Discoloration of Coating Resins Exposed to Staining Solution The Influence of Different Surface Conditions

• Published in: Dental Medicine Research Vol. 32; no. 2; pp. 74 - 80
• Main Authors: YAMAGUCHI, Mai, HISAMITSU, Hisashi, MANABE, Atsufumi
• Format: Journal Article
• Language: English; Japanese
• Published: Showa University Dental Society 31.07.2012
• Subjects: coating resin; color difference; discoloration; staining solution
• ISSN: 1882-0719; 2186-540X
• DOI: 10.7881/dentalmedres.32.74

This study evaluates in vitro the effects of discoloration induced by coating resins under various polymerization conditions. Two coating resins (WTC and BTC) were used. Disk specimens (diameter: 15.0 mm;thickness: 0.7 mm) were used uncoated, coated with a polyethylene film, or coated with an application of TopCoat for WTC or GlossRefine for BTC. Five specimens were immersed for 72 h in a staining solution of either coffee or water. The CIELAB coordinates (L*, a*, b*) of each specimen were measured against a black background using a colorimeter (Shade Eye, NCC) and the color difference [ΔE] was estimated and analyzed by one-way ANOVA and Tukey comparison. The specimen surfaces were observed by FE-SEM. The results reveal that for both materials, the uncoated group had the highest ΔE values (p<0.05). For the other groups, the ΔE values for WTC were higher than those for BTC (p<0.05). The surfaces of both materials contained fillers of various sizes and shapes. For all groups, WTC had much smaller fillers than BTC. Both White Coat and BTC exhibited a color change after 72 h under all conditions (ΔE>3.6). Coffee discolored the coating resins. Oxygen inhibition significantly affected the discoloration of the coating resins. We propose applying a coating agent for WTC and a glazing agent for BTC to suppress discoloration of coating resins.