S. Ijiri et al., ECTOPIC BONE INDUCTION IN POROUS APATITE-WOLLASTONITE-CONTAINING GLASS-CERAMIC COMBINED WITH BONE MORPHOGENETIC PROTEIN, Journal of biomedical materials research, 35(4), 1997, pp. 421-432
To accelerate the integration of ceramic implants with the surrounding
bone and to search for a suitable carrier for bone morphogenetic prot
ein (BMP), we studied ectopic bone induction in porous apatite-wollast
onite-containing glass ceramic (A-W GC) combined with partially purifi
ed bovine BMP (bBMP) and recombinant Xenopus BMP-4/7 (rxBMP-4/7). Poro
us A-W GC rods [4 mm in diameter, 5 mm in height, 70% porosity, 200 mu
m mean pore size, 17.54 +/- 3.82 MPa (mean +/- SD) compressive streng
th] were used. An apatite coating formed on the surface of porous A-W
GC that had been immersed in simulated body fluid at 36.5 degrees C fo
r 7 days. in experiment 1, porous A-W GC rods were combined with eithe
r bBMP, collagen, or with both bBMP and collagen. The rods were implan
ted into subcutaneous pouches in rats and were harvested 4 weeks after
implantation. Low-energy radiographic, scanning electron microscopic
(SEM), and histological examinations showed ectopic bone formation and
within the rods only in the porous A-W GC combined with the bBMP and
collagen group. Quantitative analysis also revealed that this group al
one showed a significant increase in bone formation. In experiment 2,
porous A-W GC rods were combined with rxBMP and collagen, implanted in
to rats, and harvested as described above. SEM and histological examin
ation showed ectopic bone formation around and within the rods. Becaus
e of its relatively high mechanical strength, ease of handling, and go
od osteoinductivity, porous A-W GC combined with BMP and collagen may
be clinically useful in patients with large cancellous bane defects or
craniomaxillofacial lesions. (C) 1997 John Wiley & Sons, Inc.