Experimental Design of Vertical Distraction Osteogenesis Using Simple 3 Screws.

Distraction osteogenesis devices are complicated. To simplify these devices, we used 3 simple screws and 1 rubber band to realize the idea and analyzed histologic changes induced by mechanical forces. Ten female New Zealand white rabbits were studied. A left or right side of the mandible was randomly selected as the experimental side (ES). The unilateral mandible was distracted, and 2 fixation screws and 1 traction screw were implanted. When the traction screw was rotated downward, the opposite force made the osteotomy block move in opposite directions to increase the bone height. The control side (CS) was not processed. The results were assessed after 20 days of traction. Bone height in the ES increased by 5 mm. Toluidine blue staining showed that the number of osteoblasts per unit area on the ES was higher than that of the CS ( P <0.01). PerkinElmer showed that the expressions of proliferating cell nuclear antigen ( P =0.016) and collagen-I ( P =0.000) on the ES were higher than those on the CS. Transmission electron microscopy showed that the number of mitochondria, endoplasmic reticulum, and Golgi apparatus on the ES was significantly greater than the CS. The results confirmed that the 3 screws vertically increase the bone height. Mechanical force signals stimulate tissue activity and lead to significant cell proliferation and differentiation in the traction zone. Collagen-I may induce osteogenesis in the early stage of traction.