The fate of implants of decalcified dentine was compared with that of decalcified bone, tendon and muscle in three different sites: muscle pouch, drill-hole in mandible, and extracted tooth socket. Within the implants of dentine and bone matrix in areas undergoing resorption by collagenolytic mesenchymal cells and sprouting capillaries, a consistently reproducible induction system was set up for osteogenesis. Similarly prepared tendon and muscle implants did not induce osteogenesis. Except that the new bone developed from the interaction of hypertrophied mesenchymal cells with extracellular substances in the matrix of dentine and bone, and that a film of cement substance generally separates the old and new tissue, the local physical-chemical reactions are obscure. Transfer of 3H-glycine does not appear to occur locally between the old dentine matrix and ingrowing new cells of the host.
