The effect of experimental osteoporosis on bone regeneration: Part 1, histology findings.

OBJECTIVES: To histologically define the healing events occurring in calvarial critical size defects (CSDs) following treatment with a collagen barrier for guided bone regeneration (GBR) and a particulate graft in healthy and osteoporotic conditions.

MATERIAL AND METHODS: Thirty-six 10-month-old, female, Wistar rats were used in this study. Half of them were ovariectomized (OVX) and fed with a low-calcium diet to induce an osteoporotic-like status. In each animal of both groups, two 5-mm CSDs were created, one in the centre of each parietal bone, and they were treated with a deproteinized bovine bone mineral (DBBM) particulate graft and a bi-layer collagen membrane. Six OVX and six healthy control rats were randomly euthanized at 7, 14 and 30 days. One defect per animal was randomly processed for decalcified histology. Three central sections were used for qualitative histology and histomorphometric analysis.

RESULTS: No significant difference in terms of percentage of newly formed bone was detected between the two groups at the different healing periods. However, a trend towards less bone formation and of poorer quality, expressed as reduced bone maturation, was detected in the OVX animals at 30 days.

DISCUSSION: According to this study, GBR with a collagen barrier and a DBBM graft can be successfully obtained also in osteoporotic-like conditions. Future studies considering longer healing periods and controlling for the confounding factors arising from the use of a particulate graft are needed to confirm these data.