Scanning and transmission electron microscopic studies of periapical lesions

Twenty chronic periapical granulomas and cysts and their corresponding teeth were examined using scanning and transmission electron microscopy, chronic periapical inflammation had caused root resorption which affected the cementum and dentin. However, root surface exposed to granulomas and cysts also indicated spontaneous cementum repair. At the periphery, cellular debris, fibroblasts, collagen fibrils, nerve bundles could be seen, which were continuations of the periodontal ligament. The surface topography of the superficial cells showed a reticular network of intercommunicating microridges surrounding micropits. Sometimes, they appeared disrupted with areas of exfoliation of the detached squamae. The transmission-electron microscopic findings revealed epithelial wide intercellular spaces, irregular base lamina, moderate numbers of inflammatory cells, increased rates of macrophages, edema, fibroblasts, enlarged and dilated blood vessels with extravasated RBCs and engulfed macrophages

Studies on the histopathological and histochemical changes in oral lichen planus and the apparently healthy nearby areas

Biopsy specimens from 20 patients affected with lichen planus [L.P] were taken from diseased oral mucosa [gingival, lip or cheek] and nearby areas. Control biopsies were taken from similar situation from 3 healthy volumteer persons. All biopsies were studied histologically using HX and E and Mallory stains and histochemically using PAS, methyl green pyronin, toluldine blue and mercury-bromophenol blue stains. Histologically it was found that parakeratosis, acanhosis, irregular downward txtension of the epithelium and hydrpic degeneration in stratum basale and stratum spinosum were prominent in the epidermis of the diseased areas. The nearby areas, showed similar epidermal affection but to a lesser degree. In the lesion areas, the underneath connective tissue [C.T.] showed wide band of cellular infiltration with dilated blood capillaries. These changes were not evident in the nearby areas but fibrosis was evident. Istochemically, the basement membrane [B.M.] was thick and irregular with rare interruptions in both diseased and nearly areas. The DNA decreased in germinal layer and increased in parakeratolic and inflammatory cells compared to the controls. The RNA was high in stratum spinosum of the diseased area only. Mast cells increased obviously in the underneath C.T. of the diseased area and to a lesser degree in the nearby area. Protein contents was decreased in hydropic cells only, but increased in parakeratotic areas. It was concluded that in L.P. the actual lesion incidence both the visible disease and the apparently normal looking nearby areas