Evaluation of the Possibility of Removing Staining by Repolishing Composite Resins Submitted to Artificial Aging

Abstract

This in vitro research verified the possibility of eliminating staining caused by coffee and red wine in five composite resins, after being submitted to thermal cycling. Thirty-six specimens were prepared and immersed in water at 37°C for 24 hours. After polishing, specimen color was measured in a spectrophotometer Cintra 10 UV (Visible Spectrometer, GBC, Braeside, VIC, Australia). All specimens were submitted to thermal cycling at temperatures of 5 and 55°C with a dwell time of 1 minute, for 1,000 cycles in a 75% ethanol/water solution. After thermal cycling, the specimens were immersed in water at 37°C until 7 days had elapsed from the time the specimens were prepared. All specimens were then taken to the spectrophotometer for color measurement. The specimens were divided into three groups (N = 12): distilled water (control), coffee, and red wine. For the staining process to occur on only one surface, all the sides, except one, of the surfaces were isolated with white wax. The specimens were immersed in one of the solutions at 37°C for 14 days. The specimens were dried and taken to the spectrophotometer for color measurement. After this, the specimens were submitted to 20 µm wear three times, and the color was measured after each one of the wear procedures. Calculation of the color difference was made using CIEDE2000 formula. According to the methodology used in this research, it was concluded that the staining caused by coffee and red wine was superficial and one wear of 20 µm was sufficient to remove the discoloration.

Color Stability of Resin Used for Caries Infiltration After Exposure to Different Staining Solutions

“…12 The second null hypothesis was also rejected, since repolishing with fine-grain abrasive discs led to a significant reduction in DE values for all groups. Similar results were also observed in a previous study with composite resins, 32 and this is due to the fact that the dyes can remain adsorbed on the surface, with little penetration into the resinous materials or the tooth substrate. 17 However, even after repolishing, the stained specimens still presented color alteration significantly higher than those immersed in deionized water.…”

“…32 Coffee exhibits a strong potential for staining both tooth structure and resinous materials. 17,33 The compatibility between the brown dye of the coffee and the resin polymer chain has been suggested, facilitating the adsorption and penetration of the dye in the resin.…”

Short and long term effects of additional post curing and polishing systems on the color change of dental nano-composites

“…Color stability is an important issue for esthetic restorations and plays a role in the clinical success of restorative treatment. Color change of the dental restorations has been implied as a multifactorial phenomenon and can be caused by extrinsic and intrinsic factors 4) . The extrinsic factors include intensity and duration of polymerization, exposure to environmental factors, including ambient and UV irradiation, heat, water and food colorants 5) .…”

Tooth whitening recovers the color of pre-stained composites

“…Such color change returned to acceptable levels after whitening for 1 week and kept decreasing during the two-week and four-week whitening (Table 1 and Figure 1). This reflected the significant decrease of L* (darkening) and increase of b* to what occurs in the clinical situation 13 . The susceptibility of the composite to percolation of staining substances is related to its chemical composition, which includes the type of monomer, the type of inorganic filler, the used photoinitiator and the quality of the matrix/filler interface 14 .…”