Color stability and fluorescence of different orthodontic esthetic archwires

Abstract

Objective: To evaluate the color stability of six esthetic archwires at different time periods and their fluorescence.

Materials and methods: Samples were evaluated after 7, 14, and 21 days of immersion in staining solution. Color measurements were performed by means of a spectrophotometer according to the Commission Internationale de I'Eclairage L*a*b* system, and color changes (ΔE*) and National Bureau of Standards units were computed. The fluorescence of as-received samples was evaluated by two observers and compared with that of a bovine central incisor. Statistical differences were investigated using analysis of variance and Tukey's post hoc test.

Results: All brands showed statistically significant color change after 21 days (ΔE* from 1.88 to 12.06). The Optis archwire (fiber-reinforced composite) presented the highest color alteration, although staining was observed only near its ends. The Trianeiro archwire (coated nickel-titanium) and the Ortho Organizers archwire (coated stainless steel) presented with less color change. The Optis archwire was the only one that presented with fluorescence similar to that of bovine teeth.

Conclusions: All esthetic archwires assessed showed clinically noticeable color change after 21 days in staining solution. The optical properties of currently available esthetic archwires may not yet be ideal.

Figure 1.

Stereoscopic images of Optis archwire tips cut (upper) and as received (lower) after immersion in staining solution for 21 days. (A) At 12× magnification. (B) At 45× magnification.

Figure 2.

Scanning electron microscope photomicrographs of Optis archwire. (A,C) Longitudinal and cross-sectional views of as-received tip; (B,D) longitudinal and cross-sectional views of the tip of the archwire cut with wire cutter.