title: Estrous-cycle-dependent variation in orthodontic tooth movement.
abstract: Sex hormones, including estradiol, play important physiological roles in bone metabolism. The purpose of this study was to investigate whether there is estrous-cycle-dependent variation in orthodontic tooth movement, and, if so, to determine the mechanism. Ten-week-old female Wistar rats were used. They received repeated orthodontic force during specific phases in the estrous cycle. Tooth movement in animals that received force principally in estrus was about 33% greater than that in animals that received such force principally in pro-estrus (p < 0.05). Serum estradiol levels also varied according to the estrous cycle, with a peak during pro-estrus and a nadir during estrus, and were inversely related to tooth movement. Furthermore, there were negative correlations between estradiol and both serum TRAP activity and pyridinoline (r = -0.42, p < 0.05; r = -0.59, p < 0.001). These results suggest that cyclic changes in the estradiol level may be associated with the estrous-cycle-dependent variation in tooth movement through its effects on bone resorption.
authors.affiliation: Division of Orthodontics, Department of Life-Long Oral Health Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Haruyama
authors.forename: K
authors.initials: K
authors.lastname: Igarashi
authors.forename: S
authors.initials: S
authors.lastname: Saeki
authors.forename: M
authors.initials: M
authors.lastname: Otsuka-Isoya
authors.forename: H
authors.initials: H
authors.lastname: Shinoda
authors.forename: H
authors.initials: H
authors.lastname: Mitani
mesh_terms: D000135:Acid Phosphatase / Q000097:blood; D000596:Amino Acids / Q000097:blood; D000704:Analysis of Variance; D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D002118:Calcium / Q000097:blood; D004958:Estradiol / Q000097:blood / Q000378:metabolism; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D007527:Isoenzymes / Q000097:blood; D015675:Osteocalcin / Q000097:blood; D010758:Phosphorus / Q000097:blood; D011374:Progesterone / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D000071681:Tartrate-Resistant Acid Phosphatase; D014087:Tooth Movement Techniques
chemical_list: D000596:Amino Acids; D007527:Isoenzymes; D015675:Osteocalcin; D010758:Phosphorus; D011374:Progesterone; D004958:Estradiol; C015484:pyridinoline; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002118:Calcium