Histological Bone Analysis.
At four months postgraft, the patient returned to the office for surgical placement of endosseous implants. Before implant placement, 3-mm core biopsies were taken in the maxillary right and left first molar regions with a trephine drill. The low power (magnification, 32.5) histological sections dramatically show the effect of the P-15 upon bone formation. The ABM shows trabeculae with new bone formation in contact with the particulate ABM. ABM/P-15 shows greater new bone contact with the particulate (Fig. 6) Higher magnification (310) shows new bone on the ABM surface and bridging between the particulate ABM. The ABM/P-15 again shows a very dense pattern of bone and ABM particulate (Fig. 7). Histomorphometric analysis compared the volume of vital bone in both the ABM and ABM/P-15. The analysis of both grafted sites revealed a high volume of vital bone in the ABM/P-15/DFDBA side. ABM/P-15 yields 45% vital bone compared with the 13% vital bone on the ABM in the absence of P-15 (Table 1).

Fig. 6. A, histology: trabeculae with new bone formation in contact with particulate ABM (32.5);
B, histology: ABM/P-15 shows greater new bone contact with the particulate (32.5).



Fig. 7. A, histology: a higher magnification shows new bone on the ABM surface (310);
B, histology: the ABM/P-15 shows a very dense pattern of bone and ABM particulate (310).



Table 1. Histmorphometric analysis.

DISCUSSION.
It has long been appreciated that accelerated healing time with corresponding greater graft quality would affect implantology. Most recently, the time factor has been addressed with the introduction of an anorganic bovine mineral impregnated with a synthetic, 15 amino acid sequence representing the cell-binding domain of Type-I collagen (P-15). This tissue engineered matrix is designed to enhance cell attachment and provide an optimal matrix for differentiation of cells into osteoblasts. The increase in the quality and quantity of bone associated with the P-15 graft suggests that re-entry into a grafted sinus may be possible in a reduced time frame to accelerate the insertion of implants.

References.

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