Morphological studies on periodontal disease in the cynomolgus monkey: I. Light microscopic observations on gingivitis.

Histologic observations were made on the primate Macaca fascicularis in order to describe the features of both naturally-occurring gingivitis and gingivitis present at non-experimental sites when selected teeth were ligated to induce periodontitis. Semi-thin sections of glutaraldehyde-paraformaldehyde fixed, EDTA-decalcified, and epon-embedded specimens were used, supplemented by routine histologic methods. The microscopic picture of the interdental areas was identical for the two types of gingivitis specimens and consisted of a chronic inflammatory reaction resembling the established lesion in humans. The highly infiltrated gingival tissue exhibited a predominance of plasma cells. Leukocytes were seen in pathways from the connective tissue, through the epithelium and to the surface of the plaque, and many neutrophils were interposed between the plaque and soft-tissue. The apical extent of the junctional epithelium was at or slightly below the cemento-enamel junction. Although perivascular inflammation was observed in the transseptal fiber region, the alveolar crest exhibited only evidence of normal bone remodelling. [ABSTRACT FROM AUTHOR]