Palatal mucosa under dentures: a qualitative histologic and histochemical analysis.

These histologic observations of the epithelium and connective tissue are in close agreement with a host of earlier workers. The striking feature is an increase in thickness of epithelium due to an increase in constituent cell layers, but a decrease in keratinization, with keratin mainly of the parakeratinized variety. There is a definite reduction of collagen fiber network in regions of stress where the fibers present an irregular arrangement in contrast to the normal wavy pattern. Marked chronic inflammatory exudate is also seen. Histochemical investigation of the connective tissue under dentures revealed the presence of a highly elastic and resistant oxytalan fiber network, especially in regions that showed a reduction in collagen fibers. Thus the connective tissue response under dentures is in sharp contrast to what is expected. This abnormal behavior of the connective tissue is probably a reaction to the changes in epithelium. As a result of reduction in keratinization, a highly resistant and protective layer, the connective tissue exhibits altered metabolism and function. We hypothesize that connective tissue takes up a more dominant role of protection and absorption of stress, a role hitherto fulfilled by the epithelium. Thus stresses exerted by dentures on connective tissues are prevented from reaching the bone where they could cause resorption. We therefore feel that denture wear not only results in change within the epithelium, but in an equally significant reaction of the connective tissue. This reaction results in the appearance of a highly resistant and elastic oxytalan fiber system, which assists the connective tissue to react successfully to the stresses exerted on it.