Effect of diabetes mellitus on bone dynamics in denture supporting tissue has not been investigated enough. The purpose of this study was to investigate the effect of diabetes mellitus on bone resorption in the tissues under denture base caused by continuous pressure exerted through denture base by using bone histomorphometry.
Two-hundreds and fifty streptozotocin-induced diabetic male rats (n=50 X 5 groups) of Wistar strain were used in this study. Denture base was applied to the molar region of the hard palate at 22 weeks of age. In 3 loaded groups, the denture bases were designed to load a continuous pressure of 1.0, 10.0 or 20.0 kPa to the palate, respectively. In covering groups, the denture base was designed to contact with the palate without any mechanical pressure. The non-denture-wearing group received no intentional treatment. The cleansing of the palate and removable denture base was carried out at 3 or 4 days intervals. Palatal tissue block was excised from 5 rats of each experimental group after the denture insertion at one week interval. The specimens were stained with Villanueva bone stain, embedded in methyl-methacrylate, and ground to 50mum thickness. Eroded surface and osteoclast surface were calculated by using two dimensional graphic analysis system. Amount of bone resorption was calculated as (A) - (B) ; (A) Formed bone tissue during 12 weeks prior to the denture insertion in covering group, (B) Remained bone tissue after the end of bone resorption in each bone resorbed group at each experimental period.
Bone resorption was observed in 10.0 and 20.0 kPa groups until 3 and 4 weeks after the denture insertion, respectively. Total amount of bone resorption was 60*16mum in 10.0 kPa group and 87*17mum in 20.0 kPa group. Comparing these results with results in normal rats in same condition as this study, it was showed that diabetes mellitus prolongs the term of bone resorption and increases total amount of bone resorption.