We have investigated the interface between bone and chronic implants of nac
re in sheep. There was no foreign body reaction over the period of 10 month
s and the implants were not broken down. Light microscopy indicated activit
y within an osteoprogenitor cellular layer lining the implant, resulting in
a complete sequence of new bone formation. Nacre appeared to bind directly
to newly formed bone without any intervening fibrous tissue. Scanning elec
tron microscopy and energy dispersive photon X-microanalysis showed calcium
and phosphate ions lining the nacre within the osteoprogenitor tissue. The
se studies show a dynamic activity of the bone/nacre interface, leading to
continuity between the nacre and the bone. (C) 1999 Elsevier Science Ltd. A
ll rights reserved.