Histomorphometrical analysis of bone formed in human maxillary sinus floorelevations grafted with OP-l device, demineralized bone matrix or autogenous bone - Comparison with non-grafted sites in a series of case reports

Bone morphogenetic proteins have proven to be effective bone inductors in a nimals and are therefore promising as inductors of bone formation in humans . In the present study we investigated the tissue formed after grafting ost eogenic protein 1 on a collagen carrier (OP-1-device) in the human sinus fl oor elevation procedure. Three patients were grafted with OP-1 device. For comparison 3 groups of 3 patients were included in the study receiving resp ectively, autogenous bone, human freeze-dried demineralized bone matrix (DB M) or no graft. This last group had a sufficient alveolar bone height for d ental implantation. Six months after grafting, at the time of implantation, biopsies were taken from the grafted area and/or the future dental positio ns. Undecalcified sections were used for histological and histomorphometric al analysis. All grafted sinuses showed an increased osteoid percentage whe n compared to non-grafted sinuses. Autogenous bone grafts all showed lamell ar bone formation. In the DBM grafts mostly woven bone had been formed, pre dominantly by what appeared to be osteo-conduction. The OP-l device gave ri se to bone formation in 2 of the 3 patients. After 6 months implants could only be placed in 1 out of the 3 patients treated with OP-1 device. This pa tient showed mature lamellar bone formation, comparable to autogenous bone grafts. In the second patient all bone found was woven and the presence of a high osteoid percentage and large osteocyte lacunae indicated that this w as recently-formed bone. Remnants of the collagen carrier were rare and new bone was never found against them, suggesting that this bone was formed by osteo-induction. In the third patient no new bone had been formed. The dev ice had been encapsulated with fibrous tissue and inflammatory reaction was present. We conclude that in the human sinus floor elevation OP-l has pote ntial bone inductive capacity, but that results in the 3 patients tested wi th the current OP-1 device are inconsistent.