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.


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.


CONCLUSIONS
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.
Department of Oral Surgery, Medical University of Vienna, Austria.
Alexander
A
Fuegl
Stefan
S
Tangl
Claudia
C
Keibl
Georg
G
Watzek
Heinz
H
Redl
Reinhard
R
Gruber
D000818:Animals; D015519:Bone Density / Q000502:physiology; D001857:Bone Matrix / Q000637:transplantation; D001861:Bone Regeneration / Q000502:physiology; D018786:Bone Substitutes / Q000627:therapeutic use*; D002417:Cattle; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D048091:Guided Tissue Regeneration / Q000379:methods; D006943:Hyperglycemia / Q000503:physiopathology*; D008689:Methacrylates; D008903:Minerals / Q000627:therapeutic use; D010012:Osteogenesis / Q000502:physiology*; D010024:Osteoporosis / Q000503:physiopathology; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000473:pathology / Q000601:surgery*; D013311:Streptozocin; D055114:X-Ray Microtomography
C077540:Bio-Oss; D018786:Bone Substitutes; D008689:Methacrylates; D008903:Minerals; D013311:Streptozocin