Comparison of gene expression of osteogenic factors between continuous and intermittent distraction osteogenesis in rabbit mandibular lengthening

Objectives. This study aimed to evaluate the effect of distraction frequency on the gene expression of osteogenic mediators in mandibular distraction osteogenesis. Study design. Forty adult New Zealand white rabbits were randomly assigned to the continuous and intermittent distraction groups. Unilateral mandibular osteotomy was performed and custom-designed manual-driven or autodriven distractor was bridged over the osteotomy segments. Animals were humanely killed at day 6, day 10, day 14, and day 21 after osteotomy. mRNA expression of the osteogenic mediators in the distraction regenerate was examined by real-time polymerase chain reaction. Results. The expression of transforming growth factor-beta(1) was significantly higher at day 6, and the expression of the bone morphogenetic protein-2 was significantly higher from day 6 to day 14, in the continuous distraction group. Conclusion. High-frequency traction up-regulates the expression of osteogenic mediators contributing to the enhanced bone formation. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: 496-499)