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

Abstract

Frictional resistance at the bracket-archwire interface has been demonstrated to impede tooth movement when sliding mechanics are used. Thus, the coefficients of friction of titanium and stainless steel brackets used in conjunction with stainless and ion-implanted beta-titanium archwires were investigated using a single contact interface between the brackets and archwires. The wear patterns between the brackets and the.016- in flat archwire surfaces were also examined using scanning electron microscopy and energy dispersive x-ray analysis. Stainless steel brackets tested with.016-in flat stainless steel wire surfaces recorded the lowest coefficient of static friction mean (0.289), whereas titanium brackets paired with.016-in flat ion-implanted beta-titanium wire surfaces produced the highest mean (0.767). Stainless steel brackets had significantly (P <.05) lower coefficients of friction than titanium brackets for all wires except.020-in round stainless steel wires. Ion-implanted beta-titanium wires generally had significantly larger coefficients of friction than stainless steel wires. The increased friction of the titanium and ion-implanted beta-titanium alloys is also reflected in the severity of their wear patterns. An inverse relationship between friction and archwire surface dimension was generally found for ion-implanted beta-titanium wires. Round stainless steel wires demonstrated lower coefficients of kinetic friction than the flat stainless steel wire surfaces. (Am J Orthod Dentofacial Orthop 2000;118:662-74)