Bone Response to Titanium Alloy Implants Placed in Diabetic Rats

Although dental implants continue to provide consistent and predictable treatment options for most patients, some people with uncontrolled systemic disease may be denied implant treatment. Diabetes is one such disease. According to the U.S. Centers for Disease Control and Prevention, diabetes is a leading cause of blindness, kidney failure, and amputations of the lower extremities. These complications result from microvascular disturbances associated with diabetes. The effect of diabetes on the healing of titanium implants has not been well established. In this study of 32 rats, diabetes was induced in 16 animals by injection of streptozotocin (65 mg/kg); the remaining 16 animals served as controls. Titanium alloy implants were placed in the tibiae of all 32 rats using standard surgical techniques. Implants healed for 14 days. Blood samples were obtained for serum glucose, osteocalcin, and alkaline phosphatase analyses. Implants were retrieved and processed for histomorphometric analyses. Three quantities were measured using light microscopy, video capture, and computer analysis: percent osseointegration (ie, linear bone interface), associated bone volume percent, and contact frequency. Diabetic animals demonstrated significantly less osseointegration than controls. However, bone volume percent in diabetic animals was about 4 times greater than controls. Biochemical analyses were mixed; diabetic animals demonstrated increased serum osteocalcin levels compared to controls but decreased alkaline phosphatase. Based on the results of this study, it was concluded that the bone response associated with titanium alloy implants in the tibiae of diabetic rats is uniquely different from controls. Keywords: alkaline phosphatase, bone, bone histomorphometry, diabetes, implants, osseointegration, osteocalcin, titanium alloy