Three-dimensional imaging analysis of CAD/CAM custom-milled versus prefabricated allogeneic block remodelling at 6 months and long-term follow-up of dental implants: A retrospective cohort study

Aim: This retrospective cohort study aimed to volumetrically investigate the bone stability rate of prefabricated allogeneic bone blocks (PBB) and computer-aided design (CAD)/computer-aided manufacturing (CAM) custom-milled allogeneic bone blocks (CCBB) for ridge augmentation. Materials and Methods: Nineteen patients were treated with 20 allografts: 11 CCBB, 9 PBB; 10 in the maxilla and 10 in the mandible. Clinical treatment history and cone beam computed tomography scans before surgery (t(0)), directly after graft surgery (t(1)) and after 6 months of healing prior to implant insertion (t(2)) were evaluated using a three-dimensional evaluation software for absolute bone volume, stability as well as vertical and horizontal bone gain. Furthermore, the inserted implants were analysed for survival, marginal bone loss (MBL) and complications for a mean follow-up period of 43.75 (+/- 33.94) months. Results: A mean absolute volume of 2228.1 mm(3) (+/- 1205) was grafted at t(1). The bone stability rate was 87.6% (+/- 9.9) for CCBB and 83.0% (+/- 14.5) for PBB. The stability was higher in the maxilla (91.6%) than in the mandible (79.53%). Surgery time of PBB was longer than for CCBB (mean Delta = 52 min). The survival rate of the inserted implants was 100% with a mean MBL of 0.41 mm (+/- 0.37). Conclusion: The clinical performance of both allograft block designs was equally satisfactory for vertical and horizontal bone grafting prior to implant placement. Clinical Trial Registration: ClinicalTrials.gov: NCT06027710.