Surface discoloration of composite resins: Effects of staining and bleaching

Abstract

Background:The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet•X HD, Clearfil AP-X, Gradia Direct) and five nanohybrid composite resins (Ceram•X, GC Kalore, G-aenial, Grandio, GrandioSO), after staining and bleaching procedures.Materials and Methods:The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany) into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness) to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h), for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco). The color of specimens was measured with a spectrophotometer according to the CIE L*a*b* system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DEab*) between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA).Results:All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index.Conclusions:Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested.

Color Shift, Color Stability, and Post-Polishing Surface Roughness of Esthetic Resin Composites

“…∆E values for CX and GA were low compared to other materials in the same investigation. In a previous study, the same authors reported that microhybrid and nanohybrid composites responded similarly when immersed in tea for 14 days [6]. A somewhat similar trend is reported in this investigation (illustrated clearly in Figure 2) with very little difference between microhybrids and nanohybrids expect CX, which is considered a nanoceramic with a novel and different resin matrix chemistry involving polysiloxane, polyurethane methacrylate, and ethoxylated bisphenol-A dimethacrylate (Bis-EMA).…”

“…In order for the esthetic restorative materials to be functional, they need to maintain color and shade in order to blend with the neighboring tooth structure. This property is important both in the short term after curing as well as in the long term during function [4,6,7]. Clinically unacceptable color change of resin composites is the primary reason for restoration replacement especially in the anterior region of the oral cavity [8,9].…”

Influência dos agentes clareadores na dureza e cor de materiais restauradores diretos

“…Embora a cor de uma restauração possa ser estável ao longo do tempo, mudanças podem ocorrer por: pigmentação da superfície, pigmentação marginal, microinfiltração, desgaste da superfície e deterioração interna do material 20 . A hipótese deste estudo foi aceita, pois os agentes clareadores não alteraram a dureza, mas alteraram a cor dos materiais restauradores testados.…”

Effects of Carbamide Peroxide Bleaching Gel on Color of Silorane- and Methacrylate-based Resin Composites

“…Moreover, the structure of the composite resin and the characteristics of its particles have a direct influence on the susceptibility to extrinsic staining. (2 ) Bleaching is an effective and conservative esthetic treatment for removing intrinsic and extrinsic stains from teeth. The bleaching agent usually contains peroxide (in the form of carbamide and hydrogen peroxide) in gel or liquid form.…”

“…The L* coordinates are located along a vertical axis that ranges from 0 (completely black) to 100 (completely white); (9)(10)(11)(12)(13) a* uses positive values (+a*) to denote red colors and negative values (-a*) to denote green colors; and b* depicts yellow color with positive values (+b*) and blue color using negative values (-b*). (2) Before each measurement session, the instrument was calibrated according to the manufacturer's recommendations. Color measurement was conducted on the top surface of each specimen against a white background.…”