| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1997: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1996: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
During the lengthening or stabilization phase of the gradual distraction technique, patients are at risk of pin loosening, fractures or infection in areas of new bone. The goal of combining electrical stimulation with the mandibular lengthening procedure is to accelerate the process of recovery of regenerate bone so that the device can be removed earlier in time to prevent complications. No previous investigations have studied the effect of electrical stimulation on the new bone formation during mandibular lengthening. This study was designed to examine if the use of electrical stimulation during mandibular lengthening accelerated the new bone formation.
Sixteen adult white female rabbits weighing from 2800 to 3200g underwent a left mandibular osteotomy. After a 3-days-latency period an external fixation device (Orthofix M-100) was activated at a rate of 0.7 mm per day for 10 days. Direct current electrical stimulators (ISO EBS-635, Tkyo) were placed on the backs of a stimulation group,
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consisting of eight rabbits. Stimulation of 10 muA was applied to the mandibles with two screws of the device used as electrodes during the lengthening phase. The other eight rabbits, the control group, were not stimulated. The device was then stabilized for periods of 10,20,30 and 60 days on both groups. A radiograph, a proportion of bone mineral density (%BMD), histological examination, and an amount of new bone formation area using an image analyzer (Densitograph, Atto, Tokyo) were used to evaluate the bone formation in the distraction gap. The BMD was measured by dual energy X-ray absorptiometry (DEXA) using a dichroma scan (DCS-3000, Aloka, Tokyo).
Results of the radiographic evaluation did not demonstrate significantly different images between the stimulation group and the control group. However, the histological examination showed that the new bone formation areas at 10 and 20 days after distraction were greater in the stimulation group than in the control group. Furthermore, at 10 and 20 days after distraction percentages of BMD and amounts of new bone formation areas indicated that there was a greater amount of new bone formation in the stimulation group than in the control group. No difference in the amount of new bone formation at 30 and 60 days after distraction was demonstrated between the stimulation group and the control group. These results suggest that electrical stimulation during gradual distraction promotes new bone formation on early stabilization periods. Less
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