Objectives: The aim of this study was to evaluate histologically the effect of natural anorganic bovine-derived hydroxyapatite matrix (ABM) coupled with a synthetic cell-binding peptide on the healing of critical size calvarial defects in rats.
Material and methods: Sixteen 4-month-old rats were used in the study. A 5 mm trephine defect was created in each parietal bone of every animal. One defect was left untreated (control) while the contralateral defect was treated with a natural ABM coupled with a synthetic cell-binding peptide (test). At 60 and 120 days post-operatively, groups of eight animals were sacrificed and 7-10-microm-thick decalcified sections were produced from both test and control sides. Three sections, 100 mum apart, representing the central area of each defect were selected for the histometric analysis.
Results: Histological analysis showed limited bone formation in both control and test defects at both observation periods. The control defects healed with fibrous connective tissue occupying the midportion of the defect and minimal new bone formation at the periphery. In the test defects, the major part of the defect was occupied by graft particles embedded in connective tissue. After 60 days of healing the residual defects accounted up to 94.6% of the original defect dimensions in the control specimens and 90.6% in the test specimens. The differences between test and control defects were not statistically significant (P=0.06). After 120 days of healing, the residual defects accounted up 89.9% of the original defect dimensions in the control specimens and 85% in the test specimens. The difference was not statistically significant (P=0.33).
Conclusion: The ABM coupled with a synthetic cell-binding peptide failed to substantially promote new bone formation in rat calvarial defects.