STATEMENT OF PROBLEM: Ceramic restorations should be made of porcelain layers of different opacity, shade, and thickness in order to provide a natural appearance. Lithium disilicate glassceramic system has superior color reproducibility, because it uses the ceramic ingot which is similar to teeth shade and uses the staining technique and layering technique. However, staining technique has a fault of discoloration. Also, porcelain is divided core and dentin layer, it is not enough to study about the influence of porcelain layer thickness and shade on the shade of ceramic restorations. PURPOSE: The purpose of this study was to evaluate the influence of porcelain layer thickness and color on the final shade of ceramic restorations. MATERIALS AND METHOD: The CIE L*a*b*(CIELAB) values of 72 assembled specimens, each consisting of 3 discs (enamel porcelain 0.2 mm/dentin porcelain - 1.2, 0.9, 0.7, 0.5 or 0.3 mm/ceramic core - 0.3, 0.5, 0.7, 0.9 or 1.2 mm, diameter is 1.0 mm) were evaluated with a spectrophotometer (Model Chromaview 300, Spectron Tech Co, Korea) for the shade A1, A2, A3 and A4. Distilled water (refractive index: 1.7) was used to attain optical contact between the layers. White, white gray, and white brown backgrounds were used to assess the influence of the background on the final shade. And the mean color difference value(delta E) was calculated. RESULTS AND CONCLUSION: The results obtained from this study were as follows. 1. There was a significant correlation between the thickness ratio of the ceramic core/dentin porcelain system and L*, a* and b* values when the total thickness of specimen combination was smaller than 1.4 mm( p<0.05). 2. The specimen which the ceramic core thickness was more than 0.7 mm had the best masking effect against background colors. 3. The mean color difference value(delta E) is smaller than 2 (delta E<2) when the ceramic core thickness was larger than 0.7 mm and the total thickness of specimen was more than 1.4 mm.
Ceramics* ; Dental Porcelain* ; Dentin ; Lithium ; Masks ; Tooth ; Water

PURPOSE: This study was undertaken to develop directions for research on nursing practice education and also for standardization of contents of Fundamental Nursing Practice (FNP) by identifying and analyzing the present content and inconsistency in FNP textbooks. METHOD: Eleven FNP textbooks published between 2007 and 2013 were selected and itemized nursing contents were compared and analyzed. Nursing professors and practicingnurses prioritized contents identified from an actual condition survey based on theoretical reason and clinical guides for each item. RESULTS: Inconsistencies were found for 34 domains with 219 sub items and of them, 21 domains and 84 items needed to be standardized. Number of items that showed consistency between professors and nurses (ICC > or = .800) was 29 (34.5%) and for complete consistency (ICC=1), 4 (4.8%). Number of items that showed inconsistency between the groups (ICC< .600) was 30 (35.7%) and very low consistency (ICC=0), 10 (11.9%). CONCLUSION: The results indicate a difference between understood validity of content by professors and by nurses and technical differences among FNP textbooks. Therefore confirmation of the items needing to be standardized and differences in understanding content by professors and by nurses shows a need for standardization of practice education between course and clinical practice. These results provide basic data for developing standardized form of FNP education.
Education* ; Education, Nursing ; Nursing*