title: Effect of low-intensity pulsed ultrasound on orthodontically induced root resorption caused by torque: A prospective, double-blind, controlled clinical trial.
abstract: OBJECTIVE
  To evaluate the effects of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced tooth root resorption caused by torque in human subjects.
  
  
  METHODS
  Ten healthy patients (12-35 years of age) who required extraction of all first premolars as a part of their routine orthodontic treatment were recruited. A 15° twist was applied in the arch wire using 0.019 × 0.025-inch TMA in a 0.022-inch bracket system (Synergy R) that produced a buccal root torque of approximately 5 N/mm at the bracket level. Using a split mouth design, randomization, and blinding, one side of the arch received LIPUS for 20 minutes per day for 4 weeks at an incident intensity of 30 mW/cm(2) of the transducers' surface area. The other side served as a self-control, which received a sham transducer. After 4 weeks, all first premolars were extracted and micro-computed tomographic analysis was performed on these extracted teeth. A linear mixed-model statistical analysis was used.
  
  
  RESULTS
  LIPUS-treated teeth showed significantly less total volume of resorption lacunae compared to control teeth by a mean difference of (0.54 ± 0.09 mm(3)) (P < .001) and percentage of root resorption by a mean difference of (0.33 ± 0.05 mm(3)) (P < .001). In addition, significantly fewer resorption lacunae were found on all root surfaces in the LIPUS group compared to the control except in the instance of the distal surface.
  
  
  CONCLUSIONS
  This study was performed on limited number of cases during a 4-week period.
  
  
  CONCLUSIONS
  LIPUS minimizes root resorption when applied during torque tooth movement over a 4-week period.
authors.affiliation: a   Former Graduate Student, Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Hasnain
authors.initials: H
authors.lastname: Raza
authors.affiliation: b   Professor and Chair, School of Dentistry, Senior Associate Dean, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Major
authors.affiliation: c   Professor of Periodontics, School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Douglas
authors.initials: D
authors.lastname: Dederich
authors.affiliation: d   Associate Professor, Department of Orthodontics, School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Tarek
authors.initials: T
authors.lastname: El-Bialy
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003739:Dental Cementum; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012391:Root Resorption; D014087:Tooth Movement Techniques; D019415:Torque; D000069453:Ultrasonic Waves; D055815:Young Adult
keywords: Human; LIPUS; Low-intensity pulsed ultrasound; Orthodontic root resorption; Torque