Studies related to reaction of supporting soft tissue to denture wear: the histological response of vervet monkey oral epithelium to a -80 mmHg vacuum.

The histological response of vervet monkey oral epithelium to a negative force similar to that experienced under dentures was investigated. Using impression trays with adherent impressions linked to a vacuum pump, the epithelia of the hard palate, attached gingiva and alveolar mucosa of 16 monkeys were subjected to a continuous vacuum of -80 mmHg, and then fixed by perfusion and immersion while in situ. After processing for light microscopy, sections were measured to obtain the rete peg length, supra-papillary width, epithelial width and basal, spinous and superficial cell density 700 microns-2. Mean values and standard deviations were calculated for each measurement and, using Student's t-test, these data were compared with results obtained for normal tissue from nine additional monkeys. The vacuum caused an increase in epithelial width in the palate and attached gingiva, and a decrease in epithelial width in the alveolar mucosa. The cell density 700 microns-2 decreased significantly in all layers of the palate, but increased in the basal layer of the attached gingiva and the basal and superficial layers of the alveolar mucosa. The alveolar mucosa within 0.5 mm of the mucogingival junction showed a variable response. This study demonstrates that a vacuum of -80 mmHg modifies the structure of the oral epithelium, and this response is directly related to the functional demands of the tissue.