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Colour stability of visible light-curing hybrid composites
A Leibrock1, M Rosentritt, R Lang
1Department of Prosthetic Dentistry, University of Regensburg, Germany.
Summary
This study assessed the color stability of dental composites under light exposure. Most composites showed clinically acceptable color changes after 24 hours, but significant discoloration occurred after 120 hours.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Biomaterials
Background:
- Dental composites are widely used restorative materials.
- Color stability is a critical aesthetic parameter for dental restorations.
- Visible light-curing fine hybrid composites are common in clinical practice.
Purpose of the Study:
- To evaluate the color stability of six visible light-curing fine hybrid composites.
- To assess discoloration after 24 and 120 hours of xenon lamp irradiation.
- To compare the color stability of different shades and brands.
Main Methods:
- Six brands of fine hybrid composites were tested.
- Four shades (A1, A2, A3.5, B2) of each material were used.
- Irradiation was performed using a xenon lamp for 24 and 120 hours.
- Color change was measured using a reflection spectrophotometer (CIE-L*a*b* system).
Main Results:
- After 24 hours, discoloration (0.7–3.8 DE*) was generally clinically acceptable, except for Z 100 (A1, B2).
- Pekafill NF and Tetric showed significantly less color difference compared to other composites.
- After 120 hours, most samples exhibited increased discoloration (3.7–7.8 DE*), with Pekafill NF (A3.5, B2) being an exception.
- Composites generally shifted towards yellow (increased b*), darker (decreased L*), and slightly greener (increased a*).
Conclusions:
- Color stability varies among visible light-curing fine hybrid composites.
- Extended light exposure significantly impacts the color stability of most tested materials.
- Pekafill NF and Tetric demonstrated superior color stability, particularly after prolonged irradiation.