Daniel A. Grant

Morphodifferentiation and Structure of Hertwig's Root Sheath in the Cat

The epithelial root sheath in the cat is a multilayered structure that consists of confluent outer and inner epithelial strata enclosing a central layer of cells, which are morphologically like those of the stratum intermedium. A continuous PAS-positive membrane separates the epithelial structure from the developing pulp. On the dental sac surface, the basement membrane is discontinuous, and even absent in some regions. This situation remains until the root and cementum are completely formed.

Lymphatic Vessels of Healthy and Inflamed Gingiva

Lymphatic vessels were traced in healthy and early inflamed gingivae of various nonhuman primates. Lymphatic capillaries and primary collecting vessels originated in the connective tissue papillae and stroma near or adjacent to the attachment epithelium. They emptied into thin-walled irregular-shaped collecting vessels that drained into the periodontal ligament. In early inflammation, all the lymphatic vessels of luminal caliber were distended within and/or surrounding the inflammatory infiltrate.

The Intraosseous Orientation of the Alveolar Component of Marmoset Alveolodental Fibers

Sections of the jaws from marmosets of all ages were impregnated with silver nitrate to demonstrate the intrabony course of the alveolar fibers of the periodontal ligament. As the interseptal bone undergoes a period of resorption and apposition, the intrabony alveolar fibers also are lost and reformed. Age changes were noted in the insertion depth of the alveolar fibers. A continuum of fibers traversing the alveolar septum could not be determined.