effect of elastomeric module degradation and ligation methods on kinetic friction between niti or stainless steel wires and stainless steel brackets

Objectives: the reduction of resistance to sliding between the archwire and bracket promotes more seamless tooth movement, leading to a faster and improved orthodontic treatment experience. this research aimed to examine how the degradation of elastomeric modules, different ligation methods, bracket-wire angle, and wire type (nickel titanium, niti or stainless-steel, ss) impact the kinetic friction resulting from the interaction between niti or ss archwires and ss brackets.materials and methods: the current in vitro study was conducted on nine groups, including niti and ss archwires with three types of ligations (o-ring, figure of 8, and ss wire ligature) and two bracket-wire angles (0˚ and 10˚). the kinetic friction in each group was measured using a universal testing machine at four time intervals: baseline, day one, week one, and week four. repeated measures anova, mauchly test of sphericity followed by the greenhouse-geisser test, and relevant post hoc tests were used for statistical analysis (p<0.05).results: the authors found a decrease in kinetic friction in all types of ligations, which confirmed the effect of time on the degradation of ligation modules. the kinetic friction of figure of 8 ligations was higher than both o-ring and ss wire ligations. no difference was observed between o-ring and ss wire ligations. furthermore, the bracket-wire angle did not affect friction.conclusion: the authors suggest that the use of figure of 8 ligations in niti and ss wires should be limited due to their high friction and replaced with other types of ligations, if possible.