Histologic Evaluation of Bone Healing Following Application of Anorganic Bovine Bone and β-tricalcium Phosphate in Rabbit Calvaria

Both anorganic bovine bone (ABB) and β-tricalcium phosphate (β-TCP) are used in clinical practice as bone substitute materials, but there is limited data comparing these two materials in standardized defects. The aim of this study was to histologically evaluate the effectiveness of ABB and β-TCP in the healing of experimentally induced bone defects. Eighteen bone defects were created on the calvaria of six rabbits. In each animal, one defect was left untreated and the other two were filled with ABB and β-TCP. After one month, histological sections were prepared. Type and vitality of newly formed bone, percentage of new bone formation and residual material, thickness of trabeculae, inflammation and foreign body reaction were assessed. The newly formed osseous tissue was vital in all defects and consisted of woven and lamellar bone. Mean percentages of new bone formation were 30.83±14.29%, 16.83±11.07% and 14.00±8.17% in β-TCP, ABB and control groups, respectively and the mean percentages of residual biomaterial were 24.17±14.01% and 36.50±8.43% in β-TCP and ABB groups, respectively. However, the differences were not statistically significant (all ps>0.05). Inflammatory infiltration was statistically higher in β-TCP compared to the control group (p=0.025), but the difference was not significant between β-TCP and ABB groups (p=0.083). Trabeculation thickness and foreign body reaction were not statistically different between β-TCP and ABB groups. β-TCP and ABB were not different with regard to the quantity and quality of newly formed osseous tissue. However, inflammatory infiltration was higher in sites filled with β-TCP.