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Alessandro Vichi

2012

Masking of temperature-induced color changes in a Thermo-sensitive fiber post

Purposes

To evaluate the efficiency of the color changing technology featured by the DT Light-Post Illusion aimed at safely identifying the post in case of retreatment and, the efficacy of a resin composite layer to mask the post if color shift occurs due to cold food and beverages.

Methods

Five "master disks" of 3 mm of thickness were prepared by embedding in a resin composite for thermo-sensitive posts and one translucent post (control) cut in bars. Discs of resin composite in 0.5/1.0/1.5 mm thickness were prepared as well. Digital images were taken of the master discs with and without the overlying of the resin composite discs, at 5° C and at 35° C temperature. By the use of Adobe Photoshop "layering function" and "multi-layer option", differences in color were calculated between the post-free and the post-containing areas.

Results

The differences between the resin color and the post color were remarkably higher when the temperature was at 5° C, showing that the technology of color change of the post was effective. With resin disk overlaid, at 35° see none of the differences in color were above the threshold for clinical acceptability. At 5° C blue and black colored posts were visible when the overlaid resin thickness was 0.5 mm, while at 1.0 mm and 1.5 mm, none of the posts were visible.

Clinical significance

Thermo-sensitive color pigment technology of DT Illusion was effective in selectively differentiating the post, by lowering the temperature, useful in case of endodontic re-treatment. Color changes due to cold food and beverage consumption were not visible if at least 1 mm of resin composite was layered over the post.