Early bone resorption after vertical bone augmentation--a comparison of calvarial and iliac grafts.

OBJECTIVE AND AIM: Severe cases of bone atrophy in the maxilla or mandible are often reconstructed using bone from extraoral donor sides. Most commonly, grafts from the iliac crest are used for augmentation, however, frequently associated with bone resorption as possible late complication. Calvarial bone grafts, often reported to show less resorption, are an alternative. The aim of this study was to compare the bone stability of vertical bone grafts from the iliac crest and the calvarium. PATIENTS AND METHODS: Twenty-three patients receiving vertical onlay bone grafts were included in this retrospective cohort study. In nine patients alveolar ridge defects were treated with bone from the iliac crest. Fourteen patients were reconstructed using calvarial bone grafts. To quantify bone resorption, the data of digital panographs were evaluated. Radiographs were taken prior to bone grafting, after augmentation surgery, 6 months after bone healing, prior to implant surgery, after implant surgery and at yearly intervals thereafter. RESULTS: Postoperative complications at the recipient site occurred equally in both groups. The complication rate was 35.7% for the calvarial group and 33.3% in the iliac crest group. No donor-site complications were reported in either group. After bone augmentation procedure, a mean vertical bone gain of 8.55 mm (SD 5.96) was measured. Bone grafts from the iliac crest showed a significantly higher bone loss of 24.16% (SD 8.47) than grafts from the calvarium (8.44%, SD 3.64) at the time of implant placement (P = 0.0003). Implant survival was similar in both groups. DISCUSSION: Both bone-grafting approaches are successful and reliable techniques, enabling implant placement in even highly atrophied alveolar ridges and with identical implant survival rates, although bone resorption differs. Within the limitations of this study bone from the calvarium shows higher bone stability in the early healing phase.