Stimulation of new bone formation on intact bones by decalcified allogeneic bone matrix

Comparative evaluation of decalcified and non-decalcified freeze-dried bone allografts in rhesus monkeys. I. Histologic findings

BACKGROUND

Controversy exists regarding the relative merits of decalcified (DFDBA) and non-decalcified (FDBA) freeze-dried bone allografts when used in periodontal or other oral surgical procedures.

METHODS

Under typical sedation, six rhesus monkeys had nylon mesh cylinders containing either DFDBA or FDBA implanted into surgically created vertical grooves on the facial aspects of all posterior quadrants. Each quadrant received three cylinders containing one type of bone, plus one empty cylinder (E) as negative control, and the full thickness flaps were closed to completely cover the cylinders. Cylinders were retrieved at 1, 2, and 3 months and processed for histologic evaluation. Photomicrographs taken at 8x were randomly evaluated using a histometric grid point counting technique for new bone and old bone within the chambers, and the data were analyzed with analysis of variance plus post-tests.

RESULTS

The nylon chambers and their contents were well-tolerated by the tissues. FDBA chambers contained more new bone and total bone than either the DFDBA or E chambers at all time periods (P <0.05). DFDBA was not statistically significantly different than E at any time period. FDBA had less old bone than DFDBA at 3 months (P<0.05). FDBA and DFDBA had more total bone (grafted plus new) present than E at all time periods (P<0.05).

CONCLUSION

These results suggest that FDBA may stimulate earlier, more rapid, and more substantial new bone formation than DFDBA in a monkey jaw defect model system.

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.

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.

The use of woven ceramic fabric as a periodontal allograft

1. The grafted material appears extremely compatible with the animals tested for the observed time periods. 2. The procedures used led to the obliteration of surgically created one-wall infrabony periodontal pockets with fibrous connective tissue and/or bone. 3. The ready access, ease of placement and flexibility of the woven ceramic materials appear to provide some definite advantages over autogenous bone and many of the alloplastic materials presently being used in the correction of infrabony periodontal pockets. 4. Although in the experimental animals the graft materials appeared to be nontoxic, nonantigenic and compatible with the growth of new bone, long-term studies are indicated to determine is compatibility and potential to obliterate "chronic" periodontal lesions.