A histomorphometric analysis on bone dynamics in denture supporting tissue under continuous pressure in streptozotocin-induced diabetic rat

The purpose of this study was to investigate bone dynamics in denture supporting tissue under continuous pressure in the diabetic condition by using bone histomorphometry in relation to initial intensity of continuous pressure exerted through the denture base. The experimental denture base, which was designed to load initial continuous pressure of 0.0, 1.0, 10.0 or 20.0 kPa to the denture supporting tissue, was applied to the molar region of hard palate of streptozotocin-induced diabetic rats. Fluorescent labelled palatal bone tissue was stained with Villanueva bone stain and was prepared for the undecalcified grinding section. In 0.0 kPa group, no bone resorption was observed and bone formation was transiently inhibited after the denture insertion. In 1.0 kPa group, although no bone resorption was observed, the beginning of bone formation after the inhibition of bone formation was later than that in 0.0 kPa group and bone formation dynamics after the resumption of bone formation was similar to that in 0.0 kPa group. In 10.0 and 20.0 kPa groups, bone resorption was observed until 3 and 4 weeks, respectively, and the amount of bone resorption for each group was 60 ± 16 and 87 ± 18 μm, respectively. The resumption of bone formation in 10.0 and 20.0 kPa groups were observed at the same stage with 1.0 kPa group, and the bone formation dynamics after the resumption of bone formation in 10.0 and 20.0 kPa groups were also similar to that in 0.0 kPa group. From the results of this study, it was revealed that bone formation following bone resorption did not cause equivalent recovery of the bone surface level to the level observed in the case without bone resorption in the diabetic condition.