PURPOSE: This study aimed to characterize the effect of bovine hydroxyapatite particles (HA) on the early stages of bone repairing in a rat femur defect model. METHODS: A non-critical 2 mm diameter bone defect was made in both femurs of 25 male albino Wistar rats. The left femurs defects were filled with HA and the right femurs defects were just let to fill with blood. Five animals were sacrificed at the 1st, 3rd, 5th, 7th or 14th post-surgery day and bone tissue sections were stained with hematoxylin and eosin for comparison of inflammatory response by light microscopy. Histomorphometrical analysis of the newly formed bone was evaluated at the three last periods, using independent t-student test to compare both groups at each period (a=0.05). RESULTS: Histological analyses showed same standard of bone repair on first and third day; however, from the fifth post-surgery day there was a higher deposit of collagen fibers surrounding the hydroxyapatite particles and a greater thickness of the opposite side periosteum. There was no significant histomorphometrical difference between groups at all periods. CONCLUSION: It can be concluded that hydroxyapatite does not accelerate the early-stage of bone repairing, despite of induction of a higher deposit of collagen fibers.
Bone regeneration; biocompatible materials; hydroxyapatite
