Effect of Ipriflavone on Osteoblasts and Osteoclasts during Guided Bone Augmentation

Abstract

We investigated the effect of ipriflavone (IP) on osteoblasts and osteoclasts during guided bone augmentation (GBA). Each of ten rabbits had two titanium caps placed into its calvarium for GBA. The animals were divided into two groups: No-IP and IP (IP orally, 10 mg/kg daily after GBA). One cap was removed from each rabbit after 3 months, and the remaining cap served as a control. One month after the removal, all of the animals were euthanized, and histologic and histomorphometric analyses were performed. The tissue generated at the test site in the two groups was resorbed, and its original shape and volume were not maintained 1 month after cap removal. In particular, roughly 20% of the newly generated tissue in the No-IP group was resorbed (72.9 ±2.6% vs. 92.4 ±3.3%, p < 0.05), while approximately 8% was resorbed in the IP group. Furthermore, more osteoblast-like cells were present in the IP group than in the No-IP group (44.4 ± 3.05 vs. 30.2 ± 3.11, p < 0.05), and the proportion of osteoclast-like cells was reduced in the IP group compared to the No-IP group (0.59±0.02 vs. 0.76±0.06, p < 0.05). Therefore, the amount of mineralized tissue generated appeared to increase as the total IP dose increased. Within the limitations of this experimental model, we conclude that daily intake of IP after GBA inhibits the resorption of the augmented tissue and may be useful for improving the quality of newly generated bone beyond the skeletal envelope.