Effects of gradually increasing force generated by permanent rare earth magnets for orthodontic tooth movement.
Effects of gradually increasing force generated by permanent rare earth magnets for orthodontic tooth movement.
复制标题
稀土永磁体产生的逐渐增加的力对正畸牙齿移动的影响。
DOI：
10.2319/071805-237
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
H. Mitani
中科院分区：
文献类型：
--
作者：
R. Tomizuka;H. Kanetaka;Y. Shimizu;A. Suzuki;K. Igarashi;H. Mitani
客观的
OBJECTIVE
To examine the effects of gradually increasing force generated by permanent rare earth magnets for orthodontic tooth movement by using a novel experimental rat model and computer simulation.
MATERIALS AND METHODS
Fifty-five male rats (age 18 weeks) were used as animal experiments. Magnetic (experimental groups) or titanium (control group) cuboids (1.5 x 1.5 x 0.7 mm) were bonded to the lingual surface of the maxillary first molars. The initial distance between materials was 1.0 mm, generating 4.96 gf (experimental group I), or 1.5 mm, generating 2.26 gf (experimental group II). Tooth movement was measured and periodontal structures were observed with microfocus x-ray computed tomography radiographs.
RESULTS
The distance between the magnets decreased with time in experimental groups I and II (P < .001), whereas there was no tooth displacement in the control group. Experimental group I showed rapid tooth movement in the initial phase followed by slower tooth movement. Experimental group II showed gradual tooth movement. Horizontal sections on microfocus computed tomgraphy radiographs revealed no pathological changes, such as root resorption, on the compressed side in the experimental groups.
CONCLUSIONS
The initial light force and gradual increasing force in magnetic attractive force induced effective tooth movement in rats without inducing any pathological changes.