title: Influence of low-level laser on bone remodeling during induced tooth movement in rats.
abstract: OBJECTIVE
  To analyze the effect of low-level laser on bone remodeling during induced tooth movement in rats.
  
  
  METHODS
  A diode laser (808 nm, 100 mW, 54 J on an area of 0.0028 cm(2)) was used. The application was continuous, punctual, and with contact. Forty-two 70-day-old Wistar rats had the maxillary left first molar moved using a force level of 25 g. In two experimental subgroups the movement was performed over 7 days and in three subgroups the movement occurred over 14 days. In the 7-day movement subgroups, one subgroup received laser irradiation on day 1 only; the other subgroup received laser irradiation on days 1, 3, and 5. In the 14-day movement subgroups, one subgroup received laser irradiation on day 1 only; the second on days 1, 3, and 5; and the third on days 1, 3, 5, 7, 9, 11, and 13. The control group was also divided into two subgroups, and movement occurred over two different periods of treatment (7 days and 14 days) without laser application; these were used as controls for the respective experimental subgroups. Inter-subgroup comparison was performed with Kruskal-Wallis, followed by Mann-Whitney and analysis of variance, followed by Tukey tests within the 7- and 14-day subgroups.
  
  
  RESULTS
  The subgroup with three laser applications showed significantly greater osteoclastic activity and bone resorption than the other subgroups in the 7-day movement subgroups.
  
  
  CONCLUSIONS
  Low-level laser application significantly increased the osteoclastic but not the osteoblastic activity during the initial phases of tooth movement. In addition, the osteoclastic activity was dose-dependent.
authors.affiliation: a  Graduate student, Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Eliziane
authors.initials: E
authors.lastname: Cossetin
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
authors.forename: Maria Goretti F
authors.initials: MG
authors.lastname: de Carvalho
authors.forename: Rejane A
authors.initials: RA
authors.lastname: de Carvalho
authors.forename: José Fernando Castanha
authors.initials: JF
authors.lastname: Henriques
authors.forename: Daniela
authors.initials: D
authors.lastname: Garib
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology*; D000539:Alveolar Process / Q000528:radiation effects*; D000704:Analysis of Variance; D000818:Animals; D016723:Bone Remodeling / Q000528:radiation effects*; D005260:Female; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D010006:Osteoblasts / Q000166:cytology / Q000528:radiation effects; D010010:Osteoclasts / Q000166:cytology / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D014087:Tooth Movement Techniques / Q000295:instrumentation* / Q000379:methods