1995 年 15 巻 2 号 p. 105-118
The purpose of this study was to determine whether the application of pulsed electromagnetic fields (PEMFs) could accelerate bone formation in the midpalatal suture after rapid maxillary expansion. Nine adult male dogs were divided into three groups. Group 1 (N=1) was kept as a sham operation control. Group 2 (N=4) was treated for 2 weeks and then separated into a non-PEMF and a PEMF-stimulated subgroup. Group 3 (N=4) was also separated as group 2 was but treated for 3 weeks. The maxilla was rapidly expanded for 1 week and left for retention of 1 or 2 weeks. The experimental groups were stimulated by PEMFs for 10 hours daily. The PEMF appliance was set to produce the specific asymmetrical repetitive 200 its pulses in burst of 4.8 ms repeated at a 15 Hz rate. Tetracycline and calcein were intramuscularly injected at intervals according to the experimental schedule. Soft X-ray photographs were taken and frontal sections of undecalcified and decalcified tissues were prepared. Contact microradiographs were then taken and bone histomorphometry was applied to quantify the areas of new bone formation. After 2 or 3 weeks of PEMF stimulation, the bone formation rate and mineral apposition rate, including total new bone volume, in the experimental groups were significantly increased. The results suggested that PEMFs enhanced acceleration of bone formation rate in midpalatal suture after rapidly maxillary expansion treatment and should be considered for clinical orthodontic application in the near future.
