Regional differences in cell surface patterns in normal human sulcular epithelium.
Studies with scanning electron microscopy in the normal human sulcular epithelium are scarce, and no precise information exists about cell surface patterns along the epithelium, the frequencies of these patterns, or possible regional differences within the mouth. In five periodontal biopsy specimens each from the anterior and posterior region of the mouth, we observed three cell patterns on the basis of the overall appearance of morphological surface markers in the coronal and apical zones of sulcular epithelium: microvilli; microplicae; and pits. The percentage of keratinocytes showing the microvillous pattern in the surface of apical sulcular epithelium of the posterior region of the mouth was significantly higher than in the anterior region. We posit that the presence, in the bottom of the normal sulcular epithelium in the posterior region of the mouth, of mainly microvillous keratinocytes (the most undifferentiated and least desquamative type of keratinocyte, and thus the most vulnerable to bacterial colonization) can be associated with observations of longitudinal clinical studies of periodontal disease, which suggest that more severe clinical findings are found in the region of the molars.