Cancellous Bone Block Allografts for the Augmentation of the Anterior Atrophic Maxilla

Background: Pre-implant augmentative surgery is a prerequisite in many cases in the anterior maxilla to achieve a stable, long-term esthetic final result. Purpose: The aim of the present study was to evaluate the outcome of ridge augmentation with cancellous freeze-dried block bone allografts in the anterior atrophic maxilla followed by placement of dental implants. Materials and Methods: Thirty-one consecutive patients were included in the study. A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography (CT) served as inclusion criteria. Sixty-three implants were inserted after a healing period of 6 months. Nineteen of sixty-three implants were immediately restored. Bone measurements were taken prior to bone augmentation, during implant placement, and at second-stage surgery. Results: Forty-six cancellous allogeneic bone blocks were used. The mean follow-up was 34 +/- 16 months. Mean bone gain was 5 +/- 0.5 mm horizontally, and 2 +/- 0.5 mm vertically. Mean buccal bone resorption was 0.5 +/- 0.5 mm at implant placement, and 0.2 +/- 0.2 mm at second-stage surgery. Mean bone thickness buccal to the implant neck was 2.5 +/- 0.5 mm at implant placement, and 2.3 +/- 0.2 mm at second-stage surgery. There was no evidence of vertical bone loss between implant placement and second-stage surgery. Block and implant survival rates were 95.6 and 98%, respectively. All patients received a fixed implant-supported prosthesis. Conclusion: Cancellous block allografts appear to hold promise for grafting the anterior atrophic maxilla.