Influence of prophylactic fluoride agents on the color changes and surface roughness of polymer and rhodium coated nickel-titanium orthodontic archwires

The effect of fluoride use on the color change and surface characteristics of coated nickel and titanium (NiTi) orthodontic archwires was investigated. Epoxy resin, PTFE or rhodium-coated archwires were exposed to acidulated phosphate fluoride (APF) or sodium fluoride (NaF) or artificial saliva (AS), simulating three-month clinical trials. Color changes (∆E) were assessed using a laboratory spectrophotometer in the three-dimensional CIELab color space. The roughness (Ra) and surface structure of the archwires were examined using a non-contact profilometer and scanning electron microscopy (SEM), respectively. Data were analyzed using two-way and one-way variance (ANOVA) and post-hoc Bonferroni test (α=0.05). The average values of ∆E and Ra were the highest for epoxy-APF archwires and the lowest for rhodium-AS archwires. A significant relationship was found between the archwires surface treatment method and the ∆E and Ra values. After three months, greater changes in color and roughness were observed with APF than with AS.