Improved healing of experimental defects in the canine mandible by grafts of decalcified allogenic bone

Induced osteogenesis--the biological principle and clinical applications

Complex orthopedic and craniofacial surgical procedures have stimulated renewed interest in the physiology of bone grafting. The experimental and clinical evidence that a nonvital implant can stimulate local host cells to become bone-forming cells (osteoinduction) is reviewed. Studies of induced osteogenesis were derived from old clinical observations of heterotopic ossification in scars and muscle. When demineralized bone is placed within soft tissues of a rat, a remarkable sequence of endochondral ossification occurs. In contrast, mineral-containing bone particles stimulate obligatory resorption by host mono- and multinucleated cells. The biochemical, endocrine, and physicochemical aspects of induced osteogenesis are actively being investigated. Present understanding of the mechanism of bone induction is discussed along with descriptions of preliminary clinical trials with allogeneic demineralized implants.

A six-month clinical evaluation of decalcified freeze-dried bone allografts in periodontal osseous defects

The osteogenic potential of decalcified freeze-dried bone allografts in the treatment of human periodontal osseous defects was evaluated over a 6 month period. Cortical bone, obtained under sterile conditions from a human donor within 24 hours after death, was decalcified, freeze-dried and ground to a particle size of 250 to 500 microns. Twenty-seven osseous defects with one-, two- and wide three-wall morphology were treated. Clinical measurements were made with a stent and a calibrated periodontal probe before surgery, at the time of surgery, and at re-entry. The combined mean osseous regeneration for all defects was 2.4 mm. This represented a 65% mean bone-fill of the original defect. The findings demonstrate that decalcified freeze-dried bone allograft has potential as an osseous grafting material in periodontal therapy.

Effects of bone grafting on maxillary bone healing in the growing pig

The healing of defects of the lateral wall of the maxilla was studied in the growing pig. In Series I the effect on bone healing of AAA-bone and Kiel bone was compared with that of autografts, and in Series II a comparison was made between autografts and AAA-bone implants. It was found that both autografts and AAA-bone implants improved the rate of healing, but the Kiel bone had no effect. Comparison between autografts and AAA-bone implants in Series II did not show any significant differences. Therefore. it was concluded that AAA-bone can be a useful substitute for autografts in grafting procedures in the maxilla.

The bone inductive capacity of decalcified bone matrix modified by diphenylhydantoin

Decalcified bone matrix was prepared from cortical bones of rats premedicated with I) Diphenylhydantoin (DPH), II) DPH + Vitamin D3, III) Vitamin D3 or IV) no premedication for 10 days. In the donor animals, DPH lowered the serum calcium level, caused a weight loss of 10 per cent, and stopped the growth of the long bones. Vitamin D3 supplementation normalized the serum calcium concentration but had no effect on the other parameters. Vitamin D3 alone caused hypertrophy of the growth cartilage, while the bone growth and structure was normal. The bone inductive capacity of decalcified bone matrix was highest in the DPH group, and the DPH + D3 group also showed significantly higher values than the D3, and control groups. The results of the present study show that the bone inductive capacity of the decalcified bone matrix is independent of Vitamin D3 metabolism.

Ossification of decalcified and nondecalcified homologous bone grafts

This two-year study examined the process of reossification and survival of decalcified and nondecalcified bone grafts implanted under the scalp tissue of 15 rabbits. Both radiologic and histologic examination showed that the nondecalcified fresh-frozen bone specimens became totally viable and recalcified while largely retaining their initial size. The decalcified bones, however, were totally absorbed within a period of four months. Possible reasons for failure of the decalcified bone to reossify are discussed.

Comparison of tricalcium phosphate and frozen allogenic bone implants in man

As part of their treatment, eight patients with 47 infrabony pockets and horizontal bone defects had 29 tricalcium phosphate and 18 frozen allogenic bone implants placed. One year after surgery the sites were reentered. At the tricalcium phosphate implant sites the average amount of bone apposition was 1.2 mm and pocket depth induction 1.8 mm; 38% of the pockets remained deeper than 3.0 mm. At the allogenic bone sites the average amount of bone apposition was 1.5 mm and pocket depth reduction was 2.0 mm; 22% of the pockets remained deeper than 3.0 mm. The implant materials were well tolerated and there were no complications during the period of the study. Though storage and handling of tricalcium phosphate was simpler, use of allogenic bone led to greater bone apposition and reduction in pocket depth.

Repair of postextraction sockets: influence of homogeneous bone implants preserved by formaldehyde. An experimental study in dogs

Small bone sticks from a dog, fixed in formaldehyde from 1 to 4 weeks, were used as homoimplants in the left postextraction sockets of dogs, and the right sockets were allowed to heal as ungrafted controls. The animals were killed 5, 11, 22, and 60 days after implantation. No obvious differences were discovered, either clinically or radiographically, between the repair of the control sockets and that of the experimental sockets. However, appreciable histologic differences could be noted. The presence of the implant disturbed and retarded both the organization of the granulation tissue and the process of intra-alveolar ossification. The attempt to use homogeneous bone implants that had been preserved in formaldehyde in order to stimulate osteogenesis in the host produced unsatisfactory results, since it retarded the process of postextraction alveolar repair.

Xenogeneic implants in primates. Collagen and chondroitin sulfate

This study was undertaken to examine histologically, in monkeys, the sequential healing phenomena of created two-walled osseous defects, which have been corrected by purified collagen and a mixed isomer of chondroitin sulfate. Four adult rhesus monkeys were used as experimental models and provided 23 specimens, from 0 to 56 days postoperatively. Sixteen of these served as implant specimens, and seven served as control specimens in which defects were corrected by curettage only. Two types of implant materials were utilized. The implants were compatible with osteogenesis. The two implant materials themselves did not differ in the healing events.