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Background/purpose: In this study, we evaluated the ability of dental students to correctly match tooth shades and examined the influence of clinical practice years, gender, eye color, and the use of eye glasses or contact lenses on the ability to match tooth shades. Materials and methods: In total, 244 dental students (138 females and 106 males, with a mean age of 22 years) in their 1 st to 5 th years of education were included in the study. Students were asked to match the color of artificial teeth (Vitapan acrylic denture teeth) using the Vita Toothguide 3D-Master. Three predefined test colors were used: 2L1.5, 1M2, and 2R1.5. Exact matching rates of all three color components (value, hue, and chroma) were calculated and analyzed by a Chi-squared test. Results: Students in the 3 rd , 4 th , and 5 th clinical years performed better with regard to exactly matching the three shades, compared to students in the 1 st and 2 nd preclinical years (29.4% vs. 22.5%, P Z 0.034). On the other hand, gender, eye color, and use of eye glasses or contact lenses had no effect on the ability to correctly match the color. Higher rates of exact matches were found for 1M2, compared to 2L1.5 (31.1% vs. 20.5%, P Z 0.007). Conclusions: The shade-matching ability of dental students seemed to improve with more education because of the inclusion of clinical practice in the educational program. However, gender, eye color, and the use of eye glasses or contact lenses had no influence.

Background: Bonding properties of luting cements are important for retention of restorative core materials. The aim of this study was to compare the bonding performance of a resin-modified glass ionomer cement and a self-adhesive resin cement to various fixed prosthodontic core materials. Methods: Cylindrical specimens with a thickness of 2 mm and a diameter of 5 mm were fabricated from Au-Pd-Ag, Co-Cr, Ni-Cr-Mo, Ni-Cr-Fe alloys, titanium, zirconia and Empress II (n = 20). Each group was divided into two subgroups to be luted with two different luting agents. Composite resin blocks were cemented onto specimens with RelyXUnicem and FujiCem. A shear bond strength machine with 50 kg load cell and 0.50 mm ⁄ min crosshead speed was used. Kruskal Wallis test, Dunn's Multiple Range test and Mann-Whitney-U test were used for statistical analysis. The results were evaluated in a confidence interval of p < 0.05. Results: The highest bond strength was obtained between Ni-Cr-Fe-RelyXUnicem (8.22 ± 2.15 MPa) and the lowest was between Empress II-FujiCem (1.48 ± 0.9 MPa). In FujiCem groups, Co-Cr and Ni-Cr-Fe showed significantly higher bond strength than Au-Pd-Ag and Empress II. In RelyX Unicem groups, Ni-Cr-Fe showed higher bond strength than Empress II. Conclusions: The types of luting agents and restorative core materials may have a significant influence on bond strength.

The luting cement, the presence of titanium, and the color of zirconium are all important factors that determine the final shade of zirconia cores in implant-supported FPDs.