Calcium phosphate ceramics are being extensively used for orthopedic, periodontal, and dental applications. This Study aimed to assess the effect of a biphasic ceramic such as Ceraform (R) on the osteogenesis in a rat calvarial defect model. 20 Wistar rats were enrolled in the study. Two symmetrical, circular, and 5-mm-wide full thickness defects were created in the parietal bones of each animal. The left defect was left empty as a control and the right defect was filled with the particular implant material. Animals were divided into two groups, and 10 animals were sacrificed at month 3 and the rest were sacrificed at month 6. The calvarial specimens were harvested for histological examinations. Defect area samples were stained with hematoxylin-eosin and Masson Thrichrom. A semiquantitative method was used to quantify the bone regeneration. The defects were mostly filled with fibrous connective tissue (3-6 months) in the control site. A loose, fibrovascular tissue was observed at the side of ceraform implantation at month 3. By 6 month, a dense collagenous tissue was observed at the same area. Multinuclear giant cells (MNGC) were detected around the implant bed at month '3 and month 6. No necrosis, tumorigenesis, or infection was observed at the implantation site at any time. There was no statistically meaningful difference regarding bone regeneration between the two defects at each observation period (p > 0.05). This Study showed that Ceraform (R) is biocompatible. However, this study indicates that biphasic ceramic do not offer any advantage over hydroxyapatite ceramics. It was also revealed that it had no effects on bone regeneration and that it seemed to be a space maintainer. (c) 2006 Wiley Periodicals, Inc.