The purpose of this study was to compare the regenerative response of autog
enous cortical and cancellous bone chips and a natural particulate resorbab
le bone mineral (RBM) (Bio-Oss(R), Geistlich-Pharma, Wolhusen, Switzerland)
in standardized bony defects relating paranasal sinuses to one another and
to bone blocks. On 13 skeletally mature female goats four standardized cri
tical-sized full thickness bone defects were made in the frontal bone overl
ying the frontal sinus. These defects were filled at random with cortical b
one chips, cancellous bone chips, spongiosa granules of a RBM or left empty
. Fluorochrome bone markers were injected subcutaneously 1 and 5 weeks afte
r transplantation, and one week before the animals were killed. The animals
were killed at 3, 6, 12 and 24 weeks after surgery. Autogenous cancellous
bone chips is the material of choice for bridging a bony defect in the maxi
llofacial area where there is no need for mechanical strength. They heal in
the same way as cancellous bone blocks do. Cortical bone chips are not rel
iable enough to be used as a solitary bone-grafting material under these co
nditions. A cortical block as a solitary implant gives better results. RBM
granules as solitary implant in a critical-sized defect do not stimulate os
teoconduction but give rise to an extensive osteoclastic activity stimulate
d by the mutual loose relation. A solid block of RBM is in a similar case m
ore reliable. (C) 1999 Elsevier Science Ltd. All rights reserved.