Scanning and transmission electron microscopic study of tissue-invading microorganisms in localized juvenile periodontitis.

This transmission and scanning electron microscope study documents the invasion of microorganisms into the gingiva and along resorbing alveolar bone surfaces in a 15-year-old patient with localized juvenile periodontitis. The invading bacteria were mainly Gram-negative fusiform, coccobacilli and spirochetes. Microorganisms identified as Mycoplasma were also found to invade in some areas. Polymorphonuclear neutrophils (PMNs) were seen in association with the bacteria. The majority of bacteria were covered by PMNs and enclosed by the phagocyte but did not appear to lie within phagosomes. High numbers of PMNs were found in the gingival connective tissue inflammatory infiltrate and in the pocket epithelium. Invasion into the gingiva and alveolar bone by bacteria and Mycoplasma in localized juvenile periodontitis may be importance in the therapy of this infection.