Effects of Combining Insulin-like Growth Factor 1 and Platelet-derived Growth Factor on Osteogenesis around 
Dental Implants.

OBJECTIVE: To explore the effects of the combination of insulin-like growth factor 1 (IGF-1) and platelet-derived growth factor (PDGF) on bone formation around dental implants.

METHODS: A total of 24 adult rabbits were included in this experiment. Titanium machine-polished dental implants were placed in the iliac bones to simulate dental implants in the alveolar bone. The rabbits were randomly divided into four groups; a saline treated control group (NS), an IGF-1 treated group, a PDGF-BB treated group, and a combination of IGF-1 and PDGF-BB treated group. The rabbits were sacrificed after 3, 7, and 10 days, and implants and soft tissues around implants were histologically evaluated.

RESULTS: All of the rabbits began to recover their appetite, move freely and the operation area started detumescence until after the fourth day. H&E staining showed that the granulation tissue formation, multinucleated giant cells, a small amount of calcium salt deposition and bone tissue were observed in the IGF-1 group and the PDGF-BB group. In the IGF-1 + PDGF-BB group, the granulation tissue had turned into fibrous connective tissue, and calcium salt deposit had formed bone tissue. Masson's trichrome staining showed that the IGF-1 group and the PDGF-BB group had more collagen fibre compared with the NS group. In the 
IGF-1 + PDGF-BB group, collagen fibre hyperplasia and repairing fibres appeared earlier than in other groups.

CONCLUSION: When applying IGF-1 or PDGF-BB alone, either has the effect of accelerating the wound healing in the short term; while in combination, earlier collagen fibre hyperplasia appeared.