title: Factors influencing efficiency of sliding mechanics to close extraction space: a systematic review.
abstract: OBJECTIVE
  To review recent literature to determine strength of clinical evidence concerning the influence of various factors on the efficiency (rate of tooth movement) of closing extraction spaces using sliding mechanics.
  
  
  METHODS
  A comprehensive systematic review on prospective clinical trials. An electronic search (1966-2006) of several databases limiting the searches to English and using several keywords was performed. Also a hand search of five key journals specifically searching for prospective clinical trials relevant to orthodontic space closure using sliding mechanics was completed. Outcome Measure - Rate of tooth movement.
  
  
  RESULTS
  Ten prospective clinical trials comparing rates of closure under different variables and focusing only on sliding mechanics were selected for review. Of these ten trials on rate of closure, two compared arch wire variables, seven compared material variables used to apply force, and one examined bracket variables. Other articles which were not prospective clinical trials on sliding mechanics, but containing relevant information were examined and included as background information. CONCLUSION - The results of clinical research support laboratory results that nickel-titanium coil springs produce a more consistent force and a faster rate of closure when compared with active ligatures as a method of force delivery to close extraction space along a continuous arch wire; however, elastomeric chain produces similar rates of closure when compared with nickel-titanium springs. Clinical and laboratory research suggest little advantage of 200 g nickel-titanium springs over 150 g springs. More clinical research is needed in this area.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, University of Missouri, Kansas City, MO, USA.
authors.forename: M
authors.initials: M
authors.lastname: Barlow
authors.forename: K
authors.initials: K
authors.lastname: Kula
mesh_terms: D001696:Biomechanical Phenomena; D002986:Clinical Trials as Topic; D006801:Humans; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D019516:Orthodontic Space Closure / Q000295:instrumentation / Q000379:methods*; D009969:Orthodontic Wires; D011446:Prospective Studies; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods