The Effect of Different Polishing Methods and Storage Media on Discoloration of Resin Composites

Abstract

Statement of Problem: Accumulation of plaque and staining due to a rough surface, and penetration of colourant agents from food and beverages in to the resin composite results in an incomplete polymerization. There is a little information on the effect of finishing and polishing techniques on the discoloration of nanohybrid and microhybrid composites when exposed to staining solutions. Objectives: To determine the degree of surface staining of nanohybrid and microhybrid composites after polishing and immersion in distilled water and two commonly used staining solutions. Materials and Methods: A nanohybrid (Ice; SDI) and microhybrid (Gradis direct; GC) composites were used. Disc-shaped specimens were prepared and treated with either a matrix finish or polished using Sof-Lex discs (3M/ ESPE) and Enhance point (Dentsply). After 24 h immersion in distilled water at 37°C the specimens were polished and colour coefficients (CIE L* a* b*) was measured by a spectrophotometer. All specimens were immersed in 37°C distilled water in an incubator for 7 days and colour coefficients were measured again. The colour change (ΔE) was calculated using the following formula: ΔE = [(Δa)2+(Δb)2+(ΔL)2] 1/2. The data were analyzed using three-way ANOVA, one-way ANOVA/Tukey HSD and Student’s t-test. Results: There was a significant interaction between resin composites, polishing systems and staining solutions (p 3.3) compared to cola and distilled water.

Keywords

• Colour
• Change Nanohybrid
• Composite Microhybrid
• Composite Storage
• Media