The role of cortical perforations in allogeneic block grafting for lateral augmentation in maxilla: A randomized clinical trial.

Background: The need of decortication on the recipient site remains unclear for bone regeneration. To our knowledge, there are no human clinical trials that studied the influence of decortication on cancellous allogeneic block grafting.

Purpose: The aim of the present study is to evaluate the influence of perforating the cortex of the recipient site on cancellous allogeneic block graft integration and revascularization in the maxilla.

Material And Methods: Twenty-six patients referred for lateral bone augmentation were included in this clinical trial. Patients received freeze-dried bone allograft cancellous blocks obtained from the iliac crest; cortical perforations of the recipient bed were performed in the test group while in the control group it was left intact. After a 4-month healing period another surgery was performed to place dental implants, and a bone biopsy was collected using a trephine. All samples underwent micro-CT scans, and were processed for histomorphometric and immunohistochemical analysis. Implant survival comparisons were made using a repeated measures analysis of variance (ANOVA) while all other variables were compared using the analysis of covariance (ANCOVA).

Results: One hundred and nineteen implants were placed into 110 augmented sites. One hundred percent implant survival rate was reported during 24 months follow-up period. No differences were reported in bleeding on probing at 1 (5.6 vs 9%) and 2 years (13.2 vs 12.1%), probing pocket depth at 1 (3.4 ± 0.95 vs 3.6 ± 1.12 mm) and 2 years (3.8 ± 1.02 vs 4.1 ± 1.46 mm), and marginal bone loss at 1 (0.2 ± 0.52 vs 0.3 ± 0.57 mm) and 2 years (0.6 ± 0.91 vs 0.5 ± 0.87 mm). No statistically significant differences were found in the micro-CT and histomorphometric analysis in terms of newly formed bone (25.7 ± 11.2% vs 22.3 ± 9.7%), soft tissue (33.0 ± 14.7% vs 36.5 ± 15.7%), remnant allograft (39.3 ± 20.4% vs 41.2 ± 22.7%), and bone mineralization (57.2 ± 10.6% vs 53.8 ± 8.7%). Perforating the cortex of the recipient site had no significant effect on angiogenesis as shown by immunohistochemical analysis of CD34 positive blood vessels (39.21 ± 10.53/mm vs 34.16 ± 12.67/mm ).

Conclusion: Cancellous allogeneic bone block grafts are a clinically acceptable alternative for horizontal bone augmentation. Cortical perforations of the recipient site in the maxilla did not improve angiogenesis nor bone formation within the block graft.