Effect of ligation method on maxillary arch force/moment systems for a simulated lingual incisor malalignment.
BACKGROUND
The objectives of this study were to determine whether there is a difference in the magnitude of forces and moments produced by elastic ligation when compared to passive ligation, and whether these forces and moments propagate differently along the arch for the two ligation types. A lingual incisor malalignment was used in this study.


METHODS
The Orthodontic Simulator (OSIM) was used to quantify the three-dimensional forces and moments applied on the teeth given a lingually displaced incisor. A repeated measures MANOVA was performed to statistically analyze the data.


RESULTS
The interaction factor illustrated convincing evidence that there is a difference in maximum force and moment values for all outcome variables between ligation types considering all tooth positions along the arch. The mean differences for FX and FY between ligation types were found to be clinically significant, with values for elastic ligation consistently higher than passive ligation.


CONCLUSIONS
It was found that the maximum forces and moments produced by elastic ligation are greater than those produced by passive ligation and that the magnitude of this difference for the mesiodistal and buccolingual forces is clinically relevant. Additionally, it was determined that elastic ligation causes forces and moments to propagate further along the arch than passive ligation for all outcome variables.
Lab Coordinator, Orthodontic Biomechanics Laboratory, University of Alberta, Edmonton, AB.
Surbhi
S
Seru
Postdoctoral Fellow, School of Dentistry, University of Alberta, Edmonton, AB.
Dan L
DL
Romanyk
Associate Professor, Department of Mechanical Engineering, University of Alberta, Edmonton, AB.
Roger W
RW
Toogood
Professor, Associate Chair Undergraduate Program (MecE), Department of Mechanical Engineering, University of Alberta, Edmonton, AB.
Jason P
JP
Carey
Professor, Senior Associate Dean, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB.
Paul W
PW
Major
Elastic ligation; force measurement; lingual incisor; orthodontic simulator; orthodontics; passive ligation.