title: The effect of low level laser therapy on the rate of tooth movement and pain perception during canine retraction.
abstract: OBJECTIVE
  This study investigated the effect of an 810 nm gallium-aluminum-arsenide (Ga-Al-As) laser on tooth movement velocity and pain perception during canine retraction in orthodontic patients.
  
  
  METHODS
  This single blind study included 20 patients requiring upper first premolar extraction on both sides. One half of the upper arch was irradiated with a GaAlAs laser (810 nm, 200 mW, 10 points, 21.4 J/cm2/point) and the other half served as the placebo group. Irradiation was performed just after loading canine retraction forces and on days 3, 7, 11 15 over the first month. At the 28th day, the coil spring was adjusted and the same protocol was continued. The extension of tooth movement and the degree of mesiodistal inclination of canines were measured on the study models prepared at 0, 28 and 56 days. The patients were also asked to bite on plastic blocks to examine the degree of pain perceived on canines at both sides.
  
  
  RESULTS
  There was no significant difference either in the speed of canine movement or in its degree of mesiodistal inclination between the laser and placebo sides. The pain perception did not differ significantly between the two groups at any of the treatment appointments.
  
  
  CONCLUSIONS
  Low level laser therapy (LLLT), with the parameter settings used in this study, did not affect canine movement velocity and its degree of mesiodistal inclination and did not influence pain perceived by the patients.
authors.affiliation: Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Vakilabad Boulevard, Mashhad, Iran, Tel: +98 511 8829502; Fax: +98 511 8829500; Mobile: +98-9151155802; e-mail: Farzaneh.Ahrari@gmail.com, AhrariF@mums.ac.ir.
authors.forename: Farzin
authors.initials: F
authors.lastname: Heravi
authors.forename: Amir
authors.initials: A
authors.lastname: Moradi
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Ahrari