| Objectives:1. The purpose of this in vitro study was to evaluate and compare the wear of Ceramage, two kinds of dental materials widely used in clinical and natural enamel. The wear mechanisms were discussed.2. ShadeEye NCC was used to evalute the effect of varying the opaque thickness on color of Ceramage, in order to improve the manufactuer and the quality.Methods:1 .Specimen preparation of wear test: Dyract, Ceramage,Vitablocs,and enamel were fabricated into thirty-six uniform specimens, nine specimens in each group. The occlusal area of each specimen is parallel with button. At the same time,titanium were fabricated into discs with the diameter of 15.0mm and thickness of 1.0mm to act as counter-sample material.2.The wear test was carried out in artificial saliva to simulate the oral environment. Each specimen was tested under a standard load (30N), rate (100 cycles/minute), and for 50,000 cycles totally. The volume loss of the materials was calculated. At the same time, the hardness and friction coefficient were measured. Finally scanning electron microscope (SEM) was used to analyze the microstructures of the wear surface of specimens and the wear mechanism was discussed.3.Ni-Cr alloy was fabricated into disc with the diameter of 10.0mm and thickness of 1.0mm to act as background.Resin was fabricated into disc with the diameter of 10.0mm and thickness of 8.0mm to act as background too.4.The shade (A2)was selected .Thirty disk specimens with the diameter of 10.0mm and thickness of 1.0mm were prepared and divided into 6 groups (n=5),and then opaque samples of 0.00,0.10,0.20,0.30,0.40,0.50mm thickness were fabricated on such plates.5.The CIE L*a*b* values of specimens were measured using a colorimeter (ShadeEye NCC) to determine the colorimetric difference, when the samples overlaid on different backgrounds.The total color difference AE and metric chroma were calculated as follows:â–³E (L*a*b*)=(â–³L*2+â–³a*2+â–³b*2)1/2 C=(a*2+b*2)1/2Results:1. The ranking of the volume loss of three restorative materials and enamel from the most to the least was: Dyract, Ceramage, enamel and Vitablocs. Dyract was the most, significant difference was found between the other groups (P<0.01). Vitablocs was the least, significant difference was found between the other groups (P<0.01). No significant difference was found between Ceramage and enamel(P>0.05).2. The ranking of the hardness of three restorative materials and enamel from the least to the most was Dyract, Ceramage, enamel, Vitablocs. Vitablocs was the most, significant difference was found between the other groups (P<0.01). No significant difference was found between Ceramage and Dyract(P>0.05).3. The result of scanning electron micrograph (SEM): Dyract: the scars and big cracks were obvious and loss a plenty of filler particles. Ceramage: the scars and big cracks were less than Dyract and loss of some filler particles. Enamel: Heavy wear traces were found and loss of some filler particles. Vitablocs: The occlusal surface was very smooth, but there were some crannies.4. The friction behavior of Ceramage was similar to Dyract.The friction coefficient of Ceramage was much close to enamel.5. For the restoration based on Ni-Cr alloys, the color of restorations was not affected by the color of metal base as the thickness of opaque reached 0.20mm,and the chromatic valueâ–³E<1.5NBS.For the restorations based on resin ,the color of restoration was not affected by the color of resin as the thickness of opaque reached 0.10mm, and the chromatic valueâ–³E< 1.5NBS.The metric chroma tends to increase with the thickness of opaque increased.Conclusions:1. Ceramage was more resistant to wear than Dyract.2. Ceramage showed a wear statistically not significantly different from human enamel.3. Vitablocs was more resistant to wear than Ceramage.4. The opaque can significant reduce the thickness of Ceramage.5. Alloy background has more evident influence on the final color of Ceramage.
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