The purpose of the present study was to evaluate the histologic results of bone cavities that were surgically created in the calvaria of rabbit and filled with HA/β-TCP composite powders, which had been developed in Korea (Dentium, Korea).

Ten young adult rabbits were used. Four defects were surgically produced in calvaria of each rabbit. Each rabbit was anesthetized with Ketamine-HCl (5 mg/kg, Yuhan Cor. Korea) and Xylazine-HCl (1.5 ml/kg, Yuhan Cor. Korea)). An incision was made to the bony cranium and the periosteum was reflected. Using a trephine bur (external diameter: 8 mm, 3i, USA), 4 'through-and-through' bone defects were created with copious irrigation, and classified into 4 groups: control group: no graft materials, experimental group I: normal saline + graft materials: experimental group II: venous blood + graft materials: experimental group III: graft materials only. The defects were randomly filled with graft materials. The defects were closed with resorbable suture material. At the end of the surgical procedure, all animals received a single intramuscular injection of antibiotics Gentamicin (0.1 mg/kg, Dae Sung Microb. Korea). Rabbits were sacrificed with phentobarbital (100 mg/kg) intravenously at 1-, 2-, 4-, 6- and 8-week after. Specimens were treated with hydrochloric acid decalcifying solution (Fisher Scientific, Tustin, CA) and sectioned by bisecting the 8 mm diameter defects. The histologic specimens were prepared in the general method with H & E staining at 6 micrometer in thickness. The results were as follows;

1. New bone formation showed from after 2-week of surgery in defect area. As time lapsed, lots of new bone formation and mature bones showed.

2. Histologically, degree of new bone formation could not be discerned among the experimental groups. But, for experimental group II, lots of cells gathered around graft materials after 1-week of surgery, new bone formed slightly faster and than the others at 1-week after. For experimental group I, a few inflammatory finding showed around graft material at after 1-week and after 2-week of surgery.

3. No bone formation did show for control group.

Based on histologic results, the new HA/β-TCP composite powders appeared to act as a scaffolding material for regeneration of osseous defects.