The friction and wear patterns of orthodontic brackets and archwires in the dry state

Frictional resistance at the bracket-archwire interface has been demonstrat ed to impede tooth movement when sliding mechanics are used. Thus, the coef ficients of friction of titanium and stainless steel brackets used in conju nction with stainless and ion-implanted beta-titanium archwires were invest igated using a single contact interface between the brackets and archwires. The wear patterns between the brackets and the .016-in flat archwire surfa ces were also examined using scanning electron microscopy and energy disper sive x-ray analysis. Stainless steel brackets tested with .016-in flat stai nless steel wire surfaces recorded the lowest coefficient of static frictio n mean (0.289), whereas titanium brackets paired with .016-in flat ion-impl anted beta-titanium wire surfaces produced the highest mean (0.767), Stainl ess steel brackets had significantly (P < .05) lower coefficients of fricti on than titanium brackets for all wires except .020-in round stainless stee l wires. ion-implanted beta-titanium wires generally had significantly larg er coefficients of friction than stainless steel wires. The increased frict ion of the titanium and ion-implanted beta-titanium alloys is also reflecte d in the severity of their wear patterns, An inverse relationship between f riction and archwire surface dimension was generally found for ion-implante d beta-titanium wires. Round stainless steel wires demonstrated lower coeff icients of kinetic friction than the flat stainless steel wire surfaces.