Enamel Color Changes at Debonding and After Finishing Procedures

Material and Method: 75 non-carious premolars were used for the study. The teeth were randomly divided into five groups of 15 each, brackets were bonded with five different adhesives (Transbond XT, 3M Unitek, Monrovia, Calif, USA; Eagle Bond, American Orthodontics, Sheboygan, WI, USA; Light Bond, Reliance Orthodontic Products Inc, Itasca, ILL, USA; blugloo, Ormco, Glendora, CA, USA; Unite, 3M Unitek, Monrovia, Calif, USA) and samples were subjected to artificial accelerated photo ageing for 24 hours. The enamel surfaces were colorimetrically evaluated before bonding; following debonding and cleaning with tungsten carbide bur and after polishing with Stainbuster (Abrasive Technology, Inc. Ohio, USA). All measurements were performed at the intersection area of middle third vertical and middle third mesiodistal of the buccal surfaces to facilitate a means to standardize the enamel surface intended for analysis. The CIE color parameters (L*, a*, b*) were recorded and color differences (ΔE) were calculated. The results were statistically analyzed by Kruskall Wallis test. Further investigation among sub-groups was performed using Dunn's multiple correlation test (p<0.05). The clinical detection threshold for ΔE value was set at 3.7 units.

Results: ΔE values between the first and second measurements showed an increase in the Transbond XT, Eagle Bond and Light Bond groups. No difference was observed in groups bonded with blugloo and Unite. The highest ΔE value in this study was recorded as 1.51±1.15. No clinically significant ΔE value was recorded.

Conclusion: Color changes of orthodontic bonding systems induced by photo ageing cannot be clinically observed. Polishing by stainbuster eliminates enamel surface roughness, which may improve reflection of light.