Dh. Carter et al., ROLE OF EXCHANGED IONS IN THE INTEGRATION OF IONOMERIC (GLASS POLYALKENOATE) BONE SUBSTITUTES, Biomaterials, 18(6), 1997, pp. 459-466
Ionomeric (glass polyalkenoate) implants are synthetic materials which
can be used for repairing bone defects. It has been suggested that io
ns are leached from these implants during healing and that they influe
nce cellular activity in the surrounding tissues. Morphological, immun
ohistochemical and microanalytical techniques were used to compare the
osteogenic capacity of implants which eluted aluminium ions with impl
ants which did not elute aluminium ions. The extracellular matrix mole
cules fibronectin and tenascin were located upon the surface of both i
mplanted materials. Thick seams of lamellar bone were apposed to impla
nts containing labile aluminium ions, but the bone was poorly minerali
zed. At the same time, transient increases were apparent in osteoblast
activity on periosteal and endosteal surfaces and in chondrocyte acti
vity in the growth plate and articular cartilages. In contrast, small
amounts of mineralized lamellar bone were apposed to substituted impla
nts (without aluminium) and the growth plate and articular cartilages
remained normal in thickness and morphology. These results suggest tha
t exchanged ions can influence the amount and quality of bone apposed
to the implant. They also suggest that the effect of the ions depends
upon their concentration and the state of differentiation of osteogeni
c cells. (C) 1997 Elsevier Science Limited.