Does osteocyte formation cause the nonlinear refilling of osteons?

Marotti (Ital J Anat Embryol 101:25-79, 1996) described a theory of osteocy te differentiation from osteoblasts during bone formation. This theory post ulates that, when a previously formed osteocyte is sufficiently covered by new bone and osteoid, it sends an inhibitory signal through its dendritic p rocesses to the neighboring osteoblasts that reduces their individual appos ition rates, The osteoblast most affected by this inhibition becomes buried by its neighbors, and becomes one of the next layer of osteocytes. By purs uing this concept, the present study develops a mathematical theory that pr edicts another observation about bone remodeling: the diminishment of the a pposition rate during the refilling of basic multicellular units (BMUs), Th is decrease in apposition rate is different in osteonal and surface (e,g,, trabecular) BMUs, and the theory shows that this result is consistent with the accrual of osteocyte inhibition throughout the refilling period, with t he different ratios of bone volume to surface area in these two types of BM Us, (C) 2000 by Elsevier Science Inc. All rights reserved.