Long-term follow-up of enamel color changes after treatment with fixed orthodontic appliances

The aim of this study was the long-term follow-up of enamel color changes observed in the middle third of buccal tooth surfaces after treatment with fixed orthodontic appliances.

The study included 120 maxillary central and lateral incisors and canines of 20 subjects who had fixed orthodontic treatment. The Spectro Shade Micro device (MHT, Verona, Italy) was used to evaluate the color changes of the teeth. Measurements were made from the middle third of the buccal surfaces of the teeth after fixed orthodontic treatment and in month 3, month 6, and year 1 of the retention phase. The Commission Internationale de l'Echairage L* a* b* system that expresses the color coordinates in L*, a*, and b* symbols was used to determine the tooth color, and ΔE values between the time periods were calculated. Repeated measurement analysis of variance was used in evaluating the color changes.

The increases in ΔL values at 3 months, 6 months, and 1 year after treatment were statistically significant, whereas they were not statistically significant from months 3 to 6, month 3 to year 1, or month 6 to year 1. The decrease in Δa and the increase in Δb values were not statistically significant. ΔE values at all time periods were statistically significant within themselves, and the greatest change was observed 1 year after treatment. ΔE values were 1.52 to 3.57, and a visible but clinically acceptable color change occurred.

In the first 3 months, there was a significant increase in the lightness of the tooth color.