, cortical struts made from human donor bone were applied in combination with allogeneic bone granules and collagen membranes. Conclusions: Similar to autologous cortical shells, the allogeneic struts functioned by creating an immobile container with which the osseous defects in all patients could be successfully restored, enabling placement of dental implants in accordance with the treatment plan. Even when the containers were solely filled with allogeneic granules, vascularized healthy tissue was present at re-entry, demonstrating the vast potential of these materials for applications in dentistry. Clinical significance: Especially when it comes to regeneration of complex alveolar bone defects, autologous bone grafts are often outlined as the only treatment modality. Here we show that innovative biomaterials like allogeneic bone grafts hold the potential to mimic the functions of autologous bone transplants and provide excellent clinical results without the requirement of a second surgical side for bone harvesting and no risk of donor-site morbidity.