Effects of low-energy laser irradiation on bone remodeling during experimental tooth movement in rats.
OBJECTIVE
Low-energy laser irradiation has many anabolic effects such as the acceleration of bone formation. However, its effects on tooth movement, performed by bone resorption and formation, have not been well characterized.


METHODS
A total of 10 g of orthodontic force was applied to rat molars to cause experimental tooth movement. A Ga-Al-As diode laser was used to irradiate the area around the moved tooth, and after 12 days, the amount of tooth movement was measured. Calcein was injected subcutaneously to label the newly formed alveolar bone for quantitative analysis. Immunohistochemical staining of proliferating cell nuclear antigen was performed to evaluate cellular proliferation. TRAPase staining was also performed to facilitate the identification of osteoclasts.


RESULTS
In the laser irradiation group, the amount of tooth movement was significantly greater (1. 3-fold) than that of the nonirradiation group in the end of the experiment. The amount of bone formation and rate of cellular proliferation in the tension side and the number of osteoclasts in the pressure side were all significantly increased in the irradiation group when compared with the nonirradiation group (P < 0. 01).


CONCLUSIONS
These findings suggest that low-energy laser irradiation can accelerate tooth movement accompanied with alveolar bone remodeling.
Kawasaki
K
K
Department of Orthodontics, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
Shimizu
N
N
D000539:Alveolar Process / Q000166:cytology / Q000528:radiation effects*; D000818:Animals; D016723:Bone Remodeling / Q000528:radiation effects*; D007150:Immunohistochemistry; D053685:Laser Therapy; D007834:Lasers; D008297:Male; D008963:Molar / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014087:Tooth Movement Techniques