Examination of new bone growth on aluminium oxide implant contact surfaces after oral administration of ossein-hydroxyapatite compound to rats.

In view of the many disadvantages of transplantation of autologous bone tissue, factors must be found which locally and systemically will adjust the balance between bone resorption and deposition in favour of new bone growth. The present study was undertaken, therefore, to examine whether oral administration of ossein-hydroxyapatite compound (OHC) could stimulate new bone growth on aluminium oxide implant surfaces and, if so, whether it was the mineral or organic part of the compound which was responsible. Whilst under anaesthesia, adult male Wistar rats each had 2 holes drilled into the femur and 2 precisely fitting aluminium oxide implants inserted. The animals were divided into 5 groups each of 5 rats and the groups received oral daily doses of 20 mg OHC, 100 mg OHC, 10 mg hydroxyapatite, 50 mg hydroxyapatite or no supplement (controls), respectively. After 20 days, each implant was evaluated by 5 cuts through the marrow area and the thickness of the newly grown layer of bone measured by a morphometric procedure. The results showed a significant increase in new bone growth for the 100 mg OHC group in comparison to the control group, and in comparison to the hydroxyapatite group. Because both supplemented groups received equivalent dosages of calcium and phosphate, the additional stimulation of new bone growth must have been due to the organic part of OHC (ossein). It is suggested that these results should stimulate in particular the clinical use of OHC in the critical initial phase of implant healing and delayed fracture healing.(ABSTRACT TRUNCATED AT 250 WORDS)