Implant Survival in Maxillary and Mandibular Osseous Onlay Grafts and Native Bone: A 3-Year Clinical and Computerized Tomographic Follow-up

Purpose: This article discusses a 3-year retrospective survey of implant clinical survival and computerized tomographic analysis of bone remodeling in atrophic alveolar crests reconstructed via various autogenous bone grafting procedures and in similar regions of native bone. Materials and Methods: The retrospective chart review included consecutive edentulous patients with severe alveolar crest atrophy treated between 2000 and 2002 with onlay autogenous bone grafts in the mandible and anterior maxilla (as needed) and implant insertion. Implant recipients were followed for 3 years. Defective areas were reconstructed by bone graft harvested from the chin or iliac crest. Implants in reconstructed areas were divided into two groups according to graft source. Implants in corresponding native areas served as controls. Cumulative survival rate (CSR), survival rate, and confidence interval (CI) were calculated, and linear measurements of bone remodeling around implants were assessed on computerized tomographic scans. Results were compared for statistically significant differences by Wilcoxon signed-rank test with a significance level α = .05. Results: Forty patients were treated with 109 screw-type, root-form, rough-surfaced implants inserted in 48 onlay grafts; 88 implants were placed in native bone. The implant 3-year CSRs were 98.9% (CI 96.7% to 100%) in native bone and 99.1% (CI 97.3% to 100%) in onlay grafts, irrespective of bone source. Mean resorption in the maxilla was 4.6 ± 0.9 mm buccally and 3.8 ± 0.8 mm palatally in areas reconstructed with chin grafts, 3.4 ± 1.7 mm buccally and 2.6 ± 1.4 mm palatally in areas reconstructed with iliac crest grafts, and 3.2 ± 1.2 mm buccally and 2.1 ± 0.9 mm palatally in native areas. Conclusions: Similar implant CSRs were seen in native and grafted sites. Maximal implant CSR was observed in onlay grafts from the chin despite more marked linear bone remodeling in this group as compared to iliac crest grafts or native bone. Keywords: atrophic mandible, atrophic maxilla, autogenous bone graft, dental implants, onlay bone graft, osseointegration