title: Treatment efficiency of conventional vs self-ligating brackets: effects of archwire size and material.
abstract: BACKGROUND
  In this prospective clinical study, we assessed the relative speed of archwire changes, comparing self-ligating brackets with conventional elastomeric ligation methods, and further assessed this in relation to the stage of orthodontic treatment represented by different wire sizes and types.
  
  
  METHODS
  The time taken to remove and ligate archwires for 131 consecutive patients treated with either self-ligating or conventional brackets was prospectively assessed. The study was carried out in the orthodontic department of a district general hospital in the United Kingdom. The main outcome measure was the time to remove or place elastomeric ligatures or open/close self-ligating brackets for 2 matched groups of fixed appliance patients: Damon2 self-ligating bracket (SDS Ormco, Orange, Calif) and a conventional mini-twin bracket (Orthos, SDS Ormco). The relative effects of various wire sizes and materials on ligation times were investigated. The study was carried out by 1 operator experienced in the use of self-ligating and conventional brackets.
  
  
  RESULTS
  The Damon2 self-ligating system had a significantly shorter mean archwire ligation time for both placing (P <.001) and removing (P <.01) wires compared with the conventional elastomeric system. Ligation of an archwire was approximately twice as quick with the self-ligating system. Opening a Damon slide was on average 1 second quicker per bracket than removing an elastic from the mini-twin brackets, and closing a slide was 2 seconds faster per bracket. This difference in ligation time between the Damon2 and the conventional mini-twin brackets became more marked for larger wire sizes used in later treatment stages.
  
  
  CONCLUSIONS
  The type of bracket and the size of wire used are statistically significant predictors for speed of ligation and chairside time. The self-ligating system offered quicker and arguably more efficient wire removal and placement for most orthodontic treatment stages.
authors.affiliation: Orthodontic Department, Queen Alexandra Hospital, Portsmouth, Hampshire, United Kingdom. nicholasturnbull@hotmail.com
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Turnbull
authors.forename: David J
authors.initials: DJ
authors.lastname: Birnie
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008297:Male; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D009971:Orthodontics, Corrective / Q000379:methods*; D011446:Prospective Studies; D013997:Time Factors