The labial mucosa is separated from the free gingiva by the space of the vestibule. The free gingival epithelium is usually parakeratinized stratified squamous epithelium that is supported by a dense lamina propria which lacks glands, muscle or adipose tissue. The sulcular epithelium is thin and nonkeratinized stratified squamous epithelium in tissue type. In the healthy state, a flat interface exists between the epithelium and the lamina propria at the site of the basement membrane. Observe the differences in thickness among the three epithelial linings and the differences in the relative prominence of the rete ridges. During the decalcification of the specimen for histologic preparation, the enamel is removed and is only evident as an enamel space. H&E, 40x