Type 2 diabetes impairs implant osseointegration capacity in rats

The effect of type 2 diabetes mellitus (adult-onset non-insulin-dependent), which is the most common form of diabetes in humans, on osseointegration capacity has not been addressed in an appropriate animal model. This study histologically and histomorphometrically examines bone healing around titanium implants in the type 2 diabetes rat model.

Titanium implants with a chamber were placed into the femurs of normal male rats and genetically modified male rats with a close symptomatic resemblance to human type 2 diabetes, as characterized by late-onset hyperglycemia and obesity. Cross-sectional histology for the tissue grown into the implant chamber was examined.

Bone volume around implants was consistently (from weeks 4 to 8 postimplantation) smaller for the diabetes group than for the control group in the cortical area, while the bone volume in the marrow area was not affected by the diabetes. Bone-implant contact percentage was considerably lower for the diabetes group in both the cortical and marrow areas, with the week 4 bone-implant contact in the cortical area being 12% for the diabetes group and 61% for the control group. A 2-fold difference remained at week 8. Bone morphogenesis in the diabetic rats was characterized by fragmented bone tissues and extensive soft tissue intervention.

Type 2 diabetes mellitus impaired osseointegration capacity disproportionally between the cortical bone and bone marrow areas. The reduction of the bone quantity in the cortical area and the bone-implant contact in both the cortical and marrow areas was remarkable.