Influence of different ligation methods on force and moment generation in a simulated condition of the maxillary crowded anterior dentition with linguo-version and rotation.

BACKGROUND Most orthodontic cases consist of varying degrees of crowding. To manage crowded dentitions, nickel-titanium archwires with various ligation methods are often used. OBJECTIVE We aimed to investigate the effect of different ligation methods with respect to force and moment and suggest the efficient ligation method for treating rotation and displacement simultaneously. METHODS We built a model that simulated the three anterior teeth of the maxilla. The teeth on the two ends were fixed, and the middle tooth was set in several different positions by manipulating the amount of displacement in bucco-lingual direction and rotation angle. The measurements were taken with three different ligation methods of self-ligation (SL), elastomeric o-ring ligation on both side wings (EB), and on one side wings (EO). RESULTS The magnitude of linguo-buccal force exceeded the standard optimal force in each condition examined and was significantly larger in EB than in other ligation methods. Moreover, the magnitude of moment generation with SL was suitable in the 0.0 mm linguo-version, whereas it was suitable with EO in the linguo-version ranging 1.0-3.0 mm. CONCLUSIONS The ligation method significantly affected the force and moment. SL and EO are recommended in dentitions with light and deep lingual displacements, respectively.