Assessment of color parameters of composite resin shade guides using digital imaging versus colorimeter.
OBJECTIVE
This study evaluated the color parameters of resin composite shade guides determined using a colorimeter and digital imaging method.


METHODS
Four composite shade guides, namely: two nanohybrid (Grandio [Voco GmbH, Cuxhaven, Germany]; Premise [KerrHawe SA, Bioggio, Switzerland]) and two hybrid (Charisma [Heraeus Kulzer, GmbH & Co. KG, Hanau, Germany]; Filtek Z250 [3M ESPE, Seefeld, Germany]) were evaluated. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2, C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc., Kyoto, Japan). The data were analyzed using two-way analysis of variance and Bonferroni post hoc test.


RESULTS
Overall, the mean ΔE values from different composite pairs demonstrated statistically significant differences when evaluated with the colorimeter (p < 0.001) but there was no significant difference with the digital imaging method (p = 0.099). With both measurement methods in total, 80% of the shade guide pairs from different composites (97/120) showed color differences greater than 3.7 (moderately perceptible mismatch), and 49% (59/120) had obvious mismatch (ΔE > 6.8). For all shade pairs evaluated, the most significant shade mismatches were obtained between Grandio-Filtek Z250 (p = 0.021) and Filtek Z250-Premise (p = 0.01) regarding ΔE mean values, whereas the best shade match was between Grandio-Charisma (p = 0.255) regardless of the measurement method.


CONCLUSIONS
The best color match (mean ΔE values) was recorded for A1, A2, and A3 shade pairs in both methods. When proper object-camera distance, digital camera settings, and suitable illumination conditions are provided, digital imaging method could be used in the assessment of color parameters. Interchanging use of shade guides from different composite systems should be avoided during color selection.
Department of Conservative Dentistry, Faculty of Dentistry, Başkent University, Ankara, Turkey.
Kivanc
K
Yamanel
Alper
A
Caglar
Mutlu
M
Özcan
Kamran
K
Gulsah
Bora
B
Bagis
D003116:Color; D003124:Colorimetry / Q000295:instrumentation*; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008029:Lighting; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry; D010781:Photography / Q000295:instrumentation; D012984:Software
C084111:Charisma composite resin; D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; C509998:Grandio; C507210:premise composite resin