title: The effectiveness of laceback ligatures: a randomized controlled clinical trial.
abstract: OBJECTIVE
  To evaluate the effects of laceback ligatures on the anteroposterior and vertical position of lower incisors and the mesial position of the lower first molars.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  Patients under treatment in the Department of Orthodontics, Royal Bournemouth Hospital, Dorset, during a 6 month period from November 1999 to March 2000.
  
  
  METHODS
  Sixty-two adolescents (mean 13.7 years, range 11.2-16.8 years) with similar malocclusions, requiring extraction of all first premolars, were randomly assigned to experimental (laceback: 30; 12 male, 18 female) and control (non-laceback: 32; 14 male, 18 female) groups.
  
  
  METHODS
  Treatment using upper and lower fixed appliances following extraction of four premolars. One group had lacebacks placed, whilst the control group had no lacebacks.
  
  
  METHODS
  The participants were examined clinically and radiographically, and lateral cephalograms with radio-opaque tooth markers and lower study casts records were taken when lower fixed appliances were placed (T1) and following sufficient leveling with a 0.018 inch stainless steel round wire (T2). Linear measurements were recorded following digitization of the lateral cephalograms and using a vernier caliper on the study casts. A Student t-test was used to examine differences between the two groups following assessment for normality.
  
  
  RESULTS
  In both groups the lower incisors retroclined during T1-T2; (Mean+/-SD: Experimental -0.53+/-1.9 mm, Control -0.44+/-1.29 mm). There was no statistical significance between the two groups (p = 0.84). The lower incisors extruded in both groups; 0.47+/-0.98 mm in the experimental group and 0.44+/-0.87 mm in the control group. There was no statistical difference between the groups (p = 0.9). The lower first molars showed 0.83 mm greater mesial movement in the experimental group, which was statistically significant (p < 0.05). Labial segment crowding decreased in both groups (experimental -3+/-1.6 mm, control -2.67+/-2.28 mm), the difference between the groups being non-significant (p = 0.51). Arch length decreased in both groups (experimental -2.08+/-2.82 mm , control -2.9+/-3.06 mm), but the difference between them was not significant (p = 0.28)
  
  
  CONCLUSIONS
  In first premolar extraction cases, the lower labial segment does not procline during the leveling stage with the pre-adjusted edgewise appliance and the use of laceback ligatures conveys no difference in the anteroposterior or vertical position of the lower labial segment. Furthermore, the use of laceback ligatures creates a statistically and clinically significant increase in the loss of posterior anchorage.
authors.affiliation: Royal Bournemouth Hospital, Bournemouth, UK.
authors.forename: R
authors.initials: R
authors.lastname: Irvine
authors.forename: S
authors.initials: S
authors.lastname: Power
authors.forename: F
authors.initials: F
authors.lastname: McDonald
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000601:surgery; D016022:Case-Control Studies; D002508:Cephalometry; D002648:Child; D003724:Dental Arch / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000473:pathology; D008297:Male; D008310:Malocclusion / Q000628:therapy; D003765:Models, Dental; D008963:Molar / Q000473:pathology; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D012690:Serial Extraction; D013193:Stainless Steel; D014087:Tooth Movement Techniques / Q000295:instrumentation
chemical_list: D013193:Stainless Steel