@article{oai:tmdu.repo.nii.ac.jp:00000973,
 issue = {4},
 journal = {The bulletin of Tokyo Medical and Dental University},
 month = {Dec},
 note = {The orthodontic tooth movement may be considered to be affected by hormones. An attempt was made to examine the relation between parathyroid hormone and osteoclast activity during tooth movement. One hundred and thirty-four Wistar strain rats were divided into three groups; sham-operated, parathyroidectomized, and parathyroidectomized plus parathyroid extract treated. Then the experimental tooth movement was made on the upper right first molar. Observations were done histologically on the interradicular septum of the first molar, and osteoclasts were counted for the purpose of estimating the degree of bone resorption quantitatively. The findings are summarized as follows: 1. Incident to the experimental tooth movement, the decrease of parathyroid hormone results in the inhibition of the appearance of osteoclasts and bone resorption on the compression side, as well as the appearance of osteoblasts on the tension side. 2. The increase of parathyroid hormone results in the accelation of the appearance of osteoclasts and bone resorption on the compression side, and the inhibition of the appearance of osteoblasts on the tension side.},
 pages = {411--425},
 volume = {19},
 year = {1972}
}