The impact of ovariectomy and hyperglycemia on graft consolidation in rat calvaria.

OBJECTIVE

Implant placement frequently depends on bone augmentation. However, the impact of systemic metabolic diseases on the consolidation of bone substitutes remains poorly understood. Our goal is to study the impact of ovariectomy and hyperglycemia on graft consolidation in rat calvaria.

MATERIAL AND METHODS

We determined a rat model in which methacrylate hemispheres filled with deproteinized bovine bone mineral were fixed on the calvaria. The first group received streptozotocin (STZ) to induce diabetes. The second group of animals underwent ovariectomy (OVX), causing osteoporosis. Control animals remained untreated, only receiving vehicle injections (STZ-control) but not sham operation, respectively. Specimens were assessed by histomorphometry and μCT.

RESULTS

Graft consolidation was similar between the two groups. The rate of new bone formation after 4 weeks was 0.61±0.53% in the STZ group (n=10) and 0.69±0.91% in the control group (n=8). After 8 weeks, the rates of new bone formation were 4.98±3.16% in the OVX group (n=7) and 2.35±1.30% in the control group (n=10). The volume occupied by the bone substitute was not affected by STZ or OVX treatment. The low amount of newly formed bone could not be quantified by μCT.

CONCLUSION

We conclude that neither STZ nor OVX altered the early phase of graft consolidation. Our findings are limited by the weak osteogenic potential of the rat calvaria in this augmentation model.