PURPOSE: Split calvarial bone graft is preferred in the reconstruction of calvarial defects. However, it is not feasible for use in some challenging cases and in children. Particulate bone graft containing viable osteoblasts could be an attractive alternative. MATERIALS AND METHODS: A total of 32 female rats were randomly separated into 4 groups. Full-thickness bone graft from rat calvaria was harvested in diameters of 8 × 8 mm. In group 1, the periosteum and skin were closed without any bone graft; bone dust particles were placed in group 2; bone fragments were placed in group 3; and full-thickness cranial bone graft was placed in group 4. After 12 weeks, all rats were killed. Degrees of resorption, foreign body reaction, and bone spicule length were assessed histologically, and an immunohistochemical study was used to show bone graft viability. RESULTS: In graft viability, osteogenesis, and osteoblastic differentiation, groups 3 and 4 were similar and superior to groups 1 and 2. No osteoblastic activity and no viable bone dust were detected in groups 1 and 2. Resorption was observed in every preparate that contains bone tissue, and foreign body reaction was prominent in small bone groups, such as in group 2. CONCLUSIONS: In the full-thickness cranial bone graft group and the bone fragment group, the preservation of bone viability was obviously superior to the bone dust group and the periosteum-only group. In conclusion, bone dust behaved like the periosteum and could not create new bone, whereas bone particles behaved like the full-thickness cranial bone graft and were capable of preserving viability. © 2014 Mutaz B. Habal, MD.