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Objective The aim of this in vitro study was to evaluate the effects of substrate colors, different levels of ceramic thickness and translucency, and cement shades on the color difference from a reference color of lithium‐disilicate crowns. Materials and Methods A premolar tooth preparation was made on a study model for 1.0 and 1.5 mm thick full‐ceramic crowns. Digital impressions were taken (3Shape TRIOS) and crowns designed in a CAD program (DentalDesigner). Shade A1 crowns were milled (Everest, Kavo) from high‐translucency (HT) and low‐translucency IPS e.max (Ivoclar Vivadent) blocks. Twelve substrates were made of different colors and materials (Natural Die Material, Co‐Cr, zirconia, and gold‐colored alloy). Three different shades of try‐in pastes were used to simulate the effect of cements (Variolink Esthetic try‐in paste; Ivoclar). Shade measurement was done three times for each crown by a spectrophotometer (VITA Easyshade Advance); averages were compared to a reference crown (A1, HT, 1.5 mm, ND2 abutment, neutral try‐in paste) with ΔE00 (CIEDE2000, according to the CIE latest standard) calculated. Results All the examined parameters influenced the ΔE00 of the crowns. The weakest effect was exerted by the try‐in paste. Conclusions All examined parameters influenced the final color of e.max CAD lithium‐disilicate ceramic crowns. Clinical Significance Matching the shade of ceramic crowns to the natural tooth color is a great challenge in dentistry. To meet patients' increasing esthetical expectations, CAD/CAM methods are very popular for full‐ceramic crowns. However, several factors such as the shade of the abutment, luting cement color, ceramic thickness, and translucency may influence the final color. Our objective was to measure the optical effect of these factors on the final shade of CAD/CAM lithium‐disilicate ceramic crowns.

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ObjectiveThe aim of this in vitro study is to evaluate the masking ability of polymer‐infiltrated ceramic‐network materials (PICN) with different translucencies and thicknesses on multiple types of substrates.Materials and MethodsCeramic samples were prepared of VITA ENAMIC blocks in two different translucencies (2M2‐T, 2M2‐HT) in a thickness range of 0.5–2.5 mm (±0.05 mm). Layered specimens were obtained using composite substrates in nine shades and transparent try‐in paste. Spectral reflectance of specimens was measured using a Konica Minolta CM‐3720d spectrophotometer and D65 standard illumination. CIEDE2000 color difference (ΔE00) between two samples was evaluated using 50%:50% perceptibility and acceptability thresholds. Specular component of the reflection was examined with Specular Component Excluded (SCE) and Included (SCI) settings. Statistical evaluation was performed by linear regression analysis, Kruskal–Wallis test, and multiplicative effect analysis.ResultsAn increase in thickness of 0.5 mm reduces ΔE00 of HT samples to 73.5%, of T samples to 60.5% (p < 0.0001). Five substrates with HT specimens, and three substrates with T specimens had significantly different results from average (p < 0.05). There is a significant difference between SCE and SCI data depending on the wavelength (p < 0.0001).ConclusionsMasking ability of PICN materials is influenced by the thickness and translucency of the ceramic, and by the substrate. Reflection of the examined PICN material is characterized by both diffuse and specular reflection.Clinical SignificanceAlthough PICN materials have been available on the market for 10 years now, there is a lack of information regarding their masking ability. Acquiring in‐depth data and thereby practical experience of the factors affecting the esthetics of PICN materials is essential for creating perfectly lifelike restorations.

The goal of this study is to examine specific optical effects of multilayered and coloured monolithic zirconia considering thickness and substrates of different colours using one of the most advanced spectrophotometers of the world. Multilayered zirconia specimens were used for the study with the thickness range of 0.5-2.5 mm and six types of substrate materials and three types of metal substrates. Measurements were carried out at Budapest Technical University with a PerkinElmer®Lambda1050UV/Vis/NIR spectrophotometer. The substrate colour and the thickness of zirconia affects the optical results, with special regard to colour perceptibility and acceptability. Monochromatic and multilayer zirconia show both similarities and discrepancies in behaviour, i.e. spectral reflectance and ΔE. Owing to the multi-coloured characteristics of multilayered zirconia the optical effect of the substrate less predictable than in the case of monochromatic zirconia thus requiring more detailed planning and implementation.

Objective: The aim of this in vitro study is to examine the optical effects of monolithic zirconia of different translucency and thickness, combined with substrates of different colours. Materials and methods: Zirconia specimens of two colours (A2P1, WHITE) were used for the study, three try-in pastes (Variolink Esthetic); substrates were prepared from nine types of materials (six VITA SIMULATE, three metals). Measurements were carried out at the Faculty of Atomic Physics of the Technical University of Budapest with the state-of-the-art PerkinElmer® Lambda 1050 spectrophotometer. Results: The colouring of zirconia has a major effect on dE values resulting in different colour perceptibility and acceptability. Try-in pastes, however, have no significant effects overall. Conclusion: Applying coloured zirconia is highly eligible for preparing aesthetic crowns as their substrate-covering effect makes it possible to reproduce the desired colour. Uncoloured zirconia nonetheless is unaffected by the substrate material, especially above a certain layer thickness.