Effect of size and shape of the allogeneic bone grafts in bridging experimental ulnar gap in rabbits.

Partially decalcified allogeneic bone matrix was cut into the sizes and shapes of cylinders, bone strips and pulverized bone powder. Large osteoperiosteal gaps were created in rabbit's ulnae. A total of 14 gaps were filled with bone strips, 20 with powder, six with cylinders and two were left unbridged to serve as control. The healing of gap was assessed at intervals with a maximum follow up of 24 weeks. Clinically at 12 weeks the bone strips could not be moved separately from each other, the whole tubular bone had also united whereas gaps filled with bone powder did not diminish in size. Radiologically union occurred earlier (around 12 weeks) in bone strips as compared to cylinders (approx-18 weeks). With bone powder only a faint line of the remnants was visible. Gross examination findings of the grafted area were in concurrence with the clinical and radiological findings. Overall the gaps filled with bone strips had 100 per cent success with early osteo induction and remodelling as compared to long cylinders whereas gaps filled with bone powder had complete failure.

Osteoinductive property of fluoride impregnated decalcified allogeneic bone matrix.

Present study was carried out in order to explore the ability of a bone graft-decalcified as well as fluoridated to form new bone when put in the rectus abdominis muscle of rabbit. A total of 66 implants placed inside the pouches created in rectus abdominis muscle of rabbits were followed for 2 to 20 weeks. Radiologically decal implants formed bone in 74% cases and fluoridated implants in 68%; whereas histologically 86% of decalcified and 80% of fluoride impregnated decal bone matrix showed evidence of bone induction. It is concluded that fluoride impregnation does not enhance the osteogenic potential of a decal bone matrix.

Autoclaved partially decalcified bone as osteogenic substances--an experimental study.

A large osteoperiosteal gap was created in rabbit's ulna. A total of 18 allogenic decalbone grafts in left ulnar gap and 20 autoclaved allogenic decalbone grafts on right ulnar gaps were implanted. Five gaps were left unbridged to serve as controls. The results were assessed by clinical, radiological, macroscopic, histological and tetracycline fluorescent studies. It is observed that whereas the decalbone can successfully bridge a large gap in a vast majority of cases; the standard autoclaving of decalbone denatures its proteins which melt and cover the outer surface. The union, incorporation and remodelling of autoclaved decalbone grafts are slower as compared to that with unautoclaved decalbone.