The aim of this work was first to study frictional forces between brackets and different arch wires, second to determine the influence of sterilization and surface treatment on the orthodontic arch wire friction coefficient. One type of bracket was chosen (stainless steel) and four kinds of wires were tested (NiTi and Ti-Mo alloys). Half of the wires were sterilized by autoclaving. Vickers hardness and roughness measurements were performed on each surface. The friction coefficient was calculated for various bracket/wire pairs at different times during the tribological test. EDX-SEM analysis was performed before and after friction tests on the surfaces and on wear debris. It was shown that TMA samples' friction coefficient and hardness are higher than those of NiTi whereas roughness is lower. The overall results highlighted two types of tribological response: abrasive and adhesive behavior. The sterilization process and surface treatment induced no significant modification of the tribological properties of any of the samples. Thus, it is important to encourage dental practitioners to practice autoclaving onto arch wires before clinical application; however, these results did not show clearly the advantage of using surface treated wires (no details available on the treatment process).