Histomorphometric analysis of bone tissue repair in rabbits after insertion of titanium screws under different torque.

Purpose: To evaluate the inflammatory response of rabbit bone after insertion of titanium screws under different torque values.

Methods: Four holes were made in the back tibia of fifteen New Zealand male albino rabbits; three screws were placed in each animal and a control hole remained without a screw. The screws were inserted with 0, 5 or 10 N.cm of torque. The animals were assigned to five groups according to the day of sacrifice after surgery (2, 7, 14, 21 or 42 days). The inflammatory cells and the thickness of the bone tissue around the screws was count.

Results: The screws were associated with a larger number of inflammatory cells when compared to the control hole. There was no statistically significant difference when several comparisons were made among the groups with different torque intensity.

Conclusions: The histological changes were not statistically significant. There was a trend toward an increase in inflammatory cells found in local bone tissue surrounding the titanium screws installed with the highest torque. There was a tendency toward the formation of a lower thickness of tissue surrounding those bone screws that were inserted with higher torque.