title: Histomorphometric study on the effects of age on orthodontic tooth movement and alveolar bone turnover in rats.
abstract: The aim of this study was to investigate, in a rat model, the effects of age on the amount of tooth movement and concomitant changes in alveolar bone turnover activity adjacent to orthodontically treated tooth roots. Rats (n = 48) of four different age groups (10, 30, 50, and 80 wk of age) were used in the experiment. Maxillary first molars were tipped mesially with a nickel titanium alloy coil-spring for 2 wk by a continuous force of 10 cN. Forty-eight age-matched untreated rats were used as controls. The changes in alveolar bone turnover were assessed histomorphometrically. Two weeks after the start of tooth movement, the amount of tooth movement was found to decrease with age and was significantly different among the four age groups. The histomorphometric study demonstrated that, in all experimental groups, turnover of alveolar bone increased significantly compared with that of each age-matched untreated group. However, the rate of increase decreased in an age-related manner. These results suggest that the age-dependent decrease in alveolar bone turnover activity, in response to mechanical forces, may negatively affect the amount of tooth movement.
authors: Department of Orthodontics, Graduate School of Oral Medicine, Shiojiri, Japan.
authors: Yasuko
authors: Y
authors: Misawa-Kageyama
authors: Toru
authors: T
authors: Kageyama
authors: Keita
authors: K
authors: Moriyama
authors: Saburo
authors: S
authors: Kurihara
authors: Hiroshi
authors: H
authors: Yagasaki
authors: Toshio
authors: T
authors: Deguchi
authors: Hidehiro
authors: H
authors: Ozawa
authors: Noriyuki
authors: N
authors: Sahara
mesh_terms: D000367:Age Factors; D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D008297:Male; D008963:Molar; D051381:Rats; D017208:Rats, Wistar; D014087:Tooth Movement Techniques / Q000295:instrumentation; D020390:Tooth Socket / Q000502:physiology / Q000648:ultrastructure*