Forces Produced by Different Nonconventional Bracket or Ligature Systems during Alignment of Apically Displaced Teeth

Introduction: The aim of this study was to analyze the forces released by 4 types of passive stainless steel self-ligating brackets and 2 nonconventional elastomeric ligature bracket systems compared with conventional elastomeric ligatures on stainless steel brackets during the alignment of buccally displaced teeth. Methods: A model consisting of 5 brackets (from second premolar through central incisor) was used to assess the forces released by the 7 bracket-ligature systems with 0.012- or 0.014-in superelastic wires with various amounts of buccal canine displacement (1.5-6.0 mm). The comparisons between the different types of bracket-wire-ligature systems were performed with 3-way ANOVA with the Tukey post-hoc test (P<0.05). Results: For buccal misalignments of 1.5 and 3.0 mm, both low-friction and conventional systems released forces for bracket alignment ranging from about 30 to 160 g. For greater buccal displacements (4.5 and 6.0 mm), the low-friction systems produced a significant magnitude of force, but it dropped to 0 g for the conventional system. Conclusions: Nonconventional elastomeric ligature bracket systems produced levels of force for tooth movement that were similar to those generated by passive self-ligating brackets.