Early bone formation capacity of PRP(platelet-rich plasma) on a distraction osteogenesis in rabbit

ABSTRACT

Distraction osteogenesis refers to the biological process responsible for new bone formation between bone segments by gradual distraction after osteotomy. For the past several years, various inconveniences including a protracted consolidation period required patients to wear a distractor frame longer. Furthermore, sideeffects such as pin tract infections and soft tissue swelling may arise due to the long treatment period. These drawbacks form the rationale of this study which purports to seek a method by which the consolidation period can be reduced. This paper examines how platelet-rich plasma(PRP), known to facilitate osteogenesis, influences bone formation when applied in distracted area. Experimental animals are included 8 rabbit, which were put external distractor frames after osteotomy on the both sides of the mandible. After a 5 days period of latency, distraction was carried out at a rate of 0.7mm/day to total 4.2mm distraction, and allow to 7 and 14 days for consolidation periods. After osteotomy was done, 1ml of PRP and a mixture of calcium chloride and thrombine were injected into the center of the distraction site and another side was set as the control site without PRP. Rabbits were sacrificed at 7 or 14 dyas after the consolidation period. Clinical and radiographic tests, histological examination and histomorphometric analysis were conducted to compare both sides. Based on the clinical examination, more remarkable cortical bone formation was found on the buccal and lingual side of the distracted area in the PRP treatment site than in the control site.Based on the radiological examination, a distinct increase in the radiopaque appearance of cortical bone of the PRP treatment site was revealed at two weeks. The histologic examination revealed that more bony trabeculae area was formed in the PRP treatment site than in the control site. Histomorphometric examinationrevealed that new bone formation were increased in the PRP treatment site than in the control site, and that were increased in the PRP treatment site at consolidation 1 week than in the control site at consolidation 2 weeks. In conclusion, PRPs stimulated early bone formation in the PRP treatment site manifest as early as two weeks. Trabeculae formation also increased throughout the whole period. If this result can be applied to further study, the consolidation period can be reduced by injecting PRP into the distracted area.