Healing of the Traumatized Dental Pulp

Abstract

Autoradiographic observations were made of the reparative process in the dental pulps of 24 male Sprague Dawley rats following various grades of trauma induced by grinding the occlusal surfaces of teeth. To study the reparative process, H3-proline was given by intraperitoneal injection at a dose of 4 micro-curies/gr body weight. The rats were sacrificed in groups of 3, 4 hr. after receiving the injection at 4, 8, and 12 hr., 1 and 2 days, 1 wk. and 1 mo. Autoradiographs were made of 5 micron thick sections. Sections then were stained through the emulsion with H and E [Hema-toxylin and Eosin] and the amounts and location of the exposed Ag granules observed. In the early posttraumatic experimental periods, microscopic analysis revealed the lack of collagen macromolecules. Collagen formation was seen after 24 hr. in such areas as evidence of an attempt of the dental pulp to repair the damaged tissue at the injured site. The greatest activity of collagen formation was observed adjacent to the odontoblasts suggesting that these cells are the main cell type involved in the mechanism of reparative dentin and dentinal bridge formation.