Biomechanical evaluation on bone regeneration in mandibular distraction osteogenesis combined with compression stimulation

Heo, June; Kim, Uk Kyu; Hwang, Dae Seok; Kim, Yong Deok; Shin, Sang Hun; Chung, In Kyo; Kim, Cheol Hun; Yun, Seok Young

Abstract

The purpose of this study was to investigate the clinical, biomechanical, and histologic changes in new distraction osteogenesis (DO) technique combined with a compression stimulation in accordance to different compression-distraction force ratio. 23 adult male rabbits underwent open-osteotomy at the mandibular body area and a external distraction device was applied. In the control group of 8 rabbits, only a 8 mm of distraction was performed by conventional DO technique. In an experimental group of 15 rabbits, a distraction followed by a compression force was performed according to the ratio of compression-distraction suggested by authors. The rate of experimental group I was set up as a 2 mm compression versus 10 mm distraction and the rate of experimental group II was set up as a 3 mm compression versus 11 mm distraction. All the rabbits were sacrificed for a gross finding, biomechanical, histomorphometric and histologic findings at the time of 55 days from the operation day. The results were as follows: 1. On the gross findings, because all rabbits had a sufficient healing time, every distracted new bone had good bone quality and we could not find any difference among all three groups. 2. In the histologic findings, rapid bone maturation (wide lamellar bone formation in the cancellous and cortical bone areas) was observed in two experimental groups compared to the control group. 3. On the bone density tests, the experimental group II showed higher bone density than the other experimental group and control group (control group - 0,2906 g/cm2, experimental group I - 0.2961 g/cm2, experimental group II - 0.3328 g/cm2). 4. On the biomechanical tests, the experimental group II had significantly higher bone microhardness than the other experimental group and control group (control group - 252.7 MPa, experimental group I - 263.5 MPa, experimental group II - 426.0 MPa). 5. On the microhardness tests, when we compared the hardness ratio of distracted bone versus normal bone, we could find experimental group II had significantly higher hardness ratio than the other experimental group and control group (control group - 0.47, experimental group I - 0.575, experimental group II - 0.80). From this study, we could deduce that the modified distraction osteogenesis method with a compression stimulation might improve the quality of bone regeneration and shorten the consolidation period in comparison with conventional distraction osteogenesis techniques.