Ultrastructure of the subgingival microflora in juvenile periodontitis

— The ultrastructure of the subgingival deposits on the root surfaces of teeth affected by juvenile periodontitis was studied on 12 teeth from nine individuals, 15–30 years of age. The deposits consisted of either microbial masses associated with a pellicle, or of a cuticular material almost free of bacteria. Gram-negative rods and filaments were the predominant microorganisms. “Corncob” configurations consisting of filamentous bacteria surrounded by Gram-positive cocci, and “bristle brush” formations comprising corncobs surrounded by long rods were observed in the superficial layer of the plaque. Spirochetes and flagellated rods constituted a major segment of the microflora. The present data indicate that the deep pockets in juvenile periodontitis harbor a sparse but relatively characteristic microbial population.