[A pathological and histochemical study of capsules of impacted teeth with special reference to keratin immunohistochemistry in the lining epithelium].

The purpose of this study was to examine and understand the nature of capsules consisted of fifty cases of unerupted wisdom teeth using radiological, pathological and immunohistochemical methods. Radiologically, the pericoronal space was measured with slide caliper and divided into three groups (-0.9 mm, 1.0-1.9 mm, 2.0mm). Pathologically, all specimens were examined by the routine paraffin method and were stained with hematoxylin.eosin and PAS-alcian blue pH 2.5 stainings. Immunohistochemically, PAP (peroxidase-antiperoxidase) method using various keratin antibodies, such as, anti-keratin K 528 (40-68 KD), anti-cytokeratin PKK 1 (40, 45, 52.5 KD), anti-cytokeratin PKK 2 (40, 46, 48, 54 KD), anti-keratin A 575 (56, 64 KD) and anti-cytokeratin high molecular weight (68 KD), and other various antibodies of anti-EMA, anti-IgA and anti-SC was used in order to study the nature of the epithelium of capsule of impacted teeth. The following results were obtained; 1. Radiologically, the width of the capsules was 1.6 mm in the average. Histopathologically, the inner surface of the capsule was covered with two types of epithelium which were composed of non-typical epithelium with cuboidal (basal layer) and columnar (superficial layer) cells, and typical stratified squamous epithelium. The epithelium lining was observed in 74% of all cases. Among the cases, cyst like structure was more often seen in the cases with typical squamous epithelial lining and with pericoronal space more than 1.0 mm width. 2. In the connective tissue's findings of capsules of impacted teeth, fibrosis was found in almost all the cases. Inflammatory and myxomatous changes were recognized in ca. half cases. Epithelial rest and calcification with dystrophy and epithelial product were observed in about one third of the cases. The epithelial proliferation in the capsule was also rarely seen in the specimens. 3. Immunohistochemically, keratins of 56 KD and 64 KD were identified in the superficial layer of non-typical epithelium and basal, intermediate and superficial layers of the typical squamous epithelium of the capsules of imparted teeth. Keratin of 68 KD was only observed in superficial layer of squamous epithelium. 4. Epithelial membrane antigen was positive in the intermediate and superficial layers of typical squamous cell epithelium. However, it was not seen in the non-typical epithelium of capsule of impacted teeth. 5. Immunoglobulin A and secretory component were negative in the epithelia of capsules.