IADR Abstract Archives
Can We Repolish Discolored Single-Shaded Composite Resins With Different Wheel-Polishers?
Objectives: To evaluate the color restitution of single-shaded composite resins immersed in a coffee solution and repolished with different wheel systems.
Methods: Twenty-four-disc samples of 8x2mm (n=120) were prepared in plastic molds for Omnichroma (OMN; Tokuyama, Japan), Zenchroma (ZEN; President, Germany), Essentia Universal (EU; GC, Japan), Charisma Diamond One (CDO; Kulzer, Germany) and NeoSpectra (NS; Dentsply, Germany). One side of the samples was left unpolished (Mylar strip) while the others were randomly polished with Twist-Dia (TWD) or Nova-Twist (NOV) for 30 sec. Specimens were immersed in a coffee solution for seven days. Color measurements according to CIEL*a*b* system were performed with a spectrophotometer (Vita Easyshade, Vident, Brea, USA) at baseline, after seven days, and after repolishing. The color change (ΔE*) values were evaluated by T-test, Multivariate ANOVA, and Dunnett-t post-hoc tests (p<0.05).
Results: The coffee discolorations that occurred were above the clinically acceptable level of ΔE = 2 in all groups. Regardless of the materials and the polishing systems used, Mylar strip groups were the more discolored ones. In TWD groups, CDO was the most discolored group (ΔE=6.45) while OMN (ΔE=2.96) and ZEN (ΔE=3.06) were the less (p=0.000). In NOV polished materials, EU (ΔE=5.85) and CDO (ΔE=5.68) were similarly the most discolored groups (p<0.05) while NS, OMN, and ZEN were the less (respectively 3.48; 3.70; 3.79). After repolishing, regardless of the polishing systems used, CDO could not reach the level of ΔE=2 (p<0.05) while the other groups had values far below.
The type of polishing system used affected the ΔE values after storage in coffee for CDO (p=0.015), OMN (p=0.000), and ZEN (p=0.011). Compared to TWD groups, NOV groups were less discolored in CDO and NS while more in EU, OMN, and ZEN.
Conclusions: Color changes after coffee immersion were perceptible in all single-shaded composite resins but repolishing could restitute the color at a level of less than ΔE=2.
Methods: Twenty-four-disc samples of 8x2mm (n=120) were prepared in plastic molds for Omnichroma (OMN; Tokuyama, Japan), Zenchroma (ZEN; President, Germany), Essentia Universal (EU; GC, Japan), Charisma Diamond One (CDO; Kulzer, Germany) and NeoSpectra (NS; Dentsply, Germany). One side of the samples was left unpolished (Mylar strip) while the others were randomly polished with Twist-Dia (TWD) or Nova-Twist (NOV) for 30 sec. Specimens were immersed in a coffee solution for seven days. Color measurements according to CIEL*a*b* system were performed with a spectrophotometer (Vita Easyshade, Vident, Brea, USA) at baseline, after seven days, and after repolishing. The color change (ΔE*) values were evaluated by T-test, Multivariate ANOVA, and Dunnett-t post-hoc tests (p<0.05).
Results: The coffee discolorations that occurred were above the clinically acceptable level of ΔE = 2 in all groups. Regardless of the materials and the polishing systems used, Mylar strip groups were the more discolored ones. In TWD groups, CDO was the most discolored group (ΔE=6.45) while OMN (ΔE=2.96) and ZEN (ΔE=3.06) were the less (p=0.000). In NOV polished materials, EU (ΔE=5.85) and CDO (ΔE=5.68) were similarly the most discolored groups (p<0.05) while NS, OMN, and ZEN were the less (respectively 3.48; 3.70; 3.79). After repolishing, regardless of the polishing systems used, CDO could not reach the level of ΔE=2 (p<0.05) while the other groups had values far below.
The type of polishing system used affected the ΔE values after storage in coffee for CDO (p=0.015), OMN (p=0.000), and ZEN (p=0.011). Compared to TWD groups, NOV groups were less discolored in CDO and NS while more in EU, OMN, and ZEN.
Conclusions: Color changes after coffee immersion were perceptible in all single-shaded composite resins but repolishing could restitute the color at a level of less than ΔE=2.