title: Impact of extracorporeal shock-wave therapy on the stability of temporary anchorage devices in adults: a single-center, randomized, placebo-controlled clinical trial.
abstract: BACKGROUND
  In this randomized, placebo-controlled clinical trial, we investigated the effect of noninvasive extracorporeal shock waves on the stability of temporary anchorage devices (TADs) under orthodontic loading.
  
  
  METHODS
  Thirty adult orthodontic patients of the Bernhard Gottlieb University Clinic in Vienna, Austria, were enrolled in this clinical trial and allocated by block randomization (size, 4) in a 1:1 ratio to either the treatment or the placebo group. Randomization was performed with software, and the allocations were concealed in sealed envelopes. Eligibility criteria included healthy adult patients with mesially directed orthodontic movement of the mandibular second molar into the extraction site of the mandibular first molar. The fixed orthodontic devices included active superelastic coil springs (200 cN) and TADs in the mandibular alveolar bone. Blinding was performed for the subjects and the outcome assessor. The treatment group received 1 shock-wave application with 1000 impulses at 0.19 to 0.23 mJ per square millimeter in the region of the TADs. The placebo group was treated with a deactivated shock-wave applicator and acoustic sham. The TADs positions were evaluated at placement and after 4 months. The reliability and precision of the impression process of the TADs were evaluated in an in-vitro model.
  
  
  RESULTS
  Thirteen participants finished the investigation successfully in the treatment group but only 12 finished in the placebo group because 1 TAD loosened. The difference of the total TAD displacement for the 4-month time period between the placebo and treatment groups was 0.17 ± 0.95 mm (95% CI: -0.96, 0.62). No statistically significant difference between the 2 groups was found when sex was evaluated. Primary stability of the TADs as measured by placement torque, amount of tooth movement, and age of the patients did not influence displacement of the TADs. The reliability and precision of TAD impressions were confirmed. No unintended pernicious effects occurred after shock-wave treatment during the study period.
  
  
  CONCLUSIONS
  A single application of extracorporeal shock-wave treatment did not improve the stability of the TADs during orthodontic loading. Sufficient interradicular space should be provided to minimize the risk of periodontal and dental root defects.
  
  
  BACKGROUND
  This trial was registered at https://clinicaltrials.gov.
  
  
  METHODS
  The protocol was published before trial commencement, NCT01695928.
  
  
  BACKGROUND
  No funding or conflict of interest to be declared.
authors.affiliation: Postdoctoral research fellow, Department of Orthodontics, Bernhard Gottlieb University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria. Electronic address: frank.falkensammer@meduniwien.ac.at.
authors.forename: Frank
authors.initials: F
authors.lastname: Falkensammer
authors.affiliation: Professor, Department of Orthodontics, Bernhard Gottlieb University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Rausch-Fan
authors.affiliation: Postdoctoral research fellow, Department of Oral Surgery, Bernhard Gottlieb University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Arnhart
authors.affiliation: Senior staff, Institute of Medical Statistics, Medical University of Vienna, Vienna, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Krall
authors.affiliation: Senior staff, Allgemeine Unfallversicherungsanstalt (AUVA) Trauma Center Meidling, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schaden
authors.affiliation: Professor, Department of Orthodontics, Bernhard Gottlieb University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Freudenthaler
mesh_terms: D000293:Adolescent; D000328:Adult; D000539:Alveolar Process / Q000528:radiation effects; D005260:Female; D005500:Follow-Up Studies; D019220:High-Energy Shock Waves; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008334:Mandible / Q000528:radiation effects; D008875:Middle Aged; D003765:Models, Dental; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D019516:Orthodontic Space Closure / Q000295:instrumentation; D009969:Orthodontic Wires; D010919:Placebos; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques / Q000295:instrumentation; D019415:Torque; D055815:Young Adult
chemical_list: D010919:Placebos