Recalcification of Decalcified Dentin in the Living Animal

¹ School of Medicine, Department of Surgery, Division of Orthopedics, Bone Research Laboratory, and School of Dentistry, University of California at Los Angeles, Los Angeles, California

In vivo experiments on the local mechanism of calcification of implants of decalcified teeth of the rat, rabbit, and man in the normal extracellular fluid of the living organism produced the following information:

1. Fetal toothbuds, decalcified in hydrochloric acid without fixation and implanted in the anterior chamber of an eye, were rapidly absorbed and did not constitute a calcifiable matrix.

2. Decalcified dentin, pretreated in strong solutions of calcium ions, became recalcified in the rat eye, even at the low serum ion products of calcium and phosphate of an adult animal.

3. The restoration and calcifiability appears to depend on lyotropic action of solutions with high ionic strength and also on the binding of calcium to components (chiefly fibrous protein) of dentin matrix.

4. The reaction between decalcified mature dentin and metal ion, to restore calcifiability requires higher concentrations of calcium than are necessary to produce comparable effects on tendon, aorta, muscle, or decalcified bone matrix.

5. The sequence of events in recalcification of implants of mature dentin, untreated and treated in various ways, has been interpreted in support of a hypothesis of a triphasic localization mechanism.