Dental material science has paid more attention to mechanical properties of as-received materials than to changes produced after intraoral exposure. Orthodontic archwires when exposed to the intraoral environment have shown a significant increase in the degree of debris, surface roughness (Ra), and frictional force. The purpose of this split-mouth study was to evaluate the effects of two methods of archwire cleaning on these variables after clinical use for 8 weeks. For eight individuals, four sets of three brackets each (n = 32) were bonded from the first molar to the first premolar. A passive segment of 0.019 × 0.025 inch stainless steel (SS) archwire was inserted into the brackets and tied by elastomeric ligature. Debris level [via scanning electron microscopy (SEM)], Ra, and frictional force were evaluated in a paired comparison after 8 weeks of intraoral exposure and after cleaning with a steel wool sponge (SWS) for 1 minute or ultrasound (US) cleaning for 15 minutes. Kruskal–Wallis, Friedman’s, and Spearman and Pearson correlation tests were used for statistical analysis.
The debris and Ra of SS rectangular wires increased significantly (P < 0.05) during clinical use, causing a significant increase in the frictional force level. These changes can be effectively eliminated by either of the investigated cleaning methods, although a SWS seems to be clinically more practical.