Maintenance of osseointegration utilizing insulin therapy in a diabetic rat model

Background: Normal wound healing processes have been shown to be altered in diabetes, and the effect of the diabetes on bone-to-implant contact (BIC) once osseointegration has been established is still unknown. The purpose of this study was to histologically evaluate the bone-to-implant contact in uncontrolled and insulin-controlled rats in which diabetes was induced following the establishment of osseointegration. Methods: Thirty-two rats were assigned to eight different treatment groups of four each. Titanium plasma-sprayed (TPS) implants were placed in the femora of each animal, and allowed to osseointegrate for 28 days before diabetic induction. Daily insulin injections were given to four groups of rats and the other four groups received no insulin (uncontrolled). The rats were sacrificed at 1, 2, 3, and 4 months following diabetic induction. Results: The results indicated that at 1, 2, 3, and 4 months, there was more BIC in the insulin-controlled groups compared to the uncontrolled groups. The differences were significantly greater at 2 3, and 4 months (P <= 0.001). Conclusions: This study demonstrated that osseointegrated dental implants in insulin-controlled diabetic rats maintained bone-to-implant contacts over a 4-month period. However, bone-to-implant contact appears to decrease with time in uncontrolled diabetic rats.