ISSN:
0021-9304
Keywords:
alumina
;
Bis-GMA
;
composite
;
mechanical properties
;
osteoconduction
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
,
Technology
Notes:
We have developed a composite (designated ABC), consisting of alumina bead powder as an inorganic filler and bisphenol-a-glycidyl methacrylate (Bis-GMA)-based resin as an organic matrix, which allows direct bone formation on its surface in vivo. Alumina bead powder was manufactured by fusing crushed α-alumina powder and quenching it. The beads took spherical form 3 μm in average size. According to powder X-ray diffraction and Fourier transform infrared spectroscopy, the alumina bead powder was composed of amorphous and δ-crystal phases of alumina in its main crystal structure. Fused-quenched silica glass-filled composite (SGC) was used as a control. The proportion of filler added to the composites was 70% w/w. Mechanical testing of the ABC indicated that it would be strong enough for use under weight-bearing conditions. No apatite formation was detected on the surfaces of either composite after soaking in simulated body fluid for 28 days in vitro. Histological examination of rat tibiae for up to 8 weeks revealed that ABC bonded to bone directly via a layer of calcium, phosphorus, and alumina with no interposed soft-tissue layer. Moreover, the amount of bone directly apposed to the ABC surface increased with time, whereas with SGC there was poor direct bone formation even at 8 weeks. The precise mechanism of direct bone formation on ABC is as yet unknown but it is possible that changes in the crystallinity of alumina, which is known to be highly biocompatible, contribute to its excellent osteoconductivity in vivo. Although bioactive materials such as Bioglass® or apatite and wollastonite-containing glass-ceramic have previously been reported to form bone-like apatite on their surfaces under acellular conditions via simple chemical reactions, ABC does not have such characteristics, and presenting favorable conditions for osteoconduction and tissue calcification may lead to direct bone formation on its surface in vivo. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 554-565, 1997.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
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