In-vitro evaluation of frictional resistance between brackets with passive-ligation designs

No significant bracket differences were found when binding occurred in second-order distances. In an ideal arch alignment, brackets with greater slot lumen have lower frictional resistance. First-order rotational control was influenced by slot depth, bracket width, and labial cover of the brackets with the same archwire. When a sliding mechanism was used with a third-order inclination change, the brackets with smaller third-order critical contact angles had greater frictional resistance.