Figure 1: Surgical images. (a) Intraoperative view of rat calvaria. Two 5 mm diameter calvarial defects were created on each side of the sagittal suture (arrow heads). The defects were filled with a beta-tricalcium phosphate disc (B) or left untreated with exposed dura (D). (b) Schematic of a cross section of the calvarial defect. The dotted square in -TCP indicates the most-central area where histomorphometric analysis was conducted.