Does sodium fluoride in bone cement affect implant fixation. Part II: evaluation of the effect of sodium fluoride additions to acrylic bone cement and the fixation of titanium implants in ovariectomized rabbits.

Bone integration of threaded implants made of cured polymethylmethacrylate containing sodium fluoride or commercially pure (c.p.) titanium were studied in normal and estrogen deficient New Zealand white rabbits. Nine had been ovariectomized through laparoscopy and nine served as controls. Four weeks after the ovariectomy two threaded implants made of cured bone cement with or without sodium fluoride addition were inserted in each tibia. One threaded commercially pure titanium implant was inserted in each patello-femoral joint flush to the cartilage. Six weeks after implant insertion measurement of the peak removal torque necessary to loosen the implants and light microscopical histomorphometrical investigations of tissue integration were performed. In the ovariectomized rabbits addition of sodium fluoride to the cement resulted in increased area of bone in the threads (p=0.04), but no corresponding effect could be noted in the controls. The removal torque was lower in the ovariectomized rabbits compared to the non-ovariectomized when comparing implant with sodium fluoride addition (p=0.02). The bone tissue response and the removal torque of the titanium implants were not influenced by ovariectomy in these rabbits.