Ultrastructural investigation of hard palate mucosa under complete dentures.

An ultrastructural investigation was made to study the tissue changes occurring under complete dentures. Biopsy from 45 patient specimens were obtained from lesions of hard palate mucosa. Narrow intercellular space with less distinct bridges, loosely knit arrangement of tonofilaments, prominent endoplasmic reticulum, and vacuolar conformation of mitochondria were observed in the cells of epithelium. The underlying connective tissue was characterized by a preponderance of newly formed collagen fibers and numerous fibroblasts. Macrophages were located in the lamina propria and perivascular regions. Lymphocytes, neutrophils, and plasma cells were seen in moderate numbers. These cells, when present in clusters, should be considered as a component of the defense system.