Effects of ipriflavone on perialveolar bone formation

The effect of ipriflavone (IP), a synthetic isoflavonoid derivative, on in vivo bone formation was studied in rat perialveolar bone by surgically producing a hole in the mandibular bone. The holes were filled either with powdered IP or with compounds containing no osteoinductive properties such as biostite and Htr (hard tissue replacement). In control animals, the holes were left to heal spontaneously. The animals were killed 3, 28, and 40 days after surgery and a detailed morphological and morphometric study was performed on the perialveolar bone surrounding the wounds. Three days after surgery (inflammatory phase) the bone wounds were occupied by hemorragic and inflammatory cells in both the untreated and IP-treated bone defects. Twenty-eight days after surgery, bone formation was evident with new bone spiculae particularly concentrated in the area of the bone lesion closest to the adjacent periodontal ligament. Morphometric measurements of the areas occupied by new bone showed that the synthesis of perialveolar bone was significantly stimulated by IP. The repair of the bone defects by new bone formation progressed by day 40, but only in the presence of IP were the original holes almost completely repaired. Conversely, biostite and Htr did not influence promotion of new bone formation. In conclusion, the results of the present study are consistent with a role of IP in stimulating osteogenesis and suggest that this compound could represent a potential therapeutic tool to promote repair of injured perialveolar bone.