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Royal Bournemouth Hospital, Bournemouth, UK
Guy’s, King’s and St Thomas’ Dental Institute, London, UK
Address for correspondence: Professor Fraser McDonald, Department of Orthodontics, Floor 22, Guys Tower, GKT Dental Institute, St Thomas St, London SE1 9RT, UK. Email: fraser.mcdonald{at}kcl.ac.uk
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.
Design: Randomized controlled trial.
Settings: Patients under treatment in the Department of Orthodontics, Royal Bournemouth Hospital, Dorset, during a 6 month period from November 1999 to March 2000.
Subjects: 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.
Interventions: Treatment using upper and lower fixed appliances following extraction of four premolars. One group had lacebacks placed, whilst the control group had no lacebacks.
Main outcome measures: 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.
Key words: Randomized controlled trial, lacebacks, pre-adjusted edgewise appliance, straightwire
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  B. S. Khambay, S. McHugh, and D. T. Millett Magnitude and reproducibility of forces generated by clinicians during laceback placement J. Orthod., December 1, 2006; 33(4): 270 - 275. [Abstract] [Full Text] [PDF]
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J. Bennett, R. Irvine, S. Power, and F. Mcdonald Observations on the use and clinical effectiveness of lacebacks J. Orthod., December 1, 2005; 32(4): 294 - 296. [Full Text] [PDF]
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