Scintigraphic evaluation of osseointegrative response around calcium phosphate-coated titanium implants in tibia bone: effect of platelet-rich plasma on bone healing in dogs.

Differential diagnoses for canine bone disease are commonly based on radiography. However, scintigraphy is a nuclear scanning test to trace bone healing during stress fracture and osteomyelitis and thus can be used to probe the osseointegration process in vivo in the context of the dental implant. The purpose of this study was to explore the possibility of using noninvasive scintigraphy to probe the effect of platelet-rich plasma (PRP) to enhance osseointegration of the implant and to confirm the result with a parallel histological examination in adult beagle dogs. Two independent calcium phosphate-coated titanium screw implants 8 mm in length and 4 mm in diameter were inserted into each tibia in 4 dogs (4 implants/animal, total = 16). The PRP-treated group was deposited with 0.5 ml of PRP into the drill hole in the right tibia; the control group was instilled with 0.5 ml of saline into the drill hole in the left counterpart before titanium screw implantation. Radiography of the implanted tibias showed complete osseointegration but no osteomyelitis. No difference in the ossification of the peri-implant bone on the radiographs was observed between the two groups during the experimental period. However, the scintigraphic findings revealed obvious differences in bone uptake between the two groups. The higher bone uptake in the PRP-treated group significantly increased bone activity and faster bone regeneration compared to the control group (p < 0.05) at 4 weeks after implantation. The percentage of the bone-to-implant contact on histological examination in the PRP-treated group showed dense cortical bone formation in close contact with the metallic surface of the titanium implant (p < 0.05). Quantitative histological analysis correlated well with that of the scintigraphic evaluation as revealed by Pearson correlation analysis (r = 0.72, p < 0.05). Thus, scintigraphy is a sensitive and noninvasive method suitable for osseointegration of the implant in vivo.