title: Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.
abstract: BACKGROUND
  Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before.
  
  
  METHODS
  This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, β > 0.99). This trial was not registered. It was self-funded by the authors.
  
  
  RESULTS
  Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001).
  
  
  CONCLUSIONS
  Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.
authors.affiliation: Department of Orthodontics, Dental Faculty, Mazandaran University of Medical Sciences, Sari, Iran. farhad_sobouti@yahoo.com.
authors.forename: Farhad
authors.initials: F
authors.lastname: Sobouti
authors.affiliation: Department of Periodontics, Dental Faculty, Mazandaran University of Medical Sciences, Sari, Iran. mzkhatami@gmail.com.
authors.forename: Maziar
authors.initials: M
authors.lastname: Khatami
authors.affiliation: Laser Research Center of Dentistry, Dental Research Institute, Tehran University of Medical Sciences, Tehran, Iran. nasimch2002@yahoo.com.
authors.forename: Nasim
authors.initials: N
authors.lastname: Chiniforush
authors.affiliation: Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Tehran, Iran. vahid.rakhshan@gmail.com.|Department of Dental Anatomy and Morphology, Dental Branch, Islamic Azad University, Tehran, Iran. vahid.rakhshan@gmail.com.
authors.forename: Vahid
authors.initials: V
authors.lastname: Rakhshan
authors.affiliation: Craniomaxillofacial Surgery Research Center, Shariati Hospital, Tehran University of Medical Sciences, Postal Code: 14174, North Kargar Ave., 16 Azar ST, Tehran, Iran. mahsa.shariati@gmail.com.
authors.forename: Mahsa
authors.initials: M
authors.lastname: Shariati
mesh_terms: D000293:Adolescent; D002648:Child; D003481:Cuspid / Q000473:pathology; D003722:Dental Alloys / Q000737:chemistry; D005260:Female; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D008437:Maxilla / Q000528:radiation effects*; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D010146:Pain / Q000517:prevention & control*; D010147:Pain Measurement / Q000379:methods; D010919:Placebos; D016037:Single-Blind Method; D013193:Stainless Steel / Q000737:chemistry; D014087:Tooth Movement Techniques / Q000009:adverse effects* / Q000295:instrumentation; D055815:Young Adult
chemical_list: D003722:Dental Alloys; D010919:Placebos; D013193:Stainless Steel
keywords: Canine retraction; Helium-neon (He-Ne) laser; Laser irradiation; Low-level laser therapy (LLLT); Orthodontic pain; Placebo; Visual analog scale (VAS)