Microcomputed and histologic evaluation of calvarial bone grafts: a pilot study in humans

Two evaluation techniques (histology and microcomputed tomography [micro-CT]) were synergistically applied to calvarial bone graft to verify whether additional bone information can be obtained for the assessment of bone grafts. Ten extensive bone defects in the anterior and posterior maxilla or mandible involving crestal bone were treated by grafted blocks and chips of autogenous calvarial bone. The grafts were fixed with lag screws and left to heal for 4 months. No complications were observed. At surgical reentry for implant placement, a cylindric bone biopsy of both graft and native bone was retrieved and analyzed with both micro-CT and standard histology. Two- and three-dimensional (2D, 3D) micro-CT analyses allowed bone connectivity indices to be evaluated. This is useful for estimating bone strength and observing bone structure. The integration of the grafted calvarial bone with the residual bone of the recipient site was considered satisfactory. Histologic analysis allowed observations to be made at a higher resolution. Calvarial bone grafts seem to have positive effects when used as grafting materials. The application of both histologic and micro-CT techniques allows a better evaluation of grafted bone by concurrently allowing 2D and 3D visual and morphometric analysis of bone vitality, structure, turnover, and strength.