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    Color match of a feldspathic ceramic CAD-CAM material for ultrathin laminate veneers as a function of substrate shade, restoration color, and thickness
    (Mosby-Elsevier, 2018) Sarı, Taylan; Ural, Çağrı; Yüzbaşıoğlu, Emir; Duran, İbrahim; Cengiz, Seda; Kavut, İdris
    Statement of problem. The final color of a ceramic restoration, especially an ultrathin veneer, is important, but selecting the correct shade is difficult because the substrate can affect the final color of the restoration. Purpose. The purpose of this in vitro study was to investigate the effect of substrate shade and thickness on the final color of ultrathin laminate veneers milled from feldspathic ceramic and to present a straightforward methodology with which a clinician can visualize the effects of substrate color, ceramic thickness, and prefabricated computer-aided design and computer-aided manufacturing (CAD-CAM) block color on the final color of the restoration. Material and methods. All specimens were fabricated by slicing CAD-CAM feldspathic ceramic material with a precision cutter into 12x10-mm slices of approximately 0.35, 0.55, 0.75, and 1.55 mm in thickness with 10 different colors (0M1-1M1-1M2-2M1-2M2-2M3-3M1-3M2-3M3-4M1). As a background substrate, composite resin disks (12x10x2 mm) were fabricated with different shades (0M1 S, 1M1 5, 2M3 S, 3M2 5, 4M3 5, 5M3 S). The CIELab values of the polished surfaces of each specimen were measured on a background (white or simulated foundation) with a spectrophotometer by a single experienced operator, and color differences (AE) were calculated. Mean SD values were calculated and subjected to ANOVA with 2 variables (substrate and ceramic color) (alpha=.05). Results. Combinations of a lighter substrate shade and a lighter value ceramic restoration and of a darker substrate shade and darker value ceramic restoration only changed the final color of the restoration minimally. Conclusions. The final color of a dental restoration is affected by the thickness of the restoration, the substrate color, and the ceramic color. Lighter and darker substrate colors show more color changes, and thin veneers cannot mask the substrate color.
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    Color stability and surface roughness of a laboratory-processed composite resin as a function of mouthrinse
    (Wiley, 2015) Cengiz, Seda; Yüzbaşıoğlu, Emir; İnanç Cengiz, Murat; Velioğlu, Neslin; Sevimli, Gaye
    Statement of the Problem: Mouthrinses can cause discoloration on indirect resin composites. Purpose of the Study: The purpose of the study was to investigate the effect of different mouthrinses on the color changes and surface roughness of a laboratory-processed composite. Methods and Materials: Fifty discs were made using GC Gradia/GC indirect composites and divided into five groups which immersed in artificial saliva and four different types of mouthrinses. The samples were immersed daily for 14 days in 20 mL of the solutions for 2 minutes twice a day (with a 12-hour interval between exposures). Measurements were carried out at four different times: 1 hour after sample preparation (t(0)), 1 day (t(1)), 7 days (t(2)), and 14 days (t(3)) after the first immersion in the solutions. The color before and after immersion was measured according to Comission Internationale de L'Eclairage (CIE L*, a*, b*) System and Delta L*, Delta a*, Delta b*, and Delta E* values were calculated. The surface roughness Ra (mu m) of the specimens was evaluated using a profilometer. Results: There were significant differences between the groups at all time representing Delta E values (p < 0.001). At (t(1)) time representing Delta Ra value, there were significant differences between the groups (p < 0.05). At (t(2), t(3)) time representing Delta Ra values, there were significant differences between the groups (p < 0.001). Pharmol Zn immersed specimens showed Delta E values between 1.04 and 3.67. Conclusions: The result of this study indicated that the mouthrinses affected the color stability of indirect composites. CLINICAL SIGNIFICANCE Based on the results of this study, patients with resin composite restorations should be warned by the dentists about the discoloration of the restorations and the time period of the mouthrinse that will be used.
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    Light transmittance and surface roughness of a feldspathic ceramic CAD-CAM material as a function of different surface treatments
    (BioMed Central Ltd., 2016) Ural, Çağrı; Duran, İbrahim; Evmek, Betül; Kavut, İdris; Cengiz, Seda; Yüzbaşıoğlu, Emir
    Background: The aim of the present study was to determine the effect of different surface treatments on light transmission of aesthetic feldspathic ceramics used in CAD-CAM chairside restorations. Methods: Forty eight feldspatic ceramic test specimens were prepared from prefabricated CAD-CAM blocks by using a slow speed diamond saw. Test specimens were prepared and divided into 4 groups (n = 12). In the control group, no surface treatments were applied on the feldspathic ceramic surfaces. In the hydrofluoric acid group, the bonding surfaces of feldspathic ceramics were etched with 9.5 % hydrofluoric acid. In the sandblasting group the feldspathic ceramic surfaces were air-abraded with 30-µm alumium oxide (Al2O3) particles and Er:YAG laser was used to irradiate the ceramic surfaces. The incident light power given by the LED device and the transmitted light power through each ceramic sample was registered using a digital LED radiometer device. Each polymerization light had a light guide with 8-mm-diameter tips. Light transmission of feldspathic ceramic samples was determined by placing it on the radiometer and irradiating the specimen for 10 s at the highest setting for each light polymerization. All specimens were coated with gold using a sputter coater and examined under a field emission scanning electron microscope. Surface roughness measurement each group were evaluated with 3D optical surface and tactile profilometers. Results: One-way ANOVA test results revealed that both surface conditioning method significantly affect the light transmittance (F:412.437; p < 0.001) and the surface roughness values (F:16.386; p < 0.001). Al2O3 and Er-YAG laser application reduced the light transmission significantly (p < 0.05). Conclusions: The laser and Al2O3 applications reduced the light transmission of 1.5 mm thickness feldspathic ceramic material below the value of 400 mW/cm2 which is critical limit for safe polymerization.